Fukushima Daiichi
Transcription
Fukushima Daiichi
June 2012 Volume 8, Number 3 ISSN 1811-5209 Fukushima Daiichi Takashi Murakami and Rodney C. Ewing, Guest Editors More than One Year Later The 2011 Tohoku Earthquake Examining the Nuclear Accident Land-Surface Contamination Atmospheric Dispersion and Deposition of Radionuclides Oceanic Dispersion Simulations of 137Cs Interactions between Nuclear Fuel and Water Elements is published jointly by the Mineralogical Society of America, the Mineralogical Society of Great Britain and Ireland, the Mineralogical Association of Canada, the Geochemical Society, The Clay Minerals Society, the European Association of Geochemistry, the International Association of GeoChemistry, the Société Française de Minéralogie et de Cristallographie, the Association of Applied Geochemists, the Deutsche Mineralogische Gesellschaft, the Società Italiana di Mineralogia e Petrologia, the International Association of Geoanalysts, the Polskie Towarzystwo Mineralogiczne (Mineralogical Society of Poland), the Sociedad Española de Mineralogía, the Swiss Society of Mineralogy and Petrology, the Meteoritical Society, and the Japan Association of Mineralogical Sciences. It is provided as a benefit to members of these societies. Elements is published six times a year. Individuals are encouraged to join any one of the partici pating societies to receive Elements. Institutional subscribers to any of the following journals —American Mineralogist, Clay Minerals, Clays and Clay Minerals, Mineralogical Magazine, and The Canadian Mineralogist—also receive one copy of Elements as part of their 2012 subscription. Institutional subscriptions are available for US$160 (US$175 non-US addresses) a year in 2012. Contact the managing editor (tremblpi@ ete.inrs.ca) for information. Copyright 2012 by the Mineralogical Society of America All rights reserved. Reproduction in any form, including translation to other languages, or by any means—graphic, electronic or mechanical, including photocopying or information storage and retrieval systems—without written permission from the copyright holder is strictly prohibited. Publications mail agreement no. 40037944 Printed in USA ISSN 1811-5209 (print) ISSN 1811-5217 (online) Volume 8, Number 3 • June 2012 Fukushima Daiichi Guest Editors: Takashi Murakami and Rodney C. Ewing 181 Fukushima Daiichi: More than One Year Later Rodney C. Ewing and Takashi Murakami A bout the Cover : Aerial photo taken by a small unmanned drone on March 20, 2011, showing the crippled Fukushima Daiichi nuclear power plant in Fukushima Prefecture, northern Japan. From top to bottom: Unit 1, Unit 2, Unit 3, and Unit 4. Photo courtesy of A ir Photo Service Co. Ltd., Japan 183 The 2011 Tohoku Earthquake 189 Examining the Nuclear Accident at Fukushima Daiichi 195 Atmospheric Dispersion and Deposition of Radionuclides from the Fukushima Daiichi Nuclear Power Plant Accident Jeroen Ritsema, Thorne Lay, and Hiroo Kanamari Edward D. Blandford and Joonhong Ahn Anne Mathieu, Irène Korsakissok, Denis Quélo, and others 201 Land-Surface Contamination by Radionuclides from the Fukushima Daiichi Nuclear Power Plant Accident Naohiro Yoshida and Yoshio Takahashi 207 Oceanic Dispersion Simulations of 137Cs Released from the Fukushima Daiichi Nuclear Power Plant Yukio Masumoto, Yasumasa Miyazawa, Daisuke Tsumune, and others 213 Interactions between Nuclear Fuel and Water at the Fukushima Daiichi Reactors Bernd Grambow and Christophe Poinssot D e pa r t m e n t s www.elementsmagazine.org www.elements. geoscienceworld.org Editorial – Breaking Boundaries . . . . . . . . . . . . . . . . . . . . . . 163 From the Editors – Elements Makes a Splash. . . . . . . . . . . . 164 Triple Point – Disconnect between Geology and Nuclear Engineering. . . . . . . . . . . . . . . . . . . . . . . . . . 165 People in the News – Norman, Dauphas, AGU Fellows . . . . 166 Perspectives – Fukushima Lessons . . . . . . . . . . . . . . . . . . . 168 Travelogue – Field Research in the Evacuation Zone . . . . . . . 172 CosmoElements – Allende Meteorite, Tissint Meteorite . . . . . 174 Meet the Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 Society News Société Française de Minéralogie et de Cristallographie . . . 221 Mineralogical Society of America . . . . . . . . . . . . . . . . . . . . . 222 European Association of Geochemistry. . . . . . . . . . . . . . . . . 224 Geochemical Society . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 Meteoritical Society . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 The Clay Minerals Society. . . . . . . . . . . . . . . . . . . . . . . . . . . 227 International Association of GeoChemistry. . . . . . . . . . . . . . 228 Mineralogical Society of Great Britain and Ireland . . . . . . . . 229 Japan Association of Mineralogical Sciences. . . . . . . . . . . . . 230 Deutsche Mineralogische Gesellschaft . . . . . . . . . . . . . . . . . 232 Mineralogical Association of Canada . . . . . . . . . . . . . . . . . 233 Sociedad Española de Mineralogía. . . . . . . . . . . . . . . . . . . . 234 International Association for the Study of Clays . . . . . . . . . . 235 Meeting Reports – Gordon Research Conference on Isotopes Journée G. Pédro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236 Book Reviews – Nature’s Nanostructures . . . . . . . . . . . . . . . 237 Calendar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238 Advertisers in This Issue . . . . . . . . . . . . . . . . . . . . . . . . 239 Parting Shots – A Ruin and Two Earthquakes . . . . . . . . . . . 240 161 PARTICIPATING SOCIETIES The Mineralogical Society of America is composed of individuals interested in mineralogy, crystallography, petrology, and geochemistry. Founded in 1919, the Society promotes, through education and research, the under standing and application of mineralogy by industry, universities, government, and the public. Membership benefits include special subscription rates for American Mineralogist as well as other journals, a 25% discount on Reviews in Mineralogy & Geochemistry series and Monographs, Elements, reduced registration fees for MSA meetings and short courses, and participation in a society that supports the many facets of mineralogy. Society News Editor: Andrea Koziol ([email protected]) The Mineralogical Society of Great Britain and Ireland is an inter national society for all those working in the mineral sciences. The Society aims to advance the knowledge of the science of mineralogy and its application to other subjects, including crystallography, geochemistry, petrology, environmental science and economic geology. The Society furthers its aims through scientific meetings and the publica tion of scientific journals, books and mono graphs. The Society publishes Mineralogical Magazine and Clay Minerals. Students receive the first year of membership free of charge. All members receive Elements. Society News Editor: Kevin Murphy ([email protected]) The Mineralogical Society 12 Baylis Mews, Amyand Park Road Twickenham, Middlesex TW1 3HQ, UK Tel.: +44 (0)20 8891 6600 Fax: +44 (0)20 8891 6599 [email protected] www.minersoc.org The Mineralogical ssociation of Canada A was incorporated in 1955 to promote and advance the knowledge of miner alogy and the related disci plines of crystallography, petrology, geochemistry, and economic geology. Any person engaged or interested in these fields may become a member of the Association. Membership benefits include a subscription to Elements, reduced cost for subscribing to The Canadian Mineralogist, a 20% discount on short course volumes and special publications, and a discount on the registration fee for annual meetings. Society News Editor: Pierrette Tremblay ([email protected]) Mineralogical Association of Canada 490, de la Couronne Québec, QC G1K 9A9, Canada Tel.: 418-653-0333; fax: 418-653-0777 [email protected] www.mineralogicalassociation.ca The Clay Minerals Society (CMS) began as the Clay Minerals Committee of the US National Academy of Sciences – National Research Council in 1952. In 1962, the CMS was incorporated with the primary purpose of stimulating research and disseminating information relating to all aspects of clay science and technology. The CMS holds an annual meeting, workshop, and field trips, and publishes Clays and Clay Minerals and the CMS Workshop Lectures series. Member ship benefits include reduced registration fees to the annual meeting, discounts on the CMS Workshop Lectures, and Elements. The Clay Minerals Society 3635 Concorde Pkwy Ste 500 Chantilly, VA 20151-1110, USA Tel.: 703-652-9960; fax: 703-652-9951 [email protected] www.clays.org Association of Applied Geochemists P.O. Box 26099 Nepean, ON K2H 9R0, Canada Tel.: 613-828-0199; fax: 613-828-9288 [email protected] www.appliedgeochemists.org Society News Editor: Seth Davis ([email protected]) Mineralogical Society of America 3635 Concorde Pkwy Ste 500 Chantilly, VA 20151-1110, USA Tel.: 703-652-9950; fax: 703-652-9951 [email protected] www.minsocam.org Society News Editor: Jeffery Greathouse ([email protected]) Society News Editor: Patrice de Caritat ([email protected]) The Geochemical Society (GS) is an international organization founded in 1955 for students and scientists involved in the practice, study and teaching of geochemistry. Our programs include co-hosting the annual Goldschmidt ConferenceTM, editorial over sight of Geochimica et Cosmochimica Acta (GCA), supporting geochemical symposia through our Meeting Assistance Program, and supporting student development through our Student Travel Grant Program. GS annually recognizes excellence in geochemistry through its medals, lectures, and awards. Members receive a subscription to Elements, special member rates for GCA and G-cubed, and publication and confer ence discounts. Geochemical Society Washington University Earth & Planetary Sciences One Brookings Drive, Campus Box #1169 St. Louis, MO 63130-4899, USA Tel.: 314-935-4131; fax: 314-935-4121 [email protected] Explore GS online at www.geochemsoc.org The European Association of Geochemistry was founded in 1985 to promote geochemical research and study in Europe. It is now recognized as the premiere geochemical organization in Europe encouraging interaction between geochemists and researchers in associated fields, and promoting research and teaching in the public and private sectors. Society News Editor: Liane G. Benning ([email protected]) Membership information: www.eag.eu.com/membership IAGC Business Office 275 Mendenhall Laboratory 125 South Oval Mall Columbus, OH 43210, USA Tel.: 614-688-7400; fax: 614-292-7688 www.iagc-society.org The Société Française de Minéralogie et de Cristallographie, the French Mineralogy and Crystallography Society, was founded on March 21, 1878. The purpose of the Society is to promote mineralogy and crystallography. Membership benefits include the “bulletin de liaison” (in French), the European Journal of Mineralogy, Elements, and reduced registration fees for SFMC meetings. Society News Editor: Anne-Marie Boullier ([email protected]) SFMC Campus Boucicaut, Bâtiment 7 140 rue de Lourmel 75015 Paris, France www.sfmc-fr.org The Association of Applied Geochemists is an international organiza tion founded in 1970 that specializes in the field of applied geochemistry. It aims to advance the science of geochemistry as it relates to exploration and the environment, further the common interests of exploration geochemists, facili tate the acquisition and distribution of scientific knowledge, promote the exchange of information, and encourage research and development. AAG membership includes the AAG journal, Geochemistry: Exploration, Environment, Analysis; the AAG newsletter, EXPLORE; and Elements. E lements Society News Editor: Michael Burchard ([email protected]) Deutsche Mineralogische Gesellschaft [email protected] www.dmg-home.de The Società Italiana di Mineralogia e Petrologia (Italian Society of Mineralogy and Petro logy), established in 1940, is the national body repre senting all researchers deal ing with mineralogy, petrology, and related disciplines. Membership benefits include receiving the European Journal of Mineralogy, Plinius, and Elements, and a reduced registra tion fee for the annual meeting. Society News Editor: Marco Pasero ([email protected]) The International Association of GeoChemistry (IAGC) has been a pre-eminent interna tional geochemical organi zation for over 40 years. Its principal objectives are to foster cooperation in the advancement of applied geochemistry by sponsoring specialist scientific symposia and the activities organized by its working groups and by supporting its journal, Applied Geochemistry. The administra tion and activities of IAGC are conducted by its Council, comprising an Executive and ten ordinary members. Day-to-day administration is performed through the IAGC business office. Society News Editor: Chris Gardner ([email protected]) The Deutsche ineralogische M Gesellschaft (German Mineralogical Society) was founded in 1908 to “promote mineralogy and all its subdisciplines in teaching and research as well as the personal relationships among all members.” Its great tradition is reflected in the list of honorary fellows, who include M. v. Laue, G. v. Tschermak, P. Eskola, C.W. Correns, P. Ramdohr, and H. Strunz. Today, the Society especially tries to support young researchers, e.g. to attend conferences and short courses. Membership benefits include the European Journal of Mineralogy, the DMG Forum, GMit, and Elements. Società Italiana di Mineralogia e Petrologia Dip. di Scienze della Terra Università di Pisa, Via S. Maria 53 I-56126 Pisa, Italy Tel.: +39 050 2215704 Fax: +39 050 2215830 [email protected] www.socminpet.it The International Association of Geoanalysts is a worldwide organization supporting the professional interests of those involved in the analysis of geological and environmental mate rials. Activities include the management of proficiency testing programmes for bulk rock and micro-analytical methods, the production and certification of reference materials and the publication of the Association’s journal, Geostandards and Geoanalytical Research. Society News Editor: Michael Wiedenbeck ([email protected]) International Association of Geoanalysts Ms. Jennifer Cook, Hon. Sec. British Geological Survey Keyworth, Nottingham, NG12 5GC, UK http://geoanalyst.org The Polskie owarzystwo MineralT ogiczne (Mineralogical Society of Poland), founded in 1969, draws together professionals and amateurs interested in mineralogy, crystallography, petrology, geochemistry, and economic geology. The Society promotes links between mineralogical science and education and technology through annual conferences, field trips, invited lectures, and publishing. Membership benefits include subscriptions to Mineralogia and Elements. Society News Editor: Zbigniew Sawłowicz ([email protected]) Mineralogical Society of Poland Al. Mickiewicza 30, 30-059 Kraków, Poland Tel./fax: +48 12 6334330 [email protected] www.ptmin.agh.edu.pl The Sociedad Española de Mineralogía (Spanish Mineralogical Society) was founded in 1975 to promote research in mineralogy, petrology, and geochem istry. The Society organizes annual conferences and furthers the training of young researchers via seminars and special publications. The SEM Bulletin published scientific papers from 1978 to 2003, the year the Society joined the European Journal of Mineralogy and launched Macla, a new journal containing scientific news, abstracts, and reviews. Membership benefits include receiving the European Journal of Mineralogy, Macla, and Elements. Society News Editor: Juan Jimenez Millan ([email protected]) Sociedad Española de Mineralogía [email protected] www.ehu.es/sem The Swiss Society of Mineralogy and Petrology was founded in 1924 by professionals from academia and industry and by amateurs to promote knowledge in the fields of mineralogy, petrology, and geochemistry and to disseminate it to the scientific and public communities. The Society coorganizes the annual Swiss Geoscience Meeting and publishes the Swiss Journal of Geosciences jointly with the national geological and paleontological societies. Society News Editor: Urs Schaltegger ([email protected]) Swiss Society of Mineralogy and Petrology Université de Fribourg, Département des Géosciences Chemin du Musée 6, Pérolles 1700 Fribourg, Switzerland Tel. +41 26 300 89 36 fax: +41 26 300 97 65 http://ssmp.scnatweb.ch The Meteoritical Society is an international organi zation founded in 1933 for scientists, collectors, and educators to advance the study of meteorites and other extraterrestrial mate rials and their parent asteroids, comets, and planets. Members receive our journal, Meteoritics & Planetary Science, reduced rates for Geochimica et Cosmochimica Acta, which we cosponsor, the Meteoritical Bulletin, and Elements. We organize annual meetings, workshops, and field trips, and support young planetary scientists worldwide. Through our medals and awards, we recog nize excellence in meteoritics and allied fields. Society News Editor: Cari Corrigan ([email protected]) Membership information: http://meteoriticalsociety.org The Japan Association of Mineralogical Sciences (JAMS) was established in 2007 by merging the Mineralogical Society of Japan, founded in 1955, and the Japanese Association of Mineralogists, Petrologists, and Economic Geologists, established in 1928. JAMS covers the wide field of mineral sciences, geochemistry, and petrology. Membership benefits include receiving the Journal of Mineralogical Sciences (JMPS), the Ganseki-Koubutsukagaku (GKK), and Elements. Society News Editor: Hiroyuki Kagi ([email protected]) Japan Association of Mineralogical Sciences c/o Graduate School of Science, Tohoku University Aoba, Sendai, 980-8578, Japan Tel./Fax: 81-22-224-3852 [email protected] http://jams.la.coocan.jp Affiliated Societies The International Mineralogical Association, the European Mineralogical Union, and the International Association for the Study of Clays are affiliated societies of Elements. The affiliated status is reserved for those organizations that serve as an “umbrella” for other groups in the fields of mine ra logy, geochemistry, and petrology, but that do not themselves have a membership base. 162 J une 2012 EDITORIAL Breaking Boundaries principal editors James I. Drever, University of Wyoming, USA ([email protected]) Georges Calas, IMPMC, France ([email protected]) John W. Valley, University of Wisconsin, USA ([email protected]) Advisory Board 2012 John Brodholt, University College London, UK Norbert Clauer, CNRS/UdS, Université de Strasbourg, France Will P. Gates, SmecTech Research Consulting, Australia George E. Harlow, American Museum of Natural History, USA Janusz Janeczek, University of Silesia, Poland Hans Keppler, Bayerisches Geoinstitut, Germany David R. Lentz, University of New Brunswick, Canada Anhuai Lu, Peking University, China Robert W. Luth, University of Alberta, Canada David W. Mogk, Montana State University, USA Takashi Murakami, University of Tokyo, Japan Roberta Oberti, CNR Istituto di Geoscienze e Georisorse, Pavia, Italy Terry Plank, Lamont-Doherty Earth Observatory, USA Xavier Querol, Spanish Research Council, Spain Mauro Rosi, University of Pisa, Italy Barbara Sherwood Lollar, University of Toronto, Canada Torsten Vennemann, Université de Lausanne, Switzerland Olivier Vidal, Université J. Fourier, France Meenakshi Wadhwa, Arizona State University, USA Bernard Wood, University of Oxford, UK Jon Woodhead, University of Melbourne, Australia Executive Committee Carlos Ayora IbáÑez, Sociedad Española di Mineralogía Liane G. Benning, European Association of Geochemistry Thomas D. Bullen, International Association of GeoChemistry Peter C. Burns, Mineralogical Association of Canada Bernardo Cesare, Società Italiana di Mineralogia e Petrologia Barbara L. Dutrow, Mineralogical Society of America, Chair W. Crawford Elliott, The Clay Minerals Society Monica M. Grady, The Meteoritical Society Bernard Grobéty, Swiss Society of Mineralogy and Petrology Guy Libourel, Société Française de Minéralogie et de Cristallographie Marek Michalik, Mineralogical Society of Poland Eiji Ohtani, Japan Association of Mineralogical Sciences Edwin A. Schauble, Geochemical Society clifford r. stanley, Association of Applied Geochemists Peter Treloar, Mineralogical Society of Great Britain and Ireland Friedhelm von Blanckenburg, Deutsche Mineralogische Gesellschaft Michael Wiedenbeck, International Association of Geoanalysts Managing Editor Pierrette Tremblay, [email protected] Editorial office 490, rue de la Couronne Québec (Québec) G1K 9A9, Canada Tel.: 418-654-2606 Fax: 418-653-0777 Layout: Pouliot Guay graphistes Copy editor: Thomas Clark Proofreaders: Thomas Clark and Dolores Durant Printer: Allen Press The publishers assume no responsibility for any statement of fact or opinion expressed in the published material. The appearance of advertising in this magazine does not constitute endorsement or approval of the quality or value of the products or of claims made for them. www.elementsmagazine.org E lements Fifteen m o n t h s logical/environmental science and materials sci have passed since a ence, as both domains become more and more gigantic earthquake interlinked on topics of mutual interest. The and resulting tsu successful “Scientific Basis for Nuclear Waste nami hit the Japanese Management” symposia and proceedings of the islands on March 11, Materials Research Society have, for the past 35 2011, resulting in years, been a forum involving mineralogists and some 20,000 people geochemists, together with materials scientists, killed or missing. and have resulted in original contributions to Subsequent flooding this area of research. But breaking boundaries of the Fukushima between mineralogy and materials science and Daiichi nuclear power sharing time and effort between both fields is Georges Calas plant led to a major sometimes not easy, as is often the case in mul crisis, with radioactive contamination developing tidisciplinary science. In fact, the extraordinary in the ensuing days and creating public fear and effort required to do research across disciplinary confusion. As observed in many countries, this boundaries may have the effect of making min accident may have superseded concerns of how eralogy seem less relevant, because little credit is Japan had been severely affected by the mega given for this effort as soon as it leaves the Earth tsunami and, to a lesser extent, science sphere. Ironically, the the earthquake of March 11. The broader application of mineralogy We must develop nuclear side of these catastrophic robust, scientifically and geochemistry to societal prob events is the subject of this issue lems may have planted the seeds based predictive of Elements, which is unusual in for their demise in some traditional its presentation due to the topic models to properly Earth science departments. treated. With six review articles, react to unusual Breaking the “boundary” between and also the Triple Point and “applied” and “fundamental” sci situations. Perspectives sections, this Elements ence is also needed: on which side issue presents a large variety of of the boundary are topics such as factual descriptions and opinions. Indeed, it is radiation-induced damage in minerals and mate expected that the Fukushima Daiichi accident will not only severely affect the continental and rials, the thermodynamic properties of actinide coastal environment of this part of Japan, it will systems, or the trapping of fission products and also have consequences for future technological actinides at mineral–water interfaces? Perhaps choices worldwide. As expressed by Koji Omi in there will be a proper answer in the time we have Science on March 9, 2012, “There are important left to answer this question: the longer the time lessons to be learned as Japan faces critical deci left to research, the more the fundamental aspects sions not only about rebuilding but also in plan may be explored. But the Fukushima Daiichi ning for the nation’s future energy needs—lessons accident reminds us that expertise is sometimes that are also relevant to many other countries.” needed on a very short timescale for decisions to Among these lessons, the contribution of nuclear be taken in a few days and for a technological energy to the global energy supply mix is now solution to be immediately made available. under reevaluation in some countries, despite the Facing the consequences of a major nuclear fact that nuclear energy contributes to limiting disaster is clearly a global issue, despite the fact greenhouse gas emissions and mitigating global that the management of a nuclear reactor is local. climate change. This is evident because the terrestrial fluid enve Nuclear energy–related topics are familiar to lopes—the atmosphere and ocean—are stirred by Elements readers: the December 2006 issue, edited global circulation and so have worldwide effects. by Rod Ewing, was devoted to the environmental International cooperation needs to be exemplary aspects of the nuclear fuel cycle, and this topic in urgent situations, and here too it is a matter of was also included in the June 2007 issue on breaking boundaries to provide the most useful energy. Also, American Mineralogist has a virtual expertise from all nations. Many countries have special issue on the topic “Mineralogy and the been and still are currently involved with damage Nuclear Industry.” Nuclear energy–related activi evaluation in Fukushima, decontamination pro ties may be accidentally impacting our environ cedures, and engineering assessment, and many ment at various stages of the nuclear fuel cycle, of us have colleagues involved in this activity. and we must develop robust, scientifically based A direct result of this work will be learning the predictive models to properly react to unusual response of these environments to such extreme situations. Geoscientists bring a unique point forcing conditions. This will help us to design of view to this effort, using their expertise on efficient remediation and reclamation procedures. how complex biogeochemical systems interact with external forces and their ability to model and anticipate long-term effects. Issues raised by uranium exploration and exploitation and by the management of nuclear waste, including its disposal in geological repositories, are the main domains of the nuclear cycle in which mineralo gists and geochemists are usually involved. Many research activities are then shared between geo 163 This issue of Elements has been organized and edited by Takashi Murakami and Rod Ewing in an unusually short time, due to the urgency of the events. We expect it will provide a large audience with advanced scientific information on this “hot” topic. Indeed, technical, political, and Cont’d on page 164 J une 2012 FROM THE EDITORS This Issue UPCOMING EDITOR A little more than one year after the Fukushima tragedy, this issue of We are delighted that Patricia (Trish) Dove of Virginia Tech has accepted our invitation to join the editorial team. She will replace Tim Drever, whose term ends in December 2012. We will formally introduce Trish in the first issue of 2013. Elements provides a summary of the nuclear accident as it has been reconstructed and the lessons that other facilities can take from it, and it gives an overview of the resulting contamination in the air, soils, and ocean. The Perspectives section provides six different points of view on the future of nuclear power in the aftermath of Fukushima. And Travelogue offers an account of a scientist’s visit to the evacua tion zone. These articles reveal that behind the human tragedy, a large number of scientists are working hard to provide the data necessary to understand the accident and find solutions. Kudos to guest editors Takashi Murakami and Rod Ewing who accepted the challenge of assembling this issue of Elements under a much acceler ated schedule: the first invitations to authors were sent out at the end of August 2011. Our gratitude also goes to the authors, who accepted the challenge of writing review articles while so much data are still being amassed—like trying to hit a moving target. At Goldschmidt 2010, I was impressed by the argument Tennessee Senator Lamar Alexander made in favor of nuclear power as the energy of the future. In his keynote presentation, he reviewed all the energy sources in terms of the land used to produce the energy. For example, the land occupied by one nuclear plant producing enough power for 90,000 homes is one square mile. To produce the same amount of energy, solar power requires 15 square miles, petroleum 18. But the Fukushima Daiichi nuclear power plant accident reminds us that when something goes wrong in this industry, a huge territory can be impacted and the economic costs of bringing an accident under control are stag gering. This does not include the suffering of people who have been displaced from their homes and face an uncertain future. About 90,000 persons who lived in the evacuation zone near the plant have not been able to return to their homes. We dedicate this issue to them, and also to the 20,000 persons who died in the aftermath of the earthquake and tsunami. About Duplicate Copies – Part 2 From time to time, we receive inquiries regarding the management of subscriptions, such as these:“I joined society X and am also member of society Y but I am still receiving only one copy of Elements. I would like this second copy to be shipped to a colleague in Estonia!” “I would be happy to only have online access to Elements and save you the mailing costs.” “My husband and I both receive Elements. We only need one copy; please eliminate mine.” As explained in the April issue (8: 84), Elements’ financial model requires that we eliminate duplicate mailings. This reduces printing and mailing costs, and these savings are passed on to the participating societies in the form of lower subscription rates. So even if you belong to more than one society, you should only receive one copy of Elements. We ask our readers to encourage colleagues who are interested in receiving Elements to join one of the participating societies. Although granting requests like online access only might seem like a good idea, it could end up being expensive, as managing these requests would be very time consuming and might necessitate the hiring of a subscription manager, thus erasing any saving and probably increasing costs, which would then have to be passed on to the societies. Put your unneeded paper copy of Elements to good use: depending on the topic, send it to your dean, give it to a student, a colleague, or a neighbor. Earth scientists are providing the scientific basis for addressing critical questions, such as when it will be safe to return to the contaminated areas. This requires multidisciplinary teams that need to avoid being made irrelevant by answering, “We need to do more work.” Answers are needed now and have to be clearly communicated to decision makers. EDITORIAL Cont’d from page 163 s ocietal aspects are interlinked in nuclear activities, due to a general atti tude of fear towards nuclear power. Better relations between technology and society rely on improved and deepened scientific knowledge and on complete disclosure of the available data. The Fukushima disaster illustrated public suspicion towards the various authorities and com pany representatives, and even towards the technological and scientific information provided by the organizations and institutions working on the site. Scientists must regain public confidence by clearly communi cating in-depth and rigorous studies of the impacts of radioactivity on the various environments and ecosystems. An optimistic vision is that by improving the information available to the public, we will reinforce the need for our authorities to explain the scientific grounds for their political decisions, helping balanced choices to be made. Georges Calas ([email protected]) University Pierre et Marie Curie, Paris E lements 164 Pierrette Tremblay, Managing Editor Elements makes a splash in Natural History W ith its timely and societally relevant topics, Elements has effectively permeated the mineralogy, geochemistry, and petrology community and has even reached other interested sci entists and administrators. When geoscientists have the chance to reach out to the general public, it is important that they make the effort to do so. Such an opportunity occurred recently when the editor-in-chief of Natural History magazine, Vittorio Maestro, contacted Barb Dutrow and Darrell Henry, guest editors of the October 2011 Elements issue on tourmaline, about writing an article for his magazine. Associated with the American Museum of Natural History, Natural History’s mission is to promote public understanding and appreciation of nature and science. Maestro had read the Tourmaline issue and felt it would draw the interest of his readers. Not since a 2004 article on zircon had Natural History focused an article exclusively on a mineral. Working with Vittorio Maestro, Barb and Darrell reconfigured and condensed the six papers from the Elements issue into a single article that is visu ally exciting, scientifically correct, and accessible to the curious public. The article entitled “The Tourmaline Diaries: An EyeCatching Mineral and Its Many Facets” appeared in the March 2012 issue of Natural History. Natural History has a circulation of about 50,000, with 1900 libraries and an audience of nearly 200,000. Barb Dutrow, Louisiana State University J une 2012 TRIPLE POINT Fukushima Lessons: The Disconnect between Geology and Nuclear Engineering Recently, several seismic events at nuclear power plants exceeded the plants’ “design bases” for ground motions. On 16 July 2007, a magnitude 6.8 earthquake damaged the Kashiwazaki-Kariwa nuclear plant in western Japan; the 11 March 2011 magnitude 9.0 quake and attendant tsunami caused mul tiple meltdowns at the Fukushima plant in northeastern Japan; and on 23 August 2011, a magnitude 5.8 earthquake caused minor damage at the North Anna nuclear plant in Allison Macfarlane Virginia, USA. These accidents have exposed a disturbing disconnect between the knowl edge needed by nuclear engineers to build safe nuclear power plants and the knowledge that geoscientists can provide to them. Some nuclear engineers have claimed that reactors can be made “earthquake-proof,” and, according to Scott Burnell of the U.S. Nuclear Regulatory Commission, “they [reactors] are designed to withstand just about everything short of a meteor strike” (Cyranoski 2007). Many in the nuclear industry claimed that the source of the Fukushima acci dent was the tsunami, not the earthquake (World Nuclear Association 2011), though the jury is still out on earthquake damage to the reactors and will be until they can be examined in detail. But the question is: can and do nuclear engineers integrate knowledge of Earth processes adequately so that reactors can be designed to withstand all that the Earth can throw at them? The seismic design basis for a nuclear reactor is usually determined by the potential for ground motions at the site, which are estimated using historical data. This primary assumption is, in itself, problematic, because the historical period represents such a small slice of the pos sible geologic processes that could occur at a given location. To assure safety, nuclear engineers add an unspecified “safety margin” to their designs. Geologists are comfortable working with the concept of “deep time,” and thus the use of historical data to guide predictions of future seismic events is inconsistent with geologic thinking. Nuclear engineers, on the other hand, design reactors that operate for 40 to 60 years, a timescale completely at odds with the geologic one. Another source of disconnect between nuclear engineers and geologists is in their abilities to make accurate predictions. Nuclear engineers base many of their analyses on probabilistic performance assessments. Geology, on the other hand, is a retrodictive science, precise about the past but qualitative, at best, when predicting the future. Earth systems are complex and many of the processes and boundary conditions are not known or not well understood. They are thermodynamically open systems with processes that occur over very long timescales, making models of them difficult to validate or verify (Oreskes et al. 1994). For instance, what matters during an earthquake at a reactor is the frequency of shaking and the acceleration of the ground. These ground motions depend on a variety of factors that go far beyond the simple energy released from the quake as indicated by magnitude measure ments. Ground motions vary depending on the seismic source and the factors affecting wave propagation. Unique to the seismic source is the direction of wave propagation and the amount and type of slip on the fault. The factors affecting wave propagation include the rock and soil types along the wave path; the presence of mountains, basins, seas, and fault zones along the path; the age of the rock; and other aspects of the geologic environment. As a result, prediction of potential ground motions is a complex and difficult task. Like Earth itself, geologic knowledge is dynamic and always in a state of flux. The nuclear industry sometimes treats this knowledge as static, not updating seismic hazard analyses for many years, for instance. Moreover, geology and its subdisciplines have experienced significant E lements Triple Point raises issues of broad interest to the readers of Elements and explores different aspects of our science (teaching, publishing, historical aspects, etc.), our societies, funding, policy, and political issues. Contact Bruce Yardley (B.W.D. [email protected]) if you have an idea for a future topic. paradigm shifts over the past decades. The theory of plate tectonics only became fully integrated into geoscience in the 1970s, a period just prior to the time when many nuclear reactors were designed and constructed. Paradigms continue to shift. Prior to the 2004 Sumatra earthquake, mag nitude 9.3, seismologists generally thought that megaquakes occured only along certain subduction zones (Ruff and Kanamori 1980). After this quake, it became clear that megaquakes could happen along any subduction zone of sufficient length (McCaffrey 2007). Similarly, little evidence for large tsunamis was known from the area near Fukushima until a 2001 study of the 869 AD Jogan tsunami (Minouri et al. 2001) Geologists are certainly not all-knowing, either. The occurrence of intraplate earthquakes, like the one at Mineral, Virginia, in August 2011, is a case in point. The geology of that section of the United States and the mechanisms that cause intraplate quakes are not well understood. Likewise, many faults, especially those that are not exposed at the sur face, have not been identified. For instance, the fault that slipped and caused earthquake damage to the Kashiwazaki-Kariwa nuclear power plant in Japan in 2007 was not known to exist prior to the plant’s construction. Geologists make it hard for nuclear engineers because they often dis agree about Earth processes. During a recent trip to Japan by the author, a number of Japanese nuclear industry colleagues pointed out that because the Jogan tsunami data were actively debated, they felt they could not act on them and increase the size of the protective seawalls. The disconnect that exists between the geologic and nuclear engi neering communities reflects their different approaches: geologists try to understand a dynamic, complex Earth with all its attendant pro cesses, while engineers consider a given system over a specified period of time—but one that must work within that complex Earth system. Given the scale of the disconnect, is there a way to make nuclear reac tors safer? Clearly, a requirement to revisit seismic hazards on a regular basis (every few years) and include in the analysis societal impacts as they change over time would be valuable. Less reliance on probabilistic performance assessments when considering complex Earth system behavior would be a significant advance. Performance assessment allows some processes that otherwise might be important to be overlooked, as the Fukushima accident has shown. Complex Earth systems must be evaluated on a more qualitative basis, using a methodology termed a “safety case,” which gathers all relevant quantitative and qualitative analysis together to predict future behavior (Ewing 2011). Finally, we must recognize there are limitations to what we can do when interacting with Nature. Perhaps some places are simply not suit able for technologies such as nuclear power, the safety of which relies heavily on the stability of the Earth. Some parts of the Earth may be too dynamic for risky technologies. Allison Macfarlane Allison Macfarlane is an associate professor of environmental science and policy at George Mason University in Fairfax, Virginia. She received her PhD in geology from the Massachusetts Institute of Technology in 1992. She was recently a member of the White House’s Blue Ribbon Commission on America’s Nuclear Future. In 2006 MIT Press published her coedited book, Uncertainty Underground: Yucca Mountain and the Nation’s High-Level Nuclear Waste. She was nominated by President Obama as the next chair of the Nuclear Regulatory Commission. References Cyranoski D (2007) Quake shuts the world’s largest nuclear plant. Nature 448: 392-393 McCaffrey R (2007) The next great earthquake. Science 315: 1675-1676 165 Cont’d on page 166 J une 2012 PEOPLE IN THE NEWS Marc Norman Incoming Executive Editor of GCA On 17 April 2012, Marc Norman was appointed as new executive editor of Geochimica et Cosmochimica Acta by the publisher, Elsevier. After a careful search, Marc was recommended by the Joint Publications Committee of the Meteoritical Society and the Geochemical Society and then nominated by the societies to Elsevier. In his e-mail greeting to the associate editors, Marc wrote, “My primary goal as executive editor will be to ensure that GCA maintains its standing as the premier journal for geochemistry.” Since 2001, Marc has been at the Research School of Earth Sciences of the Australian National University, Canberra, where he holds the posi tion of Senior Fellow. His research interests span both terrestrial and extraterrestrial topics. Six are currently listed on his home page (http:// people.rses.anu.edu.au/norman_m/): magmatic systems and related ore deposits; NiS, PGE black shales, sedimentary geochemistry; laser abla tion ICPMS; solution ICPMS; radiogenic isotopes (Sr, Pb, Nd, Os); and MC-ICPMS, TIMS. At the 43rd Lunar and Planetary Science Conference in Houston this year, he reported on the ages of lunar spherules, melt breccias, and zircons. Goldschmidt Conference in Melbourne and is now chair of the Program Committee for the 2012 Meteoritical Society meeting in Cairns. In 2011 he organized a thematic issue of the Australian Journal of Earth sciences, which will be published in early 2012. From 2008 to 2011, he served on the Steering Committee for the first Australian Academy of Science Decadal Plan for Space Science, and he chaired the planetary science working group for the National Committee for Space Sciences within that effort. His prior experience in the editorial area includes service on the edito rial boards of the Australian Journal of Earth Sciences (2009–present), pub lished by the Geological Society of Australia, and the Open Mineralogy Journal (2008–2010). James B. Macelwane Medal to Nicolas Dauphas Marc has been a councillor, associate treasurer, and a member of the Publications Committee of the Meteoritical Society. In 2006 he cochaired the Cosmochemistry Task Group (with Herbert Palme) for the Nicolas Dauphas was awarded the 2011 James B. Macelwane Medal of the American Geophysical Union. The medal recognizes significant contribu tions to the geophysical sciences by an out standing young scientist. His citationist writes that his “contributions to geochemistry and cos mochemistry are remarkable for their breadth and depth, covering geochemical processes at all scales and times, from the age of the galaxy to the evolu tion of ancient and modern igneous rocks.” 2011 AGU Fellows Among the scientists elected as Fellows of the American Geophysical Union in 2011, we high light those who have a primary affiliation with the Volcanology, Geochemistry, and Petrology Division or are members of one of Elements’s participating societies. Congratulations to all! Don E. Canfield For his outstanding contributions to under standing the biogeo chemical cycling of sulfur and the oxy genation of Earth’s atmosphere Oliver Chadwick For his novel applica tion of geographic and geochemical tools to advance understanding of how soils develop and interact with other parts of the Earth system Catherine Chauvel For key contributions to understanding mantle evolution through iso tope studies of oceanic basalts and linking sub ducted sediments to arc magmas Mark M. Hirschmann For his exceptional work on igneous phase equi libria, illuminating the simplicity underlying experimental results on complicated natural solutions Craig E. Manning For his peerless experi ments on the solubility of minerals in aqueous fluids at high tem perature and pressure, a unique combination of rigor and realism, yielding timeless data and timely applications William F. McDonough For his major contri butions to our under standing of the geochem istry of Earth’s interior Suzanne Mahlburg Kay For her contributions to understanding the growth and evolution of continental crust in sub duction zones William M. Seyfried Jr. For making major con tributions to our knowl edge of the chemistry of aqueous fluids and processes that take place near mid-ocean ridges Triple Point Cont’d from page 165 Minoura K, Imamura F, Sugawara D, Kono Y, Iwashita T (2001) The 869 Jogan tsunami deposit and recurrence interval of large-scale tsunami on the Pacific coast of northeast Japan. Journal of Natural Disaster Science 23: 83-88 Oreskes N, Shrader-Frechette K, Belitz K (1994) Verification, validation, and confirmation of nuclear models in the Earth sciences. Science 263: 641-646 Ruff L, Kanamori H (1980) Seismicity and the subduction process. Physics of the Earth and Planetary Interiors 23: 240-252 E lements Kevin J. Zahnle For advancing under standing of how plane tary-scale physical and chemical processes affect the evolution of planets and life on them World Nuclear Association (2011) Fukushima Accident 2011, 22 December 2011, www.worldnuclear.org/info/fukushima_accident_inf129. html Ewing R (2011) Standards and Regulations for the Geological Disposal of Spent Nuclear Fuel and High Level Waste. Prepared for the Blue Ribbon Commission on America’s Nuclear Future, March 4, 2011, www.brc.gov/library/commissioned_ papers/EWING%20BRC%20white%20paper%20 FINAL.pdf 166 J une 2012 PERSPECTIVES Fukushima Daiichi: Lessons Learned Note from the editors: Six prominent scholars, politicians, and policy makers were asked the question “What has been learned from the Fukishima Daiichi event and how will this impact the future of nuclear power?” The Importance of Clear Communication Ian G. McKinley1 The damage to the Fukushima reactors provided frightening images that shook confidence in nuclear power around the world. It is easy to forget that, as yet, there is no indication of radio logical harm to the general public. Confusing and incorrect comparisons with the completely different situation in Chernobyl highlight a major lesson to be learned from this incident: the importance of clear communication. Communication failed at every level. Known tsunami risks were not communicated to those charged with assessing natural hazards to nuclear facilities. The developing situation in the damaged units after the tsunami was poorly communicated to both the government and the general public, delaying decisions that could have limited the con sequences and helped avoid unnecessary panic. Tools that could have been used to help plan the response to releases of radioactivity were introduced too late, and their output was presented in a way that only increased confusion and public concern. It should be emphasized that this was not simply a result of the chaos immediately after a major disaster nor was it limited to Japan—9 months after the Fukushima event, newspaper, TV, and Internet articles continued to sow confusion around the world. At the Daiichi site, contamination levels are high and remediation will be a major challenge. Although hotspots and increased radiation levels exist off-site, health hazards from the radiocesium isotopes that now dominate activity levels are very small. Nevertheless, demonstration cleanup projects have been initiated and regional remediation will follow. A rich country like Japan can justify such actions, even if the health benefit is marginal compared to the effort invested. Such an objective perspective on the risks involved should, however, be clearly explained in order to reassure local residents and involve them in deci sions about the actions that need to be taken. Poor communication has also meant that, so far, potential options for optimizing the remediation work are being missed. Major efforts are being invested to manage lightly contaminated soil; however, this soil could be better utilized as ground cover on the more highly contami nated reactor site, providing radiation shielding and reducing doses to workers. The communication problem extends to wider, international issues resulting from this incident. In several cases, knee-jerk reactions from poorly informed politicians have resulted in moves away from nuclear power, without any balanced consideration of the potentially larger environmental and public health hazards of the fossil fuel alternatives that would be introduced in its place. More seriously, the fact that two 1 Ian G. McKinley ([email protected]) is a technical consultant at MCM, Baden, Switzerland, and, since December 2011, a visiting professor at Okayama University, Japan. He was initially involved in the synthesis of relevant international experience to help plan on-site and off-site remediation. Currently he is supporting assessment of the first demonstration remediation projects and planning subsequent regional cleanup actions. E lements recent devastating tsunamis have resulted from megathrust earthquakes has focused risk assessment on this particular hazard combination— without considering that the historical record shows much larger tsu namis from other sources, such as volcanoes and landslides. Indeed, much of the infrastructure that supports our high population densities is located in areas where a natural catastrophe in coming decades is not just possible, it is inevitable. As was the case before Fukushima, the technology exists to assess such hazards and, to a certain degree, minimize consequences or prepare responses. Unless the existence and usefulness of such technology is effectively communicated to decision makers, however, these lessons will have to be relearned after the next natural catastrophe. Further background information The Fukushima Daiichi incident in context: McKinley IG, Grogan HA, McKinley LE (2011) Fukushima: Overview of relevant international experience. Journal of Nuclear Fuel Cycle and Environment 18: 89-99 Tsunami risk overview: McKinley IG, Alexander WR, Kawamura H (2011) Assessing and managing tsunami risks. Nuclear Engineering International 56 (687): 14-17 Improving International Cooperation Catherine Cesarsky2 The Fukushima Daiichi accident undoubtedly has shaken the world of nuclear power in a very serious way and will leave indelible marks. Even after the release of the preliminary report by the Japanese investigation committee chaired by Yotaro Hatamura, not everything is known of the sequence of events and of their final consequence. Main Lessons for Present Reactors A first lesson from Fukushima is that very unlikely events may com bine with each other in unanticipated ways, so the concept of “emer gency preparedness” will have to be revisited. The main cause of the Fukushima accident was the tsunami, which resulted in the loss of the cooling capabilities and the internal electrical supply, including some of the emergency batteries. The design of the plant was highly resistant to earthquakes but had a limited protection against floods. Thus, in addition to a well-defined design basis, a nuclear plant must have some potential to resist external hazards that are “beyond design.” Most operating light water reactors already have dedicated systems to cope with severe-accident conditions. For example, in France, pas sive hydrogen recombiners to protect against hydrogen accumulation were installed years ago. France will also be putting in place a rapid intervention force with off-site power supplies and cooling capabili ties. Also, it has been proposed to identify an ultimate set of systems (“hard core”) and to have them available in bunkers at the site in case of extreme conditions. At Fukushima, for a few days after the tsunami and under very dif ficult conditions, the decay heat removal was maintained using onsite water reservoirs and pumping systems requiring no AC electrical supply. Thus a large early release of radioactive material was avoided, 2 Catherine Cesarsky is the High Commissioner for Atomic Energy in France and advisor to the French government on science and energy issues. She holds a physics degree from the University of Buenos Aires and a PhD in astronomy from Harvard University (1971). She is a member of the French Académie des Sciences and a foreign member of the National Academy of Sciences (USA), the Royal Society (UK), and the Swedish Academy of Sciences. She was visiting the Rokkasho nuclear reprocessing plant in Japan on March 11, when the earthquake and tsunami struck Japan. 168 J une 2012 PERSPECTIVES A Japanese Perspective Atsuyuki Suzuki3 and the Japanese government was able to evacuate people in time. The Hatamura committee argues that these systems could have been operated in a better way. The necessity for superior preparation and training of the plant staff is therefore another key lesson. In terms of accident progression, a significant part of the radioactive inventory has been retained in the reactor containers, and it appears that the three coriums are trapped in the concrete basements of the reactors. For present reactors, in-depth studies of the physics and chem istry of severe accidents will have to be carried out. This knowledge is essential for defining management procedures and for developing severe-accident simulators devoted to operator training. Resistant instrumentation will also be required for ascertaining, as far as pos sible, the plant condition during an accident. Future of Nuclear Power For most countries involved, nuclear energy will likely remain an essential component of the low-carbon energy mix. The Fukushima accident has demonstrated the appropriateness of the safety objectives assigned to the new generation of reactors (generation III), which fea ture additional systems dedicated to severe-accident mitigation (e.g. corium retention, hydrogen explosions). After more than thirty years of cooperation following the Three Mile Island (USA) accident, Fukushima also raises doubts about the efficiency of international cooperation. After Fukushima, improvements should be actively sought in: • Speeding up current initiatives for harmonizing safety requirements, crucial to assessing the full compliance of commercial projects to internationally agreed-upon safety criteria for generation III reactors • Progressing towards better harmonized safety regulations and sharing of best practices • Developing international training • Enhancing international cooperation in regulatory research, safety, and radiation protection • Generalizing periodic nuclear power plant “stress tests” followed by peer reviews (as done in the European Union) • Studying concrete measures to provide mutual assistance to operators in case of severe accidents, an issue especially important for small- and medium-sized electric utilities After Fukushima, nuclear energy will have to regain public and political acceptance. A rational and consensual determination of all the conse quences of the Fukushima accident and a “dynamic safety” approach with full use of lessons learned from the accident and stress tests will contribute to this challenging objective. The massive earthquake and immense tsunami on March 11, 2011, raise a fundamental ques tion: Are human beings capable of managing unprecedented natural disasters? The question is also begged by the great 1755 Lisbon earth quake, which profoundly shocked Europeans. This event compelled a number of philosophers, including Immanuel Kant, to alter their thoughts drastically. As far as the Fukushima nuclear accident is concerned, my answer is “yes.” My optimism is based on the performance of the nuclear power plants located in the coastal areas of northeastern Japan, where no serious consequences were experienced, even though these areas were subjected to a nearly equal-magnitude tsunami. As an example, consider reactors #5 and #6 at Fukushima Daiichi. One of the three emergency diesel generators installed at Unit 6 remained available, and operators were able to successfully connect it to both units and provide sufficient power for accident management at these units. This surviving generator was air-cooled, not water-cooled, and it was installed at an elevation high enough to avoid the tsunami. This is an example of a defense-in-depth safety concept, where a diversity of designs offers the greatest resilience to an extraordinarily unlikely event. In addition to diversity in design, we have learned the usefulness of prudent conservatism when considering natural phenomena that are conceivably always associated with the unknown. One of the issues that Japan’s nuclear industry missed was to take into account the his torical tsunami records in the analysis of reactor safety. The scientific knowledge obtained in recent years had indicated that a tsunami of a magnitude similar to that of the March 2011 event occurred in 869 AD in these areas; this fact was not known in the late 1960s and early 1970s, when the construction permits were granted. Unfortunately, no action was taken to reflect the new knowledge in order to enhance reactor safety. Thus, an overridingly important point raised by the accident is that new scientific findings should be adopted promptly and properly in order to improve nuclear safety. This is particularly true if the new information is related to extreme natural events that are difficult to predict. After the accident, nuclear policy in Japan was placed under review. Priority was given to the environmental remediation of contaminated off-site areas and to implementing the dismantlement of the damaged reactors. These tasks will require patience, as well as substantial expen ditures. The future of the nuclear power industry in Japan rests heavily on the successful achievement of off-site environmental remediation and the removal of nuclear material from the damaged reactors. In the aftermath of the accident, however, there are countries that have not changed their policy, but continue to pursue their plans for reactor construction, and the Japanese government has expressed its readiness to be actively committed to the international nuclear busi ness. Worldwide, energy security is critical. The political situation in the Middle East, for instance, underscores the inherently fragile nature of the international oil market, which can potentially affect the world economy. Naturally, the future of global nuclear power depends on such international energy circumstances, and my perception is that the global impacts of the accident will gradually disappear, as more realistic assessments are made. 3 Atsuyuki Suzuki is the president of the Japan Atomic Energy Agency (JAEA) and a professor emeritus of nuclear engineering at the University of Tokyo. Currently he leads the special task force at JAEA specifically dedicated to the partnership programs dealing with Fukushima matters, including environmental remediation of off-site areas as well as postaccident management of the nuclear power plants and environmental restoration of on-site areas. E lements 169 J une 2012 PERSPECTIVES Environmental Remediation, Waste Management, and the Back End of the Nuclear Fuel Cycle The Post-Fukushima Nuclear Industry in Mongolia Joonhong Ahn4 Undraa Agvaanluvsan5 The Japanese government has promised to make every effort to limit the dose rate in air in areas contaminated by the Fukushima accident to below 1 millisievert (mSv) per year (typical background exposures in Japan are 1 mSv per year). It has been estimated that decontaminating the highly con taminated areas (i.e. >1 megabecquerel/m2 will generate an estimated 24 million m3 of contami nated material. The estimated cost of disposal of the wastes from highly contaminated areas is a few trillion yen (one trillion yen ≈ 8 billion US dollars). If areas with lower contamination by radioactivity are also included in the cleanup, the total volume of waste material and the associ ated cost will be much greater; however, the health risks in areas of low contamination have been judged to be insignificant. Thus, considering the potential scale of the cleanup effort, the question “how clean is clean enough?” has emerged as a much-debated issue involving the convergence of technical, political, and societal concerns. The history of nuclear activities in Mongolia offers a good example of the development of nuclear capabilities in a developing country. Mongolia, once Communist, was closely linked to the former Soviet Union. The training of nuclear scientists began in the early 1960s, and most Mongolian scientists received their post graduate degrees and research experience in nuclear physics at the Joint Institute of Nuclear Research in Dubna, Russia. Over the past decade, the Nuclear Waste Management Organization (NUMO) of Japan has been responsible for the process of public par ticipation in the siting of a geological repository for high-level and long-lived radioactive wastes. However, no municipality has yet to vol unteer to host such a site on its territory. Now, a siting process that was deadlocked before the accident has become even more difficult. The realization of the amount of material that will result from decontami nation related to the Fukushima accident and the necessity of moving forward with a solution have delayed the siting process for a repository for high-level radioactive waste. On the other hand, this delay may be a valuable opportunity for developing trust and new approaches for decision making that could lead to a break in the deadlock over selecting a site for a geologic repository. Public discussion has also extended to a reconsideration of Japan’s nuclear fuel cycle policy, particularly at the back end, that is, interim storage, reprocessing of spent nuclear fuel, and final geological disposal. Japan is the only non–nuclear weapons country with an industrial-scale capability for uranium enrichment and spent fuel reprocessing that has been approved by the international community. The motivation for developing a full-fledged, complete fuel cycle capability has been a national policy of energy security and independence. Plutonium gen erated in light water reactors and future fast breeder reactors has been considered to be a semi-indigenous resource. Because of the sodium leak in the Monju fast breeder reactor in 1995 and the technical dif ficulties with the vitrification process at the Rokkasho reprocessing plant, there was already growing public skepticism about the current nuclear fuel cycle strategy. Due to the events at Fukushima, public agreement and perceptions concerning the development of nuclear power in Japan have changed significantly, and there is much discussion about whether the current nuclear fuel cycle policy should be revised. In any conceivable future scenario, including phasing-out nuclear power or abandoning the recy cling of plutonium, the transition will require at least a generation. To successfully manage this transition period, interim storage of spent fuel will be essential. The protection of long-term storage facilities from natural disasters and terrorism will be a crucial technical and societal issue. The fate of accumulated plutonium should also be clearly accounted for, especially in the phase-out scenarios. New fuel cycle policies should be established from the viewpoint of making spent fuel more robust against accidents and disasters and reducing the risk of proliferating weapons-usable materials. 4 Joonhong Ahn is a professor in the Department of Nuclear Engineering at the University of California, Berkeley. He has led numerous joint research projects involving institutions in Japan, South Korea, and the United States, and the IAEA. He is currently conducting a joint research project with the Japan Atomic Energy Agency, in which criticality safety is being analyzed for geological disposal of molten nuclear fuel in the Fukushima reactors. E lements Though nuclear power was held in high esteem, there was also a strong fear of nuclear activities. This was due to the dual nature of nuclear technology. The two blocs in the Cold War, one led by the United States and Europe the other led by the Soviet Union, were in a nuclear arms race. As nuclear weapons were being tested, both sides claimed that the other was an “evil” force pursuing the development of an “evil” weapon. At the same time, both sides argued that they needed nuclear weapons for their defense. In order to sustain this policy, nuclear weapons were viewed as a necessary evil. The combined feeling of fear and allure was quite widespread among the Mongolian people, and this paradox was only enhanced by the fear engendered by the Chernobyl accident in 1986 and the hope created by the Democratic Revolution in 1990. The Democratic Revolution brought Mongolia the freedom to adopt an independent nuclear policy. The anti–nuclear weapons senti ment is reflected by Mongolia’s declaration that it would be a nuclear weapons–free country. Nuclear policy making remained mostly dor mant until 2009, when Parliament approved the historic Nuclear Energy Law and Nuclear Energy Policy. With some of the world’s largest and least explored uranium reserves, Mongolia knew that it needed a new policy in order to become a supplier of uranium for nuclear fuel. Thus, Mongolia joined the “nuclear renaissance,” as did more than 30 other countries that were considering building nuclear power plants. During this time, support for the nuclear industry among the Mongolian public and political leaders was strong. The situation changed after Fukushima. Rumors that the Mongolian government was considering building a nuclear-waste-disposal site caused much anxiety and opposition among the people. Although the government refuted the accusations, opposition groups formed against the government. The public, taking advantage of the new social media technologies, was not convinced by the government. This was mainly because the Mongolian government could not articulate its position and strategy for nuclear development. The rumors and discussion only ceased with a presidential decree in 2011, which stipulated that there would be no contract negotiations or cooperation in the nuclear arena without the approval of the National Security Council of Mongolia. Mongolia does not yet have a nuclear power plant, nor is there a national consensus on how its extensive uranium reserves should be developed. Mongolia is an example of how difficult it is to develop a national nuclear policy in the post-Fukushima environment. 5 Undraa Agvaanluvsan, a nuclear physicist by training, is a former ambassador at the Ministry of Foreign Affairs and Trade of Mongolia, where she was in charge of nuclear energy and security issues at the time of the Fukushima event. Her expertise in nuclear science at Lawrence Livermore National Laboratory and in policy research at the Center for International Security and Cooperation, Stanford University, combined with her experience in nuclear-policy practice in the Mongolian foreign service, provides her with a unique and useful perspective on current concerns. The views expressed here are the author’s personal opinions and in no way express an official policy of the Mongolian government. 170 J une 2012 PERSPECTIVES Making Nuclear Power Safer and Less Proliferative after Fukushima Frank N. von Hippel6 The Fukushima disaster made obvious some of the safety weaknesses of the General Electric boiling water reactors, including their smallvolume containments. This was understood in 1972 within the U.S. Atomic Energy Commission (AEC), before Fukushima Daiichi Units 2 and 3 were licensed for operation and before the con struction of Fukushima Unit 4 had even begun. A deputy director of the AEC’s Directorate of Licensing warned, however, that questioning this design “could well be the end of nuclear power. It would throw into question the opera tion of licensed plants [and] would make unlicensable the…plants now under review.” He was later appointed chairman of the U.S. Nuclear Regulatory Commission (NRC). Even today, the majority of the political leadership of the NRC is still reluctant to revisit past decisions. A potentially more serious consequence of poor design is the way in which current nuclear fuel cycle arrangements, which legitimize national enrichment and reprocessing plants, spread the bomb while spreading nuclear power. As former International Atomic Energy Agency (IAEA) Secretary General Mohamed ElBaradei argued in 2003, we should move toward at least multinational control of such facilities. 6 Frank von Hippel is a nuclear physicist and a professor of public and international affairs at Princeton University, where he cofounded, in 1975, Princeton’s Program on Science and Global Security; in 1989, the journal Science & Global Security; and, in 2006, the International Panel on Fissile Materials. In the decades before the Fukushima Daiichi accident, von Hippel and coauthors spotlighted and suggested remedies to the dangers of reactor containment overpressure during an accident and the practice of dense-packing spent fuel pools. E lements If nuclear power is to have a future, it must be made safer and less proliferative. But even if this can be accomplished, the role of nuclear power will be limited during the next few crucial decades, as we try to cap and reduce carbon dioxide emissions, unless we get much more serious about energy efficiency. Global growth of electric-power demand is literally outrunning our ability to build non–fossil fuel capacity, even in China and India where the growth of both total electricity consumption and nuclear power are most dramatic. In 2008, nuclear power accounted for 13.6 percent of global electric power, down from a peak of about 17 percent in 1999. The IAEA’s pro jections of nuclear power have historically far exceeded reality, but in its 2011 projection, the IAEA predicts that nuclear power will account for only 6.2 to 13.5 percent of global electric power in 2050. Because of the rapid growth of demand, even this contribution will require global nuclear generating capacity to increase by 50–225 percent. The contri bution of renewable energy— still mostly traditional hydropower—also declined between 1999 and 2008, by one percent to 19 percent, despite the rapid growth of wind and biomass energy. The IAEA projections are based on its survey of national projections for the future of nuclear power, which, in aggregate, have declined by only about 5 percent since the Fukushima Daiichi accident. Many governments still believe in a future for nuclear energy, but it is no longer the dominant future many expected in the 1960s and 1970s. If nuclear and other nonfossil sources of electric power are to play a more important role in limiting climate change, we must work on the demand as well as the supply side of the energy problem. Our new refrigerators and compact fluorescent bulbs consume one quarter as much power as the devices they replace, but much more is both pos sible and necessary. 171 J une 2012 Tr avelogue Field Research inside the Fukushima Restricted Area Satoshi Utsunomiya1 On March 16, 2012, Ohkuma town, where the Fukushima Daiichi nuclear power plant is located, stood quietly and peacefully, except for workers in tyvex uniforms conducting remediation work and aban doned cows migrating along unused roads. The town appeared the same as usual, except for the absence of residents, some earthquake damage, and high beeping sounds from our survey dosimeter indicating maximum radiation readings greater than 30 μSv/h, even inside our vehicle. I was there with colleagues for a collaborative field study with Japan Atomic Energy Agency and Fukushima University. Ohkuma town and vicinity are located in the restricted area, that is, within a perimeter of 20 km from the nuclear power plant (Fig. 1). By law, no one is allowed to enter the area without governmental per mission. Security checkpoints have been set up on all roads into the area. A total of 78,200 residents were evacuated from the restricted area. Outside the restricted area, a “deliberate evacuation area” was designated, covering mainly Iitate village and Namie town, based on the area of contaminant distribution elongated toward the northwest; 10,550 residents were evacuated. The deliberate evacuation area was established by the government for those areas where the accumulated dose rate was estimated to be >20 mSv/year (Figs. 1, 2). People are not allowed to live in this area or to enter the area except for a quick return home, vehicle transit, or a short-term visit for public services or for business purposes. Although the extent of these areas was revised in April 2012 (Fig. 1), most remain deserted. A dosimeter stands in the playground of the Tsushima elementary school in Namie town within the deliberate evacuation area. The few parked cars are the property of refugees. People were first evacuated to this elementary school located outside the restricted area; however, they were forced to evacuate again, after the town was included in the deliberate evacuation area. Figure 2 Satoshi Utsunomiya sampling soil in a rice field in Iitate village within the deliberate evacuation area. The snow covering the field decreased the dose to some extent. Figure 3 The scientific challenges at Fukushima include the very low concentra tions of radionuclides that must be detected (e.g. even 160,000 Bq/kg of 137Cs is only equivalent to ~50 parts per trillion), the characterization of the phases associated with each radionuclide, the heterogeneous size distribution of these phases in soils, the large area of contaminated land, and the wide variety of vegetation. It is sometimes difficult to see how scientific studies can contribute to the mitigation of disastrous and tragic events. Mounting problems sometimes overwhelm us and obscure the scientific goals, but basic science will definitely be important to the strategies developed for restoration at Fukushima. Our group is contributing to the effort by carrying out Cs and Pu analyses in the contaminated area. (A) A prediction of the accumulated radioactivity between March 11, 2011, and March 11, 2012, with the outlines of four designated areas. (B) A map of the predicted annual dose in the area of Ohkuma and Futaba towns. Both maps modified after the Ministry of Education, Culture, Sports, Science and Technology, Japan Figure 1 Within the restricted area, especially within 3 km of the power plant, the radiation dose increases dramatically. After a few hours of field work in Ohkuma (Fig. 3), the dosimeters on our chests read >90 μSv, which is about one-tenth of the annual dose limit for public expo sure, 1 mSv/y, recommended by the International Commission on Radiological Protection. During our field work, the dose rate about 3 km south of the plant was as high as 60 μSv/h at 1 m above the ground. The highest dose rate measured was 630 μSv/h beneath a rainwater pipe at point 1 in Figure 1. Such spotty occurrences of high radioactivity have been recognized at many contaminated sites, but they do not appear on the large-scale maps of contamination. 1 Satoshi Utsunomiya has been an associate professor in the Department of Chemistry, Kyushu University, since 2007. He received a PhD from the University of Tokyo in 2000 and worked for the University of Michigan prior to his current position. As a mineralogist and geochemist, he has been studying the migration of radionuclides in the subsurface and other geochemical problems using various nanocharacterization techniques. E lements From left to right: Professors Nanba (Fukushima University), Kaneko (Kyushu University), and Utsunomiya (Kyushu University), Mr. Suenaga (Ohkuma municipal government), Mr. Saito (Ohkuma municipal government), and Mr. Iwata (Kyushu University). The photo was taken by Professor Kawatsu in front of the main building of the Ohkuma municipal government, located within the restricted area. Figure 4 Finally, I express my greatest appreciation to Professors Nanba and Kawatsu of Fukushima University and to Messrs. Saito and Suenaga of the Ohkuma municipal government for transporting us to the area near the Fukushima power plant, as they exposed themselves to the same radiation dose as we did (Fig. 4). 172 J une 2012 A hypothetical question of course! But even if we could ask them, the SPECTRO MS makes the question redundant. This novel ICP mass spectrometer analyzes the entire relevant mass spectrum completely simultaneously; faster and more precisely to boot. SPECTRO MS - Double focusing sector field mass spectrometer with newly developed ion optic and pioneering detector technology - Simultaneous measurement of more than 75 elements with 210 isotopes for improved precision together with highest sample throughput - Fast fingerprinting, internal standardization in real time and the measurement of transient signals, isotope ratios and isotope dilution - Compatible with EPA, FDA, CLP and 21 CFR Part 11 as well as additional standards and guidelines Do You Think Ions Like Queuing Up? Find out more about the new SPECTRO MS at [email protected] Tel +49.2821.892-2102 http://ms.spectro.com SPECTRO MS: A New Era in ICP Mass Spectrometry 2011 CosmoElements The Enduring Legacy of the Allende Meteorite Steven B. Simon* The Earth is a very geologically active planet. Rocks are recycled through erosion, burial, and melting, which makes it difficult to learn about the origin of the Solar System by analyzing samples from Earth. In order to understand the earliest processes in the Solar System, we have to study meteorites—specifically, chondrites, which are over 4.5 billion years old and con tain the first solids to have formed in the Solar System. The Solar System formed from a cloud of gas and dust called the solar nebula, and its bulk chemical composition is known because about 99.8% of the mass of the solar nebula ended up in the Sun and we know the Sun’s composition from spectroscopic analysis of its light. From this composition, the sequence of minerals that should form by gas-to-solid condensation at high temperatures from the cooling solar nebula can be predicted. These very minerals, Ca–Al-rich oxides and silicates, can be found in refractory inclusions within carbonaceous chondrites. However, this was scarcely appreciated until the fall of the Allende meteorite in Mexico on February 8, 1969, because until then very little material had been available for study. Within a few months of the fall, two tons of specimens of the Allende meteorite were recovered from a 50 km long strewnfield, and many specimens were distributed for study. Preliminary reports were published within a year of the fall (e.g. King et al. 1969), and an extensive report on the fall, recovery, and classification was published within two years (Clarke et al. 1970). A view of a slab surface of Allende (Fig. 1) shows that, typical of CV-type carbonaceous chondrites, the meteorite is a jumble of refractory Ca–Al-rich inclusions (CAIs) and round objects called chondrules set in a dark, carbonaceous matrix. The chon drules and inclusions are not related to each other. Before becoming enclosed in the matrix, they formed individually as discrete objects in space. They have been preserved since the formation of the Solar System because they were incorporated into a parent body that was too small to have a geologically active surface. View of a sawn and polished slice of the Allende meteorite, showing numerous white Ca–Al-rich refractory inclusions (CAIs) and round chondrules in a dark, carbonaceous matrix. Field of view is about 8 cm across. Photo by Linda Welzenbach, courtesy of the Smithsonian Institution Figure 1 terrestrial fractionation line (Clayton et al. 1977). Allende’s inclusions (e .g. Fig. 2) were found to have an average enrichment factor among the refractory elements of 17.5 relative to bulk Solar System abundances (Grossman et al. 1977), strong evidence for their formation at high temperatures. The first refractory inclusions shown to have excess 26Mg due to the decay of 26Al (Gray and Compston 1974; Lee et al. 1976) were from Allende, and the first studies of the distinctive rim layer sequences on refractory inclusions (Wark and Lovering 1977), indicative of pro cessing in the nebula after they formed and before they were enclosed in the meteorite matrix, were also based on Allende samples. In addition, the first report of trivalent Ti in a refractory inclusion was based on the analysis of Ti–Al-rich pyroxene from Allende by Dowty and Clark (1973), who termed the phase “fas saite”; the presence of Ti3+ is strong evidence for formation under very oxygen-poor (reducing) conditions, as would be expected for a system of solar composition. Note that all of these major breakthroughs in the understanding of refractory inclusions occurred within ten years of the fall of the Allende meteorite. In following years it was shown that CAIs were not simply condensates but that some had been molten at least once (MacPherson and Grossman 1981; MacPherson et al. 1984) or even twice (Simon et al. 2005). The study of At a time when geochemical laboratories were being modernized and equipped in anticipa tion of the first return of lunar samples, sci entists suddenly had several tons of unique, extraterrestrial material to study. Allende provided the material for several important advances, including a classification scheme for refractory inclusions in Type 3 carbona ceous chondrites (Grossman 1975), which is still in use today, and the discovery that the oxygen isotope compositions of refractory inclusions are 16O-rich and do not fall on the * Department of the Geophysical Sciences, The University of Chicago 5734 S. Ellis Ave., Chicago, IL 60637, USA E-mail: [email protected] E lements Two views of one of the most-studied refractory inclusions from Allende, Type B1 inclusion TS34. Transmitted light, crossed polars (left), backscattered electron image (right). Lines point to the same melilite and fassaite grains in both views. Figure 2 Cont’d on page 176 174 J une 2012 A member of Come s e Goldsch e us at midt 2 Montre 012, al Stand 3 11 Providing for the world’s leading Earth Scientists Isoprime is solely dedicated to stable isotope ratio mass spectrometry and provides market leading instruments to the world’s leading earth scientists. Utilising our comprehensive suite of high performance preparation systems and with complete support from our experienced IRMS scientists and engineers, our customers are conducting exceptional research to further our understanding of the intricate mechanisms that keep our planet alive. To find out how exploiting Earth’s stable isotopes can push your research even further, visit www.isoprime.co.uk CosmoElements Allende meteorite Cont’d from page 174 THE NEW TISSINT METEORITE Allende still results in discoveries; through work done at high magni fication, nine new minerals have been found in Allende by C. Ma and coworkers since 2007 (Table 1). Allende was also the source of the first presolar diamonds to be identified (Lewis et al. 1987). It’s a well-known secret that meteorites fall to Earth all the time, but rarely does such an event happen in a place where people see the fireball and then find space rocks on the ground. July 18, 2011, marks a remarkable event, rare even among meteorite falls—for only the fifth time, a piece of Mars was witnessed to fall to Earth. The fireball and associated sonic booms that marked the rock’s atmospheric entry occurred in Morocco, a fortuitous coincidence for two reasons: many people in Morocco are experienced meteorite hunters, and the arid environment makes it one of the best places on Earth for the preserva tion of meteorites. Beginning in October, nomads began to find fresh, fusion-crusted stones in a remote area about 48 km from Tissint vil lage, and over 10 kg have been recovered thus far. The meteorite was classified as a shergottite by Tony Irving and Scott Kuehner (University of Washington, Seattle), and its name, Tissint, was approved by the Nomenclature Committee on January 17, 2012 (search “Tissint” at www.lpi.usra.edu/meteor/index.php). Table 1 Minerals discovered in Allende since 2007 Mineral name Formula Allendeite Sc4Zr3O12 Hexamolybdenum Mo,Ru,Fe alloy Monipite MoNiP Tistarite Ti2O3 Davisite CaScAlSiO6 Grossmanite CaTi3+AlSiO6 Hibonite-(Fe) (Fe,Mg)Al12O19 Panguite (Ti,Al,Sc,Mg,Zr,Ca)1.8O3 Kangite (Sc,Ti,Al,Zr,Mg,Ca,[])2O3 The research that has been done on Allende is far too vast and varied to be adequately summarized in this brief article. Suffice it to say that this meteorite has been a valuable source of pieces to the puzzle of the formation of the Solar System, and it will continue to be one for the foreseeable future. REFERENCES Clarke RS Jr, Jarosewich E, Mason B, Nelen J, Gomez M, Hyde JR (1970) The Allende, Mexico meteorite shower. Smithsonian Contributions to the Earth Sciences 5: 1-53 Clayton RN, Onuma N, Grossman L, Mayeda TK (1977) Distribution of the pre-solar component in Allende and other carbonaceous chondrites. Earth and Planetary Science Letters 34: 209-224 Dowty E, Clark JR (1973) Crystal structure refinement and optical properties of a Ti3+ fassaite from the Allende meteorite. American Mineralogist 58: 230-242 Gray CM, Compston W (1974) Excess 251: 495-497 26Mg in the Allende meteorite. Nature Grossman L (1975) Petrography and mineral chemistry of Ca-rich inclusions in the Allende meteorite. Geochimica et Cosmochimica Acta 39: 433-454 58 g Tissint specimen from the University of Alberta Meteorite Collection, Department of Earth and Atmospheric Sciences, Edmonton, Canada Grossman L, Ganapathy R, Davis AM (1977) Trace elements in the Allende meteorite–III. Coarse-grained inclusions revisited. Geochimica et Cosmochimica Acta 41: 1647-1664 King EA Jr, Schonfeld E, Richardson KA, Eldridge JS (1969) Meteorite fall at Pueblito de Allende, Chihuahua, Mexico: Preliminary information. Science 163: 928-929 Lee T, Papanastassiou DA, Wasserburg GJ (1976) Demonstration of 26Mg excess in Allende and evidence for 26Al. Geophysical Research Letters 3: 109-112 Lewis RS, Ming T, Wacker JF, Anders E, Steel E (1987) Interstellar diamonds in meteorites. Nature 326: 160-162 MacPherson GJ, Boss A (2011) Cosmochemical evidence for astrophysical pro cesses during the formation of our solar system. Proceedings of the National Academy of Sciences 108: 19152-19158 MacPherson GJ, Grossman L (1981) A once-molten, coarse-grained, Ca-rich inclusion in Allende. Earth and Planetary Science Letters 52: 16-24 MacPherson GJ, Paque JM, Stolper E, Grossman L (1984) The origin and signif icance of reverse zoning in melilite from Allende Type B inclusions. Journal of Geology 92: 289-305 Simon SB, Grossman L, Davis AM (2005) A unique type B inclusion from Allende with evidence for multiple stages of melting. Meteoritics & Planetary Science 40: 461-475 As the freshest fall of a Martian meteorite since 1962, Tissint is currently the subject of intense scientific scrutiny: it is a typical Martian basalt, consisting of olivine phenocrysts in a pyroxene–plagioclase ground mass, with accessory oxides, sulfides, and phosphates. Many (if not all) specimens are crosscut by glassy veins and pockets that formed as a result of shock during an impact on Mars, likely the impact that lofted the meteoroid from the surface of Mars. The shock melt pockets are similar to those in another famous Martian meteorite, Elephant Moraine 79001, in which trapped Martian atmosphere was found, pro viding the crucial piece of evidence for a Martian origin. But beyond the insights that will be gained into Martian igneous and shock pro cesses, Tissint represents a unique opportunity to test curation and handling methods for future sample return (from Mars or elsewhere). Analyses to determine what contaminants the meteorite picked up in the Moroccan desert are underway, in order to establish a baseline to test whether Tissint preserves any Martian organic matter. Regardless of the outcome, Tissint is sure to become one of the most studied Martian meteorites—at least until the next one falls! Wark DA, Lovering JF (1977) Marker events in the early evolution of the solar system: Evidence from rims on Ca-Al-rich inclusions in carbonaceous chon drites. Proceedings of the 8th Lunar Science Conference: 95-112 E lements Chris Herd, University of Alberta 176 J une 2012 Irène Korsakissok did her PhD thesis in the field of air-quality modeling. Her thesis dealt with mul tiscale modeling and uncertainties in atmospheric dispersion models. Two years ago, she joined the Institut de Radioprotection et de Sûreté Nucléaire (IRSN), where she is in charge of the local-scale atmospheric dispersion model used for operational purposes. She also works on local-scale meteoro logical preprocessors and model uncertainties. Joonhong Ahn received doctoral degrees from the University of California, Berkeley (PhD, 1988) and the University of Tokyo (D Eng, 1989). He joined the faculty of UC Berkeley in 1995. His research deals with the performance assessment of advanced nuclear fuel cycles and the geological disposal of radioactive wastes. He led numerous joint research projects with institutions in Japan, South Korea, and the United States, and with the IAEA. He is currently conducting a joint research project with the Japan Atomic Energy Agency involving the analysis of criticality safety for the geological disposal of molten nuclear fuel in the Fukushima reactors. Edward D. Blandford is a Stanton Nuclear Security Fellow at the Center for International Security and Cooperation at Stanford University and an adjunct research assistant professor in the Chemical and Nuclear Engineering Department at the University of New Mexico. His research interests include nuclear reactor thermal hydraulics, probabilistic risk assessment, performance-based regulation, and best-estimate code verification and validation. He received his MS (2008) and his PhD (2010) in nuclear engineering from the University of California, Berkeley. Prior to his graduate studies, he worked at the Electric Power Research Institute overseeing steam generator thermal hydraulics research and development activities. Rodney C. Ewing is the Edward H. Kraus Distinguished University Professor in the Department of Earth & Environmental Sciences at the University of Michigan. He is also a professor in the Departments of Nuclear Engineering & Radiological Sciences and Materials Science & Engineering. Ewing’s research focuses on radiation effects in minerals, ion beam modification of mate rials, the crystal chemistry of actinide minerals and compounds, and the “back-end” of the nuclear fuel cycle. He is the past president of the Mineralogical Society of America and the International Union of Materials Research Societies. He was recently appointed by President Obama to serve on the Nuclear Waste Technical Review Board. Bernd Grambow is a Professor of Excellence at the École des Mines de Nantes, France, where he holds the chair on nuclear waste disposal. He is head of the Subatech laboratory on high-energy nuclear physics, reactor physics and radiochem istry, a joint research unit at the IN2P3/CNRS, the Ecole des Mines of Nantes, and the University of Nantes. He is also director of the new French national CNRS-academic/industrial research network NEEDS (nuclear: environment, energy, waste, society). His scientific expertise is in radio chemistry, nuclear waste disposal science, geochemical modeling, radio nuclide migration in the environment, chemical thermodynamics, and the dynamics of solid/liquid interfaces. Hiroo Kanamori is the John E. and Hazel S. Smits Professor of Geophysics, Emeritus at the California Institute of Technology. He received his PhD in 1964 at Tokyo University. He works on the physics of earthquakes and its application to hazard miti gation through real-time technology. E lements Thorne Lay is Distinguished Professor of Earth and Planetary Sciences at the University of California, Santa Cruz. He received his PhD at the California Institute of Technology in 1983. He studies earthquake rupture processes, deep-Earth structure, and seismic wave propagation. Yukio Masumoto is a principal scientist at the Japan Agency for Marine-Earth Science and Technology in Yokohama, Japan. He received a master’s degree at Kyushu University and a PhD from the University of Tokyo on climate variations and large-scale air–sea interactions in the western tropical Pacific Ocean. After working at the University of Tokyo, he moved to the Japan Agency for Marine-Earth Science and Technology in 2010. His current research topics include climate variation modes in the tropics and their influ ences on global and regional climate systems, basin-scale and regional ocean circulation, and the prediction and predictability of these ocean/ climate variations. Anne Mathieu has been a research engineer at the IRSN for six years. After a PhD on the dynamics of the atmospheric boundary layer, she became an assistant professor at the Université Saint-Quentin en Yvelines. She joined the IRSN to work on localand large-scale atmospheric dispersion during acci dental releases. Her current work focuses on the development of methods for the reconstruction of accidental releases using environmental observations. Takashi Murakami is a professor in the Department of Earth and Planetary Science at the University of Tokyo. His current research focuses on mineral– water–atmosphere interactions, including atmo spheric evolution in the Precambrian, dissolution and weathering of minerals, and the formation and transformation of nanominerals and their effects on element transport. He has worked for the Japan Atomic Energy Research Institute, the University of New Mexico, the Australian Nuclear Science and Technology Organisation, and Ehime University. He is the past editor-in-chief of the Journal of Mineralogical and Petrological Sciences and is a vice-president of the Japan Association of Mineralogical Sciences. 177 J une 2012 Yasumasa Miyazawa is a senior scientist at the Japan Agency for Marine-Earth Science and Technology in Yokohama, Japan. He received a master’s degree at Kyoto University and a PhD from the University of Tokyo on the predictability of the Kuroshio variations and mesoscale eddy activi ties around Japan. After working with a private company, he moved to the Japan Agency for Marine-Earth Science and Technology in 2004. His current research topics include numerical modeling of tide–wave–current interactions in the ocean, the implementation of data assimilation in numerical ocean models, and the utilization of simulated data products in societal applications. Christophe Poinssot is the director of the RadioChemistry & Processes Department in the French Nuclear and Alternative Energies Commission (CEA). He was also appointed as a professor in nuclear chemistry at the French National Institute of Nuclear Science and Techniques and, from 2012, as a visiting professor in actinide materials at the University of Sheffield. After his PhD in material science from the Ecole Normale Supérieure of Paris, he joined CEA Saclay in 1999, where he launched and coordi nated the research program on the long-term storage and disposal evo lution of spent fuel. His main interests are the improvement of nuclear energy sustainability and the geochemistry of uranium minerals. Denis Quélo has been a research engineer at the IRSN for five years. After a PhD in data assimilation of atmospheric chemistry, he joined the IRSN to develop an operational, large-scale atmosphericdispersion model. His current work centers on impact studies related to accidental releases from nuclear facilities. Jeroen Ritsema is the Henry N. Pollack Associate Professor at the University of Michigan. He received his PhD in 1995 at the University of California, Santa Cruz. His research is focused on the seismic imaging of Earth’s interior, computational seis mology, and Earth dynamics. Yoshio Takahashi is a professor of environmental geochemistry at Hiroshima University, Japan. In 1997, he received his PhD in environmental radio chemistry from the University of Tokyo. He then became a research associate in the Department of Earth and Planetary Systems Science at Hiroshima University and became a full professor in that department in 2009. His research interest is pri marily in speciation studies applied to environmental chemistry and geochemistry to understand the fates of contaminants, geochemical cycles, and the evolution of the Earth. He is currently participating in a project on the migration of radionuclides emitted during the accident at the Fukushima Daiichi nuclear power plant. Daisuke Tsumune is a senior research scientist at the Central Research Institute of the Electric Power Industry, Japan. He received a master’s degree and a PhD from Tohoku University, the latter on oce anic transport processes of artificial radionuclides originating from global fallout due to atmospheric weapons testing. His current research interests include tracer distribution and the transport mech anism of tracers, such as carbon, in the ocean; iron as a micronutrient; and artificial radionuclides originating from global fallout and from the Fukushima Daiichi accident. His goal is a better understanding of the role of oceans on climate and an assessment of oceanic pollution at the global scale. Naohiro Yoshida is a professor in the Department of Environmental Chemistry and Engineering, a v ice- d irec tor of t he Inter-Depa r t menta l Organization for Environment and Energy, and an assistant vice-president at the Tokyo Institute of Technology. He is also the president of the Geochemical Society of Japan. He introduced the use of isotopomers, isotopic substituted molecules, as powerful tracers in the study of the cycles of materials of biogeo chemical interest from the early Earth to present and future global change, life and biomedical diagnosis. He is currently involved in an intensive survey of radionuclide dispersal from the Fukushima Daiichi nuclear power plant. D2 PHASER XRD wherever you need it www.bruker.com/d2phaser E lements 178 J une 2012 P u blicity WDXRF as an Investigative and Analytical Tool Using Small Spot/Mapping and UniQuant™ Process control, failure troubleshooting, and in situ identification are all now pos sible using a standard laboratory wavelength dispersive X-ray fluorescence (WDXRF) with the advent of small spot/mapping capability. Narrowing a sample surface-analysis area down to 0.5 mm to obtain the chemistry of an inclusion or irregularity has helped many a scientist solve problems that could only be solved through more complex techniques previously. The test results provided below were performed using the Thermo Scientific ARL PERFORM’X WDXRF. A surface stain or inclusion on a material can quickly be targeted and elementally defined, showing where it originated in the process. Minerals can be both identified and chemically imaged in 2- and 3-dimensional displays. Homogeneity testing of a coating over a large or small area, forensics testing on minute samples or scattered residue… the list goes on and on. Elemental distribution for the examples mentioned above is easily displayed in an intensity format, and normally this would provide the required answer to the common question, “What is it?” But if concentration resolution is required, the operator may run into some trouble. How do you calibrate for a stain? What reference materials are readily available for a metal inclusion in a wire? How do you quantify components on a circuit board without removing them? This is where the second step to total small-spot analysis comes into play—UniQuant. Small Spot/Mapping Description Small-spot analysis is a rather easy concept to describe. The first step is for the XRF unit to image the sample surface. From this image it is possible, using the mouse, to click on areas of interest for analysis. For map ping, the operator selects one of a number of “shapes” and enlarges or contracts it to a size that best contains the area of interest. The sample is excited through the use of a primary X-ray beam. The secondary X-rays emitted are collimated through a 0.5 mm aperture. Small-spot analysis is a selection of one or more unique and individual points on a sample surface, each one producing a singular analytical result, whereas mapping is the joining of these individual points into a unified pattern to produce a 2- or 3-dimen sional presentation along with intensity/con centration results for the selected area. UniQuant Description UniQuant uses the original factory cali bration to determine concentrations in completely unknown samples. UniQuant is unique in its method of intensity mea surements. Unlike other semiquantitative software programs, UniQuant uses a method E lements known as peak hop ping, instead of a con tinuous scan technique, to acquire the intensi ties for all measurable elements. The procedure of peak hopping allows for faster analysis by not wasting measurement time on any location where an element peak will not be found. UniQuant will measure every theoretical 2-theta angle for each element, including alternative lines for some heavier elements and back ground positions. By focusing the elemental counting times on peak locations only, UniQuant is able to provide more accurate results and lower detection limits com pared to other scan-based semiquantitative methods. An interesting feature is that the counting time for each analytical line can be defined separately depending on the main interest of the analyst. Mapping Example: Mapped Elements in a Geological Sample Mapping imaging is a helpful way of better understanding a problem. The 2-D images can be viewed as individual element dis tributions or overlaid to give a more com prehensive correlation of the elements as a group. The 3-D images are single-element displays and can be rotated for a full 360degree visualization or even a birds-eye view. While most maps are collected as intensity-only images, empirical calibra tions can also be used to fully quantify the result. Geological samples can offer the most interesting and informative mapping images. In this example, one can see that the material is mostly Mn due to its uni form base and strong intensity response, but other elements are also present, with a large concentration of Si off to one side and the 179 possible presence of a vein containing Ca, S, and P running through the center of the sampled area. Conclusion The examples presented here are only a fraction of the applications that many ana lysts are using today. The investigative capa bilities of WDXRF have been shown to save thousands of dollars in process monitoring. With UniQuant, small samples are no longer a hindrance due to their size and a lack of calibrating materials. It is now possible to review coating thickness across a surface without the need of specialized instrumenta tion. Quantification using empirical calibra tions on undersized or irregularly shaped materials is possible through the use of a standard laboratory WDXRF, even in situ. Mapping/small-spot analysis brings many benefits especially when combined with a standardless routine such as UniQuant. Al Martin, Thermo Fisher Scientific Senior XRF Applications Specialist [email protected] Read the full article on www.thermoscientific.com/mapping Learn more on Thermo Scientific X-ray products: www.thermoscientific.com/xray Learn more on Thermo Scientific ARL PERFORM’X: www.thermoscientific.com/performx To be informed about our latest developments and special offers, subscribe to our MATERIALS ANALYST e-newsletter at www.thermoscientific.com/siregister J une 2012 Inc. Image courtesy of Dr Hanna Horsch and Roland Schmidt, Hazen Research, Mapping the world ... one micron at a time ultrafast contextural quantitative SEM-based Petrographic Analyzers www.fei-natural-resources.com Uranium ore from the Schwarzwalder Mine, in Ralston Buttes district, Jefferson County, Colorado, USA, mapped by QEMSCAN®. The image shows an atoll-like texture with veins mineralized by uranium-thorium (red), and lead (green) bearing phases. Fukushima Daiichi More Than One Year Later Rodney C. Ewing1 and Takashi Murakami2 1811-5209/12/0008-0181$2.50 DOI: 10.2113/gselements.8.3.181 T his thematic issue of Elements describes the events at the Fukushima Daiichi nuclear power plant on March 11, 2011, and the aftermath. Keywords : Tohoku earthquake, tsunami, nuclear power plant, meltdown, radioactivity In the wake of a rare 9.0-magnitude earthquake, a devastating tsunami, and the partial meltdown of the cores of the three nuclear reactors then operating, there were some 300,000 refugees displaced from their homes, fully onethird of whom were in the 20 km radius evacuation zone around the Fukushima Daiichi nuclear power plant. The three nuclear reactors have been stabilized and cooling reestablished, but huge volumes of water, contaminated by radioactivity, require treatment and disposal. In the absence of domestic sources of fossil fuels, Japan has relied on substantial imports of coal and natural gas to generate electricity. Prior to March 11, the 54 operating nuclear reactors provided approximately one-quarter of Japan’s electricity. Following the events at Fukushima Daiichi, more than half of Japan’s nuclear reactors were shut down due to safety or service concerns, and all were subjected to government-mandated stress tests. However, it has proven difficult, due to public and political objections, to bring the reactors back on line, and in May 2012, the last operating nuclear reactor, located at the Tomari plant in northern Japan, was shut down for a scheduled inspection. For the first time since 1966, Japan is not producing electricity from nuclear power plants as it enters a period of peak demand for electricity. There has also been a major review of the wisdom and cost of the Japanese closed fuel cycle, which embraces reprocessing, and it now appears that direct disposal of spent fuel in a geologic repository may be considerably cheaper. The great Tohoku earthquake has certainly shifted the ground under the future of nuclear energy in Japan, and the seismic waves of change have spread across the globe. This issue of Elements arrives on your desk some months past the first-year anniversary, March 11, a date of thoughtful remembrance for those who lost their lives. The anniversary was also the occasion for many magazine and journal “special” issues that looked back at the details of the accident at the nuclear power plant. We have moved this issue of Elements beyond the clatter and noise of the first anniversary, because in this issue we summarize the impact of the accident on the environment, and this impact will stretch far into the future, well beyond many anniversaries. This issue begins with two papers that set the stage. The first is on the natural disaster of the earthquake and tsunami, and the second is on the technological disaster of the meltdowns at the three nuclear reactors operating at the time. The next four articles deal successively with the dispersion of radioactivity into the atmosphere, the contamination of the surrounding countryside, the release of radioactivity to the ocean, and finally, the interactions of the damaged and melted fuel with water and the long-term release of radioactivity. We have also added an expanded Perspectives section, in which a diverse group of scientists and engineers with some connection to the event and its aftermath discuss the impact of this accident on the future of nuclear power. Two “boxes” provide basic information on the properties of spent fuel (Box 1) and units of radioactivity (Box 2). As we reviewed the papers for this issue, one word, “accident,” caused us to pause and wonder if “accident” was the term for this “Black Swan”* event, a rare, unanticipated event of high consequence. In what sense was the natural disaster and catastrophic failure at the Fukushima Daiichi nuclear power station an “accident”? Certainly, it was the forces of nature, the one-two punch of an earthquake and tsunami, that damaged the nuclear power plant, leading to loss of cooling and the subsequent meltdown of the nuclear reactors. But was this an accident? An accident is an “unexpected” event or “unfortunate occurrence or mishap.” Certainly, the tsunami was “unexpected” and “unfortunate,” but was it just bad luck that the seawall was too low or that the risk analysis failed to anticipate the size of a potential tsunami? Who bears the responsibility for failing to anticipate the scale and impact of this natural disaster? We now know that a tsunami of such size is rare, but it should not have been unanticipated. In fact, Japanese geoscientists warned of such a possibility in a paper published in 2001 in the Journal of Natural Disaster Science, and they pointed to a similar tsunami event—the Jogan tsunami of 869—that inundated the low-lying coast of northeastern Japan. We do not think we should find any solace in calling the March 11 event an accident, because in doing so, we relieve scientists and engineers of their responsibility to raise the appropriate warnings and absolve regulatory agencies for not listening to those warnings. A better word for the event of March 11 one year ago is “tragedy,” as in a Greek drama—a drama in which our hubris leads to a loss of contact with reality and to overconfidence in our competence and capabilities. A less confident person would have built a higher seawall. 1 Department of Earth & Environmental Sciences University of Michigan Ann Arbor, MI 48109-1005, USA E-mail: [email protected] 2 Department of Earth and Planetary Science The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan E-mail: [email protected] E lements , V ol . 8, pp. 181–182 * Nassim Nicholas Taleb (2010) The Black Swan – The Impact of the Highly Improbable, 2nd Edition. Random House, 444 pages 181 J une 2012 Box 1 Radionuclide Release during a Nuclear Accident Rodney C. Ewing The amount of released radioactivity during a nuclear accident depends on the type of nuclear fuel, the burnup or the extent to which the 235U has fissioned, the chemical properties of the radionuclide-forming compounds in the fuel, and the maximum temperatures reached during the accident. The melting of the fuel in an operating or recently shut down nuclear reactor is due to a failure in the ability to cool the reactor core. Immediately after removal from a reactor core, fuel still generates several megawatts of power per tonne of fuel. Even after the fission process in the core is stopped by the insertion of neutron-absorbing control rods, radioactive decay of fission product elements continues to generate substantial amounts of heat. The decay heat can drive the temperature to well above the melting points of the metallic zircaloy cladding and the UO2 fuel pellets, creating a corium magma. At the Fukushima Daiichi nuclear power plant, the fuel was dominantly UO2 enriched to about 3 to 5% in the fissile nuclide 235U. There was a limited amount of mixedoxide fuel (MOX), which is a mixture of UO2 fuel and ~6% PuO2 . The 32 MOX fuel assemblies in Unit 3 represented only ~6% of its core loading. In the reactor, the fission of 235U and 239Pu leads to a bimodal distribution of hundreds of fission product elements, e.g. 90 Sr and 137Cs, from the “split” uranium atoms. In contrast, the more stable 238U captures neutrons and, with subsequent decay, creates heavier, transuranium elements, such as 239Pu, 239Np, and minor amounts of Am and Cm isotopes. The concentration of plutonium in UO2 fuel typically reaches a value of approximately 1% Pu for average burnups. Thus, most of the Pu present at the Fukushima Daiichi plant was in the normal UO2 fuel in the reactors and spent fuel storage pools, as compared with the amount of Pu in MOX. UO2 structure. The distribution of the radionuclides is not uniform because of the steep thermal gradient (~1000 °C) between the center of the fuel pellet and its edge, a distance of some 5 mm. The volatile elements are driven down the thermal gradient to grain boundaries and the “gap” between the fuel cladding and the fuel pellet. Noble gases form bubbles that decorate the surfaces of the grain boundaries and occupy the cladding gap. When there is a breach of the fuel cladding at high temperature, there is an instantaneous release of the noble gases (Xe and Kr) and more volatile elements (I and Cs). The transuranium elements, mainly Pu, are released much more slowly, because they are incorporated into the fuel. However the distribution of Pu is not uniform within the fuel pellet, the Pu being more concentrated at the edge of the pellet due to enhanced neutron capture in this region. Based on experiments and the examination of damaged core material from nuclear accidents, such as the Three Mile Island meltdown, the early release of the noble gases Xe and Kr is high (~90%), of I is high (50 to 100 %), of Cs is moderate (10 to 50%), of Sr and Ba is much lower (<10%), and of the transuranium elements very low (<0.01%). Of course, a catastrophic explosion can lead to substantially higher releases due to atmospheric distribution of particulate fuel. In the case of Chernobyl, these “hot particles” spread across Europe. The hydrogen explosions at Fukushima Daiichi apparently did not release particles of the fuel. During a nuclear accident and immediately afterwards, the radionuclides of greatest interest are the shortlived isotopes of Xe, Kr, I, and Cs. However, the much longer-term environmental impact and cumulative human exposure will depend on the fate of longer-lived nuclides, such as 129I and 135Cs, long after the decay of shorter-lived 131I and 137Cs. Box 2 fission 235U + 1no ---> 2–3 neutrons (1–2 MeV) + energy neutron capture and subsequent decay 238U + 1no ----> 239U ----> 239Np ----> 239Pu Although hundreds of radioactive isotopes are created by the fission process, most have extremely short half-lives. The isotopes of greatest interest are those that are most quickly released and have half-lives of days to years, as they will be responsible for the immediate doses to surrounding populations: 131I (half-life = 8 days), 134Cs (2 years), 137Cs (30 years), and 90 Sr (29 years). Longer-term environmental effects will be determined by radionuclides with much longer half-lives, but with correspondingly lower specific activities (the specific activity is inversely proportional to the half-life): 129I (15.7 million years) and 135 Cs (2.3 million years). Other isotopes and their ratios provide the forensic evidence of what is happening in the core of the reactor. The 134Cs/137Cs ratio can be used to estimate the fuel burnup. Other radionuclides, such as selected isotopes of the noble gases Xe and Kr with very short half-lives of a few days or, in the case of 85Kr, 11 years, are monitored carefully because they provide information on the state of the reactor core, such as whether recriticality has occurred. The fission product gases, such as Xe and Kr, and more volatile elements, such as Cs and I, provide a measure of the extent of the early release of radioactivity. The chemical form of the fission product elements in the fuel will determine the ease and extent of their release. The fission product elements may be grouped into four broad types of materials: volatile elements, metallic alloys, oxide precipitates, and radionuclides incorporated into the E lements Units of Radioactivity, dose and regulatory limits Unit* Symbol Conversion factors Becquerel (SI) Bq 1 disintegration/s = 2.7 × 10 -11 Ci Curie Ci 3.7 × 1010 disintegrations/s Gray (SI) Gy 1 J/kg = 100 rads Rad rad 0.01 Gy = 100 erg/g Sievert (SI) Sv Rem rem 1 J/kg = 100 rem 0.01 Sv U.S. regulations (National Research Council 1995) Indoor radon 4 pCi/L (= 0.1 Bq/L) High-level nuclear waste standard 15 mrem/y (= 0.15 mSv/y) Emissions standards for air pollutants 10 mrem/y (= 0.1 mSv/y) Water protection standards 4 mrem/y (0.04 mSv/y) Average amount of ionizing radiation exposure to a typical person: 3 to 3.5 mSv/y (over half of which is from radon exposure) Gray is a unit (J/kg) of absorbed dose. Sievert is a unit of equivalent dose that considers the type and effect of the radiation exposure. Equivalent dose equals absorbed dose times Q, a quality factor (e.g. Q = 1 for X-rays and Q = 20 for alpha particles). Unit prefixes: kilo (k) = 103; milli (m) = 10 -3; pico (p) = 10 -12 * International units are designated SI Bibliography (in order of increasing detail) Bruno J, Ewing RC (2006) Spent nuclear fuel. Elements 2: 343-349 Burns PC, Ewing RC, Navrotsky A (2012) Nuclear fuel in a reactor accident. Science 335: 1184-1188 Lewis BJ, Thompson WT, Iglesias FC (2012) Fission product chemistry in oxide fuels. In: Comprehensive Nuclear Materials, volume 2. Elsevier Ltd., Amsterdam, pp 515-546 182 J une 2012 The 2011 Tohoku Earthquake The Tohoku earthquake in Iwate © Yoshiyuki K aneko | D reamstime.com Jeroen Ritsema1, Thorne Lay2, and Hiroo Kanamori3 1811-5209/12/0008-0183$2.50 DOI: 10.2113/gselements.8.3.183 R apid seismological analyses, carried out within minutes of the March 11, 2011, Tohoku earthquake, were crucial in providing an earthquake ground shaking and tsunami early warning and in hastening the evacuation of the population along Japan’s northeastern coast. By 20 to 30 minutes after fault rupture began, these analyses had established that the event had a moment magnitude of M w = 9 and involved shallow thrust faulting on the plate boundary megathrust. Preparation for future large earthquakes on megathrusts in Japan and elsewhere should include onshore and offshore geodetic monitoring of strain accumulation, implementation of rapid earthquake and tsunami warning systems, and public training and education for shaking and tsunami response. was prepared for such a large tsunami, and few warnings were issued, even for regions where the tsunami did not arrive until several hours after the earthquake. In contrast, seismological analysis of the 2011 Tohoku event commenced only seconds after the first ground vibrations were recorded at stations in Japan and around the world. While the rupture was still expanding (it took about 150 seconds for fault motions to complete), preliminary seismic wave analyses in an early Keywords : Japan earthquake, megathrust, tsunami, earthquake early warning, warning system had established rupture process that a great earthquake of magnitude ~8 had occurred offshore from Honshu. Much of the wellIntroduction prepared population began to evacuate after the initial The March 11, 2011, earthquake offshore from the Tohoku tsunami warnings were issued. Predictions of potential region of Japan ruptured a 300 km long by 200 km wide portion of the subduction zone megathrust fault at the tsunami run-up height (the maximum onshore water height) along the coast ranged up to 6 m, much lower than boundary of the Pacific plate (Fig. 1). It was the fourththe actual values of up to 40 m, but the early tsunami largest recorded earthquake. The seafloor movement caused warning broadcasts likely saved many lives. by the faulting generated a huge tsunami that devastated communities along the entire northeastern coast of Japan. Unprecedented video footage documented the imposing power of the ocean waves as they overtopped tsunami walls and coastal barriers, sweeping away entire towns. Flooding of the Fukushima Daiichi nuclear power plant led to a nuclear crisis that is still unfolding. The Tohoku earthquake and tsunami claimed some 20,000 lives. Many more lost their homes and livelihood, and economic losses are expected to reach $300 billion. While devastating, the Tohoku earthquake resulted in societal impacts and a scientific response that were much different from those of the 2004 Sumatra-Andaman earthquake. The Sumatra-Andaman earthquake had a moment magnitude, Mw, of 9.2 and was due to the rupture of the subduction zone megathrust in southeastern Asia. It generated a massive tsunami that struck Sumatra, Sri Lanka, India, and Thailand, taking over ten times more lives than the Tohoku tsunami. No country around the Indian Ocean 1 Department of Earth and Environmental Sciences University of Michigan Ann Arbor, MI 48109, USA E-mail: [email protected] 2 Department of Earth and Planetary Sciences University of California Santa Cruz Santa Cruz, CA 95064, USA E-mail: [email protected] 3 Division of Geological and Planetary Sciences California Institute of Technology, Pasadena, CA 91107, USA E-mail: [email protected] E lements , V ol . 8, pp. 183–188 By the time the tsunami hit the shores of northern Honshu about 15–30 minutes after the faulting began, the earthquake size had been estimated at Mw = 8.8 by the National Oceanographic and Atmospheric Administration (NOAA) Pacific Tsunami Warning Center (PTWC) and Mw = 9.0 by the U.S. Geological Survey (USGS) National Earthquake Information Center (NEIC) from analysis of seismic recordings in the western Pacific region. The fault geometry solutions clearly indicated that the Tohoku earthquake had occurred on the plate boundary megathrust and that a potentially devastating tsunami had likely formed. On the basis of rapid earthquake quantification, the PTWC issued accurate warnings for Pacific nations to be alert for significant tsunami waves over the next 24 hours. The rapid earthquake analyses in Japan were enabled by the substantial investments in infrastructure for earthquake monitoring that followed the destructive 1995 Kobe earthquake. An extensive network of recently deployed geophysical instruments recorded the Tohoku earthquake both onshore and offshore. This network includes 1200 continuously recording GPS sensors in Japan (Sagiya et al. 2000; Ozawa et al. 2011), several dozen tide gauges and seafloor pressure sensors around Japan (Sato et al. 2011), NOAA’s DART buoy network in the Pacific (expanded after the 2004 tsunami), and thousands of seismometers in regional and global seismic networks. Near real-time telemetry of the seismic and ocean-wave data was essential for the rapid determination of the location and magnitude of the Tohoku earthquake and for direct measurements of the 183 J une 2012 tsunami amplitudes near Japan and across the Pacific. Indeed, the Tohoku earthquake is by far the best scientifically recorded great earthquake to date, and it will be the best studied. A number of expert reports and over 100 reviewed scientific publications on the Tohoku earthquake have already appeared in major journals, including special issues of Earth, Planets and Space and Geophysical Research Letters. Several agencies conduct seismological analysis to report earthquake epicenters, depths, and magnitudes in near real-time. In Japan, earthquake early warning (EEW) is one of the main responsibilities of the Japan Meteorological Agency (JMA). The aim of EEW is to rapidly locate earthquakes and estimate magnitudes using 1100 stations in the JMA seismic network and stations from the Hi-net network of the Japan National Research Institute for Earth Science and Disaster Prevention. On the basis of the analysis, the JMA is mandated to warn the public of the potential for strong ground shaking and tsunami. The USGS NEIC is mandated to rapidly evaluate all significant global earthquakes (Hayes et al. 2011). The PTWC is responsible for issuing tsunami warnings after major earthquakes have occurred in the Pacific Ocean. Coordination among the JMA, PTWC, and NEIC is intended to ensure that consistent information is released to emergency responders. A timeline of the response to the Tohoku earthquake by these agencies is summarized in Table 1. Map of the 2011 Tohoku earthquake region. The map shows aftershocks from the NEIC catalog, with depth less than 50 km, that occurred between March 11, 2011, and March 31, 2011. The three green contours indicate the 2011 rupture zone, with fault slip exceeding 1 m, 10 m, and 20 m, respectively (Yue and Lay 2011). The yellow and red patches indicate rupture zones related to previous large earthquakes. There is uncertain earthquake potential in the region outlined by purple dots (the possible “slip deficit zone”). The arrow indicates the direction of movement of the Pacific plate. Prefecture names are shown along the right side of the map, opposite their actual locations. M = magnitude Figure 1 Hoshiba et al. (2011) and Ozaki (2011) describe the EEW sequence following the Tohoku earthquake. The EEW system was triggered at 14:46:40.2 Japan Standard Time when the primary (P) wave was recorded by the closest seismograph. Fifteen “forecasts” followed with updated information. After 5.4 seconds, the magnitude was estimated to be only 4.3, which is consistent with later determinations that the Tohoku earthquake began as a small, magnitude 4.9 earthquake (Chu et al. 2011). About 8 seconds after the trigger, the magnitude was updated to 7.2, and seismic intensity was predicted to be “5-lower” for the central Miyagi prefecture. In the fifteenth update, 116.8 seconds after the trigger, the EEW magnitude was estimated to be 8.1. This magnitude is at the upper limit of the JMA EEW magnitude scale because the short-period seismic instrumentation that the JMA relies on had gone off-scale. Nevertheless, within two minutes after the main trigger, it was clear that a major earthquake had occurred off the Pacific coast of Tohoku. Intensities of “6-upper” and “6-lower,” which are equivalent to ground accelerations of Table 1 Geophysical Investigations of the Tohoku Earthquake Analyses of the Tohoku earthquake had two key stages: (1) near real-time analysis of seismograms for first-order earthquake parameters and (2) integrated investigations of all geophysical recordings of the Tohoku earthquake and tsunami, foreshock and aftershock sequences, and field reconnaissance of ground shaking and tsunami impacts. Real-Time Analysis and Earthquake Warning Rapid seismic analysis is primarily based on automated procedures that estimate the location of rupture initiation, the earthquake magnitude, and the faulting mechanism. The near real-time processing of information evolves as the rupture grows, and frequent revisions are made as recordings lengthen and new seismic data become available. Very rapid analysis of the earliest seismic arrivals is crucial for immediate response to strong ground shaking and tsunami danger. E lements The first hour Time after detection Source Magnitude 5.4 sec JMA/EEW 4.3 8.6 sec JMA/EEW 7.2 116.8 sec JMA/EEW 8.1 Final update and tsunami bulletin 2½ min JMA (Mj) 7.9 The rapid JMA magnitude Remarks The first estimate 9 min PTWC 8.1 First tsunami bulletin 19 min NEIC 7.9 Coordinated with JMA and PTWC 20 min NEIC W-phase 9.0 Internal release only, limited data 22 min PTWC W-phase 8.8 First internal release; assumed event depth of 84 km 33 min rCMT (Polet and Thio 2011) 9.0 Internal release only 38 min NEIC/PTWC 8.8 Coordinated update, public release 62 min NEIC W-phase 8.9 Final automatic solution JMA = Japan Meteorological Agency, EEW = earthquake early warning, PTWC = Pacific Tsunami Warning Centre, NEIC = National Earthquake Information Center, rCMT = rapid centroid-moment tensor 184 J une 2012 0.25–0.40 g, were observed over a 400 × 100 km2 area in the Tohoku and Kanto districts. The JMA warned of possible tsunami with run-up heights of 6 m in Miyagi and 3 m in Fukushima and Iwate prefectures. Due to the high background noise from scattered waves and numerous aftershocks, the EEW system did not perform well for the next several hours. Accurate estimates of long-period seismic magnitude and characterization of overall earthquake faulting require analysis of on-scale ground-motion recordings with relatively low-frequency content. Several agencies and universities routinely analyze the magnitude and faulting mechanisms of global earthquakes using seismograms from the Federation of Digital Seismic Networks, which includes the NSF/USGS Global Seismic Network real-time data openly available online from the Incorporated Research Institutions for Seismology data center. A variety of waveform analyses are routinely conducted for all earthquakes larger than Mw 5.0. Many of these analyses involve variations of the centroid-moment tensor (CMT) method developed in the early 1980s (Dziewonski et al. 1981) and differ primarily in the types of waveform data that are analyzed. The CMT method relies on an initial estimate of the earthquake origin time, location, and depth obtained from, for example, the NEIC, PTWC, or JMA. The CMT analysis yields a point-source moment tensor. Moment tensor solutions for most earthquakes (including the solution for the Tohoku earthquake) are consistent with “double-couple faulting” in which the earthquake represents shear sliding along a planar fault. The moment tensor indicates the orientation of the fault and the strength and direction of shearing motion on the fault. The Tohoku moment tensor solution (Fig. 2) is consistent with slip on the interface between the subducting Pacific plate and the Okhotsk plate. The size of the earthquake is quantified by the seismic moment, M0, and the moment magnitude, Mw [Mw = 2 /3 (log10 M0 – 9.1)]. The seismic moment, M0, of the Tohoku earthquake is estimated to be 4.3 × 1022 N·m (newton meter), which gives Mw = 9.0. The seismic moment is indicative of the spatial extent and the amount of slip on the fault plane (and hence the deformation of the seafloor). The most rapidly produced long-period solution for the 2011 Japan event was based on analysis of the W phase (Fig. 3), the earliest very long-period signal in a seismogram (Kanamori 1993). Typically, the W phase has lower amplitude than the later surface-wave signals, but it is well recorded for moderate and large (Mw > 6.5) earthquakes. W phase analysis is particularly suited for rapid determination of the earthquake moment tensor because only a few minutes of recording are needed. Moreover, the analysis can be conducted automatically because the propagation of the W phase is accurately modeled using standard seismic models (Kanamori and Rivera 2008). Automated W phase analysis was running at three institutions: (1) the USGS NEIC, (2) the NOAA PTWC, and (3) the Institut de Physique du Globe de Strasbourg. A robust W phase moment tensor for the Tohoku earthquake was computed 22 minutes after the earthquake origin time using the initial PTWC earthquake depth estimate and waveform data for 29 channels (Duputel et al. 2011) (Table 1). This solution provided an estimate of the moment magnitude, Mw = 8.8. This was upgraded to Mw = 9.0 after the source depth estimate was revised from 84 km to 24 km and additional waveform channels became available. Other rapidly available long-period solutions include the rCMT solution (Polet and Thio 2011), which was determined 33 minutes after the Tohoku earthquake and was E lements A B (A) Sketch of the Japan–Pacific subduction zone and the relative up-dip motion of the Okhotsk plate (in which Japan is located) over the Pacific plate along a plateboundary fault plane (the megathrust) dipping ~12° to the WNW. Note that the sketch is not to scale. Maximum slip near the Japan trench was about 40–60 m, and the rupture extended down-dip about 200 km. Towards the west, the dip angle of the subducting Pacific plate increases; the fault is about 50 km deep beneath the coast of Japan. The dotted line indicates the pre-earthquake, flexed position of the upper plate, which abruptly shifted eastward and upward during the earthquake to its final position. The displacement of ocean water generated the tsunami that spread away from the region of ocean uplift. (B) Source mechanism from the W phase analysis. The “beachball” graph on the left is a lower-hemisphere projection of the compressional (yellow) and tensional (white) quadrants of the focal sphere. The blue line corresponds to the megathrust fault plane, which strikes at 196° and dips to the WNW at an angle of 12°. Figure 2 based on the analysis of slightly longer segments of longperiod seismograms. The Global CMT (gCMT) solution (www.globalcmt.org) was published after analysis of 9-hour-long recordings of multiple-orbit surface waves. The long-period seismic wave solutions indicated that the Tohoku earthquake was a thrust earthquake at shallow depth, with Mw = 8.8 to 9.1. Differences in estimated moment magnitude are due to differences in the types of seismic signals analyzed, the assumed earthquake depth, and estimates of the fault dip angle (Kanamori and Given 1981). Nevertheless, all solutions are consistent with the very first W phase solution, which had clearly established the potential for a large tsunami. Spatial Extent and Complexity of the Tohoku Earthquake Rupture In the days and weeks following the earthquake, geophysicists further used a variety of available data to develop models of space–time slip on the fault plane that could be compared to previous large earthquakes in the region. This type of detailed earthquake rupture analysis advances our understanding of earthquake processes and the influence of prior ruptures. This contributes to the long-term assessment of the earthquake hazard in northeastern Japan and to preparations for future large events. Finite-fault analysis resolves the spatial extent of the earthquake rupture and the variable slip distribution on the fault plane. Rapid analysis of finite faulting using seismic and geodetic data is now common and was applied by several groups to the Tohoku event (e.g. Hayes 2011; Lay et al. 2011; Shao et al. 2011; Simons et al. 2011). Quickly determined solutions are usually rather variable from 185 J une 2012 of ground deformation in Japan as recorded by high-resolution GPS recordings (Yue and Lay 2011). The models also can account for large seafloor offsets measured by several independent procedures. Koketsu et al. (2011) demonstrate how many seismic and geodetic data can now be reconciled with similar models. Perspectives Although Japan has a long and well-documented history of large earthquakes and tsunamis, the 2011 Tohoku earthquake was much larger than any known earthquake during the past 1100 years. Given the lack of historical earthquakes of this size, the Mw 9 Tohoku earthquake caught most seismologists by surprise. Earthquakes offshore from Honshu during the past century had estimated seismic magnitudes lower than 8.5 (Fig. 1). Among the largest earthquakes in the northern part of Japan are the 1968 Tokachi-oki (off the Tokachi coast) and 1994 Sanriku-Haruka-oki earthquakes. Off the Sanriku coast, the largest earthquakes occurred in 1896 and 1933 (Fig. 1). The 1896 Meiji-Sanriku earthquake (magnitude 8.2–8.5) was a thrust-faulting event at the northern end of the Tohoku earthquake zone that ruptured the shallow portion of the plate interface (Tanioka and Satake 1996). This was a “tsunami” earthquake according to the definition of Kanamori (1972), with strong tsunami generation as compared with the surface-wave seismic magnitude. The 1933 earthquake (magnitude ~8.3) involved extensional faulting in the bending oceanic lithosphere (Kanamori 1971). An earlier, large, tsunami-generating event, the 1611 Keicho earthquake, has poorly constrained magnitude and location, but appears to have been near the 1933 event. Examples of well-matching recorded (black) and predicted (red) W phase signals for the optimal source mechanism at stations JOHN (Johnston Island, USA), CAN (Canberra, Australia), GSC (Goldstone, USA), and KIEV (Kiev, Ukraine) The signals are filtered between 1 and 5 mHz. The analysis is applied to the W phase, which is the waveform segment between the vertical bars. Subsequent arrivals (surface waves) are also matched well. Station locations (triangles) are indicated on the globes, shown on the right, with the star indicating the Tohoku epicenter. Figure 3 model to model, as they depend on data coverage and modeling assumptions, and it often takes some time for a consensus to develop on the best representation of the rupture process of a great earthquake. The main characteristics of the Tohoku rupture are now similar in most published finite-source models (Fig. 4). The rupture duration was about 150 s, which is relatively short for an Mw 9 earthquake. The earthquake nucleated offshore from the Miyagi-oki area and involved large slip in the up-dip region near the trench and smaller slip in the regions offshore from Fukushima, Ibaraki, and Sanriku. Slip exceeded 1 m over a 300 × 200 km 2 region of the fault plane, with average values of 15–20 m. The largest slip is estimated to be 40–60 m, by far the largest earthquake slip ever reported. The slip on the fault plane was variable and accompanied by differences in seismic radiation. Koper et al. (2011) showed that high-frequency seismic waves were generated in a region down-dip from the epicenter. Little-coherent, short-period radiation came from the regions of largest slip near the trench. The slip-distribution maps in Figure 4 provide a good match to the seismic, geodetic, and tsunami data. In particular, large, shallow slip near the trench is required by the arrival time and narrow pulse of the tsunami at nearby deep-ocean pressure sensors (Fujii et al. 2011; Yamazaki et al. 2011) and by the timing of the onset E lements Before the Tohoku earthquake, the seismic risk in Japan had been perceived as highest in the off-coast region of Miyagi, south of Sanriku. Here, a number of earthquakes with a magnitude of 7 or greater occurred in 1933, 1936, 1978, and 2005. The March 9, 2011, foreshock of the Tohoku earthquake occurred seaward of this zone. The roughly 30–40-year intervals separating these earthquakes formed the basis for the proposed relatively high seismic risk in the region, although it is not clear that these earthquakes are repeating events (Kanamori et al. 2006). The 869 Jogan earthquake is the oldest and largest earthquake in the region. It left a record of tsunami deposits on the Sendai Plain (Abe et al. 1990; Minoura et al. 2001; Sawai et al. 2008). Numerical simulations of tsunami run-up and inundation suggest that the 869 event had a magnitude of ~8.5 and that it was located up-dip from the Miyagi-oki events, but possibly not extending all the way to the trench (Satake et al. 2008). Known earthquakes with magnitudes between 7.1 and 7.8 that occurred in 1938 offshore from Fukushima and Ibaraki prefectures were studied by Abe (1977). There is no tsunami or seismic record of earthquakes in the region prior to the 1938 sequence. The Tohoku earthquake ruptured across almost the entire width of the plate boundary megathrust, and the rupture extended from north of the Miyagi-oki ruptures to south of the Fukushima-oki region that ruptured in 1938 (Fig. 1). The rupture encompassed the likely area of the 869 event, but extended to the trench with large slip, similar to the 1896 rupture to the north. Thus it appears that the 2011 Tohoku event broke several adjacent portions of the megathrust that had previously failed in more localized ruptures (Lay and Kanamori 2011). The study of older earthquakes off Honshu is primarily based on analyses of tsunami records and deposits. Such analyses are uncertain and have tended to play a secondary 186 J une 2012 A B C (C) regional tsunami height observations (Fujii et al. 2011). The dotted line is the Japan trench. The numbered contours indicate the amount of slip in meters. The arrows indicate the direction of movement of the subducting Pacific plate. Maps of the total amount of slip on the fault plane (projected vertically on the surface) derived from the analysis of (A) teleseismic broadband P waves (Lay et al. 2011), (B) high-rate GPS waveforms in Japan (Yue and Lay 2011), and Figure 4 role in assessing the seismic risk in the region. Nevertheless, tsunami heights related to previous large earthquakes provided valuable guidance on the potential inundation and tsunami height of the Tohoku earthquake (Mori et al. 2011; EERI 2011), although the high run-up of the Tohoku tsunami had a much wider spread (Fig. 5). The maximum run-up height of the Tohoku tsunami was 39.7 m at Miyako. The historical records of maximum run-up height are 38.2 m for the 1896 Meiji Sanriku tsunami and 28.7 m for the 1933 Showa Sanriku tsunami. Deposits of the Keicho tsunami of 1611 have mostly been erased by human activity, but Hatori (1975) suggested that 6 to 8 m high tsunamis devastated the Sendai Plain and northern Fukushima areas. Tsunami deposits in the Sendai Plain associated with the 869 Jogan earthquake extend 1–3 km inland (1 km from the present coast) (Abe et al. 1990; Minoura et al. 2001). There is no evidence that large earthquakes had occurred prior to 1938 along the Japan Trench east of Fukushima and Ibaraki prefectures. This region slipped in 2011, but probably less than 10 m or so. Allowing for 8 cm/year of convergence, there could be a significant “slip deficit” in this region if no other earthquakes occurred in the past 1000 years (Fig. 1). There is thus some concern for another large event in the future. The potential for this depends on the nature of strain accumulation in the region. While Japan has an extensive network of GPS ground-motion instruments, and these revealed that strain was accumulating in the mainland in Fukushima, but less so near Boso to the south (e.g. Suwa et al. 2006; Hashimoto et al. 2009), it is unclear whether there is still earthquake potential in this region. Japan has led the world in developing technology to monitor offshore deformation, and this will be particularly valuable for assessing the nature of strain accumulation along the megathrust south of the region of large slip in 2011. This is a costly and technically challenging endeavor. However, the important observations of seafloor deformation after the Tohoku earthquake in the Miyagi region (Sato et al. 2011) motivate long-term data acquisition, as these would have helped to recognize the potential for an earthquake as large as the Tohoku event. E lements Tsunami run-up heights for the 2011 Tohoku (grey); 1960 Chile (green); and 1933 (yellow), 1896 (red), and 1611(blue) Sanriku earthquakes as a function of latitude along Japan’s northeastern coast. Run-up measurements for the Tohoku tsunami were not available in the 30 km long restricted area around the Daiichi nuclear power plant, but direct observations indicate a 15 m run-up at the site. The names of prefectures are shown on the right. Figure 5 Earthquake risk assessment is notoriously complicated because only a very short earthquake record is available. The Tohoku earthquake experience shows how difficult it is to anticipate infrequent, catastrophic events based on a short recorded history. However, the event also 187 J une 2012 emonstrated the value of efforts to mitigate the effects of d earthquake shaking and tsunami; the high construction standards in Japan appear to have limited loss from shaking, and while the tsunami overtopped many tsunami walls, rapid warning and public preparation for response reduced the loss of lives, as compared with the 2004 Sumatra earthquake. The most promising technological approach is to extend rapid warning and faulting-quantification procedures, exploiting both onshore and, ideally, offshore measurements of ground motion to develop more precise early estimates of faulting displacements and tsunami heights. Duputel et al. (2011) have demonstrated References Abe K (1977) Tectonic implications of the large Shioya-oki earthquakes of 1938. Tectonophysics 41: 269-289 that a stable magnitude and fault-plane solution can be determined by W phase inversion within 7 minutes after the earthquake origin time using regional broadband seismic and geodetic signals. Widespread use of the most advanced capabilities to monitor the plate interface, with real-time analysis of the data, can certainly speed up robust tsunami warnings. To save lives, this technological capability needs to be coupled to emergency-response procedures and to societal awareness and preparation. Japan has learned this lesson; the rest of the world should do so as well. Kanamori H (1971) Seismological evidence for a lithospheric normal faulting; the Sanriku earthquake of 1933. Physics of the Earth and Planetary Interiors 4: 289-300 Abe H, Sugeno Y, Chigama A (1990) Estimation of the height of the Sanriku Jogan 11 earthquake-tsunami (A.D. 869) in the Sendai Plain. 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Journal of Geophysical Research 86: 2825-2852 EERI (2011) The Japan Tohoku tsunami of March 11, 2011. Special Earthquake Report November 2011. Earthquake Engineering Research Institute Fujii Y, Satake K, Sakai S, Shinohara M, Kanazawa T (2011) Tsunami source of the 2011 off the Pacific coast of Tohoku Earthquake. Earth, Planets and Space 63: 815-820 Hashimoto C, Noda A, Sagiya T, Matsu’ura M (2009) Interplate seismogenic zones along the Kuril–Japan trench inferred from GPS data inversion. Nature Geoscience 2: 141-144 Hatori T (1975) Scales and source areas of Sanriku-oki historical earthquakes. Bulletin of the Earthquake Research Institute 50: 397-414 Hayes GP (2011) Rapid source characterization of the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake. Earth, Planets and Space 63: 529-534 Hayes GP, Earle PS, Benz HM, Wald DJ, Briggs RW, USGS/NEIC Earthquake Response Team (2011) 88 hours: The U.S. Geological Survey National Earthquake Information Center response to the 11 March 2011 Mw 9.0 Tohoku earthquake. Seismological Research Letters 82: 481-493 Hoshiba M, Iwakiri K, Hayashimoto N, Shimoyama T, Hirano K, Yamada Y, Ishigaki Y, Kikuta H (2011) Outline of the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0)—Earthquake Early Warning and observed seismic intensity. Earth, Planets and Space 63: 547-551 E lements Kanamori H (1993) W phase. Geophysical Research Letters 20: 1691-1694 Kanamori H, Miyazawa M, Mori J (2006) Investigation of the earthquake sequence off Miyagi prefecture with historical seismograms. Earth, Planets and Space 58: 1533-1541 Koketsu K and 10 coauthors (2011) A unified source model for the 2011 Tohoku earthquake. Earth and Planetary Science Letters 310: 480-487 Koper KD, Hutko AR, Lay T, Ammon CJ, Kanamori H (2011) Frequencydependent rupture process of the 2011 Mw 9.0 Tohoku Earthquake: Comparison of short-period P wave backprojection images and broadband seismic rupture models. Earth, Planets and Space 63: 599-602 Lay T, Kanamori H (2011) Insights from the great 2011 Japan earthquake. Physics Today 64(12): 33-39 Lay T, Ammon CJ, Kanamori H, Xue L, Kim MJ (2011) Possible large neartrench slip during the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake. Earth, Planets and Space 63: 687-692 Minoura K, Imamura F, Sugawara D, Kono Y, Iwashita T (2001) The 869 Jogan tsunami deposit and recurrence interval of large-scale tsunami on the Pacific coast of northeast Japan. Journal of Natural Disaster Science: 23: 83-88 Mori N, Takahaski T, Yasuda T, Yanagisawa H (2011) Survey of 2011 Tohoku earthquake tsunami inundation and run-up. Geophysical Research Letters 38: doi:10.1029/2011GL049210 Ozaki T (2011) Outline of the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0)—Tsunami warnings/advisories and observations. Earth, Planets and Space 63: 827-830 Ozawa S, Nishimura T, Suito H, Kobayashi T, Tobita M, Imakiire T (2011) Coseismic and postseismic slip of the 2011 magni- 188 tude-9 Tohoku-Oki earthquake. Nature 475: 373-376 Polet J, Thio HK (2011) Rapid calculation of a Centroid Moment Tensor and waveheight predictions around the north Pacific for the 2011 off the Pacific coast of Tohoku Earthquake. Earth, Planets and Space 63: 541-545 Sagiya T, Miyazaki S, Tada T (2000) Continuous GPS array and present-day crustal deformation of Japan. Pure and Applied Geophysics 157: 2303-2322 Satake K, Namegaya Y, Yamaki S (2008) Numerical simulation of the AD 869 Jogan tsunami in Ishinomaki and Sendai plains. Annual Report on Active Fault and Paleoearthquake Researches 8: 71-89 Sato M, Ishikawa T, Ujihara N, Yoshida S, Fujita M, Mochizuki M, Asada A (2011) Displacement above the hypocenter of the 2011 Tohoku-Oki earthquake. Science 332: 1395 Sawai Y, Shishikura M, Komatsubara J (2008) A study on paleotsunami using hand corer in Sendai plain (Sendai City, Natori City, Iwanuma City, Watari Town, Yamamoto Town) Miyagi, Japan. Geological Survey of Japan 8: 17-70 Shao G, Li X, Ji C, Maeda T (2011) Focal mechanism and slip history of the 2011 Mw 9.1 off the Pacific coast of Tohoku Earthquake, constrained with teleseismic body and surface waves. Earth, Planets and Space 63: 559-564 Simons M and 14 coauthors (2011) The 2011 magnitude 9.0 Tohoku-Oki earthquake: mosaicking the megathrust from seconds to centuries. Science 332: 1421-1425 Suwa Y, Miura S, Hasegawa A, Sato T, Tachibana K (2006) Interplate coupling beneath NE Japan inferred from threedimensional displacement field. Journal of Geophysical Research 111: 1997-2002 Tanioka Y, Satake K (1996) Fault parameters of the 1896 Sanriku tsunami earthquake estimated from tsunami numerical modeling. Geophysical Research Letters 23: 1549-1552 Yamazaki Y, Lay T, Cheung KF, Yue H, Kanamori H (2011) Modeling near-field tsunami observations to improve finitefault slip models for the 11 March 2011 Tohoku earthquake. Geophysical Research Letters 38: doi: 10.1029/2011GL049130 Yue H, Lay T (2011) Inversion of high-rate (1 sps) GPS data for rupture process of the 11 March 2011 Tohoku earthquake (Mw 9.1). Geophysical Research Letters 38: doi:10.1029/2011GL048700 J une 2012 Examining the Nuclear Accident at Fukushima Daiichi Photo of two of the units after hydrogen explosions damaged the roofing structure of the reactor buildings. This picture was taken on March 15, 2011, four days after the earthquake and tsunami. Source : TEPCO website Edward D. Blandford1 and Joonhong Ahn2 1811-5209/12/0008-0189$2.50 DOI: 10.2113/gselements.8.3.189 T he major nuclear accident at the Fukushima Daiichi nuclear power plant more than one year ago was the result of a combination of four interrelated factors: site selection, external hazard assessment and site preparation, the utility’s approach to risk management, and fundamental reactor design. The reactor accident was initiated by a magnitude 9 earthquake, followed by an even more damaging tsunami. An insufficient tsunami defense-in-depth strategy led to significant core damage in three units and radioactive release to the environment. This paper provides a summary of the sequence of events that led to the accident and current efforts to contain and manage the released radioactivity. The Nuclear Reactors The six Fukushima Daiichi nuclear reactors were able to produce a Keywords : Fukushima Daiichi, nuclear power, accident, radioactive release total of 5480 megawatts of electricity (MWe) at full capacity, Introduction making it one of the largest nuclear power stations in the In the early afternoon of March 11, 2011, Units 1, 2, and world. All units were General Electric (GE) boiling water 3 at the Fukushima Daiichi nuclear power plant (Fig. 1) reactors (BWR). Unit 1, the first one built, was a GE design, were operating at full power, while Unit 4 was undergoing BWR/3, with Mark I containment (Fig. 2). Units 2 through fuel unloading and Units 5 and 6 were undergoing routine 5 were a later GE design, BWR/4, which still utilized scheduled maintenance. A magnitude 9.0 earthquake Mark I containment. occurred off the eastern coast of Honshu at 2:46 pm. The earthquake was the most powerful in the history of Japan. Unit 6, the youngest and largest reactor, was a GE design, BWR/5, with Mark II containment. The plant was designed The three operating units immediately shut down autosuch that all the units have some common facilities and matically, as designed. Breakers and off-site power distribustructures, such as a conventional island housing the tion towers failed due to the effects of the earthquake, turbines (Fig. 3). Facilities for handling the used fuel after causing a complete loss of power from the outside. irradiation, such as spent fuel pools and dry-cask storage Following the automatic shutdown of Units 1, 2, and 3, facilities, were designed for use by all the units. Additionally, backup emergency diesel generators immediately started, Units 1 and 2 shared a control room, as did Units 3 and 4. providing backup electric power to critical emergency safety systems. Forty-one minutes after the earthquake and thirty-eight minutes after a tsunami alert was issued, the first of a series of seven tsunami waves arrived at the site. The maximum wave height was 14–15 meters, well above the 5.7-meter seawall designed to protect the site (IAEA 2011). All electric power was lost to Units 1 through 4 within fifteen minutes after the first tsunami wave hit the station, and this led to a station blackout condition, that is, the complete loss of all sources of power. This paper is based on a detailed timeline of events that was developed by the Institute of Nuclear Power Operations (INPO 2011), which derived much of its information from direct and indirect interactions with the Tokyo Electric Power Company (TEPCO), the owner and operator of the station. 1 Center for International Security and Cooperation Stanford University Encina Hall E210, Stanford, CA 94305-6165, USA E-mail: [email protected] 2 Department of Nuclear Engineering University of California, Berkeley 4157 Etcheverry Hall MC 1730, Berkeley, CA 94720-1730, USA E-mail: [email protected] E lements , V ol . 8, pp. 189–194 Aerial view of the Fukushima Daiichi nuclear power station before March 11, 2011. Unit 1 was the first one built and started operation in 1971; it is the smallest, at 460 megawatt electrical (MWe). Units 2–5 each provided 784 MWe, and they started operation during the 1970s. Unit 6 is the largest of the units at 1100 MWe, and started operating in 1979. Source : TEPCO website Figure 1 189 J une 2012 Nuclear Power Primer T he majority of nuclear power plants operating around the world are light water reactors (LWRs), which are either pressurized water reactors (PWRs) or boiling water reactors (BWRs). A LWR produces heat through controlled fission occurring in the fuel of the reactor core, and steam is ultimately used to drive powergenerating turbines. In a BWR, steam is generated in the core and used to directly drive turbines, while in a PWR, a secondary loop is used to transfer the heat and ultimately drive the turbines. Both reactor types have been built over a range of electrical power outputs, typically ranging from several hundred megawatt electrical (MWe) to well over a gigawatt electrical (GWe). LWR fuel uses U-235 that has been enriched to roughly 3–5% (naturally occurring uranium contains 0.71% U-235) and fabricated into fuel rods that are approximately 1 cm in diameter and 3 m long. These fuel rods are bundled into square fuel assemblies that can be loaded into the reactor core. The reactor cores at Fukushima Daiichi contained 400 fuel assemblies in Unit 1, 548 fuel assemblies in each of Units 2–5, and 764 fuel assemblies in Unit 6. One of the safety challenges with LWRs is that they produce decay heat from the decay of fission products remaining in the fuel after the reactor has been shut down. Due to the decay heat, the reactor core requires continuous cooling following shutdown. Spent fuel is stored in spent fuel pools until it is cool enough for potential interim storage in dry-cask storage. According to TEPCO, the Fukushima Daiichi plant had a total of 1760 metric tons of fresh and spent nuclear fuel (Marshall and Reardon 2011). The Accident All on-site power was lost 55 minutes after the earthquake because many of the emergency diesel generators and switchgear rooms were flooded by the tsunami. Of equal importance, the seawater intake structure was destroyed by the tsunami, compromising the ability to remove heat from the shut-down reactors. Key plant equipment began to fail as plant operators started to lose all lighting and instrumentation due to damage and shorting in the DC backup batteries. Only one of the five emergency diesel generators in Units 5 and 6 continued to operate after the tsunami. The air-cooled emergency diesel generator in Unit 6 continued to function and supply electrical power so backup cooling systems could maintain functionality. Nuclear power safety is rooted in a defense-in-depth philosophy that involves the use of multiple, independent, redundant, and diverse barriers to prevent problems and accidents, together with corresponding emergency planning to address residual risks. However, it is shown in this paper that the defense-in-depth approach for dealing with tsunamis at the Fukushima Daiichi plant was insufficient. Station Blackout After losing all on-site AC power, plant personnel contacted the Japanese government and requested backup electric generators to restore critical safety equipment. Due to severe damage from the tsunami, the transportation of critical backup equipment to the site was delayed until later that evening. Helicopter transport of backup diesel generators was considered, but the weight of the generators exceeded the helicopter’s lift capacity. Finally, in the evening of March 11, backup, portable generators were put in service. Restoring the backup on-site power was made significantly more complicated by the fact that the tsunami had damaged the station’s electrical distribution system. The initial inspection of the station switchyard confirmed that standby pumps for Unit 2 were functional, and therefore backup power efforts were directed towards Unit 2. Massive, temporary power cables were laid by station workers, and a connection was made to the associated power panel at 3:30 pm on March 12. It took approximately forty employees to lay the cable through the rubble and flooded areas. At 3:36 pm an explosion occurred in the Unit 1 reactor building due to a buildup of hydrogen near the top of the building. The hydrogen came from steam reactions with overheated zirconium alloy fuel cladding, and was a result of the inability to cool the reactor core. This explosion distributed debris and damaged recently laid backup equipment, such as cables and portable generators. As a result of the explosion, five workers were injured, and the safety protocol for plant personnel was changed. Workers were required to wear protective equipment. The initial hydrogen explosion at Unit 1 certainly changed the nature of the emergency response and added much to the confusion. The site superintendent ordered personnel to proceed with preparations for venting Unit 3 just after 8 am and Unit 2 just before 2 pm on March 13. Reactor Core Cooling Cutaway view of the General Electric boiling water Figure 2 reactor with Mark I containment. The reactor pressure vessel (depicted in red) ranged from 4.8 m to 6.4 m in length with Unit 1 having the smallest reactor pressure vessel. The core containing the fuel assemblies is located inside the reactor pressure vessel. The Torus suppression chamber ranges from 18 to 25 m in diameter and contains 1750 to 3200 lbs of water. Units 1–5 all had Mark I containments, while Unit 6 had Mark II. Source : NRC and G eneral Electric website E lements All nuclear power plants have some form of emergency makeup system to ensure there is water available in the event of a major pipe break. Heat in a BWR is removed during normal operation by generating steam in the reactor vessel, which then drives a turbine to generate electrical energy. When a reactor shuts down, the decay heat generated in the core is removed by bypassing the turbine and sending the steam directly to the condensers. When the 190 J une 2012 The physical arrangement of the Fukushima Daiichi nuclear power plant. Some of the buildings housed equipment that was shared among the units. A total of 6600 assemblies of spent fuel were stored in the common water pools, which had a capacity of 6840 assemblies. In the figure, the height above sea level is indicated in red and green and is relative to sea level as measured at the port of Onahama (O stands for Onahama; P stands for Peil). Source : TEPCO Figure 3 website pressure in the reactor system drops to an acceptable point, the residual-heat-removal system is used to finish cooling down the reactor system (Fig. 4). In the event that the normal supply of water to the reactor vessel is lost, an isolation cooling system provides makeup water to the reactor vessel. Unit 1 was the oldest unit and utilized an isolation condenser (IC) to passively cool the core. The IC works on the principle that the heated, two-phase mixture of water and steam is buoyant, thus establishing a natural circulation loop with large heat exchangers located above the reactor for residual-heat removal. Units 2 and 3 utilized a reactor core isolation cooling system (RCIC) instead of an IC to cool the core in the case of an accident. The RCIC performs a function similar to that of the IC. It consists of a turbine-driven pump, associated piping, and required valves, and is used to deliver water to the reactor vessel at operating conditions. All of the units have an emergency core-cooling system (ECCS) that is capable of providing core cooling in the event of a loss-of-coolant accident. The ECCS consists of two high-pressure and two low-pressure systems. The high-pressure systems include the high- pressure coolant-injection (HPCI) system and the automatic-depressurization system (ADS), which is capable of depressurizing the reactor in the event of HPCI system unavailability. The low-pressure system in Unit 1 consists of a core-spray (CS) system, while Units 2 and 3 also utilize a low-pressure coolant-injection (LPCI) mode of the residual-heat-removal system in addition to the CS system. All of the units also have a borating system, which is used to shut down the reactor in the event that reactivity cannot be controlled. This system contains borated water, which is an effective neutron absorber and is used to stop the fission chain reaction in the core. Immediately following the tsunami, all cooling and highpressure makeup water to the reactors was lost. Steamdriven injection pumps were used to activate the RCIC E lements system in Units 2 and 3; however, Unit 1 was unable to reestablish cooling through the IC. In all three units, the HPCI system was unavailable due to the absence of DC power. The steam-driven pumps ultimately failed, and the RCIC system stopped cooling Units 2 and 3. According to TEPCO estimates (TEPCO 2011a), Unit 1 was left without Notional diagram showing key safety cooling systems and differences among the various units (not drawn to scale). Systems are depicted by number: (1) residual-heat-removal system, (2) low-pressure core spray, (3) high-pressure core injection, (4) reactor core isolation cooling (Units 2, 3), (5) isolation condenser (only Unit 1), and (6) borating system. A dapted from U. Stoll, ENEF Special R isk Working G roup on Safety of N uclear Facilities, B russels, March 24, 2011 191 Figure 4 J une 2012 any water injection for 14 hours and 9 minutes following the station blackout. Units 2 and 3 were able to maintain adequate cooling for nearly 70 hours after the reactor shutdown and they eventually lost cooling capabilities for approximately 6 and a half hours. Because of this long period with no core cooling, substantial core damage occurred in Units 1, 2, and 3. “Core damage” refers to a core condition during a severe accident where the fuel can no longer maintain a geometry capable of allowing cooling and where temperatures exceed the melting point (~2800 °C) of the fuel. Boiling water reactors have a number of connections that penetrate the bottom of the reactor pressure vessel for core instrumentation and control rods. These penetrations provide potential pathways for leakage from the reactor pressure vessel. Interested readers should consult a recently released report from the United States Nuclear Regulatory Commission (NRC 2012), which discusses a research effort, initiated long before the Fukushima accident, to realistically estimate the outcomes of postulated severe-accident scenarios. Core cooling was finally reestablished once the pressure in the primary system dropped enough to allow fire engines to inject seawater, and later freshwater; but by then it was too late, as substantial core damage had occurred. According to INPO (2011), core damage in Unit 1 most likely started within an hour and a half of the tsunami. Conservative estimates indicate that the cores in both Units 2 and 3 most likely melted and might have slumped approximately a meter to the bottom of the reactor pressure vessel. The full state of the damaged cores is not well known, and it will likely take many years before we fully understand the extent of fuel damage. It took nearly 4 years to assess the extent of damage to the fuel at Three Mile Island (NRC 1994) after the accident in 1979. Containment Venting The reactor containment structure is designed to prevent the release of radioactive material to the immediate environment. During severe accidents, the pressure inside the containment structure can be controlled through monitored venting in order to release stored energy. However, when venting occurs after damage to the core, the possibility of releasing radioactive material is much increased. At Fukushima Daiichi, safety procedures required venting when the operating pressure reached nearly double the maximum operating pressure. According to TEPCO severeaccident procedures, the chief of the Emergency Response Center, the site superintendent, is solely charged with determining whether to vent, but he can solicit input from other management personnel at the station. According to Japanese law, TEPCO did not need government permission to vent; however, government concurrence is preferable (INPO 2011). For Unit 1, the site superintendent informed the government that he intended to vent the containment structure in order to reduce pressure. The government concurred; a press statement was issued just after midnight on the first day of the accident, and immediate evacuation measures were initiated in the nearby communities for those who remained. Shortly after the evacuations were completed, the procedure for venting the containment structure began just after 9 am on the morning of March 12. Five and a half hours passed before the containment structure was vented successfully due to the complexity of the operation. The radiation-exposure dose to workers had to be limited to no more than 300 mSv/h, with an additional limit of no more than 100 mSv in 17 minutes (for reference, the global average background dose for a human is approximately 3 mSv/y). Additionally, a lack of contingency proceE lements dures for venting containment under severe-accident conditions hindered progress (INPO 2011). These delays were the major factors involved in holding up the injection of water into the core of Unit 1, and they ultimately contributed to the severity of the accident. As with Unit 1, a series of hydrogen explosions occurred in Units 3 and 4 several hours following the venting of units 2 and 3. The source of the released hydrogen was, again, exothermic reactions occurring at the exposed zirconium fuel cladding. While the pressure in the containment structure was increasing, the most likely source of hydrogen outside of containment was by leakage through the drywell head, which is used to access the drywell during maintenance ( see Fig. 2). The hydrogen explosion in Unit 3 occurred just after 11 am on March 14 and significantly damaged secondary containment equipment and injured eleven workers. Finally, a hydrogen explosion occurred in the shut-down Unit 4 on March 15, the day after the explosion in Unit 3. The explosion at Unit 4 was peculiar since the plant was shut down; thus the hydrogen must have come from another unit. Currently, the most accepted explanation is that containment vent exhaust from Unit 3 circulated into Unit 4 through the shared standby gastreatment system (SGTS). Spent Fuel Pool Status The status of the spent fuel pools was of considerable concern as the events of the accident unfolded. The location of the spent fuel pools in the older-generation BWR designs with Mark I containment is particularly vulnerable during a severe accident because the pools are located at the top of the reactor building and in close proximity to the reactor pressure vessel (see Fig. 2). This design was originally to make fuel offloading easier by minimizing the distance the fuel had to move during refueling. With the exact source of the hydrogen and key spent fuel pool diagnostics unknown, there was early speculation that the pools had been compromised and that water might have been lost from at least one of the pools. Spent fuel at Fukushima Daiichi is stored in each unit’s own spent fuel pool, as well as in a common pool and in on-site dry-cask storage. Once the station was under blackout conditions, all cooling capabilities for the unit spent fuel pools were lost, but this situation was not of immediate concern once emergency diesel generators were started. Water in the spent fuel pools experienced some “sloshing,” similar to the estimated minimal release of a few cubic meters of water from the pool at the KashiwazakiKariwa plant after a magnitude 6.6 earthquake in 2007 (NISA 2009). Visual inspections using robots and analyses of the isotopic composition of the water in the spent fuel pools a month after the accident indicated that there was no serious damage to spent fuel in any of the pools or to the pools themselves. Any potential damage to the spent fuel was caused by flying debris from the hydrogen explosions. TEPCO inspections of the dry-cask storage building showed negligible damage. Reactor Stabilization and Decontamination Efforts As soon as the core coolant capability was restored by using the fire engine pumps, first with seawater and later with freshwater, another serious problem developed. Injected water that came in contact with the damaged fuel became highly contaminated with radioactivity. Because coolant circulation was not possible, the discharged water had to be stored separately. Soon, the floors of the turbine and reactor buildings were covered by highly radioactive water, 192 J une 2012 indicating that injected water was leaking from the reactor containment vessels. According to a TEPCO report (2011b) written two months after the accident, the concentrations of Cs isotopes (Cs-137 and 134) as of March 27, 2011, were about 3 million Bq/cm3 for each of them. The contaminated water soon started to overflow from the trench that connects buildings underground. This presented a very difficult situation. Water had to be injected into the cores to cool them, but this created the possibility of release of radioactivity to the seacoast environment by overflow of contaminated water. Due to the limited storage capacity, TEPCO had to release into the sea, with government approval, ~9000 m3 of contaminated water (6.3 Bq/cm3) kept in the storage facility in the centralized waste-treatment building. With the approach of the rainy season in June and July, it was urgently necessary to secure space for this contaminated water and to establish coolant circulation systems with a decontamination capability. As of the end of May 2011, the total volume of contaminated water was estimated to be 105,000 m 3, containing about 7 × 1017 Bq of radioactivity; the volume would have been expected to reach 200,000 m3 by the end of 2011 if no treatment and circulation had been established. The contaminated water contained high concentrations of Na, K, Mg, Ca, Sr (nonradiogenic), and Cl, which originated from the seawater, as well as radioactive Sr, Cs, and I, which came from the damaged fuel. The major element composition of the seawater was the main difference between the wastewater at Fukushima and the wastewater generated in the Three Mile Island accident in 1979, where there was no injection of seawater. The treatment system for the contaminated water had specific requirements. First, the system had to be simple, so that it could be operated without remote handling. Second, the system had to be immediately available, which excluded options that required additional research. Third, the processing material had to be durable in a radiation field, and this excluded organic solvents and synthesized resins. Fourth, the system had to achieve sufficiently high decontamination factors, particularly for Cs, under high-salinity conditions, in order to eliminate the need for a secondary separation process. TEPCO started operating the treatment system (Fig. 5) on June 17, 2011. This was important, because contaminated water in the trench was expected to overflow into the sea on June 20. At that time, there was 99,900 m3 of contami- nated water in the reactor and turbine buildings of Units 1 through 4. Additionally, 21,700 m3 of contaminated water were stored in the centralized waste-treatment building, whose capacity was only 30,000 m3. Approximately 400 m3 per day of freshwater were required for cooling the three crippled reactors. The treatment system consists of four parts: (1) An oil separator. (2) A Cs-adsorption system, developed by the US company Kurion, which consists of three subparts: (i) a pretreatment column packed with the sorbent SMZ, a surfactant modified zeolite, for removal of remaining oil and technetium; (ii) four parallel columns of the sorbent herschelite, for removal of Cs; and (iii) a column packed with the sorbent Ag-impregnated herschelite (AGH), for removal of iodine. The Kurion Cs-adsorption system was used in the water-treatment process at Three Mile Island. (3) A system for removing the remaining Cs, provided by the French company Areva, in which precipitation and coagulation are used. The decontamination factors for these processes have been relatively constant and high. The Kurion system has achieved decontamination factors for Cs ranging between 100 and 1000. The Areva system has achieved decontamination factors of 1000 to 10,000. Thus, an overall decontamination factor of 10,000 to 1,000,000 has been achieved for Cs. (4) On August 19, a second line, called Sarry, was added in parallel to the Kurion-Areva line. Developed by Toshiba-Shaw, this line uses Cs adsorption by titanates, and it has achieved about the same level of decontamination as the Kurion-Areva line. Desalination by reverse osmosis and by evaporation was added on June 24 and August 7, respectively. The total throughput of the system from the oil separation stage through desalination was designed to be 1200 metric tons per day, and to generate 480 tons of freshwater a day. Thus, circulation of coolant water was begun on June 24. Since implementation, the system has operated relatively free of difficulty. As of November 30, 2011, more than 175,000 m3 of contaminated water had been processed by this system. The volume of contaminated water stored in the reactor and turbine buildings has been reduced to 77,000 m3 from the initial 100,000 m3 in June. The volume of contaminated water stored in the centralized wastetreatment building has decreased from 22,000 m 3 to 12,000 m3. In turn, 581 m3 of sludge containing Cs and Process diagram for the wastewater treatment system at Fukushima Daiichi. Source: TEPCO website, www.tepco.co.jp/ cc/ press / betu11 _ j / images /110609g .pdf Figure 5 E lements 193 J une 2012 298 vessels of wastes have been generated by the wastewater treatment system. After desalination, a total of 85,000 m3 of salt water, which still requires treatment, has been generated and accumulated. Since the addition of the evaporation process in August 2011, condensation and volume reduction have been ongoing. With the successful and stable operation of the contaminated-water treatment system, cooling of the reactor cores has also been attained. On December 16, 2011, the Japanese government announced that the three crippled reactors were in a cold shutdown state. However, final disposal of used adsorbent containing high concentrations of Cs will be an important issue as site cleanup, remediation, and decommissioning move forward. One important issue involving this spent adsorbent is hydrogen generation by radiolysis, as this process is enhanced by the presence of seawater, because hydrogen reoxidation reactions are hindered (Kumagai et al. 2011). Summary The fuel in Unit 1 began to fail only a few hours after the station blackout caused by the tsunami. The fuel structurally failed and slumped to the bottom of the reactor pressure vessel as a melt. Reports from TEPCO have indicated that 0.7 m of the concrete below the reactor pressure vessel in Unit 1 was eroded by the molten corium interacting with the concrete (corium refers to the molten mixture of melted reactor-core constituents that exists during a severe accident). There are just over 10 m of additional reinforced concrete and steel protecting the environment below the damaged concrete. The cores melted in Units 2 and 3 as well; however, there is no evidence to date that there has been any basemat erosion in their respective drywells. The sequence of events in Japan led to one of the most unsafe plant states for a light water reactor—a complete loss of on-site and off-site power, known as a station blackout. Insufficient defensive actions and an inadequate accident-mitigation response led directly to the overheating of three cores and resulted ultimately in controlled radionuclide release to the nearby environment. The true failure at Fukushima Daiichi was the result of a completely inadequate defense-in-depth approach against a tsunami event. Defense-in-depth is a strong tool to utilize when dealing References IAEA (2011) IAEA International Fact Finding Expert Mission of the Fukushima Dai-Ichi NPP Accident Following the Great East Japanese Earthquake and Tsunami, 160 pp, www-pub.iaea.org/mtcd/meetings/ pdfplus/2011/cn200/documentation/ cn200_final-fukushima-mission_report. pdf INPO (2011) Special Report on the Nuclear Accident at the Fukushima Daiichi Nuclear Power Station. Institute of Nuclear Power Operations INPO 11-005, 97 pp, www.nei.org/resourcesandstats/documentlibrary/safetyandsecurity/reports/special-report-on-the-nuclearaccident-at-the-fukushima-daiichinuclear-power-station Kumagai Y, Nagaishi R, Kimura A, Taguchi M, Nishihara K, Yamagishi I, Ogawa T (2011) Measurement and evaluation of hydrogen production from E lements Diagram illustrating the concept of defense-in-depth. The events at Fukushima following flooding by the tsunami were a direct consequence of insufficient tsunami defensein-depth. Please note the barriers depicted are notional. G raphical concept adapted from Managing the R isk of O rganizational A ccidents, by James R eason (1997) Figure 6 with unusually large events; however, it is not failure proof. All barriers ultimately have “holes,” such as the states of systems, equipment failure, human error, and equipment being in maintenance or out-of-service (Reason 1997). Figure 6 illustrates the concept of defense-in-depth, where the ideal implementation of defense-in-depth differs from the actual implementation. The events at Fukushima following the tsunami were a direct consequence of an insufficient tsunami defense-in-depth approach. An obvious example of this at Fukushima was not placing critical backup equipment in waterproof vaults or at high enough elevations so as to provide accident mitigation in the event that the seawall was compromised or insufficient. The defense-in-depth philosophy can fail when the “holes” in the barriers are aligned (notional barriers are given for illustration). This figure illustrates why one cannot assume the accident was due only to an inadequately sized seawall. The events at Fukushima Daiichi were due to a series of failures, including failures in plant defensive actions, mitigation efforts, and emergency response. mixtures of seawater and zeolite in decontamination of radioactive water. Journal of Atomic Energy Society of Japan 10: 235-239 Marshall E, Reardon S (2011) How much fuel is at risk at Fukushima? Science Insider. http://news.sciencemag.org/ scienceinsider/2011/03/how-much-fuelis-at-risk-at-fukushima.html NISA (2009) Measures taken by the Nuclear and Industrial Safety Agency concerning the Kashiwazaki-Kariwa Nuclear Power Station, affected by the Niigataken Chuetsu-oki earthquake (2nd Interim Report). Nuclear and Industrial Safety Agency, pp 11-12, www.nisa.meti.go.jp/genshiryoku/ doukou/files/090629eiyaku02.pdf NRC (1994) TMI-2 Vessel Investigation Project Integration. United States Nuclear Regulatory Commission Report NUREG/CR-6197 194 NRC (2012) State-of-the-Art Reactor Consequence Analyses (SOARCA). United States Nuclear Regulatory Commission Report NUREG-1935, 101 pp, http://pbadupws.nrc.gov/docs/ ML1202/ML120250406.pdf Reason J (1997) Managing the Risks of Organizational Accidents. Ashgate England, pp 11-13 TEPCO (2011a) The Great East Japan Earthquake and Current Status of Nuclear Power Stations Public Presentation, www.tepco.co.jp/en/nu/ fukushima-np/f1/images/f12npgaiyou_e.pdf TEPCO (2011b) Results of Analysis for Water in the Turbine Buildings by JAEA, released on May 22, 2011, www.tepco. co.jp/nu/fukushima-np/images/ handouts_110522_04-j.pdf J une 2012 Atmospheric Dispersion and Deposition of Radionuclides from the Fukushima Daiichi Nuclear Power Plant Accident Anne Mathieu, Irène Korsakissok, Denis Quélo, Jérôme Groëll, Marilyne Tombette, Damien Didier, Emmanuel Quentric, Olivier Saunier, Jean-Pierre Benoit, and Olivier Isnard* 1811-5209/12/0008-0195$2.50 DOI: 10.2113/gselements.8.3.195 O n March 11, 2011, an earthquake and tsunami hit the northeast coast of Japan and damaged the Fukushima Daiichi nuclear power plant, leading to the release of radioactive material into the atmosphere. We trace the evolution of radioactivity release to the atmosphere and subsequent dispersion as simulated by models, and we compare these to actual measurements. Four main release periods are highlighted. The first event had limited consequences to the north of the power plant along the coast; the second had no impact on Japanese territory because the plumes travelled toward the Pacific Ocean; the third was responsible for significant and longterm impact, especially northwest of the plant; and the last had consequences of lesser impact on the Tokyo area. Keywords : Fukushima Daiichi nuclear power plant, nuclear accident, contamination, atmospheric dispersion models, radioactive release Introduction The recent disaster at the Fukushima nuclear power plant was the most serious nuclear accident since Chernobyl in 1986. To accurately assess its impact on human health, an evaluation of the exposure due to radioactive materials dispersed in plumes and deposited on the ground is necessary. This objective was partly achieved by direct measurements. First, ground deposition was measured during and after the accident. In the early phase of the crisis, airborne measurements were made by the U.S. Department of Energy (DOE 2011). Moreover, since April 2011, a comprehensive and systematic survey of the environment based on soil samples has been completed by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) and a group of Japanese researchers (e.g. Yoshida and Takahashi 2012 this issue). Using both sources of data, maps of ground contamination due to mediumand long-lived radionuclides (especially 134Cs and 137Cs) have been created. However, many uncertainties remain regarding the ground contamination due to short-lived radionuclides, such as 131I and 132 I, which are major contributors to the gamma dose rate [gamma energy absorbed by the material per unit of mass and time (Gy/h)]. Second, from the beginning of the crisis, Japanese networks of measurement devices provided gamma dose rates and concentration measurements. About 80 stations showed significant gamma dose rates. Half the stations are located in Ibaraki Prefecture and the other half mainly in Fukushima, Kanagawa and Tokyo prefectures. However, many devices were not functioning because of earthquake and tsunami damage. Thus, the spatial coverage provided by the network was too limited to document in time and space the evolution of the plumes and their changing composition. Because the observational data are not sufficient, models of release, dispersion and deposition are required in order to assess the environmental and health impact of the Fukushima accident. This study offers a reconstruction of the atmospheric transport and deposition of the releases and provides the data required for the assessment of doses taken by the population. Atmospheric Dispersion Models and Input Data Atmospheric Dispersion Models The long-range Eulerian operational model ldX was used to model the dispersion of radioactivity at the scale of Japan, typically up to a few hundred kilometres from the source. The ldX model is based on the chemistry transport model Polair3D (Boutahar et al. 2004) and has been validated on the European Tracer Experiment (ETEX-I) and the Algeciras and Chernobyl accidents (Quélo et al. 2007). The statistical indicators for model-to-data comparisons have indicated the advantages of ldX as compared to other models. For instance, the analysis using the ETEX-I data indicated that 73% of the simulated concentrations were within a factor of 2 of the observations, and 80% of the values were within a factor of 5. Since Eulerian models are known to have difficulty in resolving steep gradients near point sources, the operational Gaussian puff model pX (Soulhac and Didier 2008) was used within 80 km of the Fukushima source. Both models include consideration of radioactive decay. They also account for particle and gas removal from the plume and deposition on the ground through dry deposition and scavenging due to rain. Dry deposition was modelled using a simple scheme with a constant deposition velocity: vdep = 2 × 10 -3 m/s. For wet scavenging, the parameterization used was of the form Λs = Λ0 p 0 , where Λ0 = 5 × 10 -5 h/(mm.s) and p 0 the rainfall intensity in millimetres per hour (Baklanov and Sørensen 2001). Depending on the atmospheric stability, the vertical diffusivity in the ldX model followed either Louis (Louis 1979) or TroenMahrt schemes (Troen and Mahrt 1986). Pasquill stability * All from IRSN, Institute of Radiation Protection and Nuclear Safety, Fontenay-aux-Roses 92262 Cedex, France Corresponding author e-mail: [email protected] E lements , V ol . 8, pp. 195–200 195 J une 2012 classes (Pasquill 1961) were used for pX. The spatial resolution for ldX simulations was the same as for the meteorological data input, and ten vertical levels were used. Meteorological Data The Fukushima plant is located in complex terrain, close to the sea and within 10 km of a mountainous area, where meteorological conditions are sometimes difficult to forecast. Therefore, several sources of meteorological data were considered. Operational forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF) and Météo-France (based on the ARPEGE model) were used, with a time resolution of 3 hours. ECMWF data have a spatial resolution of 0.125° × 0.125° (about 11 km × 11 km), and ARPEGE data have a resolution of about 0.5° × 0.5° over Japan. However, these models do not resolve the complex topography of Japan. Measurements of wind velocity and rainfall rate, collected at various sites in Japan, were used to evaluate the quality of the meteorological forecasts. The comparisons showed rather good model-todata agreement, except for three events: forecast wind fields appear to be inaccurate on March 15 in the Fukushima area and on March 16 and 21 in the Ibaraki area. Despite these weaknesses, no other data have proven to be better for the characterization of the meteorological conditions at the Japan and hemispheric scales. Therefore, ldX simulations were driven by ECMWF data at the Japan scale, and ARPEGE data were used for hemispheric simulations. For local-scale simulations, wind observations were used to compensate for the shortcomings in the forecasts. Following the analysis of forecasts and comparisons with observations, three-dimensional ECMWF data were used for pX simulations, except for March 15, when we preferred to use the uniform wind fields built from wind observations at the Fukushima Daiichi site. This solution had its own limitations, since we assumed that wind observed at Fukushima was homogeneous within the domain of simulation (80 km), but this did not take into account the natural spatial heterogeneity of flow. Several rain events occurred in Japan during the Fukushima accident. The timing, spatial resolution and intensity of rain fields are of prime importance for the proper simulation of scavenging and deposition caused by rain. The resolution of meteorological models is too crude for an accurate representation of the spatial and temporal variability of rain episodes. Thus, radar observations of rain available at 10 -minute intervals are best suited. Unfortunately, such data are only available for the pX spatial domain. Therefore, radar observations of rain were used for pX simulations, whereas the ldX model used ECMWF rain fields. tionality factor to account for the nominal reactor power. Seventy-three different radioisotopes were considered. The approach led to an overall estimate of 7.2 × 1018 becquerels (Bq) discharged into the atmosphere, including 5.9 × 1018 Bq of 133Xe, 1.9 × 1017 Bq of 131I and 2.0 × 1016 Bq of 137Cs. The proposed assessment is consistent with the released amount provided by NISA (2011) and NSC (2011), except for the noble gases, where xenon is underestimated by a factor of two. The time evolution of the release was more difficult to determine. The quantity of each radioactive species released during venting or an explosion as well as the release duration were uncertain. Some information could be inferred from environmental measurements, but only to a point. Indeed, dose rates measured in the environment included all the gamma emitters present in the ground and in the atmosphere in the vicinity of the receptor. These measurements did not allow us to determine the isotopic composition or to distinguish the plume contribution from wet deposition. Activity concentration measurements or gammaray spectra analysis may help to infer the plume composition, but such measurements at Fukushima were far too few to remove the larger uncertainty. Besides, no near-field deposition or ambient air measurements could be used to improve the release estimates whenever the plume from Fukushima Daiichi was carried towards the ocean. One year after the accident, the radioactive release still remains the key source of uncertainty in the simulations. Some preliminary and partial assessments of the release kinetics have become available (Chino et al. 2011; Stohl et al. 2011; Winiarek et al. 2012). All are based on environmental measurements. In the present study, the release kinetics were defined, first, by the chronology of events as provided by Tokyo Electric Power Company (TEPCO) (i.e. time of containment venting, flushing, onset of smoke, etc.) and by plant measurement parameters (i.e. water level and pressure in the reactor vessel, pressure in the containment), and second, by considering dose-rate peaks measured by on-site monitoring devices. In order to improve estimates of release rates and duration, dose-rate measurements distributed over Japan were used. The resulting source terms induced by damage to reactors 1, 2 and 3 are plotted in Figure 1. Four main periods of emission have been Source Term The radioactive species released into the atmosphere during the Fukushima accident depended on the respective nuclide inventories per reactor unit and on the state of the reactors. They can be classified into three categories: aerosols, gases and noble gases. Noble gases are unique in that they neither react with other species nor are deposited on the ground. During the crisis, the source term (the quantity of each radionuclide released into the atmosphere) used for the simulations presented here was estimated first by analysing the state of the reactors following the methodology proposed by Herviou and Calmtorp (2004). The Fukushima Daiichi core inventories (i.e. the initial mass and activity of radioisotopes in Units 1, 2 and 3) were calculated using the French reactor core inventory, corrected by a proporE lements Estimated rate of released activities per reactor in becquerels per second (Bq/s), including the contribution of 73 radioisotopes. Event 1 corresponds to March 12, event 2 to March 13–14, event 3 to March 15–16 and event 4 to March 17–26. 196 Figure 1 J une 2012 identified. Until March 16, the timing of the releases is based on specific events, such as venting and explosions, and thus is fairly reliable. The release rate and its distribution among radioisotopes were highly uncertain until March 14. From March 15 to 17, many measurements helped in estimating the release rate, but the composition of the release, in particular, the proportions of the noble gases, remains uncertain. From March 17 to 26, many uncertainties remain concerning both the sequence of events and the composition (rate and isotopic distribution) of the source term. Event 1: Venting and Hydrogen Explosion at Unit 1 The first release followed the explosion of Unit 1 on March 12 at 15:36 JST (Japanese Standard Time). Simulations suggest that the radioactive plume travelled first to the north along the Japanese coast and then turned towards the Pacific Ocean (Fig. 2a). Contamination of Japanese land resulting from the first event was due only to plume exposure and dry deposition northward along the coast. Only one gamma dose-rate station, located in Minamisoma, about 25 km north of the nuclear plant, detected the plume. The observed signal is in good agreement with pX simulations (Fig. 2b). However, the use of only one dose-rate station is not sufficient to validate the modelled release scenario. Ambient dose rate (µGy/h) 2011/03/12 23h00 (JST) Ambient dose rate at Minamisoma Rain [mm/h] Dose rate [µGy/h] B Date and time (JST) (A) Map of the ambient dose rate in micrograys per hour (μGy/h), due to event 1 (March 12), simulated with pX. The circles correspond to 20 km, 50 km and 80 km from the Fukushima plant. (B) Comparison between dose rate (cloud and ground shine) observed in Minamisoma, 25 km north of the Fukushima plant, and simulated by pX Figure 2 E lements The second event occurred between March 13 and 14 and was triggered by venting and an explosion at Unit 3. Fortunately, the wind was blowing towards the ocean, and no contamination of Honshu Island was detected. Again, the lack of observational stations prevents us from validating the release scenario. The consequences of the first two events for the Pacific Ocean have been described by Bailly du Bois et al. (2012). Event 3: Venting and Breach of the Wetwell at Unit 2 Dispersion Analysis for Each Event A Event 2: Venting and Hydrogen Explosion at Unit 3 The third event occurred between March 15 at 00:00 and March 16 at 12:00. First, between 0:00 and 5:00 JST, the venting of Unit 2 led to a released plume that moved to the south and then west. Second, at 6:00 JST on March 15, the sound of an explosion was heard, which may have come from Unit 3. This may have contributed in a minor part to that day’s releases. Around the same time, the pressurizing of reactor vessel 2 created a breach in the wet well (suppression chamber). Pressure-vessel measurements showed that during one day, the reactor vessel totally depressurized, leading to significant atmospheric releases. The resulting plume first went west, then northwest, and finally turned south toward the Pacific Ocean on March 16. Forecasts by most of the meteorological services predicted the flow of the contamination toward the south and west of the nuclear plant, but they did not reproduce correctly the wind field carrying the plume to the northwest. Moreover, significant precipitation over Japan occurred when the flow travelled to the northwest. The most contaminated areas were those that experienced plume wash-out by precipitation. Thus, correct estimates of wind directions, precipitation timing and intensity, and release time and duration are crucial for accurately simulating the effective contamination. During the crisis, the significance of the contamination was first hinted at by an increase of dose rate in Iitate, located 40 km northwest of the power plant. Car-borne surveys and airborne observations by DOE and MEXT provided the data for mapping the high-doserate zone and deposition northwest of the Fukushima plant (Fig. 3a, b). Simulations by the System for Prediction of Environmental Emergency Dose Information (SPEEDI; Terada and Chino 2008) were the first to model the March 15 contamination in the northwestern area (NSC and MEXT 2011). The ldX model driven by ECMWF data failed to accurately simulate the contamination to the northwest. The highdose-rate area predicted by ldX is too far west, whereas pX simulations driven by wind observations at the Fukushima Daiichi site and radar observations of rainfall are in better agreement with observations (Fig. 3). Simulations show that contamination in the northwest was caused by wet deposition between March 15 at 21:00 JST and March 16 at 3:00. The pX deposition area is slightly too far north. This may be due to the use, during this episode, of a homogeneous wind field on a domain that was larger than the representative scale of the observations. Figure 4 gives examples of comparisons between model and observations for various dose-rate stations. The main contamination was observed in Iitate. Model-to-data comparisons are generally in good agreement; nevertheless, the peak values are often overestimated by pX, and the plume arrival is simulated with a delay of a few hours. The reconstruction proposed by Chino et al. (2011) shows the same deficiency in the modelled values. The discrepancies between model and observations may be due to several factors: inaccurate wind speed and direction, delays in the precipitation timing 197 J une 2012 Ambient dose rate (µGy/h) 30/03/2011 00h00 JST B Cs-134 deposit (Bq/m2) 30/03/2011 00h00 JST (especially in Iitate where rain was observed before it was detected by radar), underestimates of the amount of noble gas released and deposition models that do not account for complex processes (e.g. land-use spatial variability and particle-size variations). Event 4: Damage to Reactors 1, 2 and 3, Sprayings and Smokes (A) Map of ambient dose rate in micrograys per hour (μGy/h) due to the plume on March 30, observed (painted areas) and simulated with pX (iso-contours) (B) Map of observed (dots) and pX-simulated (iso-contours) 134Cs deposits on March 30, in becquerels per square metre (Bq/m2). The circles correspond to distances of 20 km, 50 km and 80 km from the Fukushima Daiichi nuclear power plant. Figure 3 Between March 17 and 26, new releases occurred due to the very poor condition of the reactors and perhaps the re-scattering of materials. White and grey smokes from Units 2 and 3 were also reported by TEPCO, especially on March 21 and 22 (TEPCO 2011). These releases were probably less significant than earlier ones, but they cannot be ignored because they explain some of the contamination caused mainly by wet deposition in the Tokyo and Ibaraki areas. Since there were no specific events, such as a venting or an explosion, the evaluation of the smoke releases can only be based on the on-site, observed gamma dose-rate signal. Various plumes travelled first east and then west. A Ambient dose rate (µGy/h) 21/03/2011 06h JST Ambient dose rate at Kawauchi Rain [mm/h] Dose rate [µGy/h] A B Ambient dose rate (µGy/h) 21/03/2011 11h JST Date and time (JST) B Ambient dose rate at Iitate Rain [mm/h] Dose rate [µGy/h] A Date and time (JST) Comparisons of ambient dose rate (cloud and ground shine), in micrograys per hour (μGy/h), between ground measurements (in black) and pX simulations (in red) in (A) Kawauchi (20 km west) and (B) Iitate (40 km northwest of the Fukushima nuclear plant). Radar observations of rainfall rate, in millimetres per hour, are plotted in green. Figure 4 E lements Comparisons of ambient dose rate (cloud shine only) in micrograys per hour, between ground observations (dots) and ldX simulations (painted areas) on March 21 at (A) 6:00 and (B) 11:00. The circles correspond to 50 km, 100 km and 160 km from the Fukushima plant. Figure 5 198 J une 2012 On March 21, a plume was measured in the morning in Ibaraki Prefecture, where ldX simulations have a delay of a few hours, probably due to inaccurate meteorological data (Figs. 5a, 6a). Later in the morning, the plume arrived in the Tokyo area (Figs. 5b, 6b). However, measurements in the Tokyo region showed that the main contamination occurred around March 15–16 (Fig. 6b), following event 3. A Dispersion and Deposition on Honshu Island and in the Northern Hemisphere Model-to-data comparisons have been completed using available gamma dose-rate observations (SPEEDI and prefectural measurements). The comparison between observed and modelled gamma dose rates due to ground shine (after the plume is supposed to have left the area) shows an agreement within a factor of 5 to 10, and most of the time a factor of two. Model-to-data comparisons show an agreement within a factor of 5 for the gamma dose rate during the plume passage. Most of the time, the dose rate due to radionuclides in the air (“cloud shine”) is underestimated, and the dose rate due to radionuclides deposited on the ground only (“ground shine”) is over estimated. The airborne map of 137Cs deposition (see Fig. 1 in Yoshida and Takahashi 2012 this issue ) (MEXT 2011) shows that the long-term impact of the accident is mainly located northwest of the plant where wet deposition occurred. Figure 7a, b illustrates the total deposition of 137Cs simulated at large and local scales. The locations of the contaminated areas are correctly identified by both models. Nevertheless, deposition fields modelled with ldX are smoothed because of the size of the mesh of the model. The northwestern contamination is too far to the west as modelled by ldX, Ambient dose rate at Ebisawa town, Ibaraki Rain [mm/h] Dose rate [µGy/h] A B Simulation of total 137Cs deposited using (A) ldX and (B) pX. Values are given in becquerels per square metre (Bq/m2). Compare it with the airborne survey results published in Yoshida and Takahashi (2012 this issue). The circles correspond to the distances from the Fukushima Daiichi plant. Figure 7 Date and time (JST) Ambient dose rate at Tokyo Rain [mm/h] Dose rate [µGy/h] B Date and time (JST) Gamma dose rates (cloud and ground shine), in micrograys per hour, observed (black) and simulated with ldX (red) in (A) Ebisawa in the Ibaraki region and (B) in Tokyo. The rainfall rate, in millimetres per hour, from ECMWF data is plotted in blue. Figure 6 E lements but better reproduced by pX because of the use of wind observations. The pX simulations slightly underestimate the maximum values of radioactivity deposition close to the power plant, and the northwestern contamination is slightly too far north. Otherwise, the values of the pX deposition are correct as compared to observations. The proposed scenario for the Fukushima accident can be indirectly evaluated by comparing simulations with observations recorded on other continents. Indeed, radioactive materials were detected on the western coast of the United States as early as March 16 (Bowyer et al. 2011; Diaz Leon et al. 2011) and arrived in most European countries on March 23–24 (Masson et al. 2011). The ldX model has been used to model the transport and evolution of the plume in the northern hemisphere. Preliminary comparisons in Masson et al. (2011) show that the predicted plume arrival times and the global patterns are consistent with observations over Europe. 199 J une 2012 Conclusions and Perspectives Models have been used to describe four different periods of radioactivity release as a result of the accident at the Fukushima Daiichi nuclear power plant. Three of the releases resulted in exposures to the population because of the movement of the plumes. The main ground contamination in Japan was caused by wet deposition northwest and south of the plant. When comparisons between model and observations are possible, results show that the modelled results are realistic. For some events, the lack of actual observations prevents validation. Despite the good agreement between model and observations, many uncertainties remain in the source term and the meteorological conditions. An inverse modelling approach, as proposed by Winiarek et al. (2012), which was extended to gamma dose-rate measurements, may improve the source term assessment. For uncertainties, an ensemble approach may also be used (Mallet and Sportisse 2008). This method is based on an ensemble of simulations and is carried out using several dispersion models and/or a set of perturbed input data to describe their uncertainties. This approach allows one to quantify the uncertainties in References Bailly du Bois P, Laguionie P, Boust D, Korsakissok I, Didier D, Fiévet B (2012) Estimation of marine source-term following Fukushima Dai-ichi accident. Journal of Environmental Radioactivity, in press Baklanov B, Sørensen JH (2001) Parameterisation of radionuclides deposition in atmospheric long-range transport modelling. Physics and Chemistry of the Earth B26: 787-799 Boutahar J, Lacour S, Mallet V, Quélo D, Roustan Y, Sportisse B (2004) Development and validation of a fully modular platform for numerical modelling of air pollution: POLAIR. International Journal of Environmental Pollution 22: 17-28 Bowyer TW, Biegalski SR, Cooper M, Eslinger PW, Haas D, Hayes JC, Miley HS, Strom DJ, Woods V (2011) Elevated radioxenon detected remotely following the Fukushima nuclear accident. Journal of Environmental Radioactivity 102: 681-687 Chino M, Nakayama H, Nagai H, Terada H, Katata G, Yamazawa H (2011) Preliminary estimation of release amounts of 131I and 137Cs accidentally discharged from the Fukushima Daiichi nuclear power plant into the atmosphere. Journal of Nuclear Science and Technology 48: 1129-1134 Diaz Leon J, Jaffe DA, Kaspar J, Knecht A, Miller ML, Robertson RGH, Schubert AG (2011) Arrival time and magnitude of airborne fission products from the Fukushima, Japan, reactor incident as measured in Seattle, WA, USA. Journal of Environmental Radioactivity 102: 1032-1038 DOE (2011) Radiation monitoring data from Fukushima Area 04/04/2011. U.S. Department of Energy, www.slideshare. net/energy/ams-data-april-4v1 Herviou K, Calmtorp C (2004) Method ology and tools for source term assessment in case of emergency. Radiation Protection Dosimetry 109: 53-57 E lements the model output. Inverse modelling and ensemble methods appear to be powerful tools that should be used for operational purposes during emergency management. The Fukushima accident has also highlighted other needs, such as the importance of having a monitoring strategy. As an example, gamma dose-rate observations were very useful, and airborne observations played a key role during the crisis. Nevertheless, even with these methods, the uncertainties are large. More activity-concentration and gamma-ray spectroscopy measurements, combined with rainfall measurements, would have significantly reduced the uncertainty in the modelled values. Acknowledgments The source term assessment was done in collaboration with D. Corbin and J. Denis. They are gratefully acknowledged. The authors thank Météo-France for providing meteorological forecasts and especially J. P. Tonnelier for his decisive help in interpreting meteorological data and for sharing his expertise. The authors gratefully acknowledge the stakeholders of the IRSN technical crisis centre for their work during the Fukushima crisis. Louis J-F (1979) A parametric model of vertical eddy fluxes in the atmosphere. Boundary-Layer Meteorology 17: 187-202 Mallet V, Sportisse B (2008) Air quality modeling: From deterministic to stochastic approaches. Computers & Mathematics with Applications 55: 2329-2337 Masson O and 81 coauthors (2011) Tracking of airborne radionuclides from the damaged Fukushima Dai-Ichi nuclear reactors by European networks. Environmental Science & Technology 45: 7660-7677 MEXT (2011) Airborne observations of Cs-137 deposit. Ministry of Education, Culture, Sports, Science and Technology of Japan, http://radioactivity.mext.go. jp/ja/1940/2011/08/1940_0831.pdf NISA (2011) Regarding the evaluation of the conditions on reactor cores of Unit 1, 2 and 3 related to the accident at Fukushima Dai-ichi Nuclear Power Station, TEPCO. Nuclear and Industrial Safety Agency, news release June 6, 2011, www.nisa.meti.go.jp/english/ press/2011/06/en20110615-5.pdf NSC (2011) Trial estimation of emission of radioactive materials (I-131, Cs-137) into the atmosphere from Fukushima Dai-ichi Nuclear Power Station. Nuclear Safety Commission, press release April 12, 2011, www.nsc.go.jp/NSCenglish/ geje/2011%200412%20press.pdf NSC and MEXT (2011) SPEEDI dose prediction maps. http://www.nsc.go.jp/ mext_speedi/index_2-1.html Pasquill FA (1961) The estimation of the dispersion of windborne material. Meteorological Magazine 90-1063: 33-49 Quélo D, Krysta M, Bocquet M, Isnard O, Minier Y, Sportisse B (2007) Validation of the Polyphemus platform on the ETEX, Chernobyl and Algeciras cases. Atmospheric Environment 41: 5300-5315 200 Soulhac L, Didier D (2008) Projet pX, note de principe pX 1.0. Note technique IRSN/DEI/SESUC/08-39 Stohl A, Seibert P, Wotawa G, Arnold D, Burkhart JF, Eckhardt S, Tapia C, Vargas A, Yasunari TJ (2011) Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition. Atmospheric Chemistry and Physics Discussions 11: 28319-28394 TEPCO (2011) Plant status of Fukushima Daiichi Nuclear Power Station (as of 2:00 PM Mar 23). Tokyo Electric Power Company, press release, www.tepco.co. jp/en/press/corp-com/release/11032312e.html Terada H, Chino M (2008) Development of an atmospheric dispersion model for accidental discharge of radionuclides with the function of simultaneous prediction for multiple domains and its evaluation by application to the Chernobyl nuclear accident. Journal of Nuclear Science and Technology 45: 920-931 Troen IB, Mahrt L (1986). A simple model of the atmospheric boundary layer; sensitivity to surface evaporation. Boundary-Layer Meteorology 37: 129-148 Winiarek V, Bocquet M, Saunier O, Mathieu A (2012) Estimation of errors in the inverse modeling of accidental release of atmospheric pollutant: Application to the reconstruction of the cesium-137 and iodine-131 source terms from the Fukushima Daiichi power plant. Journal of Geophysical Research 117: D5, doi: 10.1029/2011JD016932 Yoshida N, Takahashi Y (2012) Landsurface contamination by radionuclides from the Fukushima Daiichi nuclear power plant accident. Elements 8: 201-206 J une 2012 Land-Surface Contamination by Radionuclides from the Fukushima Daiichi Nuclear Power Plant Accident Naohiro Yoshida1 and Yoshio Takahashi2 1811-5209/12/0008-0201$2.50 DOI: 10.2113/gselements.8.3.201 R adionuclides, such as 134Cs, 137Cs, and 131I, were released during the Fukushima Daiichi nuclear power plant accident in March 2011. Their distribution was monitored by airborne surveys and soil sampling. The most highly contaminated areas are to the northwest of the plant and in the Naka-dori region of Fukushima Prefecture; this contamination was mainly the result of wet deposition on March 15. Radionuclides were also released on March 21, and they were dispersed up to 200 km south of the plant. The Cs/I ratios are different for these two events, probably because of differences in the initial ratios in the airborne plumes and the amount of wet deposition. Numerical simulations of the dispersion process and vertical profiles of radionuclides in soils are used to describe the contamination of soils. conducted four times in Fukushima between March and November 2011 (MEXT and DOE 2011; MEXT 2011a). Airborne monitoring is done using large sodium iodide ( Na I ) sc i nt i l lator detec tors installed in an aircraft. These instruments can quickly measure γ-rays emitted from radioactive materials on the ground and determine the distribution of radionuclides over large areas. The first airborne monitoring was done by DOE using 40 hours of flying time between March 17 and Keywords : airborne monitoring, soil analysis, wet deposition, vertical profile, 19 (DOE 2011); this survey revealed Fukushima Daiichi nuclear accident, radionuclides a highly contaminated area northwest of the Fukushima plant. INTRODUCTION Three subsequent surveys, conducted by MEXT and DOE, The Fukushima Daiichi nuclear power plant accident provided details on the distribution of radioactive materesulted in the release of huge amounts of radionuclides rials, generally consistent with the results of the first DOE into the environment. The total amounts of the two main survey, and showed that the area in which deposition of volatile radionuclides, 131I and 137Cs, released into the 134Cs and 137Cs totaled more than 3000 kBq/m 2 (kilobecatmosphere between March 12 and April 6, 2011, were querels per square meter) extended from the plant towards estimated to be approximately 1.5 × 1017 and 1.3 × 1016 the northwest, affecting Namie town, Minami-Soma city, becquerels (Bq), respectively (Chino et al. 2011). Due to a Katsurao village, Kawamata town, and Iitate village (Fig. strong wind from the west, most of the radionuclides were 1). Several areas in which 134Cs and 137Cs totaled more than transported out over the Pacific Ocean (Yasunari et al. 300 kBq/m 2 were also found, such as at Date city in the 2011). However, it is estimated that about 10–20% of the Naka-dori region (Fig. 1). Very high radioactivity (>3000 total radiocesium and radioiodine emitted from the power kBq/m 2 ) extended from the power plant to the Naka-dori plant were deposited over land in northeastern Japan region through the Abukuma Highland, whose elevation (Morino et al. 2011). As a consequence of the land contami- is ca 1000 m (Figs. 1 and 2). nation shown by the airborne monitoring until April 2011, The highly contaminated area (>60 kBq/m 2 ) extends into the area within 20 km of the Fukushima plant is now restricted, while other areas, such as Iitate village and a the northern parts of Tochigi and Gunma prefectures (compare this value with that originating from global part of Kawamata town, have been designated as “planned fallout around Japan, namely, a few kBq/m 2 level; Aoyama evacuation areas.” To assess the health risks and impact on et al. 2001). In particular, the highly contaminated area is food production in Fukushima Prefecture and neighboring clearly evident along the fronts of the Ohu, Shimotsuke, prefectures, the spatial distribution of the radionuclides is and Echigo mountainous regions. A three-dimensional of critical importance. image (Fig. 2) confirms the close relationship between the distribution of the radionuclides and the higher elevations AIRBORNE MONITORING (MEXT 2011b). Planned evacuaon areas OF LAND CONTAMINATION Airborne monitoring of radioactivity by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and the U.S. Department of Energy (DOE) was 1 Department of Environmental Chemistry and Engineering Tokyo Institute of Technology G1-17, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan E-mail: [email protected] 2 Department of Earth and Planetary Systems Science Graduate School of Science, Hiroshima University 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan E-mail: [email protected] E lements , V ol . 8, pp. 201–206 RADIONUCLIDE DISTRIBUTION IN SOILS Endo et al. (2012) sampled soils in March 2011 in areas northwest of the Fukushima plant to study the radioactive distribution at ground level. They detected the following radionuclides (with maximum depositional density values in parentheses, decay corrected to 17:00 on March 15, 2011): 129mTe (2.97 × 103 kBq/m2), 129Te (1.80 × 103 kBq/m2), 131I (1.25 × 10 5 kBq/m 2 ), 132 Te (7.53 × 10 4 kBq/m 2 ), 132I (6.98 × 10 4 kBq/m 2 ), 134 Cs (9.78 × 10 3 kBq/m 2 ), 136 Cs (3.95 × 10 2 kBq/m 2 ), 137Cs (1.01 × 10 4 kBq/m 2 ), 201 J une 2012 Emergenc evacuao prepara areas N Miyagi Prefecture Yamagata Prefecture K akuda Pacific Ocean Date F ukus hima Miyagi Yamagata Fukushima Prefecture K awa mata MinamiS oma Iitate 30 km 20 km Nihonmats u F DNP P K ats urao Fukushima Namie F ig. 2 F DNP P K oriyama Tochigi Gunma Ibaraki Saitama Tokyo Chiba F ig. 2 0 50 The MEXT team collected soil samples from 220 0 locations throughout Fukushima Prefecture and in northern Ibaraki and southern Miyagi prefectures. The depth of the sampled soil can affect the measured radioactivity, since the analytical result is reported as becquerels per kilogram (Bq/kg) after homogenization of the soil sampled between the surface and the given depth. Thus, the soil sample up to 5 cm depth was collected using a 5 cm core sampler with a specific cross-sectional area, since more than 90% of the 131I, 134Cs, and 137Cs was found above this depth; after analysis, the radionuclide concentrations were converted to the unit Bq/m 2 . Maps showing the distribution of 134 Cs, 137Cs, 129mTe, and 110m Ag were prepared (MEXT 2011c, d). Total deposition of 134Cs and 137Cs (Bq/m2) > 3000 k 1000 k–3000 k 600 k–1000 k 300 k–600 k 100 k–300 k 60 k–100 k 30 k–60 k 10 k–30 k < 10 k No data 100 km Naka-dori region Tochigi Prefecture Ibaraki Prefecture 0 10 km Distribution of 134Cs + 137Cs measured during airborne monitoring. (A) Distribution in the northern part of Honshu Island. The red dashed box corresponds to the area in Figure 2. The red arrow indicate the direction of view in Figure 2. (B) Distribution within 80 km of the Fukushima Daiichi nuclear power plant (FDNNP). Decay corrected to July 2 and November 1, 2011, in (B) and (A), respectively. Modified from MEXT and DOE (2011) and MEXT (2011a) Figure 1 140Ba (1.03 × 102 kBq/m 2 ), and 140La (1.16 × 102 kBq/m 2 ). Kinoshita et al. (2011) reported the spatial distributions of 129mTe, 131I, 134 Cs, 136 Cs, and 137Cs based on the analysis of soil samples collected in March and April 2011 in Fukushima and Ibaraki prefectures. Later, the MEXT team made accurate radionuclide maps with a 2 km mesh within a 100 km radius of the power plant (MEXT 2011c). After the accident at the Fukushima plant, volatile radionuclides, such as 134Cs, 137Cs (the boiling points of Cs, I, and Te are 671 °C, 184 °C, and 988 °C, respectively), were S himots uke m. Gunma Tokyo N E chigo m. Saitama Ohu m. Tochigi Chiba Fukushima Ibaraki Yamagata Total deposition of 134Cs + 137Cs > 3000 k 1000 k – 3000 k 600 k – 1000 k 300 k – 600 k 100 k – 300 k 60 k – 100 k 30 k – 60 k 10 k – 30 k (unit: Bq/m2) < 10 k Abukuma highland Miyagi F DNP P Three-dimensional map showing an oblique view of exaggerated topography and 134Cs + 137Cs concentrations measured during airborne monitoring; these results show that radiocesium was deposited outside of the mountainous areas. Decay corrected to October 13, 2011. Modified from MEXT (2011b) Figure 2 E lements presumed to have been released to the atmosphere as gases, considering that the temperature in the reactor at the time of the meltdown was possibly 2100–2300 °C (Barrachin et al. 2008). Although the chemical species of the radionuclides during emission are not known, their volatilities can be estimated from the elemental boiling points. On the other hand, some radionuclides, such as 95Zr, 103Ru, and 106Ru, which were found in Chernobyl fallout, were not observed in the soil analyses, possibly due to the refractory properties of these radionuclides (Tagami et al. 2011). After release to the environment, the chemical species of Cs, I, and Te may have been, respectively, Cs +; I2, CH3I, I-, and IO3 - ; and HTeO4 - (Santschi et al. 1988). The distribution of 137Cs in soils (MEXT 2011c; Fig. 3) showed that the highly contaminated area was to the northwest of the power plant; this result was consistent with measurements from the airborne survey. The activity of 137Cs was highest in Okuma town (15,500 kBq/m2 ; point 1 in Fig. 3), close to the plant (<3 km), where the radiation dose at 1 m height was 480 mSv/y (millisieverts per year) as measured at each sampling site by the MEXT team. The activity of 137Cs was second highest around the border between Namie town and Iitate village (7900 kBq/m 2 ; radiation dose: 367 mSv/y; point 2 in Fig. 3), about 30 km northwest of the plant. Moderate radioactivity (100–600 kBq/m2) was found in the Naka-dori region. The 2 km scale sampling mesh used in this MEXT project revealed that there was a heterogeneous distribution even within small areas, which was not evident in the airborne survey. For example, point 2 mentioned above was located near a lowactivity location (870 kBq/m 2 ; point 3), as shown in the inset of Figure 3. The distribution of 129mTe (MEXT 2011d; data not shown) was similar to that of 137Cs, suggesting that 129mTe was also emitted as a gas. A larger concentration of 129mTe was found south of the plant, possibly because of the migration of radioactive plumes with different 129mTe/137Cs ratios. However, the distribution of 110m Ag (data not shown) was not similar to that of 137Cs. The emission and distribution mechanisms of 110m Ag may be different from those of 137Cs and 129mTe, because 110m Ag may not be emitted as a gas on account of its refractory nature (boiling point of Ag = 2164 °C). Determination of the concentrations of 129I, 131I, 89Sr, and 90 Sr in soil is in progress (e.g. MEXT 2011e, f). Since the soil sampling and analysis by MEXT were conducted between June 4 and 29, data for short-lived nuclides, such as 131I, were obtained only for about 20% of the sites (MEXT 2011e). If it is assumed that the 129I/131I ratio is constant 202 J une 2012 Point 3 Point 2 Different spatial distribution patterns for 129mTe, 131I, and 137Cs can be generated by variable air movements and rainfall patterns, coupled with variable 131 I/137Cs and 129mTe/137Cs ratios in the plume, as seen from the contrasting ratios of I and Cs released from the power plant (Fig. 5). Considering the possibility that 131I can cause more serious health effects, as was seen at Chernobyl (Cardis et al. 2005), the distribution of 131I obtained by Kinoshita et al. (2011) is very important, particularly for the radiological dose assessment of the accident. The 129I mapping planned by MEXT is expected to confirm the 131I results obtained by Kinoshita et al. (2011). 100 km 80 km Point 1 2 km Plutonium isotope ratios different from those of the global fallout were found in a sample collected 1.7 km from the power plant and in three soil samples taken northwest and south of the plant in the 20–30 km radius zone (Zheng et al. 2012; Yamamoto et al. 2012). Further studies on the distribution of plutonium within 20 km of the plant are needed. COMPARISON OF SIMULATED AND OBSERVED RESULTS 137Cs Emergency evacuaon preparaon areas Planned evacuaon areas (Bq/m2; As of June 14) > 3000 k 1000 k–3000 k 600 k–1000 k 300 k–600 k 100 k–300 k 60 k–100 k 30 k–60 k 10 k–30 k < 10 k Distribution of 137Cs as determined from soil samples collected on a 2 or 10 km grid. Decay corrected to June 14, 2011. Modified from MEXT (2011c) Figure 3 for the radioiodine emitted during the accident, the determination of 129I using accelerator mass spectroscopy (Matsuzaki et al. 2007) allows one to estimate the distribution of 131I. Thus, the analysis of 129I is important as a complement to the 131I mapping. Kinoshita et al. (2011) collected soil samples from shortly after the accident until the end of April 2011 and determined the distributions of short-lived nuclides, such as 131I (half-life = 8.0 days), 129mTe (34 days), and 136Cs (13 days) (F ig. 4). In addition, the sampled area extends from Fukushima through all of Ibaraki Prefecture. The ratios of the three radiocesium isotopes (134Cs, 136Cs, and 137Cs) were constant over the whole area. On the other hand, the distributions of 129mTe, 131I, and 137Cs were different, especially in Ibaraki Prefecture. Also, 129mTe was more concentrated immediately south of the power plant, as compared to 137Cs (see 129mTe/137Cs activity-ratio map in Fig. 4). A similar tendency is also shown by the 131I/137Cs ratio (Fig. 4). According to previous studies of radionuclide emissions from the Chernobyl reactor (Muramatsu et al. 1987), most radionuclides are distributed as wet deposition (rainfall events). The main wet-deposition events after the Fukushima accident occurred on March 15–16 in northern Fukushima Prefecture and on March 21–23 in Ibaraki and Chiba prefectures, south of Fukushima, when transient cyclones entered these areas (Figs. 4, 5). Kinoshita et al. (2011) pointed out that the air mass around the power plant stayed in northern Fukushima Prefecture and that the radionuclides were deposited with rainfall and snowfall in the area on March 15 and 16 (Fig. 4). On the other hand, from March 21 to 23, air flowed from the plant southwards to Ibaraki and Chiba prefectures, accompanied by rainfall. E lements In order to understand the temporal variation of radionuclide deposition and the mechanisms of contamination, numerical models that consider the meteorological conditions, the concentration and depositional amounts of radionuclides, and the resulting radiation doses have been developed. Such simulations have been done for radionuclide distributions on land (Chino et al. 2011; Morino et at al. 2011; Katata et al. 2012) and in the Pacific Ocean (Yasunari et al. 2011; Honda et al. 2012). Details about simulation studies of the atmospheric and oceanic dispersion of radionuclides are given by Mathieu et al. (2012) and Masumoto et al. (2012), respectively, in this issue. Here, we focus on simulation studies of the temporal variation of radionuclide emission and deposition over land. Katata et al. (2012) estimated temporal variations in the release rates of radionuclides, in plume movement, and in the spatial distributions of radionuclides at various times after the accident (Fig. 6). Briefly, the dispersion from the nuclear plant on March 15–16 can be attributed to two main processes: (1) release on the morning of March 15 by a plume moving southwestwards from the plant, which created high radioactivity in the Naka-dori region; (2) release in the afternoon of March 15 from another highconcentration plume flowing northwestwards from the plant, which, coupled with rainfall, resulted in high activities in the northern part of Fukushima Prefecture (i.e. Iitate village). Temporal variations in the deposition and emission rates from the power plant in March are summarized in Figure 5 (Morino et al. 2011). On March 15–16, high emission rates of 137Cs and 131I, coupled with easterly winds and precipitation, caused the deposition of large amounts of radionuclides in Fukushima, Miyagi, Ibaraki, and Tochigi prefectures. On March 21–23, although the emission rates were lower, large amounts of radioactive materials were transported over land by easterly or northeasterly winds, during periods of continuous precipitation, resulting in the second-largest event of radionuclide deposition over land. Dry deposition contributed to the concentration of 131I much more than to the concentration of 137Cs, a fact that can be explained by differences in their chemical properties (Fig. 5). Under ambient conditions, radiocesium cannot be present as gas, suggesting that all radiocesium was transported in aerosol form. These aerosols can be readily 203 J une 2012 129mTe Air parcel 16:00 March 15 Air parcel 11:00 March 21 131I 1000 100 100 10 10 1 134Cs 137Cs Rainfall amount March 15-16 Rainfall amount March 21 136Cs 30 30 20 20 10 10 10 1 0 0 100 10 100 10 1 1 0.1 129mTe/137Cs 131I/137Cs 129mTe/131I Figure 4 Distributions of 131I, 129mTe, 134Cs, and 137Cs as determined from soil samples, along with three maps of radionuclide ratios. The four maps on the right show air parcels at 16:00 JST on March 15 and at 11:00 JST on March 21, and rainfall amounts on March 15–16 and on March 21. Modified from K inoshita et al. (2011) 136Cs, 1 0.1 0.01 10 0.1 1 0.01 0.1 0.001 washed out during rainfall. However, a part of the radioiodine can be present as gas (I 2 , CH3I) that cannot be readily dissolved in water. Thus, dry deposition on land can be important in the removal of radioiodine from the atmosphere. The dry deposition fraction was larger near the power plant, in both the southwestern and northwestern directions (Katata et al. 2012). However, radionuclides in the Iitate village and Naka-dori regions were supplied mainly by wet deposition. Katata et al. (2012) also noted that topography is important in the distribution of radionuclides resulting from wet deposition. In summary, simulations of the temporal variations of emission, deposition, and distribution of radionuclides are basically in good agreement with measured distributions obtained by airborne surveys and soil sampling. VERTICAL SOIL PROFILES Examination of the vertical migration of the radionuclides in soils after deposition has shown that more than 90% of the radiocesium and 131I deposited on the soil surface was retained in a surface layer no more than 5 cm thick and that 131I penetrated to greater depth than radiocesium (Kato et al. 2012; Tanaka et al. 2012). The depth of radiocesium infiltration in the Fukushima area was deeper than that reported for cultivated soil near the Chernobyl nuclear power plant, which may be related to the smaller clay content in the Japanese soil (Kato et al. 2012). Information on vertical migration is obviously useful for present and future decontamination strategies and also for modeling the migration of radiocesium into groundwater. Direct evidence of the fixation mechanisms of the radionuclides in the top layer of the soil is limited, because the molar concentrations of the radionuclides are far below the level that can be measured by normal physicochemical methods. Indirect methods can be used only to estimate the chemical processes and to determine the host phases of the radionuclides in the soil; such methods include E lements sequential extraction and particle size analysis, followed by radioactivity measurements and imaging techniques that measure radioactivity (autoradiography). Tanaka et al. (2012) suggested that less than 1% of the radiocesium in soils can be leached either with water at various pH values or even with 2 M HCl solution (soil: 5 g; solution: 15 mL). With the addition of 1.0 M NH4Cl solution, the leached fraction increases to 5–15%, which suggests that radio cesium is strongly adsorbed into the interlayer of clay minerals (Wauters et al. 1996). Bostick et al. (2002) employed X-ray absorption spectroscopy (XAS) to show that Cs + ions are strongly bonded with oxygen atoms within the SiO4 sheets in the interlayers of clay minerals (montmorillonite and vermiculite); thus, an inner-sphere complex is formed between Cs + and the clay structure. Cations that are smaller than Cs +, such as Na + and Ca 2+, are adsorbed by clays through the formation of outersphere complexes, the stability of which is much lower than that of inner-sphere complexes. Thus, these small cations are readily exchangeable through ion-exchange reactions. On the other hand, Cs + and other cations (e.g. K+ and Tl+) are not readily exchanged because of the formation of inner-sphere complexes with the clay structure. Most likely, the Cs + species in the Fukushima soils also forms inner-sphere complexes with clays, which reduces the mobility of Cs + in soil. Less than 10% and about 30% of the 131I were leached by water and an NaOH solution (pH 10.5), respectively, from soil collected one month after the accident (Tanaka et al. 2012). The NaOH solution, with its contained 131I, was subsequently acidified to pH 2; more than 60% of the 131I in the solution precipitated, possibly with humic materials that can bind iodine to the phenyl group in the polyorganic structure (Schlegel et al. 2006). This leaching–precipitation behavior suggests that part of the iodine is associated with organics in the soil, which may be the cause of the low rate of leaching of 131I from the soil by water. The formation of organic iodine in natural soil has been suggested 204 J une 2012 I deposition (kBq/m2day) deposition (kBq/m 2day) Emission rate (Bq/h) C (a) 131I deposition 1200 1000 Total (wet + dry) deposion 800 600 Wet deposion 400 200 0 150 (b) 137Cs deposition Total (wet + dry) deposion 100 Wet deposion A B 50 137Cs B cesium onto soil particles, the migration of radiocesium into groundwater as a result of the infiltration of water through the soil layer is unlikely (e.g. Ohta et al. 2012). On the other hand, strong adsorption to soil particles facilitates the migration of radiocesium, mainly as particulate matter, in rivers that receive the runoff from the contaminated area. A high content of particulate matter, such as colloids, results in the redistribution of radioactivity from highly contaminated areas into the fluviatile environment, and finally into lake and ocean sediments. Migration through river systems has been suggested by results from airborne monitoring within 80 km of the Fukushima plant 1400 131 A 0 10 16 10 15 10 14 10 13 (c) Emission rate 131 I 137 Cs 10 12 12 16 20 24 28 March Figure 5 Wet and total (= wet + dry) deposition rates over land (Fukushima, Miyagi, Ibaraki, and Tochigi prefectures) for (A) 131I and (B) 137Cs obtained by the simulation of Morino et al. (2011). (C) Temporal variation in March 2011 of emission rates of 137Cs and 131I from the Fukushima plant (Chino et al. 2011). Shaded bars show the periods when transient cyclones passed over Japan, accompanied by northeasterly, easterly, or southeasterly winds. previously by XAS and by X-ray fluorescence analysis using an X-ray microbeam (Shimamoto et al. 2011). The formation of organo-iodine species in soil with a high organicmatter content proceeds over a relatively short period, even within a day (Yamaguchi et al. 2010; Shimamoto et al. 2011). Thus, the formation of organo-iodine is possible for 131I in the soil within about a month after it is deposited. FUTURE MIGRATION IN THE ENVIRONMENT In addition to determining the initial distribution of the radionuclides at ground level, it is equally important to follow the migration of the radionuclides in various environments via the atmosphere and hydrosphere (Yoshida and Kanda 2012). Redistribution of radionuclides through the atmosphere has been suggested (e.g. MEXT 2011a). In particular, the secondary transport of radioactive dust that has been resuspended and redeposited by wind and/or rain has been monitored in Fukushima. This effect may be responsible for the apparently more rapid decay of the measured activity in the highly contaminated areas, that is, by the removal of highly radioactive dust particles and their redistribution into moderately contaminated areas (Yamauchi 2012). In addition, the dispersion of radionuclides by pollen is being followed during the pollen season, February to May, because it is suspected that a part of the radiocesium in soil can be absorbed by plants and trees and dispersed via the pollen from these plants. However, the main pathway for the redistribution and migration of radionuclides must be through the hydrological system. Considering the strong adsorption of radioE lements Simulated spatial distributions of (A) air dose rate and (B) rainfall intensity (colored areas) and surface wind directions (small arrows). Values beside circles represent observed air dose rates at monitoring posts, given in micrograys per hour. Modified from K atata et al. (2011) 205 Figure 6 J une 2012 (MEXT and DOE 2011) between October 22 and November 5, 2011 (MEXT 2011a). When compared to data obtained between May 30 and July 2 (the wet season is roughly from June to September), these results suggest that there has been a redistribution of radionuclides into the estuaries of several rivers in Minami-Soma (see Fig. 1) and into a basin in the middle of the Abukuma River in Kakuda city, in Miyagi Prefecture (see Fig. 1). More quantitative data on the runoff of the radionuclides from land and their flux and pathways to the ocean must be obtained as a References Aoyama M, Hirose K, Miyao T, Igarashi Y, Povine PP (2001) Temporal variation of 137 Cs inventory in the western North Pacific. Journal of Radioanalytical and Nuclear Chemistry 248: 785-787 Barrachin M, Chevalier PY, Cheynet B, Fischer E (2008) New modelling of the U–O–Zr phase diagram in the hyperstoichiometric region and consequences for the fuel rod liquefaction in oxidising conditions. 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Proceedings of the National Academy of Sciences 108: 19530-19534 Yoshida N, Kanda J (2012) Tracking the Fukushima radionuclides. Science 336: 1115-1116 Zheng J and 9 coauthors (2012) Isotopic evidence of plutonium release into the environment from the Fukushima DNPP accident. Scientific Reports 2: 304, doi:10.1038/srep00304 J une 2012 Oceanic Dispersion Simulations of 137 Cs Released from the Fukushima Daiichi Nuclear Power Plant Yukio Masumoto1, Yasumasa Miyazawa1, Daisuke Tsumune2 , Takaki Tsubono2 , Takuya Kobayashi3, Hideyuki Kawamura3, Claude Estournel4, Patrick Marsaleix4, Lyon Lanerolle5, 6, Avichal Mehra7, and Zulema D. Garraffo8 1811-5209/12/0008-0207$2.50 DOI: 10.2113/gselements.8.3.207 F ive models have been used to estimate the oceanic dispersion of 137Cs from the Fukushima Daiichi nuclear power plant during March and April 2011, following the accident on March 11, 2011. The total discharged activity of 137Cs is estimated to be 2 to 15 petabequerels. A weak southward current along the Fukushima coast was responsible for the initial transport direction, while mesoscale eddy-like structures and surface-current systems contributed to dispersion in areas beyond the continental shelf. Most of the discrepancies among the models in April are caused by differences in how the mesoscale current structures off the Ibaraki coast are represented. Keywords : oceanic dispersion simulation, radionuclides, 137Cs, Fukushima Daiichi nuclear power plant, regional ocean simulation, mesoscale eddy INTRODUCTION A devastating earthquake and huge tsunami struck the Tohoku area, Japan, on March 11, 2011, causing major damage to the cooling systems of reactors in the Fukushima Daiichi nuclear power plant, operated by Tokyo Electric Power Company (TEPCO). In order to cool the reactor cores and the spent fuel in storage pools, large amounts of seawater and freshwater were used. A significant part of this radioactivity-contaminated water was discharged into the Pacific Ocean close to the power plant. In addition, several hydrogen explosions between March 12 and 15 resulted in the release of significant radioactivity into the atmosphere, some of which was deposited onto the sea surface over a wide area of the Pacific Ocean. Careful monitoring combined with modeling of the dispersion of the radioactivity provide critical information (1) on the processes responsible for dispersion of the radionuclides, (2) for simulation and prediction of the spread of radioactivity in the seawater, and (3) for the evaluation of the impact on the health of marine ecosystems and humans. Since the accident at the Fukushima plant, several groups have been conducting numerical dispersion simulations of radionuclides discharged into the ocean, each group having different objectives. Some of the results from the simulations have been used to determine locations of monitoring observations off the east coast of Japan. This article reviews the present status of such simulations, without considering 1 Research Institute for Global Change Japan Agency for Marine-Earth Science and Technology Yokohama, Kanagawa 236-0001, Japan 2 Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko Abiko-shi, Chiba-ken 270-1194, Japan pp. 207–212 DISPERSION SIMULATION MODELS Numerical simulations of the dispersion of radionuclides in the ocean basically consist of two parts: an ocean circulation model and a radionuclide dispersion model. The ocean circulation model provides evolving circulation patterns for the dispersion model, while the dispersion model calculates the movement and spread of radionuclides in the ocean. In this article, we compare results from five groups: the Central Research Institute of Electric Power Industry (CRIEPI), the Japan Atomic Energy Agency (JAEA), the Japan Coastal Ocean Predictability Experiment (JCOPE) group at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the Simulation Réaliste de l’Océan Côtier (Sirocco) group from the Observatoire Midi-Pyrénées, Centre National de la Recherche Scientifique and Toulouse University, and the National Oceanographic and Atmospheric Administration (NOAA) group. Each group utilized a different set of models (Table 1). All of the models have their finest regional domain resolution focused on the area close to the nuclear plant, with various grid spacings in both the horizontal and vertical directions. Lateral boundary conditions of the circulation models are typically obtained from larger domain ocean circulation models, with relatively coarse resolutions, into which observed data, such as temperature, salinity, and sea-surface height, are assimilated to provide realistic upper-ocean conditions. With these assimilation schemes, mesoscale eddies and meandering of ocean currents, which are crucial 4 CNRS, Toulouse University, Laboratoire d’Aérologie, 14 Avenue Edouard Belin F-31400 Toulouse, France 5 Earth Resources Technology, Inc. Laurel, Maryland 20707, USA 6 National Oceanic and Atmospheric Administration Silver Spring, Maryland 20910, USA 3 Japan Atomic Energy Agency, 2-4 Shirane Shirakata, Tokai-mura, Naka-gun Ibaraki 319-1195, Japan E lements , V ol . 8, atmospheric deposition, and describes common aspects and discrepancies among the simulated results. The article also points out potential problems and provides guidance for future studies. This is the first attempt to conduct an intercomparison of models for the oceanic dispersion of 137Cs from the Fukushima plant. 207 7 National Centers for Environmental Prediction/National Weather Service/ National Oceanic and Atmospheric Administration Camp Springs, Maryland 20746, USA 8 I.M. Systems Group, Inc. Camp Springs, Maryland 20746, USA Corresponding author: Yukio Masumoto ([email protected]) J une 2012 Table 1 Model name Model specifications Base model Circulation Dispersion JAEA Kyoto U./ JMSF b SEA-GEARNc CRIEPI ROMSf JCOPET Resolutiona Nesting (parent model) Winds Data assimilation Tides Integration period Reference NCEP reanalysis 2 d 4D-VAR and JMA- MSMe No March 11– April 30 Kawamura et al. (2011) Passive tracer 1/72° × 1/54° 2-step, (1/24° × 1/18° near Japan, 1/8° × 1/6° North Pacific, Kyoto U./JMSF b) 1 km 1-step, (1/12° HYCOMg) NuWFASh Yes Tsumune et al. (2011) JCOPE i Passive tracer 1/36° NCEP analysis and JMA-MSM Sirocco Siroccoj Passive tracer 600 m 2-step, (1/12° Northwest Pacific, 1/4° North Pacific, JCOPE2i) 1-step, (NCOM k) March 1– May 31 March 21– May 6 Toulouse University (2011) NOAA ROMSf Passive tracer 1 km 1-step, (NCOM k)) March 11– to present March 10– June 27 ECMWF forecast l US Navy’s COAMPSm (via NCOM) Included in HYCOM 3D-VAR in JCOPE2 Included in NCOM Included in NCOM Yes Yes Yes a The finest grid spacing is indicated, if grid system is variable in space. b Kyoto University and Japan Marine Science Foundation (Ishikawa et al. 2009). c Kobayashi et al. (2007). d Kanamitsu et al. (2002). e Japan Meteorological Agency – Meso-Scale Model. f Regional Ocean Modeling System (Shchepetkin and McWilliams 2005). g Hybrid Coordinate Ocean Model (http://hycom.org/). h Numerical Weather Forecasting and Analysis System (Hashimoto et al. 2010). i Japan Coastal Ocean Prediction Experiment (Miyazawa et al. 2009). j http:// sirocco.omp.obs-mip.fr/outils/Symphonie/Produits/Japan/SymphoniePreviJapanDescript.htm/. k The U.S. Navy Operational Global Ocean Model (Barron et al. 2004). l European Centre for Medium-Range Weather Forecasts (http://www.ecmwf.int/). m Coupled Ocean/ Atmosphere Mesoscale Prediction System (http://www.nrlmry.navy.mil/coamps-web/web/home) for the radionuclide dispersion in the open ocean, are adequately represented. Tidal currents are also included in several models in order to reproduce realistic spatial– temporal current variations near the coastal regions. Although most of the groups are conducting dispersion calculations for several radionuclides, such as 131I, 134Cs, and 137Cs, we focus only on 137Cs in this article, since it has a significantly long half-life of ~30 years and is observed in a wide area of the northwestern Pacific Ocean. All five groups are now considering both direct discharge and atmospheric deposition in their calculations, but we discuss here only the results without atmospheric deposition. SOURCE ESTIMATION The temporal evolution and amount of radioactivity released to the ocean and atmosphere from the plant are key pieces of information for dispersion simulations. In general, the source conditions are not readily available for this kind of accident, leaving a large uncertainty in the simulated results. One of the main purposes of the oceanic dispersion simulations is, therefore, to estimate the source information, using inversion techniques, as accurately as possible. So far, several estimates of the amount of 137Cs discharged into the ocean have been reported, which are summarized in Table 2 and Figure 1. Note that the values come not only from peer-reviewed scientific papers but also from unreviewed articles. TEPCO reported that the estimated total amount of 137Cs discharged directly into the ocean through a crack in the concrete wall near the reactor of Unit 2 during April 1–6 was 0.94 petabecquerels (PBq), which is equivalent to about 25 kilocuries (kCi) (TEPCO 2011a). In Figure 1, this amount is indicated by a gray bar, assuming that the discharge occurred constantly for five days from April 1. On a few other occasions, TEPCO reported discharges of contaminated water into the ocean, but those were two to five orders of magnitude smaller in terms of radioactivity than the amount released during April 1–6. Kawamura et al. (2011) estimated the amount of 137Cs discharged into the ocean (red line in Fig. 1) using radioactivity data measured near the power plant by TEPCO (2011b) (black line in Fig. 1); they assumed that the contaminated water of the observed concentration occupied an area of 1.5 km 2 in front of the plant and was 1 m E lements deep. After adjustment to the values reported by TEPCO for the period of April 1–6, a value of 4 PBq was obtained. The time series of the source information thus estimated (red line in Fig. 1) shows two peaks of release at the end of March and the beginning of April, with a magnitude of about 0.4 PBq day-1. After April 7, the discharge diminished exponentially to about 0.001 PBq day-1 at the end of April. On the other hand, Tsumune et al. (2011) estimated a source function of 137Cs by multiplying by a factor to adjust their model results, with a unit release of the radionuclide, to the observed values, giving a total of 3.5 PBq of 137Cs discharged directly into the ocean (Fig. 1, blue line). They provided a simple scenario for the time evolution of the radionuclide discharge, in which they assumed that the time fluctuation of the observed radioactivity is associated with dispersion processes after entering the ocean. Indeed, Tsumune et al. (2011) are successful in reproducing a detailed time evolution similar to that observed at several locations along the coast south of the plant, including 137Cs maxima observed on March 30 and April 6 near the plant. Time series of source information for 137Cs. The black line with solid circles is the time series of 137Cs radioactivity in the open ocean near the Fukushima plant (right scale, in becquerels per liter). The values were obtained by averaging the radioactivity observed by TEPCO at the northern and southern drainage points of the plant. The red and blue lines are the time series of 137Cs released into the ocean as estimated by Kawamura et al. (2011) and Tsumune et al. (2011), respectively (left scale, in petabecquerels per day). The gray bar indicates the 137Cs discharge estimated by TEPCO, assuming a constant discharge between April 1 and 5 (left scale). 1 petabecquerel (PBq) = 1015 Bq 208 Figure 1 J une 2012 Several other estimates, including those by the Sirocco, NOAA, and JCOPE groups, were basically obtained from numerical models using the TEPCO data. The values obtained by Sirocco and NOAA, about 3 to 4 PBq of 137Cs discharged directly into the ocean, are similar to those derived by Kawamura et al. (2011) and Tsumune et al. (2011). The second report from the Institut de Radioprotection et de Sûreté Nucléaire (IRSN) on the impact of radioactivity released from the plant on the marine environment (IRSN 2011a) estimated the amount of radioactivity discharged until April 11 to be 2.3 PBq, which is somewhat smaller than other estimates. Another IRSN report shows a significantly large value of 27 PBq of 137Cs (IRSN 2011b), which seems to have been derived by simple interpolation of sparsely observed data and assuming constant radioactivity within a relatively thick surface mixed-layer in March. A relatively large estimate of 14.8 PBq from JCOPE is mainly due to relatively coarse horizontal resolution with a simple boundary condition, in which the simulated 137Cs concentration at the sea surface in front of the plant is forced to adjust toward the observed value. Most of the above estimates rely on radioactivity measurements by TEPCO near the nuclear plant. Errors in the TEPCO data, if any, can propagate into these estimates directly. Another factor affecting the value of estimated source information is the vertical distribution of radionuclides, especially in the oceanic surface layer. The surface mixed-layer defined by temperature or water density can be relatively thick in March due to winter cooling at the sea surface and subsequent vertical convective motion. We do not know at this stage, however, whether or not the radionuclides are also evenly distributed vertically within the surface mixed-layer. In this regard, the values in Table 2 should be considered to have large uncertainties. DISPERSION SIMULATIONS With the above-mentioned source information for simulating the dispersion of radionuclides in the ocean, time series of the three-dimensional distribution of 137Cs were obtained from each model. In this section, we compare these results, focusing on the surface distribution of 137Cs in the coastal and continental shelf regions during the first two months after the accident. We present 10-day averaged surface horizontal-velocity fields and 137Cs distributions for two periods, from March 22 to 31 (Fig. 2) and from April 21 to 30 (Fig. 3). These periods correspond, respectively, to a time of southward dispersion along the Fukushima coast and to a time of gradual dispersion toward the margin of the continental shelf. Monitoring of the radionuclides was conducted by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Table 2 a Estimated amount of 137Cs TEPCO during March and April, 2011 (MEXT 2011; TEPCO 2011b), and comparisons of the simulated results with the observations are also made for the two periods. March 22–31 A lack of observational data prevents us from providing a detailed description of the 137Cs distribution at the end of March. The monitoring observations, however, indicate high concentrations of 137Cs along the coast, near the nuclear plant (Fig. 2g). The data along a line 30 km offshore from the coast also show 137Cs contamination, with a magnitude of about 10 to 15 Bq L -1. These observed values are significantly higher than those observed in Japanese coastal waters before the accident, a typical value of which is about 0.003 Bq L -1 (Kasamatsu and Inatomi 1998). In general, the surface current fields in all the models show a strong eastward or northeastward flow—the Kuroshio current—along the coast of Japan south of Inubo Peninsula. The current separates from the coastal area off Inubo Peninsula. The models also show a broad southward flow, with a speed of 0.2 to 0.5 m s-1, in the region east of 141.5° E and north of the Kuroshio current (Fig. 2a-e). All models demonstrate a weak southward flow, with a speed of 0.1 m s-1 or less, along the coast in front of the Fukushima plant. This southward current along the coast is responsible for the southward distribution of 137Cs at the end of March. The southward flow along the coast can be traced back up to 38° N in all the models, while the speed of the flow varies among the models and, in the JCOPET model, is partially associated with a cyclonic circulation off the coast of Fukushima. The local flow pattern in this region is susceptible to wind forcing, which shows higher temporal variability associated with synoptic weather disturbances. All the models fail to simulate the relatively high concentration of 137Cs along a line 30 km offshore. Since the results shown here are the dispersions of 137Cs released directly from the plant, it is reasonable to expect that this offshore contamination at the end of March was due to deposition from the atmosphere. This is consistent with the conclusion of Tsumune et al. (2011), who showed the importance of deposition from the atmosphere by checking the 131I/137Cs activity ratio. Another important surface current pattern is eddy-like structures off the coast of Ibaraki in the region between 36.7° N and the Kuroshio current; in this region, the differences among the models are rather large. A clear example is an anticyclonic circulation centered at 36.4° N, 141° E in the CRIEPI result. A similar eddy structure can also be seen in other model results, but it is relatively weak and shifted slightly to the east in the JCOPET model, and it appears as a part of a strong dipole eddy structure in the discharged directly into the ocean Institution Period 137Csa TEPCO April 1~April 6 0.94 Based on observed data Media release IRSN Up to April 11 2.3 Based on observed data IRSN (2011a) IRSN March 25~July 18 27 Simulated results with observed boundary conditions IRSN (2011b) Method Reference JAEA March 21~April 30 3.58 Based on observed data Kawamura et al. (2011) CRIEPI March 26~May 31 3.54 Unit release experiment with adjustment to observed values Tsumune et al. (2001) JCOPE March 21~May 6 14.8 Based on observed data NOAA March 10~June 27 3.6 Based on observed data (data from Kawamura et al. 2011) Sirocco March 20~June30 4.2 Inverse model based on observed data In petabecquerels (1 PBq = 1015 Bq) E lements 209 J une 2012 Horizontal distribution of Cs and horizontal current velocity at the sea surface (0–1 m below the sea surface for (A) CRIEPI model, (B) JAEA model, (C) JCOPET model, (D) Sirocco model, and (E) NOAA model. (F) Ensemble mean weighting the five models, averaged over 10 days from March 22 to 31. Note that the averaged period for the CRIEPI model is from March 26 to 31, since their discharge scenario started on March 26. (G) Observed horizontal distribution of 137Cs averaged over the same 10-day period. Current speeds are given by the lengths of the arrows (see scale). Radioactivity concentrations are given in becquerels per liter (Bq L-1). UDL = below detection limit; F1-NPP = Fukushima Daiichi nuclear power plant Figure 2 137 A B C D E F JAEA model. The Sirocco and NOAA models show relatively broad southward flow off Ibaraki. Satellite images of the sea-surface temperature distribution indicate a weak, warm-core, eddy-like feature off the coast of Ibaraki at the end of March and in early April (not shown). The 137Cs concentration had not reached the region of these eddies by the end of March. An ensemble mean of the five model results, giving equal weight in the averaging (Fig. 2 f ), captures most of the above-mentioned velocity and 137Cs distributions. It is rather difficult, however, to show that the ensemble mean field is better at representing the observed distribution, since the observational data are so sparse and limited to a region close to the plant. April 21–30 The high 137Cs concentration had spread offshore by the end of April, while the radioactivity along the line 30 km offshore diminished slightly to a value of around 10 Bq L -1 or less, except for two locations, where values of more than 20 Bq L -1 were detected (Fig. 3g). New monitoring stations were installed in the region off Ibaraki, but the observed values were all under the detection level of about 10 Bq L -1 for this time period. All the models show southward or southeastward dispersion of the 137Cs in the latter part of April (Fig. 3a– e). The offshore dispersion seems to be associated with a nearshore, northeastward surface flow broadly distributed near the power plant in all models. The southward or southeastward movements of 137Cs in the offshore region south of 37° N, however, show large differences among the models. While the anticyclonic circulation brings the 137Cs distribution southeastward in the CRIEPI and JCOPET E lements G models, the JAEA, Sirocco, and NOAA results show southward dispersion along the coast associated with a weak southward flow near the coast. The NOAA results indicate strong eddy features beyond the coastal region, but the radionuclide distribution was not affected by the eddies at the end of April. The differences among the models suggest that the surface circulations in the region between 37° N and the Kuroshio current are susceptible to mesoscale eddy activity and to variability of the Kuroshio, and the modeled Kuroshio current is in turn strongly affected by data- assimilation processes in the larger domain models. In addition, the radionuclide distribution is affected by velocity fields not only during April 21–30 but also before that period. Again, the ensemble mean fields capture reasonably well the main features of the 137Cs distribution and the velocity characteristics off Fukushima and Ibaraki (Fig. 3f). In addition to the mesoscale eddy activity, the magnitude of horizontal and vertical mixing processes in the ocean may strongly influence the 137Cs distribution. For example, the CRIEPI and NOAA results show relatively weak values of less than 10 Bq L -1 in most of the region affected by radionuclide contamination as compared with other model results. One possible reason for this discrepancy could be differences in the magnitude of the vertical diffusivity; in general, the larger the vertical diffusivity, the weaker the surface concentration of the 137Cs. However, it is not straightforward to deduce this effect in a simple comparison among the models in Figures 2 and 3, since each model uses different schemes for advection and diffusion as well as different diffusion coefficients. 210 J une 2012 Same information as in Figure 2, but for the period April 21–30. Note that the average period for the JAEA and NOAA models ends on April 29 and 26, respectively. For other explanations, see the caption of Figure 2. Figure 3 A B C D E F Another possible cause for the discrepancy is the degree of horizontal movement of the radionuclides within the 10-day-average window. When the radionuclides move around in a large area, the averaged concentration becomes smaller as compared with a case where radionuclides stay in the same location. This aspect strongly depends on the variability in the current system and should be evaluated in the future in order to clarify the detailed dispersion processes in this region. G The degree of vertical mixing in a model, as well as the vertical distribution of the source term, may also affect the surface distribution of the radionuclides. During March and April, several low-pressure systems passed through the Fukushima region, and these could have produced relatively large vertical mixing in this region. We need to At the end of April 2011, the relatively strong southward flow in the offshore region had strengthened as compared with the end of March. A major part of the 137Cs distribution, however, was confined within the region between the coast and the offshore southward flow. The 137Cs dispersed to the south or southeast was eventually captured in early May by the northern flank of the Kuroshio current and spread rather quickly to the east into the Pacific Ocean. This eastward movement of 137Cs can be seen in all the model outputs, and one example for the JCOPET model is shown in Figure 4. FUTURE ISSUES Comparison of the surface horizontal distributions of 137Cs among the dispersion models for the Fukushima accident demonstrates general agreement of the flow fields and associated 137Cs distributions at the end of March and April 2011. However, there are noticeable differences among the models as well, in particular for the region between 37 °N and the Kuroshio current, where cyclonic or anticyclonic eddy-like circulations can be seen in some models. Accurate representation of such mesoscale structures and associated radionuclide dispersion near the coast is an important challenge for simulations on the regional scale. E lements Horizontal distribution of daily mean 137Cs concentrations (in becquerels per liter) and surface velocities on May 6 simulated by the JCOPET model. Surface velocity vectors (arrows) are drawn only in regions where the magnitude of the surface current exceeds 0.5 m s-1 to highlight the location of the simulated Kuroshio current. 211 Figure 4 J une 2012 complete systematic sensitivity analyses and more detailed model intercomparisons in order to resolve these issues. In this article, we have focused only on the dispersion of the 137Cs discharged directly from the Fukushima plant into the ocean. However, 137Cs was also deposited as atmospheric fallout on the sea surface over a wide region. Investigations of the relative importance of these two sources and the distribution of total 137Cs concentration in the ocean are now being undertaken by several groups. Kawamura et al. (2011), for example, have discussed the noticeable impact of atmospheric deposition of 131I over a large area of the northwestern Pacific. NOAA’s simulations in a larger area of the northwestern Pacific, including a component of atmospheric deposition of 137Cs, also agree with this assessment. Tsumune et al. (2011) pointed out that the contribution by direct release to the observed 137Cs concentrations near the Fukushima coast in the latter part of March and in April was larger than that resulting from atmospheric deposition. Further intercomparison studies on the impact of atmospheric deposition are necessary. Other possible contributors to the contaminated water, such as rivers and groundwater, should also be taken into account. Another important point for accurate dispersion calculations is to consider ocean processes that scavenge radionuclides, including adsorption onto particulates and absorption due to biological processes. At present, only a few groups are trying to integrate these processes into their models. The incorporation of better-performing models of scavenging mechanisms into dispersion simulations in the ocean will be essential. CONCLUDING REMARKS We have reviewed the present status of oceanic dispersion simulations of radionuclides discharged from the Fukushima nuclear plant. There are large differences in the References Barron CN, Kara AB, Hurlburt HE, Rowley C, Smedstad LF (2004) Sea surface height predictions from the Global Navy Coastal Ocean Model (NCOM) during 1998–2001. Journal of Atmospheric and Oceanic Technology 21: 1876-1894 Hashimoto A, Hirakuchi H, Toyoda Y, Nakaya K (2010) Prediction of regional climate change over Japan due to global warming (Part 1) – Evaluation of Numerical Weather Forecasting and Analysis System (NuWFAS) applied to a long-term climate simulation. CRIEPI report N10044, 22 pp (in Japanese) IRSN (2011a) Impact on marine environment of radioactive releases resulting from the Fukushima-Daiichi nuclear accident. Institut de Radioprotection et de Sûreté Nucléaire, 9 pp, www.irsn.fr/ EN/news/Pages/201103_seism-in-japan. aspx IRSN (2011b) Update: Impact on the marine environment of radioactive releases following the nuclear accident at Fukushima Daiichi. Institut de Radioprotection et de Sûreté Nucléaire, May 13, 2011, 16 pp, www.irsn.fr/EN/ news/Pages/201103_seism-in-japan.aspx Ishikawa Y, Awaji T, Toyoda T, In T, Nishina K, Nakayama T, Shima S, Masuda S (2009) High-resolution synthetic monitoring by a 4-dimensional variational data assimilation system in the northwestern North E lements models and model settings among the research groups, leading to different results for ocean currents near Fukushima and, hence, for the distributions of radionuclides such as 137Cs. At the moment, we cannot say that one model is better than another. Rather, we need to be able to explain the discrepancies and reduce the overall uncertainty of the dispersion simulations. The International Atomic Energy Agency is now coordinating a more detailed model intercomparison in order to facilitate this research. Insights into oceanic dispersion gained through such international efforts will facilitate implementation of more predictive models. According to the TEPCO data obtained near the Fukushima plant, 137Cs radioactivity at the end of April 2012 was of the order of 1 Bq L -1. Results from recent observations and numerical models indicate that the distribution of 137Cs has expanded and shifted to the east into a large portion of the North Pacific Ocean, while the radioactivity in most of the area is of the order of, or below, 0.01 Bq L -1. In order to describe what happened and is happening in terms of the dispersion of radionuclides from the Fukushima plant, research-based, accurate observations and analyses in a wide area of the North Pacific Ocean for more than a few decades are needed; as well, detailed comparisons and a synthesis of the simulated results and observations are strongly required. ACKNOWLEDGMENTS YM and YM thank Drs. Sergey M. Varlamov, Ruochao Zhang, Toshimasa Doi, and Toru Miyama for their support of JCOPE simulations. LL is deeply grateful for support from Dr. John Cortinas, Dr. Frank Bub, Mr. Robert Daniels, Mr. Richard Patchen, and Ms. Hong Lin for NOAA dispersion simulations. Pacific. Journal of Marine Systems 78: 237-248 Kanamitsu M, Ebisuzaki W, Woollen J, Yang S-K, Hnilo JJ, Fiorino M, Potter GL (2002) NCEP–DEO AMIP-II Reanalysis (R-2). Bulletin of the American Meteorological Society 83: 1631-1643 Kasamatsu F, Inatomi Y (1998) The effective environmental half-life of 90 Sr and 137Cs in coastal seawaters of Japan. Journal of Geophysical Research 103: 1209-1217 Kawamura H, Kobayashi T, Furuno A, In T, Ishikawa Y, Nakayama T, Shima S, Awaji T (2011) Preliminary numerical experiments on oceanic dispersion of 131I and 137Cs discharged into the ocean because of the Fukushima Daiichi Nuclear Power Plant disaster. Journal of Nuclear Science and Technology 48: 1349-1356 Kobayashi T, Otosaka S, Togawa O, Hayashi K (2007) Development of a non-conservative radionuclides dispersion model in the ocean and its application to surface cesium-137 dispersion in the Irish Sea. Journal of Nuclear Science and Technology 44: 238-247 MEXT (2011) Monitoring information of environmental radioactivity level. http://radioactivity.mext.go.jp/en/ monitoring_around_FukushimaNPP_ sea/ Miyazawa Y, Zhang R, Guo X, Tamura H, Ambe D, Lee J-S, Okuno A, Yoshinari H, Setou T, Komatsu K (2009) Water mass 212 variability in the western North Pacific detected in a 15-year eddy resolving ocean reanalysis. Journal of Oceanography 65: 737-756 Shchepetkin AF, McWilliams JC (2005) The regional ocean modeling system (ROMS): a split-explicit, free-surface, topography-following-coordinate oceanic model. Ocean Modelling 9: 347-404 TEPCO (2011a) Fukushima Daiichi Nuclear Power Station Unit 2: Countermeasures to stop the outflow of contaminated water and the water amount flowed out into the sea. Tokyo Electric Power Company, press release April 21, 2011, www.tepco.co.jp/en/ press/corp-com/release/11042103-e.html TEPCO (2011b) Detection of radioactive materials from seawater near Fukushima Daiichi Nuclear Power Station, www. tepco.co.jp/en/nu/fukushima-np/f1/ index2-e.html Toulouse University (2011) http://sirocco. omp.obs-mip.fr/outils/Symphonie/ Produits/Japan/SymphoniePreviJapan. htm Tsumune D, Tsubono T, Aoyama M, Hirose K (2011) Distribution of oceanic 137Cs from the Fukushima Dai-ichi Nuclear Power Plant simulated numerically by a regional ocean model. Journal of Environmental Radioactivity (in press) J une 2012 Interactions between Nuclear Fuel and Water at the Fukushima Daiichi Reactors Bernd Grambow1 and Christophe Poinssot2 1811-5209/12/0008-0213$2.50 DOI: 10.2113/gselements.8.3.213 U sed nuclear fuel is a redox-sensitive semiconductor consisting of uranium dioxide containing a few percent of fission products and up to about one percent transuranium elements, mainly plutonium. The rapid increase in temperature in the cores of the Fukushima reactors was caused by the loss of coolant in the aftermath of the damage from the tsunami. Temperatures probably well above 2000 °C caused melting of not only the UO2 in the fuel but also the zircaloy cladding and steel, forming a quenched melt, termed corium. Substantial amounts of volatile fission products, such as Cs and I, were released during melting, but the less volatile fission products and the actinides (probably >99.9%) were incorporated into the corium as the melt cooled and was quenched. The corium still contains these radionuclides, which leads to a very large long-term radiotoxicity of the molten reactor core. The challenge for environmental scientists is to assess the longterm interactions between water and the mixture of corium and potentially still-existing unmelted fuel, particularly if the molten reactor core is left in place and covered with a sarcophagus for hundreds of years. Part of the answer to this question can be found in the knowledge that has been gained from research into the disposal of spent nuclear fuel in a geologic repository. Keywords : corium, spent fuel, radionuclide release, environmental impact, radiotoxicity, Fukushima Daiichi nuclear power plant Characteristics of the reactors and NUCLEAR fuels There are six boiling water reactors (R1–R6) at the Fukushima Daiichi nuclear power plant. Four reactors (R1– R4) were destroyed by the accident: the three reactors (R1– R3) operating at the time of the earthquake and the neighboring reactor, R4, whose fuel had been removed and stored in cooling ponds. The cores of R1–R3 contained about 256 metric tons of nuclear fuel (400 fuel assemblies in R1 and 548 assemblies in each of R2 and R3; one assembly contains 60 fuel rods, each 3.70 m long, and each assembly weighs about 170 kg). Reactors R5 and R6 were shut down for routine inspection. In September 2010, 32 of the fuel assemblies in the core of reactor R3 were mixedoxide (UO2 + PuO2 ) MOX fuel (IAEA 2011) totaling about 5.5 tons. The other assemblies were uranium oxide fuels, UO2 (named UOX fuels). The spent fuel storage tanks located in the four destroyed reactor buildings contained an additional 461 tons of nuclear fuel, including 395 tons 1 SUBATECH UMR 6457, Ecole des Mines, Université de Nantes CNRS-IN2P3, F 44307 Nantes, France E-mail: [email protected] 2 French Nuclear and Alternative Energies Commission CEA, Nuclear Energy Division, RadioChemistry & Processes Department, BP11, F-30207 Bagnols sur Cèze, France E-mail: [email protected] E lements , V ol . 8, pp. 213–219 of discharged irradiated fuel and 66 tons of unirradiated UO2 fuel waiting to be loaded into the reactors. When reactors 1–3 shut down automatically after the earthquake, about 89% of the 6.1 gigawatts (GWth) of thermal nuclear fission energy being produced was immediately interrupted, i.e. the kinetic energy of fission products, neutrons, and photons. However, 11% of the energy remained in the cores of R1–R3 after shutdown, 6% (360 megawatts) in the form of beta decay heat essentially from fission products (see Fig. 1a) and 5% in the form of antineutrinos. Initially, this energy was rapidly released, and later, more slowly. Indeed, spent nuclear fuel is considered to be an important heat source for thousands of years in most concepts of geological disposal (Fig. 1b). The radiotoxicity of the used fuel is in part due to the accumulation of the radioactive isotopes (“fission products”) that were generated by the nuclear fission of uranium and plutonium atoms during reactor operation. It is also due to the transuranium elements (actinides beyond uranium in the periodic table) created by neutron capture on 238U in the fuel. These radionuclide inventories depend on the length of time the fuel was “burned” in the nuclear reactor, i.e. on the “burnup,” which is the energy released expressed in gigawatt-days per metric ton of uranium and plutonium (GWd/t). After a typical burnup during reactor operation for some years, the radioactivity of the fuel has increased by a factor of a million (1017 becquerels/metric ton of fuel). One year after discharge from a reactor, the dose rate measured one meter from the fuel assembly is one million millisieverts per hour (for comparison, the natural background dose is on the order of three millisieverts per year). A person exposed to this level of radioactivity at a distance of one meter would receive a lethal dose in less than a minute (Hedin 1997; Bruno and Ewing 2006). Fissionproduct inventories are roughly proportional to burnup, while actinide-element inventories (Pu, Am, Np, Cm) are more complicated functions of burnup because the fissile transuranium elements are partly consumed at high burnups and the production rates of higher actinides (Am, Cm) increase with burnup. 213 J une 2012 toxicities of this type of fuel are probably lower than the average inventories of a pure UO2 fuel. But the Pu inventory of MOX fuel is much higher. Endo et al. (2011a) report a value of 3.9 wt% Pu in the MOX fuel in reactor 3. Considering that UOX fuel with an average burnup of 23 GWd/tU contains about 0.8 wt% Pu and that only about 6% of the fuel in reactor 3 was MOX fuel, the total loaded inventory of Pu in this reactor was about 0.98 ton, roughly 30% greater than the 0.75 ton (0.8% of 95 tons of fuel) in reactor 2, which contained a similar total fuel mass but without MOX. A As an example of the evolution of toxicity over time, Figure 2 shows the toxicity inventory of one ton of spent nuclear fuel (UO2 ) for a rather high burnup of 47.5 GWd per ton of the initial uranium inventory (calculations were made as part of the MICADO project; Grambow et al. 2010). Indeed, even for this UO2 fuel, the Pu inventory dominates the long-term toxicity; therefore, the greater Pu inventory of the MOX-containing reactor would increase the long-term toxicity by about 30%. However, this does not directly represent the potential impact since the toxicity also depends on the mobility of plutonium, which can be very low depending on the chemical conditions (for instance in a reducing environment or in the presence of organics). B (A) The residual thermal power (in megawatts per ton of uranium) of the nuclear reactors calculated as a function of time after shutdown for the two types of spent fuel present in the Fukushima reactors, BWR UOX fuel (3.1% initial enrichment) and BWR MOX fuel (6% initial Pu content), assuming a mean burnup of 30 thermal gigawatt-days per ton uranium or plutonium (GWd/t) (calculated with the DARWIN code, using the CEA2005V4 database). (B) Relative residual thermal power of representative fuels over the geological timescale (data calculated with the CESAR code, Samson et al. 1998). 1E+0 = 1.0, 1E-1 = 0.1, etc. Figure 1 Typical end-of-life burnups are about 40 GWd/t, which are achieved after 3 to 4 years in the reactor. Due to the replacement of only a part of the used fuel by unirradiated UO2 fuel in normal reactor operation, a reactor core is always a mix of old and rather fresh fuel, and burnups for individual fuel assemblies range from 3 GWd/t to 41 GWd/t. The average burnup of the Fukushima Daiichi reactors is assumed to be about 20 GWd/t. The average burnup has not been reported “officially,” but the “official” total 137Cs inventory of reactors 1–3 can be calculated from the release fractions and total releases given in IAEA (2011) as 7.1 × 1017 Bq. This would correspond to an average burnup of about 23 GWd/tU. Endo et al. (2011a) estimated an average burnup of 17.2 ± 1.5 GWd/tU, based on the average ratio of 134Cs/137Cs (0.996 ± 0.07) measured in soils within a radius of 100 km. Average core burnups were reported in the same publication as 25.8, 23.2 and 21.8 for reactors R1, R2, and R3, respectively, closely matching the value of 23 GWd/tU derived from the IAEA (2011) data. The lower burnup calculated by Endo et al. (2011a) may be due to the postulated core meltdown (i.e. differences in the degree of damage and associated Cs release for the fuel in the center of the core versus at the periphery) or to greater damage of once-burned fuel due to its higher temperature. The presence of MOX fuel in reactor 3 was considered in the world press to be a strong additional risk factor due to the higher plutonium content. For a given burnup, MOX fuel is more toxic than conventional fuel, but the short residence time in the reactor—only 5 months—means that the average fission-product inventories and associated E lements Evolution, in years, of the long-term toxicity (by ingestion) of one ton of spent nuclear fuel with a burnup of 47.5 GWd/tU, expressed in sieverts (Sv) per ton of UOX. The total toxicity of the 3 reactor inventories (not including fuel storage ponds) is about 100 times greater (256 tons of fuel with an average burnup of 23 GWd/t U) than the values in this figure. The data were calculated using the CESAR code (Samson et al. 1998) for fuel evolution. Figure 2 Considering that the dose limit for ingestion according to regulations in Europe is 1 mSv/y (millisievert per year), the high toxicity of the radionuclides in the damaged fuel cores requires isolation well beyond hundreds of thousands of years in order to avoid exposing the fuel cores to natural waters, which might lead to the release of toxic radionuclides into the food chain. Isolation for such long times is also necessary to avoid exposing people in the vicinity of the damaged cores to lethal doses of external gamma radiation. 214 J une 2012 How much was released from the reactors? How much remains? Toxicity is not identical to risk. Risk depends on the accessibility of radionuclides to humans and to their mobility in the environment. In the future, important measures will have to be taken in order to reduce the short- and long-term risks of the highly toxic inventory of the reactors, for example, by strict confinement and/or geological disposal of the fuel. Today, the largest risk stems from those fractions of the toxicity inventory that have been released to the environment, i.e. 2.2% and 2.5%, respectively, of the total 137Cs and 131I inventories in the reactor cores 1–3 (IAEA 2011, attachment IV-2). Recent data (IRSN 2011) indicate that actual releases might have been even higher. Latest estimates by TEPCO (2012) give release fractions of 1.9% for 137Cs and 8% for 131I. For the most volatile elements, as indicated by 133Xe data, the release is estimated to be close to 100% (Stohl 2011; IAEA 2011). However, the information is not yet sufficient to conclude that the entire cores in reactors 1–3 have melted. Indeed, considering that the diffusion of Cs or Xe is similar to that of I, which is governed by a diffusion coefficient of ~2.5 × 10 -11 cm2 /s at 2200 °C, at the high temperature encountered in the accident (~2200 °C), Cs would diffuse at a velocity of 1 mm per day, which is much greater than the grain size (~8 µm) of the fuel. The situation is quite different for the transuranium elements (Pu, Am, Np, Cm). These elements are responsible mainly for long-term toxicity (see Fig. 2) since they are long-lived alpha emitters (in case of ingestion, alpha particles, 4He2+, cause more damage to human cells due to their larger size). But the actual risk originating from these nuclides is much lower since, even in the immediate vicinity of the damaged reactors, for example, at a distance of 500 m, Pu concentrations in the soil (239/240Pu activities are 0.055 ± 0.029 Bq/kg) are identical to the Pu concentrations in Japanese soil that resulted from atmospheric testing of nuclear weapons (0.02–0.4 Bq/kg for 239/240Pu) (Hirose et al. 2003). The activities of plutonium and other nuclides measured by the Tokyo Electric Power Company (TEPCO) over a period of 8 months are shown in Figure 3 (original data taken from a series of Web references from TEPCO 2011: www.tepco.co.jp). These data can be used to compare the ratios of the measured activities to the activity ratios of fission products and actinides in the nuclear fuel in the reactor. The large symbols in Figure 3, corresponding to the date of the accident, represent reference values (see explanation in the caption). As can be seen, the measured activities still have, with an uncertainty of about a factor of 2, the signature of the inventory ratios in the original fuel as far as the releases of 137Cs, 131I, 110m Ag, and 129m Te are concerned, when corrected, as in the case of 131I, for radioactive decay since the date of release (March 15) from the reactors. In contrast, measured activities of the alkali earth element nuclides, such as 140Ba and 90 Sr, are about a thousand times lower than the reference value of the activity ratios in the fuel. Finally, for the actinides 241Am, 242Cm, and 238Pu, the measured activities are about 5 orders of magnitude lower than the reference values in the nuclear fuel. Comparing the concentrations of the actinides with each other, their measured activity ratios correspond to their inventory ratios in the fuel, indicating a similarly slow mechanism of release for all actinides. Thus, for the Pu inventory in the reactor, about 105 times less is released to the environment as compared with the Cs inventory. Considering this low release of Pu, even fuels of higher Pu content, such as MOX fuel, will release very E lements little Pu. Thus, no significant additional short-term risk will arise from Pu release from the MOX fuel. In contrast, long-term risks depend on Pu inventories, particularly if Pu release from the reactor is increased by oxidizing groundwater coming into contact with the fuel. Recently, careful activity measurements were reported at 15 soil-sampling points between 5 and 60 km from the Fukushima plant (Endo et al. 2011b). Using these data, the activity ratios 129mTe/137Cs, 131I/137Cs, and 140Ba/137Cs were calculated to be 1, 20, and 0.06, respectively, which can be compared with the same ratios in the original spent fuel, i.e. 0.7, 12, and 22, respectively. This corroborates the previously discussed measurements made in close proximity to the Fukushima plant: 129mTe, 131I, and 137Cs show similar release behaviors, whereas about 1/400 th as much 140Ba is released as Cs. These findings confirm that the data obtained in the vicinity of the Fukushima plant are representative of the general release patterns. Graphical representation of radioactivity measurements, reported periodically by TEPCO (2011) between March and November 2011 for the Fukushima plant at soil-sampling locations (denoted “Playground”) located about 500 m north-northwest of the stacks of Units 1 and 2. The large symbols at the date of the accident represent reference values, which correspond to hypothetical activities for the case in which all nuclides have been released to the same extent (i.e. the same fraction of reactor core inventory of a given nuclide) as that of Cs. Measured values lower than the reference value indicate a much lower extent of release than Cs. Figure 3 The relative behavior of the different nuclides near the Fukushima plant also matches very well with experimental results. In a Knudsen cell experiment, spent nuclear fuel fragments were heated stepwise in a closed, confined space to temperatures in excess of 2000 °C, and the stepwise volatilization of the various elements were measured by mass spectrometry (Rondinella et al. 2008). Figure 4 presents a typical result obtained from MOX fuel samples. Volatilization starts at 1000 °C with the release of Te and He (produced by alpha decay), while Cs and I start to volatilize at 1100 °C. Finally, uranium begins to volatilize above 1600 °C. Interestingly, Ba shows an intermediate level of volatility. From these data, temperatures in the Fukushima reactors were probably high enough to cause the volatilization of most of the Xe inventory and a large fraction of the Cs, but certainly not the actinides (U, Pu, and minor actinides such as Am, Cm, and Np). The confinement of most of the actinides within the reactors is, on one hand, reassuring, as these elements carry the highest long-term toxicity burden. On the other hand, a direct consequence of this confinement is that the longterm risk assessment requires the evaluation of the fate of 215 J une 2012 corium, Pontillon and Durcos (2010) identified four groups of released elements: 1. Volatile fission products, including fission gases (Xe, Kr), I, Cs, Sb, Te, Cd, Rb, and Ag 2. Semivolatile fission products, including Mo, Rh, Ba, Pd, and Tc 3. Low-volatility fission products, such as Ru, Ce, Sr, Y, Eu, Nb, and La 4. Nonvolatile radionuclides, including Zr, Nd, Pr, and some of the actinides (U, Pu, Np, Am, Cu) Knudsen cell analysis of the volatile release of radionuclides during heating of irradiated MOX fuel beyond normal conditions, from the European project NF-PRO. “M.S.” means “mass signal”; for the present discussion, only relative values are of importance. The left scale applies to all radionuclides except Xe and UO2, which are plotted against the scale on the right. Modified from Rondinella et al. (2008) Figure 4 the remaining fuel in the reactor. How can we proceed with this assessment, considering the fact that due to high radiation fields direct access to the fuel will probably not be possible for at least a few decades? Some indirect information on the release behavior of the radionuclides in the reactor core can be derived from chemical analyses of the cooling water collected from the three damaged reactor cores. A cooling circuit was installed by TEPCO in July 2011, which runs decontaminated water through the three destroyed reactor cores and collects outflowing contaminated water for decontamination and desalination, after which the decontaminated water is reinjected. Decontamination factors for 137Cs were 106, meaning that Cs activity in the water was a million times lower after a decontamination cycle than before. About 180,000 m3 of highly contaminated water were collected for decontamination, with a specific activity for 137Cs varying between 1.8 Bq/mL in July 2011 to 0.7 Bq/mL in November 2011 (data on the volumes collected and the associated activities are from TEPCO reports; TEPCO 2011). These data indicate a total release to the water of 1.7 × 1017 Bq, or about 27% of the total 137Cs inventory in the cores of reactors 1–3. However, some fraction of the volatile elements, such as Cs, may have recondensed in the coldest parts of the primary cooling circuits during the accident. This figure is therefore a minimum amount of Cs release from the fuel. Specific activities for the nuclides 89+90 Sr were 6 × 105 Bq/mL in July 2011. No data were reported for longer contact periods. The Cs/Sr activity ratio in water collected in July is about 10 times higher than in the fuel, indicating reduced mobility of Sr as compared with Cs. Due to the very high temperature during the meltdown, fuel pellets, as well as the zircaloy cladding and steel, melted and mixed, yielding an ill-defined material called corium. Earlier work, as in the French VULCANO experiments or the characterization of the core of reactor 2 at Three Mile Island, demonstrated that corium consists of several phases: an oxic phase and one or two metallic phases, depending on the accident conditions, which can cause the separation of the heavier and lighter metallic elements. How can we estimate the long-term stability of corium? In laboratory experiments performed on simulated E lements These laboratory results are consistent with the behavior of the measured radionuclides at the Fukushima plant: group 1 corresponds to radionuclides that have been significantly released (30 to 100%) into the cooling water (Cs) and into the environment (Xe, Cs, I, Te); groups 2 and 3, as indicated by Ba and Sr, seem to have been significantly released from the fuel (0.01%; see the discussion related to Fig. 3), but only a small part of these elements has reached the environment, probably due to their lower volatility and their propensity to recondense within the primary circuit (see Fig, 3); and group 4 essentially was not released from the fuel (99.9999% retained). Long-Term Corium Alteration in Water Characteristics of the Two Main Alteration Mechanisms Oxic corium is a solid solution with a tetragonal structure. Although it has not been demonstrated that corium is a single phase, it may be possible to consider the oxic corium as hyperstoichiometric UO2+x: stoichiometric deviations of the fuel were about x = 0.14 for samples obtained from the molten core of the Three Mile Island Unit 2 reactor (Bottomley and Coquerelle 1989). This value is lower than the threshold value of x = 0.25, which corresponds to U4O9. Corium compositions obtained from fuel treated in the PHEBUS severe-accident facility (Barrachin et al. 2008) were close to U0.99Zr 0.01O2.23 and U0.86Zr 0.12Fe 0.005Cr 0.001 Nd 0.006 Pu 0.004 Ce 0.004 O 2.42 for irradiated fuel and to U0.95Zr 0.04Fe 0.001O2.32 for nonirradiated fuel. In the latter cases, these compositions correspond to an average deviation of x = 0.33 from the normal stoichiometry. Considering corium as hyperstoichiometric UO2+x allows the use of certain analogue materials for assessing the longterm behavior of corium in contact with natural waters. Indeed, many studies have been performed worldwide over at least 30 years on different types of uranium oxides in order to assess the long-term behavior of spent nuclear fuel under geological repository conditions. For instance, solid– water reactions have been studied for different solid solutions, such as UO2+x; partly oxidized or fresh spent nuclear fuel; pure UO2 ; oxidized UO2 ; alpha-doped UO2 simulating long-term irradiation fields; and natural uraninite (Forsyth 1995; Grambow et al. 1996, 2000; Stroes-Gascoyne et al. 1997; Röllin et al. 2001; Ollila et al. 2003; Werme et al. 2004; Poinssot et al. 2005; Ollila 2008). The Europeanfunded MICADO project (Grambow et al. 2010) recently assessed the uncertainties in the different models describing the dissolution processes of spent nuclear fuel disposed of in a deep repository for geological periods. Based on this knowledge, some key issues can be considered. First, as for UO2 -derived solids, two radionuclide fractions can be distinguished: (1) fast-dissolving radionuclide inventories (the so-called “instant release fraction,” or IRF), which correspond to radionuclides that are not bound into 216 J une 2012 the matrices (either corium or spent fuel); (2) a slow-release fraction of radionuclides, which are located in the matrices (corium or spent fuel) and released as the corium matrix dissolves. Instant Release Fraction (IRF) The so-called IRF release is not governed by any mechanism but corresponds to radionuclides that are dissolved fast upon fuel–water contact. Therefore the only issue to address is the quantity of fast release upon water contact. No experimental data are available for corium. For spent fuel, IRF values are in the range of 5–10% of the total inventory, depending on the radionuclides (Ferry et al. 2007). Considering the typical corium-formation scenario (a transient event at very high temperature, >2300 °C, followed by a decade-long phase during which the corium is cooled under water), it is likely that a large part of the unbound radionuclides has already been released in the reactor core and to the cooling water and that these radionuclides are no longer retained in the fuel matrix. The remaining long-term IRF fraction in the corium is therefore anticipated to be very limited. Slow-Release Fraction The dissolution process of the corium matrix in water is likely to be electrochemically controlled, as for spent fuel (see Figure 5 for spent fuel). Due to the large difference in uranium solubility under oxidizing and reducing conditions (roughly 10 -6.5 and 10 -9.5 mol L -1, respectively), the corium matrix will probably undergo two competing dissolution mechanisms: (1) under oxidizing conditions, a relatively fast surface-interaction-controlled dissolution and (2) under reducing conditions, a slow solubility-controlled dissolution. Under oxidizing conditions, spent fuel or UO2 leaching requires, first, a surface oxidation of UO2 to a mixed U(IV)/ (VI) oxidation state of hyperstoichiometric UO2+x, with x > 0.33 (U3O7), and then complete oxidizing dissolution as dissolved U(VI) species. As measured on synthetic samples, the corium matrix is likely to be already oxidized so that its stochiometric deviation is given by x = 0.33, and no additional surface-oxidation step prior to oxidative leaching is probably necessary. One can anticipate a faster oxidation rate than for spent nuclear fuel. Oxidant influx is however necessary for transforming the remaining U(IV) into U(VI): oxygen may come from an external source under aerated conditions or from the radiolytic decomposition of water (oxidizing radiolysis products are H2O2 and O2 ). The fractional release rates for fractured spent fuel rods under oxidizing conditions are between 10 -5 and 10 -7/day. The fractional release rates for corium may be underestimated due to the preoxidized state. Finally, the alteration rate strongly depends on surface areas, which are unknown and likely different from that of the original spent nuclear fuel. Under reducing conditions, corium stability is anticipated to be higher and governed, as for spent fuel, by the relative solubilities of the dissolving phases (UO2 in the case of spent fuel, UO2+x, x ≈ 0.33 for corium). This implies that equilibrium U concentrations would be lower than in the previous case, in the range of 10 -9 to 10 -10 M for spent fuel (Grambow et al. 2010). However, corium solubility will depend on the actual chemical state of the corium, and its solubility might be much higher than that of UO2 . Due to the lack of information on the state of the corium, and for the sake of simplicity, all the radionuclides that have not been released into the cooling water and the environment are assumed to be integrated into the corium matrix as solid solution components. This implies that E lements The various alteration mechanisms affecting spent nuclear fuel in contact with water as a function of the environmental redox conditions (oxidation potential, Eh). “RN” stands for “radionuclide.” The numbers refer to the consecutive steps in the alteration process. Modified from Poinssot and Gras (2008) Figure 5 equilibrium conditions will govern the maximum concentrations in the aqueous solution of uranium and other radionuclides (like actinides, fission products, and activation products). Whether oxidizing or reducing conditions prevail in the damaged reactor cores may be assessed by analyzing the concentrations of U and Pu in the cooling water and by studying solubility controls: high concentrations (>10 -5 mol/L) are, for example, typical of oxidizing conditions. The experimental database on the interaction of UO2 -derived solids with water shows that temperature, the solubility limits of radionuclides, fuel-damage conditions, burnup, and the presence of remaining cladding play major roles in the effective radionuclide release from the corium matrix. Furthermore, the dissolution rates are not expected to be directly proportional to the specific surface areas. As far as water chemistry is concerned, redox potential and carbonate concentrations are key parameters (Bruno and Ewing 2006), whereas salinity (seawater versus freshwater) will play only a minor role in radionuclide release (Loida et al. 1994). Colloidal particles and dissolved organic matter are important for the transport of sparingly soluble radioelements such as Pu and Am (Kim and Grambow 1999). Potential Influence of Radiation Fields The temporal evolution of the redox conditions at the corium–water interface has an important effect on the radionuclide release behavior. The evolution of this behavior will be quite different under oxic surface conditions than under the reducing conditions in a deep geological repository. Air ingress is indeed omnipresent under oxic surface conditions, but in a geological repository, it only occurs during the operations phase, and thereafter all remaining air is consumed by redox reactions, in particular, with the metal of the disposal containers. Spent nuclear fuel and the corium short-term radiation field mainly give off oxidizing gamma radiation, while over the very long term (>>100 years) the radiation field is characterized mainly by alpha-decay radiation. During the first few hundred years, gamma radiation may strongly increase 217 J une 2012 the oxidation potential, even under oxic surface conditions. Over the long term, many thousands of years, as for geological disposal, alpha radiation will locally produce at the solid–water interface oxidizing species that could significantly increase the material dissolution rate, as has already been demonstrated on α-doped UO2 samples (Cachoir et al. 2005). However, the net effect is directly related to the overall balance at the local scale between the oxidants produced by the radiolytic decomposition of water [of which the primary oxidizing or reducing products are the radicals OH, OH 2 , e - (aq), and H, or molecular species like H 2 O2 , and H 2 ], the transport constraints involving the radiolytic producs, and the reactive reducing species that are present in the environment. Options for Corium Management From the available data on the total inventory of radionuclides that were released into the environment during the Fukushima accident, we have derived some important information regarding the potential state of the spent nuclear fuel in the three melted cores of the reactors. In particular, the relative behavior of the different radionuclides is consistent with the knowledge gained about fuel behavior at high temperature: volatile elements are released at much lower temperatures (<1300 °C) than actinides. This is consistent with the absence of a significant release of actinides around the Fukushima site. The ratios of the activities of 137Cs, 131I, 110m Ag, and 129m Te reported for soil samples correspond to inventory ratios in the reactors, and the 131I content in soil samples is much larger than the value that would be expected if a large contribution came from the fuel storage ponds. The large quantity of radionuclides released from the three reactors probably masks any contribution from the fuel storage ponds, which confirms a much lower fuel alteration in the ponds. Furthermore, from the large data set that has been acquired in the last few decades about the long-term evolution of spent nuclear fuel in water, some insights may be gained about the behavior of the oxic corium, whether in a geological repository or in long-term storage (such as within a protective sarcophagus). By comparison with spent nuclear fuels, after the passage of cooling water, oxic corium is anticipated to have a much lower IRF, potentially zero, and its radionuclide release behavior should be dominated by matrix alteration, which should be faster than for spent nuclear fuel. Three main options are therefore possible for corium management: Recovery of the corium in order to condition it inside suitable containers without further treatment, as was done with reactor 2 at Three Mile Island, while waiting for subsequent disposal in a deep geological repository. However, the amount of fuel lost in the melted core at Three Mile Island in 1979 was about 30 tons, less than one-twentieth the inventory at Fukushima (reactors and pools). In this case, the long-term release behavior of the corium is anticipated to be less desirable than that of spent nuclear fuel, since the long-term alteration rate of the corium will be higher. However, little or no IRF is anticipated, which would be favorable since the IRF dominates the long-term impact of spent fuel in a repository. Treatment, in order to decrease long-term toxicity and to optimize the stabilization of corium in dedicated waste matrices. Indeed, the most toxic elements, such as the actinides, could be recovered by separation processes, such as hydrochemistry or pyrochemistry. Pyrochemical processes may be of great interest due to the presence of numerous metallic components and the E lements anticipated refractory behavior of part of the corium. Such treatment may allow confining the most mobile radionuclides in a stable matrix instead of having them dispersed in the ill-defined corium matrix. In this option, the long-term release performance of the waste will depend on the specific matrix to be used. If vitrification of corium is chosen, good performance for up to 106 years can be anticipated. Finally, the site can be stabilized by creating some kind of protective sarcophagus. During a period lasting hundreds of years, natural waters will probably find access to the corium inside the sarcophagus, and the corium will likely corrode and release radionuclides; these would have to be recovered and managed. This is not a long- term option (thousands of years), but it may be a solution for a time period during which institutional control can be assured, which is intrinsically difficult to assess (what about the stability of current societies over hundreds of years?). Whether option 1 or 2 is chosen, only a preliminary estimate of the long-term performance is possible based on the present knowledge of spent nuclear fuel behavior. Studies of real corium samples from Fukushima will have to be performed, either to develop a treatment process or to characterize the radionuclide release properties of untreated corium. In the absence of relevant and robust experimental data, conservative assumptions in performance assessment will probably lead to prohibitively expensive solutions. Upper limits for radionuclide release predictions from the corium matrix can be obtained by developing a site-specific performance model for the Fukushima corium. Such a model could be created based on actual observations of the corium in the reactors in the presence of water. In the present study, we used the reported activities of 137Cs and 90 Sr in the outflowing cooling water to conclude that about 30% of the Cs inventory and about 3% of the Sr inventory were mobilized from the three reactors. In a similar way, one could analyze the evolution of the activities of other radionuclides ( 239Pu, etc.) in the cooling water of the reactor to assess the mobility of these nuclides in the core and to quantify source terms for water contact for the various conditioning and disposal scenarios. The continued flushing of the molten cores with water will in the long term also reduce the inventories of radionuclides that can be mobilized rapidly during disposal. Conclusion Comparison of radionuclide release from the reactors with the radionuclide inventories remaining in the reactor and estimation of corium–water interaction from known spent fuel–water interaction provide important insight for developing assessment and management strategies for the molten fuel in the reactor cores. If corium is to be disposed of without treatment, models for corium stability and for radionuclide release from corium upon contact with water will have to be developed based on (1) analyses of radionuclide activities in actual cooling waters, (2) chemical modeling of the analytical results in the context of the kinetics and thermodynamics of actinide and fission product release (solubility constraints, redox states, etc.), and (3) comparison with spent fuel behavior and experimental corium databases. If corium treatment is being considered in view of either confining it in a more stable matrix or even recovering the most radiotoxic radionuclides, specific processes will have to be developed based on the corium properties and the wide knowledge available about fuel treatment. 218 J une 2012 References Barrachin M, Chevalier PY, Cheynet B, Fischer E (2008) New modelling of the U–O–Zr phase diagram in the hyperstoichiometric region and consequences for the fuel rod liquefaction in oxidising conditions. Journal of Nuclear Materials 375: 397-409 Bottomley PD, Coquerelle M (1989) Metallurgical examination of bore samples from the Three Mile Island unit 2 reactor core. Nuclear Technology 87: 120-136 Bruno J, Ewing RC (2006) Spent nuclear fuel. Elements 2: 343-349 Cachoir C and 13 coauthors (2005) Effect of alpha irradiation field on long-term corrosion rates of spent fuel. In: Grambow B (ed) European Commission Report JRC-ITU-SCA-2005/1 Endo T, Sato S, Yamamoto A (2011a) Estimation of average burnup of damaged fuels loaded in Fukushima Dai-Ichi reactors by using the 134 Cs/137Cs ratio method. Symposium on Nuclear Data, Techno Plaza Ricotti, Tokai-mura, Ibaraki-ken, Japan, November 17, 2011 Endo S, Kimura S, Takatsuji T, Nanasawa K, Imanaka T, Shizuma K (2011b) Measurement of soil contamination by radionuclides due to the Fukushima Daiichi Nuclear Power Plant accident and associated estimated cumulative external dose estimation. Journal of Environmental Radioactivity, doi:10.1016/ j.jenvrad.2011.11.006 Ferry C, Piron JP, Poulesquen A, Poinssot C (2007) Radionuclides release from the spent fuel under disposal conditions : re-evaluation of the instant release fraction. In: Lee WE. Roberts JW, Hyatt NC (eds) Scientific Basis for Nuclear Waste Management XXXI, Materials Research Society Proceedings, Sheffield Forsyth R (1995), Spent nuclear fuel. A review of properties of possible relevance to corrosion processes. Swedish Nuclear Fuel and Waste Management Co., Stockholm, SKB technical report TR 95-23, 46 pp Grambow B, Loida A, Geckeis H, Dressler P, Casas I, Torrero ME, Giménes J, de Pablo J, Gago J (1996) Chemical Reaction of Fabricated and High Burnup Spent UO2 Fuel with Saline Brines. Final Report of EU Project, Wissenschaftliche Berichte, FZKA 5702, Forschungszentrum Karlsruhe. Commission of the European Union EU 17111 EN, 222 pp Grambow B, Loida A, Martinez-Esparza A, Diaz-Arocas P, de Pablo J, Paul JL, Marx G, Lemmens JPK, Ollila K, Christensen H (2000) Source Term for Performance Assessment of Spent Fuel as a Waste Form. Final Report for the EU contract FI4W-CT95-0004, Forschungszentrum Karlsruhe Final Report FZKA 6420, European Commission EUR 19140 EN, 222 pp E lements Grambow B and 35 coauthors (2010) MICADO Model Uncertainty for the Mechanism of Dissolution of Spent Fuel in Nuclear Waste Repository. Final Report. European Commission, EUR 24597 EN, 52 pp Hedin A (1997) Spent Fuel – How Dangerous is It? Swedish Nuclear Fuel and Waste Management Co., Stockholm, SKB Technical Report TR 97-13, 60 pp Hirose K, Igarashi Y, Aoyama M, Kim CK, Kim CS, Chang BW (2003) Recent trends of plutonium fallout observed in Japan: plutonium as proxy for desertification. Journal of Environmental Monitoring 5: 302-307 IAEA (2011) Report of Japanese Government to the IAEA Ministerial Conference on Nuclear Safety – The Accident at TEPCO’s Fukushima Nuclear Power Stations. Nuclear Emergency Response Headquarters Government of Japan June 2011, www.iaea.org/newscenter/focus/fukushima/japan-report low-volatile fission products and actinides. Nuclear Engineering and Design 240: 1867-1881 Röllin S, Spahiu K, Eklund UB (2001) Determination of dissolution rates of spent fuel in carbonate solutions under different redox conditions with a flowthrough experiment. Journal of Nuclear Materials 297: 231-243 Rondinella VV, Serrano-Purroy D, Hiernaut JP, Wegen D, Papaioannou D, Barker M (2008) Grain boundary inventory and instant release fractions for SBR MOX. Proceedings of the 12th International High-Level Radioactive Waste Management Conference, pp 418-424 Samson M, Grouiller JP, Pavageau J, Marimbeau P, Pinel J, Vidal JM (1998) CESAR: A simplified evolution code for reprocessing applications; RECOD 98. 5th International Nuclear Conference on Recycling, Conditioning and Disposal, Nice, France Kim JI, Grambow B (1999) Geochemical assessment of actinide isolation in a German salt repository environment. Engineering Geology 52: 221-230 Stohl A, Seibert P, Wotawa G, Arnold D, Burkhart JF, Eckhardt S, Tapia C, Vargas A, Yasunari TJ (2011) Xenon-133 and caesium-137 releases into the atmosphere from the Fukushima Dai-ichi nuclear power plant: determination of the source term, atmospheric dispersion, and deposition. Atmospheric Chemistry and Physics Discussions 11: 28319-28394 Loida A, Grambow B, Dressler P, Friese K, Geckeis H (1994) Chemical durability of high burnup LWR-spent fuel in concentrated salt solutions. Materials Research Society Symposium Proceedings 333: 417-424 Stroes-Gascoyne S, Johnson LH, Tait JC, McConnell JL, Porth RJ (1997) Leaching of used CANDU fuel: Results from a 19-year leach test under oxidizing conditions. Materials Research Society Symposium Proceedings 465: 551-558 Ollila K (2008). Dissolution of Unirradiated UO2 and UO2 Doped with 233U in Low- and High-Ionic-Strength NaCl under Anoxic and Reducing Conditions. Working report 2008-50, Posiva Oy Olkiluoto, Finland, 34 pp TEPCO (2011) Data source: measurements at Fukushima Daiichi nuclear power station at periodic soil sampling spot of activities “Playground” at about 500 m from stacks of Unit 1 and 2 in direction west/north-west. Updated periodically on the Web IRSN (2011) Synthèse actualisée des connaissances relatives à l’impact sur le milieu marin des rejets radioactifs du site nucléaire accidenté de Fukushima Dai-ichi, 26 octobre 2011 Ollila K, Albinsson Y, Oversby V, Cowper M (2003) Dissolution Rates of Unirradiated UO2, UO2 Doped with 233U, and Spent Fuel under Normal Atmospheric Conditions and under Reducing Conditions Using an Isotope Dilution Method. Swedish Nuclear Fuel and Waste Management Co., Stockholm, SKB Technical Report TR-03-13, 88 pp Poinssot C, Gras JM (2008) Key scientific issues related to the sustainable management of spent nuclear fuels in the back-end of the fuel cycle. Materials Research Society Symposium Proceedings 1124: 85-97 Poinssot C and 22 coauthors (2005) Spent Fuel Stability under Repository Conditions – Final Report of the European Project. European Commission 5th Euratom Framework Program, contract nº FIKW-CT-200100192, 104 pp TEPCO (2012) The estimated amount of radioactive materials released into the air and the ocean caused by Fukushima Daiichi nuclear power station accident due to the Tohoku-Chihou-TaiheiyouOki earthquake (as of May 2012). Tokyo Electric Power Company press release, May 24, 2012 Werme LO, Johnson LH, Oversby VM, King F, Spahiu K, Grambow B, Shoesmith DW (2004) Spent Fuel Performance under Repository Conditions: A Model for Use in SR-Can. SKB Technical Report TR 04-19, Stockholm, 34 pp Pontillon Y, Ducros G (2010 Behaviour of fission products under severe PWR accident conditions. The VERCORS experimental programme—Part 3: Release of 219 J une 2012 Publish your next research article in Geochemical Transactions 1.92 Official Journal of the Geochemistry Division of the American Chemical Society Editors-in-Chief: Gregory Druschel and Carla Koretsky Geochemical Transactions is an open access, peer-reviewed journal encompassing all areas of chemistry as it relates to materials and processes occurring in terrestrial and extraterrestrial systems. www.geochemicaltransactions.com Rare Minerals for Research F rom our inventory of over 200,000 specimens, we can supply your research specimen needs with reliably identified samples from worldwide localities, drawing on old, historic pieces as well as recently discovered exotic species. We and our predecessor companies have been serving the research and museum communities since 1950. Inquiries by email recommended. Tufted crystal groups of cuprosklodowskite over malachite from the Musonoi Mine, Kolwezi, Katanga, Democratic Republic of Congo (formerly Shaba Province, Zaire). From the Photographic Guide to Mineral Species CD, a production of Excalibur Mineral Corporation Excalibur Mineral Corp. 1000 North Division St. Peekskill, NY 10566 USA Telephone: 914-739-1134; Fax: 914-739-1257 www.excaliburmineral.com | email: [email protected] www.chemistrycentral.com Call for Session Proposals for IMA 2014 Preparations are well under way for the 21st meeting of the International Mineralogical Association (IMA) in South Africa. The overall theme of the IMA 2014 meeting is “Delving Deeper – Minerals as Mines of Information.” The logo is symbolic of South Africa’s rich mineral resources, from which has sprung its dynamic mining heritage, also the backbone of the country’s economy. The meeting will take place on 1–5 September 2014 at the Sandton Convention Centre, in the heart of Johannesburg, the City of Gold. The IMA 2014 meeting will be held under the auspices of the Geological Society of South Africa and the Mineralogical Association of South Africa, and is already generating sponsorship from the mineral industry, which will enable a professional, vibrant atmosphere for a memorable conference. South Africa’s sizeable community of mineralogists will contribute to the hosting of this first IMA meeting on African soil, and all aspects of mineralogy will be covered. The Organizing Committee is headed by Dr Sabine Verryn as conference chair, along with Dr Desh Chetty as scientific committee chair and Dr Craig Smith as finance chair. Proposals for sessions and topics to be covered are invited (e-mail: [email protected]), and further information is available on the conference website (www.ima2014.co.za). Please register to receive updated information if you are not already on the communications list. The Organizing Committee looks forward to welcoming everyone to South Africa in September 2014. Société Française de Minéralogie et de Cristallographie www.sfmc-fr.org WELCOMING NEW COUNCIL MEMBERS FOR 2012–2014 FROM THE PRESIDENT With my two vice-presidents, Guy Libourel and Javier Escartin, and the support of a renewed Council composed mainly of young scientists, it is a true pleasure and great honour for me to be the president of the SFMC for the term 2012–2013. I am convinced that, in France and in Europe, these two years will be known in the future as the beginning of the “renaissance” of the idea that minerals are key products for the development of our civil societies, as occurred in the past during the Stone, Bronze and Copper ages. A milestone for this new age happened in February 2012, when the European Commission identified nonenergy, non-agricultural raw materials as one of the three societal and economic challenges for the future, along with health and agriculture. This is a response to the ever-growing pressure on industry's access to critical elements, like the rare earths. Minerals and materials of natural or artificial origin are thus at the heart of the scientific and technical issues raised by the global management of our raw-materials resources. The issues involve extracting, recycling and substitution processes, and they require consideration of the whole chain of environmental impacts and the necessity to reinforce, and rebuild in some cases, research, education, training centres and networks. This renewal coincides with the emergence of nanomaterials, which, because of their novel properties, may help to reduce material consumption; but they also bring many disturbing questions about their impacts on the environment and human health. So it is an exciting time for mineralogical societies in general and the French community in particular to be involved in these two crucial issues. We must work on maintaining bridges between academic research on one hand and industry and the public on the other. I am convinced, as were SFMC past-presidents Anne Marie Karpoff and Patrick Cordier before me, that societal and economic questioning will provide our community with many opportunities to increase the visibility, attractiveness and notoriety of our discipline worldwide. Bruno Goffé, SFMC President Bruno Goffé (CEREGE, Marseille) 1st Guy Libourel (CRPG, Nancy) vice-president: 2nd vice-president: Secretary general: Alain Cheilletz is a full professor at the École Nationale Supérieure de Géologie de Nancy, Lorraine University. As an economic geologist, he has worked on tungsten, copper, lead–zinc and gold deposits around the world. He is the co-holder of three international patents devoted to determining the geographic origin of emeralds and was an associate editor of Mineralium Deposita (2001–2005). Sylvain Bernard is a CNRS research scientist at the Muséum National d’Histoire Naturelle (Paris). During his PhD in 2008 at the Laboratoire de Géologie de l’ENS, he documented the preservation of traces of life in rocks that had experienced intense metamorphic conditions. His scientific goals can be synthesized in a single question: How do biomolecules (and biominerals) evolve during fossilization processes? Javier Escartin is a CNRS senior scientist at the Institut de Physique du Globe de Paris and adjunct scientist at Woods Hole Oceanographic Institution. His main areas of interest are the formation and evolution of the oceanic lithosphere and the use of experimental rock mechanics to understand the rheology and mode of deformation of alteration products (e.g. serpentinites) in the oceanic environment. Mathieu Roskosz is an assistant professor at Lille I University. He is an experimentalist in the field of mineral physics and chemistry, with applications in astrophysical and magmatic environments. Recently, he has been applying an experimental approach to the study of isotopic fractionation and equilibration processes. SFMC ELECTION RESULTS FOR 2010–2012 President: Bruno Goffé, CNRS, senior scientist at CEREGE Aix-Marseille, was the head of the Earth sciences division at the National Earth and Astronomy Institute (INSU) from 2006 to 2011. He is a mineralogist, petrologist and geologist specialized in mountain building, metasediments, experimental mineralogy and materials science. He has supervised 30 PhD and 50 master’s students and is the author or co-author of 150 peer-reviewed publications and 17 patent publications. Javier Escartin (IPGP, Paris) NEXT EVENT SPONSORED BY SFMC Marc Blanchard (IMPMC, Paris) serpentine days Assistant secretary general: Maryse Ohnenstetter (CRPG, Nancy) Treasurer: Stéphanie Rossano (U. Marne-la-Vallée) Assistant treasurer: Christian Chopin (ENS, Paris) News editor/Elements: Anne-Marie Boullier (ISTERRE, Grenoble) •Mineralogy, Crystallochemistry Councilors: Muriel Andréani (UCBL, Lyon), Anne Line Auzende (IMPMC, Paris), Etienne Balan (IMPMC, Paris), Sylvain Bernard (MNHN, Paris), Delphine Charpentier (UFC, Besançon), Valérie Chavagnac (LMTG, Toulouse), Alain Cheilletz (CRPG, Nancy), Stéphanie Duchêne (CRPG, Nancy), Mathieu Roskosz (UMET, Lille), Denis Testemale (Institut Neel, Grenoble) •Origin of Life, Primitive Planets •Magnetic properties •Rheology, Deformation •Thermodynamics •Societal implications •Geodynamics 2-6 September, 2012 Porquerolles Island, 83412 Hyeres, France http://www.sfmc-fr.org contact : [email protected] Deep Carbon Observatory Organizing Committee : Muriel Andréani (LST, Lyon), Anne-Line Auzende (IMPMC, Paris), Isabelle Daniel (LST, Lyon), Adélie Delacour (GET, Toulouse) E lements 221 J une 2012 Mineralogical Society of America www.minsocam.org What gas phase reactions are catalyzed on mineral–dust surfaces in the atmosphere, and what is their impact on atmospheric chemistry? President’s Letter Which abundant airborne minerals, if any, have important radiative properties and thus affect climate change? Mineralogy to the Fore In this President’s Letter, I want to talk about global climate change science and opinion, which I believe can help inform us about a transformation that is happening today in the science of mineralogy and all the other sciences that mineralogy touches. Recently, I saw reported in the New York Times the results of an opinion poll that had been very carefully designed and comMichael F. Hochella Jr. missioned by academics at Yale and George Mason University. By roughly a 2-to-1 margin, the poll reports that Americans perceive that weather extremes have increased in recent years and that “global warming is affecting weather in the United States.” Contrast this apparent sea-change with the deep aggravation that most scientists have experienced (at least in the United States) over the last several years, where a vanishingly small number of vocal scientists with alternative opinions to standard scientific views on global climate change have had the bulk of public opinion on their side. I was also impressed by an article published in Physics Today (March 2012) by Jane Lubchenco and Thomas Karl, administrator and director, respectively, of the U.S. National Oceanic and Atmospheric Administration. In that article, they lay out the quantifiable evidence for the increase in extreme weather events over the last few decades, and they remind us that this is a prediction of mainstream global climate change science, which climatologists are continuing to refine. I believe that we are far from a general public understanding of the views that we are conducting a very dangerous experiment by burning fossil fuels as fast as they can be pulled from the ground, that the cost of energy in the near term is not nearly as important as the cost to the planet in the long term, and that debating these issues in the political arena can only break down into dramatic counterproductivity. But I am delighted that at least there is a move to wake up the general public about topics that people must (eventually) understand, for this really is one of the very most important issues of our time. These and related questions put mineralogy squarely in the core of future, critical climate change science, and as a result, into the public (and political) eye. But clearly, that is exactly where we want mineralogy to be, helping to understand these critical issues relevant to Earth sustainability. Answering questions like the two above take large numbers of interdisciplinary scientists, who are at least in part serious mineralogists, working for many years to sort through these challenges. In the process, if done well with skill and patience, the great questions of our time are answered, along with attracting the public and political support that is ultimately so important. This example is just one of many. Within the “100 Most Important Questions in Mineralogy” exercise to date, many deeply insightful questions have been submitted. In several cases, revealing mineralogical questions addressing key issues have been put forward, spanning the fundamental and applied sciences, in fields from the origin of life to aspects of geophysics, from plate tectonics to heat transfer. For example: What does the temporal distribution of minerals through >4 billion years of Earth history reveal about global tectonics and the supercontinent cycle? Other areas addressed by these questions have to do with everything from ocean science to nanogeoscience. For instance: What is the inventory of mineral nanoparticles in the world’s oceans, and what biogeochemical role do they play, including the role they play in supplying limiting nutrients to the vital photosynthetic microorganisms of the oceans? The science of mineralogy has moved to the fore. It is a science that is now sophisticated enough to integrate with other advanced disciplines to gain valuable insight into the most pressing fundamental, as well as practical, questions of this age. For a mineralogist, what could be more valuable and rewarding than that? Let’s do our job effectively, and contribute. How could this possibly have anything to do with the way we, as mineralogists, currently perceive our science, and where it is going in the future? There are many ways to answer this question, and I have already written, albeit indirectly, about this kind of thing in my previous presidential letters, Elements editorials, and certain published articles. However, here, we will take a slightly different tack to see the connection. Richard Harrison at Cambridge is currently leading a remarkable initiative, sponsored by the Mineralogical Society of Great Britain and Ireland, known as the “100 Most Important Questions in Mineralogy.” The stated purpose? “We aim to identify 100 mineralogical questions that, if answered, would have the greatest impact on resolving current and future challenges in the Earth, planetary, and environmental sciences.” With input from mineralogists the world over (including, undoubtedly, many of you, and, for better or worse, myself), they are well on their way to doing this. Well over 200 questions have been proposed to date, and we have been challenged to assess these entries according to several criteria, including by considering the following question: “What does the list convey to funding agencies and the wider public about the research we are doing as a community?” This is where global climate change comes back into the picture. Several submitted mineralogy-based questions speak to the heart of the global climate change research picture. Here are just two, whose answers are largely missing in climate change science, but sorely needed: E lements 222 Michael F. Hochella Jr. ([email protected]), Virginia Tech, President, Mineralogical Society of America The MSA, CMS, and Meteoritical Society offices are at the southern end of the north-south runways of Dulles Airport and adjacent to the Smithsonian National Air and Space Museum’s Steven F. Udvar-Hazy Center. On April 17, 2012, the staff was treated to the sight of the space shuttle Discovery being brought to the museum’s annex on the back of a Boeing 747 jet after a flying tour around the Washington, DC, area. J une 2012 Notes from Chantilly Balloting for the 2012 election of MSA officers and councilors is underway. Here is the slate of candidates for the 2012 MSA Council election – president: John M. Hughes; vice president: David J. Vaughan and Harry Y. McSween Jr.; treasurer: Edward S. Grew and Howard W. Day; councilors (two to be selected): Joshua M. Feinberg, Horst R. Marschall, Isabelle Daniel, and Kirsten P. Nicolaysen. Andrea Koziol continues in office as secretary. Continuing councilors are Pamela C. Burnley, Guy L. Hovis, Christine M. Clark, and Kimberly T. Tait. MSA members should have received voting instructions at their current e-mail addresses. Those who do not wish to vote online can request a paper ballot from the MSA business office. As always, the voting deadline is August 1. The MSA had a booth at the Tucson Gem and Mineral Show, Tucson, Arizona, on 9–12 February 2012, a show celebrating Arizona’s “Centennial” with the theme of “Minerals of Arizona.” The Dana Medal will be presented to Roberta L. Rudnick at the 2012 Goldschmidt Conference in Montreal, Québec, Canada, to be held on 25 June–1 July 2012. There will be a special session in her honor, “Formation, Evolution, and Destruction of Cratons and Their Lithospheric Roots,” during which she will give her Dana Lecture. MSA will have a booth at the GSA Annual Meeting in Charlotte, North Carolina, USA, on 4–7 November 2012. During that week, MSA will hold its Awards Lunch, MSA Presidential Address, Joint Reception among MSA, GS, and GSA’s Mineralogy, Geochemistry, Petrology, and Volcanology Division, annual business meeting, Council meeting, and breakfasts for the past presidents and associate editors. Do not forget the lectures by Roebling Medalist Harry W. Green II and MSA Awardee recipient Karim Benzerara. More information will be available through the MSA website. MSA has in stock the newly published Landmark Paper Number 4 (2012): Classic Papers in Granite Petrogenesis. The volume includes the selected papers and a commentary by John Clemens and Fernando Bea. MSA also has the previous 3 volumes of the series. Descriptions, tables of contents, and ordering of these and other volumes can be accessed on the MSA home page, www.minsocam. org/MSA/Mineralogical_Society.html#landmark. J. Alex Speer, MSA Executive Director [email protected] Zara Gerhardt Lindenmayer Peter McSwiggen David W. Mogk George B. Morgan VI Toshiro Nagase Roger L. Nielsen Mark I. Pownceby John F. Rakovan James S. Scoates Michael S. Smith Yong-Sun Song Michael N. Spilde Heinz G. Stosch Charles H. Trupe III Peter Ulmer Quentin C. Williams Bjoern Winkler Mineralogical Society of America Under graduate Prizes for Outstanding Students The Society welcomes the following exceptional students to the program’s honor roll and wishes to thank the sponsors for enabling the Mineralogical Society of America to join in recognizing them. MSA’s Undergraduate Prizes are for students who have shown an outstanding interest and ability in mineralogy, petrology, crystallography, and geochemistry. Each student is presented a certificate at an awards ceremony at his or her university or college and receives an MSA student membership, which includes a subscription to Elements and a Reviews in Mineralogy or Monograph volume chosen by the sponsor, student, or both. Past Undergraduate Prize awardees are listed on the MSA website, as well as instructions on how MSA members can nominate their students for the award. The following individuals will reach 50 or 25 years of continuous membership in the Mineralogical Society of America during 2012. Their long support of the Society is appreciated and is recognized by this list and by 25- or 50-year pins, mailed in early January. If you should be on this list and are not, or have not received your pin, please contact the MSA business office. Donald H. Lindsley Malcolm E. McCallum Stearns A. Morse Peter C. Rickwood Germain Sabatier Yukio Sakamaki Sponsored by Dr. David London Kara E. Marsac Eastern Michigan University Benjamin S. Murphy Pomona College Sponsored by Dr. John Brady Sponsored by Dr. Jade Star Lackey Marisa Davies University of Victoria Abbey Nastan University of Montana Sponsored by Prof. Dante Canil Sponsored by Dr. Julia Baldwin Bradley W. Pitcher Central Washington University Sponsored by Dr. Robert Popp Lauren Finkelstein George Washington University Sponsored by Dr. Richard Tollo Sponsored by Dr. Christopher Mattinson Allison Ricko Towson University Sponsored by Dr. David Vanko James C. Gossweiler Towson University Nathalie Elizabeth Sievers University of Maryland Sponsored by Dr. David Vanko 50-Year Members Thao P. Le University of Oklahoma Sponsored by Dr. Christine Clark Jennifer Axler Smith College Nicholas Davis Texas A & M University 50- and 25-Year MSA Members Robert L. Christiansen Edward Dale Ghent Philip C. Goodell Stefan Graeser Lawrence Grossman Friedrich Liebau Donald J. DePaolo Robert T. Downs Martin Engi Carol D. Frost Bruno J. Giletti Priscilla C. Grew Bradley R. Hacker David P. Hawkins Marc M. Hirschmann Richard S. James Wei-teh Jiang Raymond L. Joesten Rhian H. Jones Herbert Kroll T. Kurtis Kyser Bernd Lehmann Charles E. Lesher Sponsored by Prof. Roberta Rudnick David W. Hawkins George Mason University Emily Stewart Indiana University Sponsored by Dr. Julia Nord Cooper Kathryn Kumamoto Williams College Sponsored by Prof. Reinhard Wobus Sponsored by Prof. David Bish Jacob van Wesenbeeck Indiana University Sponsored by Prof. David Bish 25-Year Members Robert L. Bauer Lukas P. Baumgartner James S. Beard Adrian J. Brearley Maarten A. T. M. Broekmans L. Taras Bryndzia Paul K. Carpenter J. M. D. Coey Mark E. Conrad Cameron Davidson E lements In Memoriam Friedrich Liebau 223 – Senior Fellow – 1962 J une 2012 European Association of Geochemistry www.eag.eu.com The President’s Corner Funding Geochemistry and Other News For the most part, geochemistry is perceived as an academic discipline whose impact on society is limited. However, as time passes, geochemBernard Bourdon istry and its related multiple subfields have become essential in showing the way towards solutions for the major challenges that our society has to face in the future. EAG Past President Eric Oelkers, in a provocative plenary lecture at the Goldschmidt meeting in Knoxville, told us “how geochemistry can save the world.” There is no end to the list of domains where geochemists can help in this noble cause. Energy: The future depends on finding and better managing new energy resources, be they unconventional gas and oil or new sources of uranium and coal, until other more renewable and ecologically friendlier energy sources can take over. The underground capture and storage of CO2 also require the advanced and multifaceted knowledge of geochemists. Water: Being able to predict the quality of water resources and the pathways of contaminants released by human activities clearly requires the know-how of geochemists. Mineral resources: The scarcity of several strategic materials is a challenge for geochemists involved in understanding the genesis and long-term utilization strategies for ore deposits. This list could be further expanded by adding climate change, forensic geochemistry, soil conservation, etc. However, while specific programs are targeted at these societal questions, it can be said that the geochemical community has failed at being identified as the prime science at the root of and leader in the applications mentioned above. From that perspective, our community should “reclaim its copyrights” and become more proactive in increasing its visibility to governments, funding agencies and the European Union. In my own subdiscipline, isotope geochemistry, it is rather obvious that the boundary between basic science and the science that funding agencies or governments include in their focused programs is very fuzzy. Many tools and approaches originally developed for understanding mantle geochemistry or the early Solar System have been used in more applied geochemical approaches. Overall, this is true for most geochemical fields, where much of the basic understanding upon which applied geosciences are based stem from more fundamental investigations that are nowadays unfortunately looked down upon by funding agencies. All this is probably rather obvious to most geochemists. Yet, I am convinced that one has to be relentless in making this message known, if we are to halt and perhaps even reverse the ever-diminishing funding stream for fundamental geochemical research. There is a clear need for raising awareness about this topic, and our societies should be at the forefront of this endeavour. On another front, I would like to talk to you about the recently launched EAG blog (http:// blog.eag.eu.com/). It is a new endeavour that started in March 2012; we have several regular geochemical bloggers and various intermittent bloggers and storytellers, and naturally, contributions from the community are highly encouraged and more than welcome. I would like to congratulate Juan Diego RodriguezBlanco (University of Leeds) and his team, as well as Marie-Aude Hulshoff from the EAG, for making our association even more lively through this blog. Bernard Bourdon, EAG President Lyon, April 2012 Florence, birthplace of the Renaissance and a UNESCO World Heritage Site, hosts the Goldschmidt conference in August 2013. Set in one of the most beautiful cities in the world, Goldschmidt2013 boasts cultural delights and an excellent science program. The Goldschmidt conferences, co-sponsored by the EAG and the GS, is now the foremost conference in Geochemistry, with over 3300 delegates attending the 2011 meeting in Prague. Call for additional sessions starts September 2012 Do put these dates into your diary and join us for what looks set to be Copyright R and B an outstanding meeting. goldschmidt.info/2013 E lements 224 J une 2012 Geochemical Society www.geochemsoc.org Why Join a Professional Society? This question was recently posed to the membership of the Geochemical Society in a survey whose goal was to ensure that the Society continues to best serve the needs of its membership. The responses were eye-opening, and reflective of scientists’ changing expectations and needs as they increasingly rely on social media for peer-to-peer communication and access to journals through library e-subscriptions. The strongest message received concerned many aspects Rick Carlson of the journal we cosponsor with the Meteoritical Society, Geochimica et Cosmochimica Acta. Some parts of this story we already knew. The number of personal subscriptions to GCA is becoming vanishingly small as the membership, and everyone else, gets access to the journal electronically through their library. Many respondents noted the turmoil, hopefully solved by the time you read this, that accompanied the most recent contract negotiation with the publisher and the change in editorial leadership. The role of a commercial publisher in society journal production was a particularly prickly topic among respondents, with many pointing out the diminishing society editorial control and questioning the wisdom of letting commercial publishers profit from the authors’ products and the editorial services provided, generally for free, by our community. What was less often noted is that GCA has been the numberone-cited full-length journal in the category of geochemistry/geophysics for many years, in part because of the fair and even-handed peer review managed by Frank Podosek and the selfless service of a large board of dedicated associate editors. Other positive features include the fact that, in most cases, authors can publish in GCA for free, that the web presentation of the journal, created by the publisher, allows the reader easy discovery of related papers and, in the near future, the ability to link with other related datasets. Where the balance lies between the strengths and weaknesses of the Society’s current publishing activities is front and center in the mandate given to the recently restaffed Publication Advisory Committee, which will be examining the types of publishing activities that would best address the needs of the membership. GCA is but one of many publications cosponsored by the Geochemical Society, one of which you are reading now. One experiment in our publications inventory is the redesigned Geochemical News (www.multibriefs.com/briefs/gs), now e-mailed weekly to the membership. The GN provides the opportunity to communicate news of interest to the geochemistry community quickly and link the membership to newsworthy stories across the broad field of geochemistry. The GN is at your disposal to advertise meetings and publications and to post funding announcements and other news items of interest to the geochemical community. Also appearing in GN are job postings listed in our Career Center (www.geochemsoc.org/careercenter), an economical way to have your job postings viewed by over 4000 subscribers to the GN. Another traditional raison d’etre for a professional society is conferences, and here the nearly 3000 abstracts submitted to this year’s Goldschmidt Conference in Montreal reflect the continued popularity of the Goldschmidt and its increasing ability to attract attendees from across the breadth of geochemistry. Going forward, our efforts will be focused on keeping Goldschmidt strong by looking for ways to reduce the expense of the meeting for attendees, increasing support for student participation, providing additional content, and rotating the meeting location through a larger proportion of the world, in keeping with the international nature of the Geochemical Society. As with our multiple publishing activities, the Goldschmidt Conference is not our only E lements conference-related activity. The Meeting Assistance Program offers grants of up to $2000 to support smaller, thematic meetings (www. geochemsoc.org/programs/meetingassistanceprogram). You can read a report on a meeting we sponsored on page 236. Along these lines, we also have joined forces with the EAG in establishing an outreach program, whose goal is to bring modern approaches and interesting applications of geochemistry to audiences that have fewer opportunities to interact routinely with the international geochemical community. Perhaps the most distressing survey responses were from those who noted their desire to partake in Society activities but could not afford to do so. The US$30 membership fee of the GS is small by western standards, but not for some developing countries. We hope to address this issue with some form of sliding membership fee that ties the fee to an index of relative income. We already do something similar for students and retirees, who pay a membership fee that is just enough to cover their subscription to this magazine; so, in essence, they receive the other benefits of GS membership for free. The ongoing programs mentioned above address the majority of member services requested by survey respondents. Beyond these, the survey responses provided a number of ideas for ways in which the GS can expand its activities to better address the needs of the geochemical community. The leadership takes these suggestions seriously and will work to implement as many as feasible. This path thus provides at least one answer to the question “Why join a professional society?” because a professional society can marshal and direct a critical mass of energetic individuals to make highly cited publications a reality, organize wellattended conferences, provide rapid reporting of news relevant to the community, connect those offering jobs to those looking for employment, and provide a variety of other services of benefit to the membership. The GS greatly appreciates the membership participation in the benefits survey and looks forward to making many of the suggested new benefits a reality. Rick Carlson ([email protected]), GS President Notes from St. Louis Remember the 15 October 2012 deadlines for the 2013 GS awards: Goldschmidt Medal, Clarke Medal, Patterson Medal, Treibs Medal, and the GS/EAG Geochemical Fellow. Nomination requirements and procedures are available online at www.geochemsoc.org/ awards/makeanomination. The GS Meeting Assistance Program (MAP) was established in 2002 to allocate up to five sponsorships of up to US $2000 each ($10,000 annually) in support of geochemistry sessions/symposia at any scientific conference of geochemical relevance. Past sponsorships and application procedures are available at w w w.geochemsoc.org/programs/ meetingassistanceprogram/. The GS weekly e-newsbrief, Geochemical News, now has more than 4000 subscribers. Subscription is included with membership, but anyone may subscribe for free at: http://multibriefs.com/optin.php?gs. Archives of recent issues are also online at http://multibriefs.com/briefs/gs/. Geochemical Society Business Office Seth Davis, Business Manager Kathryn Hall, Administrative Assistant Washington University in St. Louis Earth and Planetary Sciences, CB 1169 One Brookings Drive, Saint Louis, MO 63130-4899, USA E-mail: [email protected] Phone: 314-935-4131 • Fax: 314-935-4121 Website: www.geochemsoc.org 225 J une 2012 Meteoritical Society http://meteoriticalsociety.org 2012 METEORITICAL SOCIETY FELLOWS Philip Bland (UK/ Australia) – For original and diverse studies of important meteorite problems, helping establish the Western Australia camera network, and contributions to the society Christine Floss (USA) – For superior ion microprobe studies of isotopes and trace elements in diverse meteorites and in presolar grains, as well as for contributions to the society Makoto Kimura (Japan) – For outstanding studies of the mineralogy and petrology of primitive chondrites and of highpressure minerals in shocked meteorites, and for his contributions to the society Thorsten Kleine (Germany) – For his fundamental studies of the Hf–W system and the chronology of the early Solar System Yangting Lin (China) – For contributions to the understanding of the origins of chondritic components, most notably presolar grains and CAIs, and the petrology of Martian meteorites, for his role in the Chinese Antarctic meteorite collection program, and for his contributions to the society Katharina Lodders (USA) – For the application of thermodynamics to our understanding of Solar System processes and the compilation of huge amounts of Solar System data so that it is readily accessible to scientists E lements Bernard Marty (France) – For outstanding studies on the noble gases and nitrogen in meteorites and Genesis samples, and for contributions to the society Akira Yamaguchi (Japan) – For major contributions to our understanding of the petrogenesis of achondrites, leadership in the collection/curation of Antarctic meteorites at NIPR, and contributions to the society Edward Young (USA) – For significant studies of C, O, and Mg isotopes in meteorites and protoplanetary disks, for studies of the hydrology of asteroids, and for contributions to the understanding of isotopic fractionation during evaporation of silicates Hisayoshi Yurimoto (Japan) – For innovative isotopic studies of chondritic components, particularly CAIs and fluid inclusions, and the mentoring of many students Jutta Zipfel (Germany) – For significant research on a range of differentiated meteorites and on planetary missions to understand igneous processes on asteroids and Mars, for work on meteorite curation and classification, and for contributions to the society NOMENCLATURE COMMITTEE REPORT The purpose of the Nomenclature Committee (NomCom) is to approve new meteorite names, and to establish guidelines and make decisions regarding the naming of meteorites. We are also charged with keeping the community apprised of new meteorites through the Meteoritical Bulletin and the Meteoritical Bulletin Database (www.lpi.usra.edu/meteor/ metbull.php). Since the last report, Meteoritical Bulletin (MB) 99 has been completed; it contains 1075 meteorites, 468 of which are nonAntarctic. MB99 will be published shortly in the new online format. A further 1509 meteorites have been approved thus far for MB100. The type specimen (TS) repository review process is underway, with curators of TS repositories now required to update their contact information in an online database. Any new meteorite submission will not be considered if the information about the TS repository listed in the submission is incomplete. Our guidelines for meteorite nomenclature continue to be revised to keep up with the times. A recent addition is a section entitled “Meteorites Found on Celestial Bodies Other than Earth”! The complete, up-to-date guidelines can be found at www.meteoriticalsociety.org/bulletin/nc-guidelines.htm. Please do not hesitate to contact me (herd@ ualberta.ca) with questions or concerns about NomCom and especially with suggestions for improvement. As always, essential information on meteorite nomenclature, instructions, and the template for reporting new meteorites can be found on our homepage: http://meteoriticalsociety.org/ simple_template.cfm?code=pub_bulletin. A list of current NomCom members can be found at www.meteoriticalsociety.org/bulletin/TermExpirations2011.htm. Chris Herd Chair of the Nomenclature Committee The Meteoritical Society wishes Marc Norman great success as executive editor of Geochimica et Cosmoschimica Acta. Read about his appointment on page 186. 226 J une 2012 The Clay Minerals Society www.clays.org STUDENT RESEARCH SPOTLIGHT THE PRESIDENT’S CORNER The United Nations declared October 31, 2011, to be the day (+/– about a year) that the Earth’s population reached 7 billion. Less well publicized but far more significant is that the projection for peak global population was raised from 9 billion to slightly over 10 billion and will occur somewhere around 2050. This brings me to the critical question, “Will we be able to feed 10 billion people in 2050?” The problem is not so much a growing population as it is a changing of diets. The people of China, India, and other rapidly developing countries are eating more meat and dairy products as their economies grow, and it takes 3 to 10 calories of grain to produce one calorie of meat. Thus global economic growth is accelerating growth in demand for grain far faster than the effect population growth is having on this demand. My children and as yet unborn grandchildren have little risk of facing a food shortage: we live in Iowa, the greatest grain-producing region the world has ever known! For that matter, people living throughout North America, South America, and Europe have little risk of food shortages, as these regions have excess food-production capacity and their populations have either stabilized or are rapidly doing so. The people of China, India, Japan, South Korea, and Southeast Asia are also at low risk of food shortages; populations in these countries are also rapidly stabilizing, and as long as their economies continue to grow they will be able to afford to import the surplus food produced in the Americas. My concern is for the people of sub-Saharan Africa, a region with rapidly growing populations, abysmal economies, and degraded soils. The poverty and deprivation that grips sub-Saharan Africa is rooted in the mineralogy of their soils. The young loess and glacial till soils of Iowa are dominated by smectites, illites, and randomly interstratified S/I (not really smectite/illite because the layer charge of the “illitic phase” is way too low, but that is another story). These 2:1 phyllosilicate clay minerals hold water and nutrients and help both to form and to stabilize soil organic matter by adsorbing fragments of biopolymers and physically protecting humic substances from rapid microbial decomposition. Soil organic matter in turn stabilizes soil structure and is a reservoir of slowly released nutrients that nourish crop growth. Iowa soils are incredibly productive! The soils of sub-Saharan Africa are dominated by quartz sands and old, highly weathered Fe- and Al-oxyhydroxide clay minerals. Because these minerals have lowactivity surfaces, they are not effective at forming and stabilizing soilenriching humus. Furthermore, the soils of sub-Saharan Africa have little capacity for retaining plant nutrients and are easily leached and/ or depleted of nutrients by cropping. Congratulations to Conni De Masi for winning a CMS Student Research Grant Award. Conni is a graduate student at California State University, Long Beach, where she is working on a master of science degree in biology. In her research, she uses clay mineralogy and stable isotopes to determine the paleoclimate and paleo elevation of Owens Valley, California, and the surrounding mountains. CLAY AND PHYLLOSILICATE MINERALS IN EXTRATERRESTRIAL MATERIALS On Earth, many clay minerals and related phyllosilicates form from reactions involving water during weathering, diagenesis, and hydrothermal alteration. Clay and phyllosilicate minerals have been detected by spectroscopy on the surface of Mars and in some classes of meteorites by analyses in terrestrial laboratories. Occurrences of phyllosilicate minerals in extraterrestrial materials are widely understood to indicate the former presence of water on some rocky bodies elsewhere in the Solar System. The landing site for the Mars Science Laboratory (MSL) mission (successfully launched in November 2011 and due to land on Mars in August 2012) was chosen largely because clay-mineral-bearing strata, in their stratigraphic context and in relation to other water-soluble minerals, will be accessible to the ten scientific instruments on MSL rover Curiosity, including the first X-ray diffractometer to be flown to another planet. NASA recently selected a mission to return samples from a primitive asteroid, of a spectroscopic class that may contain phyllosilicates, in the coming decade. The August 2011 issue of Clays and Clay Minerals assembles five papers on clay and phyllosilicate minerals in extraterrestrial materials. Four are case studies of mineral assemblages detected by orbital spectroscopy of the surface materials on Mars; the fifth reviews the occurrence and significance of serpentine-group phyllosilicates in one class of carbonaceous chondrites. This thematic issue embodies the overlapping interests and emerging connections between planetary geologists and clay mineralogists. Michael Velbel, Michigan State University The challenges facing sub-Saharan Africa have many social, political, economic, and historical causes, but the fragility of their soils has been a major factor reinforcing the poverty trap. We are wise to remember the words of Franklin Delano Roosevelt, “A nation that destroys its soils destroys itself.” But we must also bear in mind that Iowa was endowed with resilient soils, while Africa was given fragile soils; the difference is in the mineralogy. David Laird ([email protected]) President, The Clay Minerals Society E lements 227 J une 2012 International Association of GeoChemistry www.iagc-society.org 2012 IAGC Awards Vernadsky Medal to Robert A. Berner The Vernadsky Medal is awarded biennially to honor a distinguished record of scientific accomplishment in geochemistry over the course of a career. Robert A. Berner obtained his BS and MS degrees from the University of Michigan and his PhD from Harvard University. He then went to the Scripps Institution of Oceanography as a Sverdrup Postdoctoral Fellow. In 1963 he joined the faculty at the University of Chicago and later moved to Yale University, where he was promoted to professor in 1971. He remains at Yale as an emeritus professor, after retiring in 2007. Dr. Berner is a member of the U.S. National Academy of Sciences. Among his many awards are the 1991 Doctor Honoris Causa, Université AixMarseille (France), the 1991 Huntsman Medal in Oceanography (Canada), the 1993 Goldschmidt Medal of the Geochemical Society, the 1995 Arthur L. Day Medal of the Geological Society of America, and the 1996 Murchinson Medal of the Geological Society of London. One of the most internationally recognized and valuable research accomplishments of Dr. Berner, along with colleagues Bob Garrels and Tony Lasaga, has been the now famous BLAG model of atmospheric CO2 variations through the Cretaceous. Dr. Berner has gone on to refine this model by extending it to the beginning of the Phanerozoic in the GEOCARB models. His modeling efforts have been confirmed by various proxies, such as the density of stomata in fossil plant leaves. Dr. Berner’s current research deals with computer modeling of the carbon and sulfur cycles, emphasizing their coupling to controls on atmospheric CO2 and O2, the effect of CO2 on paleoclimate and of O2 on biological evolution, the role of plants in rock weathering and their controls on atmospheric CO2 oscillations in the Phanerozoic, and weathering of kerogen in fossil shales as a measure of the modulation of atmospheric O2 . Dr. Berner has tackled a number of other significant problems as well. This work includes studies of the kinetic behavior of carbonates in the ocean, experiments on the stabilities and kinetics of carbonate minerals and other sedimentary mineral types, field observations of the processes of early diagenesis, and studies of geochemical cycles. Distinguished Service Awards to Ernest E. Angino and Luca Fanfani The Distinguished Service Award recognizes outstanding service by an IAGC member to the Association or to the geochemical community that greatly exceeds the normal expectations of voluntary service. Ernest E. Angino is being honored for his dedicated service to IAGC as treasurer from 1980 to 1994. He was a professor and is now an emeritus professor in the Department of Geology at the University of Kansas. Ernie did research and teaching in the area of aqueous geochemistry. He contributed significantly to the understanding of the aqueous geochemistry of trace metals and the chemistry of Antarctic lakes and participated in the development of the important research area of geochemistry and health. During his tenure as chair of the Department of Geology at the University of Kansas, he was instrumental in organizing the alumni association, which has resulted in significant gifts to the department. Ernie brought his organizational and management E lements skills to IAGC during his time as treasurer. He worked to increase the assets of IAGC, handing to his successor, D. T. Long, an association in an extremely stable financial state. He also proved to be an invaluable resource for the president and secretary of IAGC, as he contributed to negotiations with the publisher of the society’s journal, Applied Geochemistry, worked with international collaborators, and helped in the formulation of the various awards bestowed by the society. Ernie’s dedicated service to IAGC went well beyond that of being treasurer. Luca Fanfani’s career as a geochemist-mineralogist has spanned more than 40 years. He has been full professor at the University of Cagliari, Italy, since 1976 and dean of the Faculty of Sciences since 2009. Luca is an active member of the committee of the Water–Rock Interaction Working Group (WRI) and, as general secretary, organized the WRI-10 conference in 2001. He served as a mentor to many young geochemists in Italy and other countries. He has authored or coauthored more than 60 scientific articles, addressing a wide range of geochemical issues. He recognized, long before most of his colleagues, the important connection between geochemistry and mineralogy for understanding the transport and fate of harmful and toxic elements in the near-surface environment. Luca has had a strong impact on the foundation of environmental mineralogy and geochemistry in Italy. He created a research group that became a nationwide reference, stimulating the birth and growth of similar groups around the country. Luca was also a pioneer in understanding the importance of international cooperation and interaction. He stimulated scientific cooperation with less-developed countries, giving rise to several projects in Latin America and North Africa, and he contributed significantly to the progress of environmental geochemistry. Urban Geochemistry Working Group The IAGC is reinvigorating the Urban Geochemistry Working Group under the leadership of Dr. Berry Lyons (The Ohio State University, USA). The group will be cochaired by Dr. David Long (Michigan State University, USA). To kick off this new working group, Dr. Lyons and Dr. Russell Harmon (U.S. Army Corps of Engineers) will be guest editors of the December 2012 issue of Elements, which will feature urban geochemistry as the thematic topic. Additionally, Dr. Lyons and Dr. Long will be cochairing a session devoted to urban geochemistry at the annual Geological Society of America (GSA) meeting in November 2012 in Charlotte, North Carolina, USA. If you would like to be involved in this exciting, newly reorganized working group, please contact the IAGC business manager, Chris Gardner, at [email protected]. Elsevier/IAGC Student Research Grants The Elsevier/IAGC Student Research Grant Program is designed to assist PhD students in geochemistry in undertaking and acquiring geochemical analyses in support of their research. Selection is based upon a meritorious proposal. In addition to their grant stipend, each student receives a one-year membership in IAGC. This year’s recipients are: Alice DuVivier, Durham University, UK ($2500) – “Using Ca isotopes to evaluate the weathering influx in seawater: Implications for the driving mechanisms of the Cenomanian–Turonian boundary oceanic anoxic event (OAE 2)” Jill Ghelerter, Georgia State University, USA ($2000) – “Enhanced bioremediation of oiled salt marsh sediments using clay minerals” Peter Tollan, Durham University, UK ($1500) – “Modern arc peridotites – Analogues for continental-root evolution” 228 J une 2012 Mineralogical Society of Great Britain and Ireland www.minersoc.org The key aim of this meeting is to bring together workers from academia (mineralogy, chemistry, ‘materials’ and others), industry and regulatory bodies to discuss mineralogy under the following four themes: Become a Chartered Scientist Now! The Mineralogical Society has become a body licensed to award the Chartered Scientist status to its members. We are now ready to begin receiving applications. The benchmark route is the successful completion of a programme of study leading to an MSc (visit our website to read about ‘M’-level equivalence). All candidates need to have at least four years of postgraduate experience in the practice, application or teaching of science. Additionally applicants must have undertaken continuing professional development commensurate with the level of attainment required for a minimum of two years immediately prior to the application. Applicants must demonstrate that their scope of practice requires them to: Demonstrate a systematic understanding of knowledge, and show critical awareness of current problems and/or new insights in their area of mineralogical science Have a comprehensive understanding of techniques applicable to their scope of practice and the ability to critically evaluate current research Deal with complex issues both systematically and creatively, make sound judgements in the absence of complete data, and communicate their conclusions clearly to specialist and non-specialist audiences Exercise self-direction and personal responsibility in solving problems, and exercise personal autonomy in planning and implementing tasks at a professional level Continue to advance their knowledge, understanding and competence to a high level Visit www.minersoc.org/chartered.html for more details and an application form. Members of long standing may be particularly interested in our ‘fast-track’ method of application. There is an initial cost of £50 plus a charge of £45 per year thereafter. Major meetings in 2013 The Society will be involved in two major meetings in 2013. Details are given below below and on the Society website. Volcanism, Impacts and Mass Extinctions: Causes and Effects On 27–29 March 2013, London’s Natural History Museum will host an international, multidisciplinary conference that brings together researchers from across the geological, geophysical and biological disciplines to assess the state of research into the causes of mass extinction events. The main goal of this conference will be to evaluate the respective roles of volcanism, bolide impacts, sea level fluctuations and associated climate and environmental changes in major episodes of species extinction. More details are available at http://massextinction.princeton.edu/. This event is supported by the Volcanic and Magmatic Studies Group and the Mineralogical Society. Strategically Important Mineral Resources includes the sustainability of mineral resources, such as strategically important elements (considering both primary and secondary sources), ethically/responsibly sourced metals and gems, and related topics such as resource recovery and management. The recycling of minerals will be addressed here as appropriate. Functional Materials and Minerals deals with nano-, micro- and mesoporous materials (both synthetic and natural), such as zeolites, pillared clays and the like; thin films of (or on) mineral surfaces; and mineral catalysts. This topic may include any ‘functional’ mineral application (or mineral-derived material), such as sensors and transducers, sorbents, ion-exchange media, cements and others. Minerals for Environmental Protection includes both nuclear and nonnuclear applications. It considers the use of minerals as retarding media in engineered chemical barriers, alongside physically engineered subsurface structures such as mineral liners; permeable reactive barriers; and examples of environmental remediation in which mineral technology has had significant impact. Carbon capture and storage is another important part of this theme. Biological Processes in Mineral Science and Technology includes a range of biological processes, both naturally occurring and industrially applied. These will include biomining and bioremediation applications, and also emerging biological synthesis routes for commercially useful materials. Other geologically important biomineralization processes, in both prokaryotic and eukaryotic systems, will also be of interest. Go to www.minerals-for-life.org for more information. Clays Used in Beadmaking Modern lampwork* glass beadmaking can trace its lineage back 500 years to the Italians (e.g. Murano glass), who made beads by wrapping hot glass around copper wire. After the glass cooled, the bead was cut off with the copper wire still inside. It was then dropped into a caustic solution that dissolved the copper wire, leaving a clean hole behind. The American lampwork bead movement started around the 1970s. Glass-bead artists found they could use techniques similar to those of the Italian beadmakers by wrapping molten glass around a mandrel (a piece of stainless steel welding rod) that had been dipped in a sludge (generally a mixture of clay, water and other ingredients, called bead release) beforehand and dried so that the bead could be twisted off after cooling. When I started making lampwork beads in 1991, I had problems getting the beads off the mandrels and I decided to try to make my own bead release. It took 6 months of experimenting and testing to settle on a good basic formula using kaolin as the main ingredient. It’s been eight years since the first test batches of bead release were handed out in pickle jars. Now I have three formulas sold in many parts of world. Robin J. Foster Minerals for Life: Overcoming Resource Constraints On 17–19 June 2013, our ‘Minerals for Life’ meeting will be held in Edinburgh. The meeting is a collaborative venture with the Geological Society, the British Zeolite Association and the Institute of Materials. E lements * A type of glasswork that uses a torch to melt rods and tubes of clear or colored glass; the molten glass is then shaped with tools, gravity and hand movement. 229 J une 2012 Japan Association of Mineralogical Sciences http://jams.la.coocan.jpe_index.html Japan Association of Mineralogical Sciences Awardees The Japan Association of Mineralogical Sciences (JAMS) is proud to announce the recipients of its 2011 society awards. The Japan Association of Mineralogical Sciences Award is given to a maximum of two scientists per year for exceptional contributions to the mineralogical and related sciences. The Manjiro Watanabe Award, named in honor of Professor Manjiro Watanabe, a famous Japanese mineralogist, and funded by his contribution, is presented yearly to a scientist who has contributed significantly to mineralogical and related sciences over his/her career. The Japan Association of Mineralogical Sciences Research Paper Award is given annually to the authors of two excellent papers in the Journal of Mineralogical and Petrological Sciences (JMPS) and Ganseki-Kobutsu-Kagaku (GKK) published in the last three years. Congratulations to all the winners! Japan Association of Mineralogical Sciences Award to Tetsumaru Itaya Tetsumaru Itaya, from Okayama University of Science, Japan, is a leading expert in the geochronology of orogenic belts around the world. His research spans a wide range of subjects, in addition to geochronology , including studies of volcanic, metamorphic, and plutonic rocks, accretionary complexes, and fault rocks for predicting earthquake activity; ore petrology and mineralogy; the development of high-quality analytical techniques; contributions to anthropology and archeology; and paleomagnetic studies related to global tectonics. Highlights of his recent research include the following: Discovery of a very large excess of argon in kyanite and of the regional excess argon wave occurring in a Barrovian-type metamorphic belt Elucidation of the mechanism underlying argon depletion from phengites during ductile deformation accompanying the exhumation of high-pressure metamorphic rocks and the formation of excess-argon-free phengites in ultrahigh-pressure metamorphism His research has contributed to the understanding of orogenic processes around the world. The most challenging part of his research has been revealing the precise K–Ar chronology of Holocene volcanic rocks, which allows for dating island-arc volcanic rocks using a few grams of a sample with 2 wt% potassium, while applying a precise correction for the mass fractionation of argon isotopes. Japan Association of Mineralogical Sciences Award to Kazumasa Sugiyama Kazumasa Sugiyama, from the Institute for Materials Research (IMR), Tohoku University, Japan, is a mineralogist whose research concerns the development of new functional materials. He started his scientific career by focusing on the application of X-ray diffraction to the structural analysis of natural minerals with complex structures. His research interests also include the elucidation of the structure of amorphous materials. Conventional X-ray diffraction has a drawback in that it is not useful for distinguishing between elements with similar atomic numbers. Kazumasa Sugiyama used anomalous X-ray scattering (AXS) to address the above-mentioned problem and obtained finestructural information for materials with complex structures. This new E lements approach is one of the most promising methods for the structural analysis of disordered materials, including nanoscale natural minerals. He also developed new equipment for the fine-structural analysis of high-temperature liquids by energy-dispersive X-ray diffraction (EDXD), and he used the equipment to obtain structural images of a variety of liquid materials. Recently, he extended his research to the structural analysis of minerals with more complex structures. He also developed an advanced AXS-RMC (reverse Monte Carlo) method and solved the structures of complex and disordered materials. His research has contributed significantly to the advancement of fundamental Earth science knowledge and the development of new functional materials. Manjiro Watanabe Award to Fumiyuki Marumo Professor Fumiyuki Marumo started his scientific research studying the crystal structure of harmotome by single-crystal X-ray diffraction under the supervision of Prof. R. Sadanaga at the University of Tokyo in 1955. In 1961, he moved to the University of Bern in Switzerland and pursued structural research on sulfosalt minerals from Lengenbach. He solved many complicated structures and contributed to the determination of the structural scheme of arsenic-bearing sulfosalts. He also reported three new sulfosalt minerals from Lengenbach. He returned to Japan in 1966 and continued structural research at the Institute for Solid State Physics at the University of Tokyo. He was engaged in the structure determination of crystals of metal complexes, charge-transfer organic complexes, and natural organic materials, and he obtained valuable results in these fields. In 1972, he was offered a faculty position at the Tokyo Institute of Technology, where he started a structural investigation of crystals of ferroelectrics, ferroelastics, ionic conductors, transition metal silicates, etc. Most importantly, he confirmed the anisotropic distribution of 3d electrons, which was suggested by crystal-field theory, by determining accurate electron-density distributions in a series of spinel-type transition metal silicates using X-ray diffraction. This research attracted the attention of numerous inorganic crystal chemists. He also succeeded in growing high-quality nonlinear optical crystals of the low-temperature form of BaB2O4 from a supercooled melt of pure BaB2O4, by making the melt temperature about 100 °C higher than the phase transition point between the low- and high-temperature forms of BaB2O4. Japan Association of Mineralogical Sciences Research Paper Awards Tetsuo Kawakami and Tomokazu Hokada (2010) Linking P-T path with development of discontinuous phosphorus zoning in garnet during high-temperature metamorphism—an example from the Lützow-Holm Complex, East Antarctica. Journal of Mineralogical and Petrological Sciences 105: 175-186 Tetsuo Kawakami 230 Tomokazu Hokada J une 2012 Masayuki NISHI, Tomoaki KUBO and Takumi KATO (2009) Metastable transformations of eclogite to garnetite in subducting oceanic crust. Journal of Mineralogical and Petrological Sciences 104: 192-198 Koichi Momma (left) and Katsumi Nishikubo Masayuki Nishi Tomoaki Kubo peaks attributable to other guest molecules, such as CO2, N2, or H2 S, were not detected. Therefore, the ideal formula of chibaite is SiO2 ∙n(CH4, C2H6, C3H8, i-C4H10 ), with nmax = 3/17. Takumi Kato The Discovery of Chibaite Koichi Momma, a mineralogist from the National Museum of Nature and Science, has found and described a new silica clathrate species, “chibaite,” in collaboration with other members of JAMS. The new mineral incorporates hydrocarbon molecules such as CH4, C2H6, C3H8, and i-C4H10 in its silica framework. In 1998, Chibune Honma, a fossil collector, discovered white quartz in tuffaceous sediments of Early Miocene age (Hota Group) in the southern Boso Peninsula, Chiba Prefecture, Japan. Naoki Takahashi from the National H i stor y Mu s e u m a nd Institute, Chiba, analyzed the quartz specimen, which had an unusual, thick, hexagonal, platy shape; however, electron microprobe analysis revealed the presence of ordinary, simple silica. A few years l at e r, K at s u m i Nishikubo, a mineral collector from Chiba, collected Chibaite more specimens. Masayuki Takada, a mineralogist from Kyoto, studied the crystal morphology of the distinctive quartz and revealed it to be a pseudomorph composed of {111} twins of octahedral crystals with cubic symmetry. Nishikubo sent some transparent euhedral crystals to Tohoku University, where Momma was studying silica minerals under the supervision of Toshiro Nagase and Yasuhiro Kudoh. Momma carried out Raman spectroscopic analyses on the crystals and detected methane and other hydrocarbons occluded in the crystals. X-ray investigations revealed that the crystal structure of Nishikubo’s sample is different from that of melanophlogite, the only silica clathrate mineral hitherto known. Chibaite has been approved by the IMA Commission on New Minerals, Nomenclature and Classification (#2008-067) and is described in detail in Momma et al. (2011)1. The Hota Group includes fore-arc sediments related to the Paleo-Izu arc deposited near the plate margin at the triple junction of the Pacific, Philippine Sea, and North America plates. Veins containing chibaite fill fissures related to minor faults, in which thermogenic hydrocarbons were deposited from fluids originating from deeply buried sediments. Silica clathrate minerals store hydrocarbons that have vanished from sedimentary rock and, therefore, provide new evidence for geological carbon cycling at active plate boundaries. 1 Momma K, Ikeda T, Nishikubo K, Takahashi N, Honma C, Takada M, Furukawa Y, Nagase T, Kudoh Y (2011) New silica clathrate minerals that are isostructural with natural gas hydrates. Nature Communications 2: 196 (7 pages) Chibaite is isotopological to the cubic structure II gas hydrate. It is epitaxially intergrown with a minor amount of another, as-yet-unnamed silica clathrate mineral, which is isotopological to the hexagonal structure H gas hydrate. Chibaite is colorless, has a vitreous luster, and has no cleavage. Its refractive index, Mohs hardness, and calculated density are 1.470(1), 6.5–7, and 2.03(1), respectively. The empirical formula derived from the electron microprobe data is Na0.99 (Si134.53Al1.63)O272, excluding the guest gas molecules in the cages. These constituents comprise 90−92 wt% (average: 90.89 wt%), and the gas molecules comprise the remaining 8−10 wt%. Four types of hydrocarbons—CH4, C2H6, C3H8, and i-C4H10 —were confirmed from the Raman spectra. Raman E lements 231 Journal of Mineralogical and Petrological Sciences Vol. 107 no 2, April 2012 Diffusion-controlled melting in granitic systems at 800–900 °C and 100–200 MPa: Temperature and pressure dependence of the minimum diffusivity in granitic melts Takashi Yuguchi, Takashi Yamaguchi, Manji-rou Iwamoto, Hibiki Eguchi, Hiroshi Isobe, and Tadao Nishiyama Development of a fully automated open-column chemical-separation system—COLUMNSPIDER—and its application to Sr-Nd-Pb isotope analyses of igneous rock samples Takashi Miyazaki, Bogdan Stefanov Vaglarov, Masakazu Takei, Masahiro Suzuki, Hiroaki Suzuki, Kouzou Ohsawa, Qing Chang, Toshiro Takahashi, Yuka Hirahara, Takeshi Hanyu, Jun-Ichi Kimura, and Yoshiyuki Tatsumi Silica dissolution catalyzed by NaOH: Reaction kinetics and energy barriers simulated by quantum mechanical strategies Osamu Tamada, Gerald V. Gibbs, Monte B. Boisen Jr., and J. Donald Rimstidt Finding of prehnite-pumpellyite facies metabasites from the Kurosegawa belt in Yatsushiro area, Kyushu, Japan Kenichiro Kamimura, Takao Hirajima, and Yoshiyuki Fujimoto TES microcalorimeter SEM-EDS system for rare-earth elements analyses Seiichiro Uehara, Yasuhiro Takai, Yohei Shirose, and Yuki Fujii Rhabdophane-(Y), YPO4 ·H2O, a new mineral in alkali olivine basalt from Hinodematsu, Genkai-cho, Saga Prefecture, Japan Yasuhiro Takai and Seiichiro Uehara Raman and NMR spectroscopic characterization of high-pressure K-cymrite (KAlSi3O8.H2O) and its anhydrous form (kokchetavite) Masami KANZAKI, Xianyu XUE, Julien AMALBERTI, and Qian ZHANG J une 2012 German Mineralogical Society www.dmg-home.de Siemens Research Center on Rare Earth Elements at RWTH Aachen University EMPG XIV in Kiel, Germany The fourteenth Experimental Mineralogy, Petrology, and Geochemistry (EMPG) Conference took place between March 4 and 7 at the Christian Albrechts University in Kiel and was organized by the Department of Mineralogy of that institution. More than 260 participants from 30 countries found their way to northern Germany, thus fulfilling the organizers’ intention to bring together researchers from all fields of experimental geosciences. Altogether, 230 abstracts were submitted (104 posters and 126 oral presentations). The whole range of experimental research, including geochemical, mineralogical, and petrological aspects, was covered. Because of the long distance to Kiel, the participation of some attendees was made possible with the support of the European Mineralogical Union (EMU) and the German Mineralogical Society (DMG); this support is gratefully acknowledged by the organizers. A wide range of topics was covered during the conference, including the evolution of terrestrial planets and the early Earth, subduction zone processes, and the deep Earth. Another theme concentrated on new frontiers and developments in experimental applications and applied geosciences. Examples were found in sessions dealing with the capture and storage of CO2 and the exploration and disposal of energy-related and hazardous materials. During the last EMPG Conference, in Toulouse in 2010, an effort was made to encourage closer links between theoretical simulations and experimental approaches. Especially in topics like diffusion, reaction kinetics, and small-scale deformations, stronger collaborations might have great potential. During EMPG XIV, researchers with numerical backgrounds presented their research in at least two sessions. Hopefully, this effort will be continued or even enlarged in future conferences. In their first research program at a university anywhere in the world, the Siemens group is providing €6 million in funding for a program of strategic collaboration on rare earth elements with RWTH Aachen University. The main objective of the research proPeople at the Siemens Rare Earth Element gram is the development of Research Center at RWTH Aachen University methods and processes for ensuring an environmentally friendly and efficient supply of rare earth elements for permanent magnet production. This strategic project is a result of a long-term cooperative agreement between Siemens and RWTH Aachen, a partner university in the international Center of Knowledge Interchange (CKI) program. The Siemens Research Center (SRC) follows the program structure of the German Research Foundation (DFG) “Collaborative Research Centers” (CRC). Like a CRC, it concentrates and coordinates RWTH resources in the fields of economic geology and mineralogy, ore dressing, metallurgy, and recycling, and enables researchers to pursue a long-term research program across discipline boundaries. Taking part in the SRC are five departments from RWTH Aachen University, another from Forschungszentrum Jülich, and experts from Siemens’ Industry Sector. At least nine PhD students will conduct their research under the auspices of the program over the next four years. The organization of this conference was exemplary. From the efficient online registration, through the icebreaker event, to the conference itself and the conference dinner, many helping hands made sure that everything was working perfectly. Let’s not forget the many small details, like continuously available coffee and cake, the friendly staff in the cloakroom, and the speakers’ ready room. Special thanks go to Philipp Kegler, Astrid Holzheid, their team, and all the helpers. The SRC involves RWTH, Siemens, and experts in the supply chain from REE minerals, ore deposits, ore processing, and metallurgical refining to products. Thus, the research focus spans a “mine to magnet” approach, from the identification of alternative REE deposits with detrimental components, through the development of environmentally friendly and sustainable processes for recovery and extraction, to the design of efficient methods for recycling and life cycle analyses. The aim is to extend rare earth supply through improved mineralogical resource information and ore beneficiation, and innovative separation and recovery technologies. Bastian Joachim Michael Meyer The First European Mineralogical Conference will be held at the Goethe-University in Frankfurt, Germany, 2-6 September 2012. The contributing societies are: DMG MinSoc MinSocFin ÖMG PTMin RMS SEM SFMC SIMP SSMP Deutsche Mineralogische Gesellschaft Mineralogical Society of Great Britain & Ireland Mineralogical Society of Finland Österreichische Mineralogische Gesellschaft Mineralogical Society of Poland Russian Mineralogical Society Sociedad Española de Mineralogía Société Française de Minéralogie et de Cristallographie Società Italiana di Mineralogia e Petrologia Swiss Society of Mineralogy and Petrology The themes for the conference are as follows: Mantle petrology and geochemistry; Magmatism and volcanology; Metamorphism; Applied mineralogy; Mineral physics; Mineralogical crystallography; Planetary materials; Mineral deposits and raw materials; Low T geochemistry; Geochronology; Geobiochemistry; Advanced analytical techniques; Archaeometry, care and preservation; Open session. Invited lectures will be given by Hilary Downes, Thomas Stachel, Rod Ewing, Tim Elliott, and the IMA medallist David Green. The scientific committee consists of one representative of each society. WEB: emc2012.uni-frankfurt.de The local organizing committee: Gerhard Brey, Heidi Höfer E lements 232 MAIL: [email protected] J une 2012 Mineralogical Association of Canada www.mineralogicalassociation.ca GAC-MAC Winnipeg 2013 The 2013 joint annual meeting of the Geological Association of Canada and the Mineralogical Association of Canada will be held from May 22 to 24 at the Convention Centre in downtown Winnipeg. The city is located 29 km west of the longitudinal center of North America and sits on the sediments of the immense glacial Lake Agassiz. It is just a short distance from one of the world’s largest rare-metal pegmatites at Tanco, spectacular outcrops of Paleozoic carbonate rocks in the Interlake region, Precambrian rocks of the Superior craton and Trans-Hudson orogen, and a score of other geological attractions. As is customary at a GAC-MAC meeting, the field trip offering is exceptional. Here is a great opportunity to discover the Tanco pegmatite, the Flin Flon mining district, the Thompson nickel belt, for example. Several short courses will be offered before and after the meeting. Details on registration, programs, and events are available at: www.gacmacwinnipeg2013.ca Here are some of the symposia, special sessions, and field trips that will be of great interest to the mineralogy–geochemistry– petrology community. Check the website for the full list. Uranium: Cradle to Grave Mineralogical Association of Canada Short Course Winnipeg, Manitoba, Canada May 20–21, 2013 Magmatic Ni-Cu-PGE-Cr Deposits: OreForming Processes with Implications for Exploration Michel Houlé, Valérie Bécu, Doreen E. Ames, Xue-Ming (Erik) Yang, Paul Gilbert Metamorphism in the Ore Environment Chris Couëslan, Doug Tinkham, David Pattison, Simon Gagné Geomicrobiological and Biogeochemical Advances in Environmental Systems Ian Power, Lachlan MacLean Impact Cratering: A Geological Process Gordon Osinski, Richard Grieve Terrestrial Analogues for Comparative Planetary Geology and Astrobiology Ed Cloutis, Gordon Osinski Symposia Earth Materials, Petrological and Geochemical Processes (in Honor of Frank C. Hawthorne) Elena Sokolova, Norman Halden Granitic Pegmatites – From Fascinating Crystals to High-Tech Elements (in Honor of Petr Černý) Milan Novák Special Sessions Diamond: From Birth in the Mantle to Emplacement in Kimberlite Maya G. Kopylova, Yana Fedortchouk Uranium: Cradle to Grave Peter Burns Rare Earth Elements in Melts, Fluids, and Crystal Structures Anton Chakhmouradian, Ian Coulson The focus of this short course, which will immediately precede the GAC-MAC meeting, will be the many aspects of uranium, an element that changed the course of the world like no other. Content will span the mineralogy, geochemistry, and ore deposits of uranium, and will include nuclear waste challenges and solutions, weapons proliferation, and nuclear forensics for attribution and nuclear security. The short course will bring together a panel of international experts focused on educating graduate students, earlycareer scientists, and researchers seeking a deeper involvement in the field. We invite you to join us and enjoy topics central to this fascinating element’s history, complexity, environmental impact, and importance in global security. Topics and confirmed speakers/authors include: History of Uranium – Jessica Beard, University of Notre Dame Mineralogy and Crystallography – Sergey Krivovichev, Saint Petersburg State University Field Trips Ore Deposits and Economic Geology – Mostafa Fayek, University of Manitoba The Tanco Mine: Geological Setting, Internal Zonation, and Mineralogy of a World-Class Rare Element Pegmatite Deposit Tania Martins, Paul Kremer, Peter Vanstone, Gary Poetschke, Blair Skinner Thermochemistry of Uranium Minerals and Compounds – Alexandra Navrotsky, University of California–Davis Neoarchean Mafic-Ultramafic Intrusions in the Bird River Greenstone Belt: Tectonic Setting and Economic Significance Paul Gilbert, James Scoates, Jon Scoates, Erik Yang, Caroline Mealin, Michel Houlé, Carey Galeschuk Precious and Rare Metals in the Volcanogenic Massive Sulfide Environment Patrick Mercier-Langevin, Harold Gibson, Simon Gagné The Volcanological and Structural Evolution of the Paleoproterozoic Flin Flon Mining District: The Anatomy of a Giant VMS System Harold Gibson, Bruno Lafrance, Sally Pehrsson, Michelle Dewolfe, Kelly Gilmore, Renée-Luce Simard Testing Links among Large Igneous Provinces, Iron Formations, and Volcanogenic Massive Sulfide Deposits Andrey Bekker, Richard Ernst Metamorphosed Alteration Zones and Regional Metamorphism: Examples from the Trans-Hudson Orogen Chris Couëslan, Doug Tinkham, Al Bailes, Simon Gagné Layered Intrusions: New Paradigms and Approaches to Understanding Magmatic Processes James S. Scoates, Jim Miller Tectonic Evolution of the Thompson Nickel Belt, Manitoba: Sedimentation, Structure, and Magmatism in a Continent-Continent Collisional Zone Josef Macek, Herman Zwanzig, Chris Couëslan E lements Organizers : Peter C. Burns and Ginger E. Sigmon, University of Notre Dame 233 Aqueous Geochemistry of Uranium – Jeremy Fein, University of Notre Dame Materials at the Nanoscale – Peter Burns, University of Notre Dame Mine Tailings Characterization and Remediation – Michael Schindler, Laurentian University Ceramic Waste Forms for Actinides – William Weber, University of Tennessee, and Rodney Ewing, University of Michigan Subsurface Uranium Mobility – John Zachara, Pacific Northwest National Laboratory Spent Nuclear Fuel – David Shoesmith, University of Western Ontario Actinide Borate Waste Forms for Actinides – Thomas Albrecht-Schmitt, University of Notre Dame Pre-Detonation Nuclear Forensics – Ian Hutcheon, Lawrence Livermore National Laboratory Post-Detonation Nuclear Forensics – Antonio Simonetti, University of Notre Dame J une 2012 Sociedad Española de Mineralogía www.ehu.es/sem STUDENT TRAVEL GRANTS Thirteen travel grants worth 200 € each and financed by the Spanish Mineralogical Society (SEM) will be available to help qualified master’s and PhD students, as well as recent PhDs, attend the following meetings: SEM-SEA 2012 (5 grants). This conference is the joint scientific meeting of the Spanish Mineralogical Society (SEM) and the Spanish Clay Society (SEA). It will be held in Bilbao (Abandoibarra Paraninfo, Bizkaia Aretoa Building) from 27 to 30 June 2012. This conference will be the 32nd meeting of the SEM and the 22nd meeting of the SEA. The local organizing committee is composed of members of the Department of Mineralogy and Petrology of The Basque Country University (UPV/ EHU). An international seminar entitled “Archaeometry and Cultural Heritage: The Contribution of Mineralogy” will be held on 27 June 2012. Two optional post-congress geological field trips in the Bizkaia region will be organized: “Intracretaceous Volcanism in the Basque Cantabrian Basin” and “Mineralogy of the Carranza Valley.” First European Mineralogical Conference (emc2012) (5 grants). This meeting will be held in Frankfurt am Main, Germany, on 2–6 September 2012. Registration and abstract submission are now open. More information is available on the emc2012 website, http://emc2012.uni-frankfurt.de. Fourth EuCheMS (3 grants). This conference will be the 4th congress of the European A ssoc iat ion for Chemical and Molecular Sciences. It will take place in Prague, Czech Republic, on August 26–30, 2012. More information is available on the 4th EuCheMS website, http://euchems-prague2012.cz. The travel grants will be awarded on the basis of the quality of the submitted abstract, the absence of other sources of support available to the recipient, and previous travel grants provided to attend meetings. Applicants must send a copy the submitted abstract, their CV, and a copy of the registration fee bank receipt to SEM Secretary Salvador Morales ([email protected]). Lyell_ad_185x135mm_v1_10-2011_Layout 1 07/10/2011 11:22 Page 1 New developments for 2012 Geological Society publications online What is the Lyell Collection? 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The meeting was organized by Christian Feller, director of research at the Research Institute for Development (IRD), on behalf of the French Association of Soil Studies (Association Française pour l’Étude du Sol, AFES) and the French Clay Group (Groupe Français des Argiles, GFA). About 100 colleagues and former students from near and far came to share this special day. Georges Pédro is a world-scale figure in clay mineralogy and soil science. He was a precursor in the domains of nanoparticles, biogeochemical cycles and light chemistry. He is a member of several academies, among which are the Academia Europaea, the French Academy of Sciences and the Agriculture Academy of France. He has long been a scientific advisor in agronomic sciences The Gordon Research Seminar and Conference on Isotopes in the Biological and Chemical Sciences met in Galveston, Texas, USA, on February 5–10, 2012. The conference celebrated both the centennial of the first observation of a stable isotope, the detection of Ne-22 by Francis Aston, and the contributions of Jacob Bigeleisen to the calculation and interpretation of isotope effects on physical and chemical processes. Isotopes in biogeochemical processes were prominently featured in sessions organized by Thomas Hofstetter and Ariel Anbar. In the initial session, devoted to biogeochemistry and pollutant dynamics, Thomas Hofstetter provided an introduction to the types of studies that employ isotope-effect measurements. Martin Elsner (Institute of Groundwater Ecology, Helmholtz Zentrum München) and Daniel Hunkeler (University of Neuchâtel) presented research on isotopic fractionation in the environment attributable to microorganisms and the interpretation of the mechanisms of decomposition. Alex Sessions (Cal Tech) and Karen Casciotti (Stanford University) communicated data on the use of H and N isotope fractionation to infer pathways of microbial metabolism. On the second day, the presentations veered more towards the geochemical. Edwin Schauble (University of California, Los Angeles) gave a talk on isotope thermometry requiring high-precision measurements. This was followed by presentations by Laura Wasylenki (Indiana University) on metal ion coordination and David Johnston (Harvard University) on sulfur fractionation. The Gordon Research Conference on isotopes has long focused on the development and application of the theory of isotope fractionation. The introduction and adaptation of the “Bigeleisen equation” was covered by Alex van Hook, and other contributions toward the calculation of isotope effects were presented by Steven Schwartz and Piotr Paneth. The synergy of studying isotope fractionation in the environment coupled with the determination of isotope effects on enzyme systems was apparent during the discussions at this meeting. The Geochemical Society (through its Meeting Assistance Program), the Biological Chemistry Division of the American Chemical Society, and Thermo Fisher Scientific provided support for the conference. The next planned meeting will be held in early February 2014 in Galveston. Vernon Anderson Conference Chair at the OECD and a member of the DGXII Committee at the EEC. A close friend of George Brindley and Jacques Mering, Georges Pédro made pioneering contributions in clay science, including (1) the crystal structure of clay minerals, (2) the spatial organization of weathering profiles, (3) the global distribution of soils and weathering covers with their specific mineral composition as related to the major climatic processes and (4) the protection of the soil resource and the role of soils in sustainable development. He was the first to use extensively experimental approaches to constrain the physicochemical parameters governing weathering. He was among the first to use modern mineralogical techniques to understand the nature, crystal chemistry and state of hydration of clays and associated minerals in soils. He demonstrated how the texture of soils, defined as an organized system, is directly connected to environmental conditions and affected by anthropic actions. During the morning session, colleagues spoke of their interactions with Georges Pédro at various stages of his 55-year-long career: Christian Feller, André-Bernard Delmas, Daniel Tessier, Hélène Paquet, Alain Ruellan, Adrien Herbillon, Jean-Paul Legros and Jean-Claude Leprun. The morning session ended with a talk by Georges Pédro entitled “Vision on a Life Devoted to Investigating Clays and Soils.” The afternoon session illustrated some recent developments: properties of soil clays (Laurent Caner, University of Poitiers), interactions among clays, organic matter and biological activity (Claire Chenu, AgroParisTech, Grignon; Christian Feller, Institut de Recherche pour le Développement), clays and health (Hervé Quiquampoix, Agronomic Research Institute, Montpellier; Nicole Liewig, University of Strasbourg; Michel Rautureau, University of Orléans), and clays as nanomaterials (Claudine Noguera, University Pierre and Marie Curie). With a cocktail reception at lunch time and extensive discussions at the end of the meeting, this special day was an occasion for transmitting experience among generations of scientists working on clays, soils and the environment. Georges Calas and Hélène Paquet E lements 236 J une 2012 BOOK REVIEW Nature’s Nanostructures* The Earth system, comprising geologic, hydrologic, biologic, atmospheric, and anthropic subsystems, cannot be studied effectively without crossing many traditional disciplinary boundaries. Nature’s Nanostructures is a strategically named volume, edited by Amanda S. Barnard and Haibo Guo, that exemplifies not only the ease with which boundaries can be crossed but also the necessity of doing so. There is a natural tendency in nanogeoscience to want to show how nanoparticles are “special” in that their chemical behavior differs from that of their macroscopic structural counterparts. While interesting and important, this can sometimes lead to the impression that nanoparticles are merely idiosyncratic, an oddity. Overall, this book gives a different impression—that nanoscale materials and structures are a major part of the world we live in. Nature’s Nanostructures includes explorations into biomaterials, photonic crystals, extraterrestrial particles, aerosols, and anthropogenic/engineered particles in the environment. The book consists of an introductory overview and 20 chapters grouped into four categories: Nanominerals and Mineral Nanoparticles (with an emphasis on inorganic nanomaterials and aqueous settings), Biominerals, Nanoparticles in Space and in the Atmosphere, and Engineered Nanoparticles in the Environment. Covering these subjects in about 550 pages is a feat of brevity, considering that there are about 130 pages of references, along with a 9-page index and 20 blank or title pages between chapters. Separate from the 550-page text is a 32-page section at the end consisting of color versions of many of the figures in the text. The book is thus an unusually broad overview and not a deep exploration of one subject (though certain chapters might be considered exceptions). While some chapters delve into moderate mathematical detail, for the most part the chapters are relatively short and liberally referenced to encourage further reading. An initial chapter attempts a rough quantification of global nanoparticle reservoirs and fluxes, akin to an elemental geochemical cycle. Following this are several chapters on oxides, particularly iron oxides and hydroxides, and a chapter on pyrite surface energies. Proceeding along largely inorganic lines, subsequent chapters deal with noble metal nanoparticles (including so-called “invisible gold” in sulfide ore minerals), diamondoids, and “negative curvature” nanoparticles (nanoscale pores) with a focus on uranium transport. The section on biominerals then starts with an overview of nanoscale biominerals of many different types (from shell and bone minerals to bio- magnetites). The next two chapters are concerned with magnetic biominerals, including nanoscale magnetoreceptors in birds and bird navigation. A theory-based chapter deals with ways in which organisms can direct nucleation and growth of nanominerals. The last chapter in the section notes that “all iridescence in nature arises from photonic crystals” and discusses the case of photonic crystals in beetles. Anyone who has taught an introductory course in which the origin of the Solar System is related to literally nebulous “dust clouds” will appreciate the three chapters at the beginning of the section on nanoparticles in space and in the atmosphere. These chapters treat everything from vapor condensation models and aggregation to dust that enters the Earth’s atmosphere. The discussion gradually comes down to Earth (sorry, I couldn’t help it) in the form of a chapter on the formation of atmospheric aerosols. Aerosol-formation events mostly occur in the daytime, emphasizing the importance of photochemistry in such processes. The final section covers engineered nanoparticles, although the degree to which nanoparticles are intentionally (as opposed to inadvertently) “engineered” is open to debate. The section essentially deals with anthropogenic nanoparticles in the environment. Diesel engines and bioparticles (including everything from viruses to pollen) exemplify inadvertent nanoparticle production. Chemical processes in industry taking advantage of chemical vapor deposition, particle deposition, and aggregated particle deposition result in nanomaterials that can also enter the environment. The final paragraphs in this chapter deal with the relatively new field of nanotoxicology. Allophane and imogolite in soils are treated next (with relevance to soil organic matter and carbon sequestration), followed by a final chapter focusing largely on organic nanomaterials in the environment and their transformations (one section even deals with engineered quantum dots and their effect on algal photosynthesis). This is not a textbook in which one will find separate chapters on the chemical and physical underpinnings of nanoscience. No chapters are devoted to the origin of quantum size effects, to the nature of the aqueous electric double layer around nanoparticles, or to the lack of band bending and potential differences between the surface and interior of small particles. Some of this information is scattered throughout the chapters, of course, but the book largely assumes basic familiarity with physical chemistry. Nature’s Nanostructures will be of interest to those wanting to learn more about the broad field of nanostructures in the environment. It will also be useful as a reference source, in which brief chapters are backed up with many references. It will be less useful as a textbook on nanogeoscience. That said, the book occupies an important niche between what one might call the “primary literature” (the papers referenced in each chapter of the book) and basic information that one can obtain in a few seconds in a Google search. It contains a great deal of information that is difficult to assemble in any other form. For anyone even remotely concerned with nanoparticles and nanoscience in the environment, this book is worth reading because it just might change and broaden one’s perspective. Carrick M. Eggleston ([email protected]) Center for Photoconversion and Catalysis and Department of Geology and Geophysics 1000 E. University Ave. University of Wyoming, Laramie, WY 82071, USA * Barnard AS, Guo H (eds) (2012) Nature’s Nanostructures. Pan Stanford Publishing, Singapore, ISBN 978-981-4316 (hardcover), ISBN 978-981-4364 (eBook), 554 pages E lements 237 J une 2012 CALENDAR 2012 June 23 Short Course Workshop: The Role of Metasomatism in Geological Processes, Montreal, Canada. Web site: www.vmgoldschmidt.org/2012/index. htm. June 24–29 Gordon Research Conference: Grand Challenge Frontiers in the Aquatic Environmental Sciences, Holderness, NH, USA. Web page: www. grc.org/programs.aspx?year=2012&prog ram=enviwater June 24–29 Gordon Research Conference: Flow & Transport in Permeable Media, Les Diablerets, Switzerland. Web page: www.grc.org/programs. aspx?year=2012&program=flow June 24–29 Gordon Research Conference: Research at High Pressure, Biddeford, ME, USA. Web page: www. grc.org/programs.aspx?year=2012&prog ram=highpress June 24–29 Goldschmidt 2012, Montreal, Canada. E-mail: helpdesk@ goldschmidt2012.org; website: www. goldschmidt2012.org June 25–28 Comparative Climatology of Terrestrial Planets, Boulder, CO, USA. Web page: www.lpi.usra.edu/ meetings/climatology2012 June 27–30 SEM-SEA 2012 Congress (joint scientific meeting of the Spanish Mineralogical Society and the Spanish Clay Society), Bilbao, Spain. Web page: www.ehu.es/semsea2012/home.htm July 2–6 4th International Congress Eurosoil 2012, Bari, Italy. Website: www. eurosoil2012.eu July 7–11 49th Clay Minerals Society Annual Meeting, Golden, CO, USA. Web page: www.clays.org July 8–13 Gordon Research Conference: Corrosion – Aqueous, New London, NH, USA. Web page: www.grc. org/programs.aspx?year=2012&progra m=corrosion rd July 9–13 Inter/Micro: 63 Annual Applied Microscopy Conference, Chicago, IL, USA. Web page: www.mcri. org July 13–15 Second Conference on the Lunar Highlands Crust, Bozeman, MT, USA. Web site: www.lpi.usra.edu/ meetings/lunarhighlands2012 Applications, New London, NH, USA. Web page: www.grc.org/programs.aspx? year=2012&program=solidstate July 28–August 1 International Symposium on Zeolites and Microporous Crystals (ZMPC2012), Hiroshima, Japan. E-mail: [email protected]; web page: www.zmpc.org July 28–August 2 American Crystallographic Association (ACA) Annual Meeting, Boston, MA, USA. Web page: www.AmerCrystalAssn.org July 29–August 2 Microscopy and Microanalysis 2012, Phoenix, AZ, USA. Web page: www.microprobe.org/events/ microscopy-microanalysis-2012 July 29–August 3 Gordon Research Conference: Organic Geochemistry, Holderness, NH, USA. Web page: www.grc.org/programs. aspx?year=2012&program=orggeo July 29–August 3 Gordon Research Conference: Scientific Methods in Cultural Heritage Research: Non-Destructive Imaging and Micro-Analysis in Cultural Heritage, West Dover, VT, USA. Web page: www.grc.org/programs. aspx?year=2012&program=heritage August 1–4 6th International SHRIMP Workshop, Queensland, Australia. E-mail: [email protected]. au; web page: www.ga.gov.au/minerals/ projects/current-projects/geochronologylaboratory/geochronology-workshop. html August 2–10 34th International Geological Congress, Brisbane, Australia. E-mail: [email protected]; web page: www.34igc.org July 15–20 9th International Symposium on Environmental Geochemistry, Aveiro, Portugal. Web page: http://9iseg. web.ua.pt July 22–27 Gordon Research Conference: Design and Properties of Materials for Energy and Environment August 6–11 ECM-27 – European Crystallographic Meeting, Bergen, Norway. Web page: http://ecm27. ecanews.org September 1–8 Formation of the Sierra Nevada Batholith: Magmatic and Tectonic Processes and Their Tempos, Sierra Nevada, CA, USA. Web page: www.geosociety.org/ fieldForums/12sierraNevada.htm October 7–11 MS&T’12: Materials Science & Technology Conference and Exhibition, combined with ACerS 114th Annual Meeting, Pittsburgh, PA, USA. Web page: www.matscitech.org September 3–7 Planet Formation and Evolution 2012, Munich, Germany. Web page: www.usm.uni-muenchen. de/people/preibisch/planets2012/index. html September 4–9 MECC2012: 6th MidEuropean Clay Conference, Prague, CZ. Website: www.mecc2012.org September 10–12 The Mantle of Mars: Insights from Theory, Geophysics, High-Pressure Studies, and Meteorites, Houston, TX, USA. Web page: www.lpi.usra.edu/meetings/marsmantle2012 August 12–17 Annual meeting of the Meteoritical Society, Cairns, Queensland, Australia. Details: Trevor Ireland, e-mail: [email protected]. au; web page: http://shrimp.anu.edu. au:16080/metsoc2012/Welcome.html September 13–17 ICDP Workshop: Scientific Drilling of the Samail Ophiolite, Sultanate of Oman, Palisades NY, USA. www.ldeo.columbia.edu/gpg/ projects/icdp-workshop-oman-drillingproject August 12–17 Gordon Research Conference: Water & Aqueous Solutions, Holderness, NH, USA. Web page: www.grc.org/programs. aspx?year=2012&program=water August 20–24 AGU Chapman Conference on Hawaiian Volcanoes: From Source to Surface, Waikoloa, HI, USA. Web page: www.agu.org/meetings/ chapman/2012/dcall October 8–12 AGU Chapman Conference: The Agulhas System and Its Role in Changing Ocean Circulation, Climate, and Marine Ecosystems, Stellenbosch, Western Cape, South Africa. Web page: www.agu.org/meetings/chapman/2012/ecall October 9–11 Russian Mineralogical Society Annual Session combined with the Fedorov Session, Saint Petersburg, Russia. Web page: www.minsoc.ru/confs. php?cid=988 October 15–19 7th Annual Short Course: Fluids in the Earth, Naples, Italy. E-mail: [email protected]; web page: www.fluidenv.unina.it October 19–21 Meteorites: Insights into Planet Composition: 19th Meeting of the Petrology Group of the Mineralogical Society of Poland, Obrzycko, Poland. E-mail: [email protected]; web page: http://ptmin2012.amu.edu.pl October 22–25 5th International ANDRA Meeting: Clays in Natural and Engineered Barriers for Radioactive Waste Confinement, Montpellier, France. Website: www.montpellier2012. com October 22–26 Short Course: Introduction to Secondary Ion Mass Spectroscopy in the Earth Sciences, Potsdam, Germany. Web page: www. gfz-potsdam.de/portal/gfz/Struktur/ Departments/Department+4/sec42/ Infrastruktur/GFZ+SIMS+Laboratory/ ShortCourse September 17–20 Geoanalysis 2012, Búzios, Brazil. Web page: www.ige. unicamp.br/geoanalysis2012 November 4–7 Geological Society of America (GSA) Annual Meeting, Charlotte, NC, USA. Web page: www. geosociety.org/meetings September 19–21 Japanese Association of Mineralogical Sciences Annual Meeting, Kyoto University, Japan. Web page: jams.la.coocan.jp/e_meeting.html November 7–9 MEI Process Mineralogy 12 Conference, Cape Town, South Africa. Web page: www.min-eng. com/processmineralogy12/index.html September 23–26 SEG Conference Latin America: Integrated Exploration and Ore Deposits, Lima, Peru. E-mail: [email protected]; web page: www. segweb.org/activities/PeruConferenceFlyer.pdf November 16–17 10th Swiss Geoscience Meeting, Bern, Switzerland. Web page: http://ssmp.scnatweb.ch September 23–29 4th International Workshop on Collapse Calderas, Vulsini, Italy. E-mail: acocella@uniroma3. it or [email protected]; web page: www.gvb-csic.es/CCC.htm August 19–24 Gordon Research Conference: Feedback Processes in Rock Deformation, Andover, NH, USA. Web page: www.grc.org/programs. aspx?year=2012&program=rockdef E lements October 1–5 Workshop on Application of Diffusion Studies to the Determination of Timescales in Geochemistry and Petrology, Bochum, Germany. Web page: www.minsocam. org/MSA/SC/#diffusion September 5–13 The 4-D Adamello Conference, Bagolino, Italy. Web page: www3.unil.ch/wpmu/adamello2012 August 19–23 244th ACS National Meeting & Exposition, Philadelphia, PA, USA. Web page: www.acs.org July 15–20 Gordon Research Conference: Geochemistry of Mineral Deposits, Andover, NH, USA. Web page: www.grc.org/programs. aspx?year=2012&program=geochem August 27–31 AGU Chapman Conference on Communicating Climate Science: A Historic Look to the Future, Thira, Santorini, Greece. Web page: www.agu.org/meetings/ chapman/2012/ccall September 2–6 Serpentine Days, Porquerolles Island, France. E-mail: Gaelle Dufour ([email protected]. fr), web page: http://sfmc-fr.org/spip. php?article131 August 12–17 Gordon Research Conference: Solid State Studies in Ceramics, South Hadley, MA, USA. Web page: www.grc.org/programs. aspx?year=2012&program=ceramics July 15–20 BIOGEOMON 2012: The 7th International Symposium on Ecosystem Behavior, Northport, ME, USA. Web page: www3.villanova.edu/ conferences/biogeomon September 26–27 11th Geochronological Conference “Dating of Minerals and Rocks XI”, Kielce, Poland. Web page: www.ujk.edu.pl/ geochronology2012 September 2–6 First European Mineralogical Conference, EMC2012: Planet Earth – from Core to Surface (joint meeting), Johann Wolfgang Goethe-University, Frankfurt, Germany. E-mail: [email protected]; web page: emc2012.uni-frankfurt.de August 12–17 Gordon Research Conference: Biomineralization, New London, NH, USA. Web page: www.grc.org/programs. aspx?year=2012&program=biomin July 15–19 International Congress on Ceramics (ICC4), Chicago, IL, USA. Web page: http://ceramics.org/4thinternational-congress-on-ceramics-icc4 August 27–29 7th International Conference on Mineralogy and Museums, Dresden, Germany. E-mail: [email protected]; web page: www.conventus.de/mm7 September 24–26 2nd Conference “Contemporary Problems of Geochemistry”, Kielce, Poland. Web page: www. ujk.edu.pl/geochemistry2012 238 November 18–23 Cities on Volcanoes 7, Colima, Mexico. E-mail: cov7@ citiesonvolcanoes7.com; website: www. citiesonvolcanoes7.com November 25–27 Third Conference on Terrestrial Mars Analogues, Marrakech, Morocco. Web site: www. ibnbattutacentre.org/conf/mars2012 November 25–December 3 International School on Fundamental Crystallography, Uberlândia, Brazil. E-mail: Mathcryst.Commission@crm2. uhp-nancy.fr; web page: www.crystallography.fr/mathcryst/uberlandia2012.php Cont’d on page 239 J une 2012 CALENDAR Cont’d from page 238 November 26–30 MRS Fall Meeting, Boston, MA, USA. Web page: www.mrs. org/s_mrs/index.asp December 1–8 International Workshop on Magmatic Ore Deposits. Karnataka, India. E-mail: sisir.mondal@ gmail.com; web page: www.sites.google. com/site/ptsymposium December 3–7 AGU Fall Meeting, San Francisco, CA, USA. Details forthcoming th December 5–8 13 European Meeting on Environmental Chemistry, Moscow, Russia. Web page: www.europeanace.com/about/meetings 2013 January 16–19 Granulites and Granulites 2013, Hyderabad, India. Web page: http://geology.curtin.edu.au/ granulites2013.cfm January 27–February 1 37th International Conference and Expo on Advanced Ceramics and Composites, Daytona Beach, FL, USA. Webpage: http://ceramics.org/meetings/acersmeetings June 9–14 Water–Rock Interaction 14 (WRI 14), Avignon, France. E-mail:[email protected]; web page: www.wri14-2013.fr/en/home.html 2014 January 26–31 38th International Conference and Expo on Advanced Ceramics and Composites, Daytona Beach, Florida, USA. Details forthcoming July 2013 11th International Congress of Applied Mineralogy, China. Details forthcoming March 16–20 247th ACS National Meeting & Exposition, Dallas, TX, USA. Web page: www.acs.org July 1–5 1st International Conference on Tomography of Materials and Structures, Ghent, Belgium. E-mail: [email protected]; website: www. ictms.ugent.be June 9–13 Goldschmidt Conference, Sacramento, CA, USA. Details forthcoming July 7–12 17th International Zeolite Conference, Moscow, Russia. Website: www.izc17.com August 10–14 248th ACS National Meeting & Exposition, San Francisco, CA, USA. Web page: www.acs.org July 8–12 11th European Congress for Stereology and Image Analysis, Kaiserslautern, Germany. Details: Prof. K Schladitz (katja.schladitz@itwm. fraunhofer.de) September 1–5 21st General Meeting of the International Mineralogical Association (IMA2014), Johannesburg, South Africa. E-mail: [email protected]; web page: www. ima2014.co.za July 20–24 IAVCEI General Assembly 2013: Forecasting Volcanic Activity, Kagoshima, Japan. Details: Masato Iguchi, e-mail: [email protected]; web page: www.iavcei.org/IAVCEI.htm September 7–14 Annual Meeting of the Meteoritical Society, Casablanca, Morocco. Webpage: www.meteoriticalsociety.org July 29–August 2 Annual Meeting of the Meteoritical Society, Edmonton, Alberta, Canada. Web page: www. meteoriticalsociety.org February International DTTG-Workshop on Qualitative and Quantitative Analysis of Clays and Clay Minerals, Karlsruhe Institute of Technology (KIT), Germany. Web page: www.dttg.ethz.ch/ home_en.html March 3–7 TMS Annual Meeting, San Antonio, TX, USA. Web page: www. tms.org/Meetings/Meetings.aspx March 18–22 44th Lunar and Planetary Science Conference (LPSC 2013), Houston, TX, USA. Web page: www.lpi.usra.edu/meetings/lpsc2013 October 12–16 MS&T’14: Materials Science & Technology Conference and Exhibition, Pittsburgh, PA, USA. Web page: www.matscitech.org/about/futuremeetings October 19–22 Geological Society of America Annual Meeting, Vancouver, BC, Canada. E-mail: [email protected]; web page: www.geosociety. org/meetings The meetings convened by the societies participating in Elements are highlighted in yellow. This meetings calendar was compiled by Andrea Koziol (more meetings are listed on the calendar she maintains at http:// homepages.udayton.edu/~akoziol1/ meetings.html). To get meeting information listed, please contact her at [email protected]. Parting Quote It is not enough to have a good mind; the main thing is to use it well August ECM-28 – XXVIII European Crystallographic Meeting, Warwick, UK. Details forthcoming R ené Descartes • 1596-1650 August 4–8 Microscopy & Microanalysis 2013, Indianapolis, IN, USA. Web page: www.microprobe.org/events Advertisers in this Issue August 25–30 Goldschmidt 2013, Florence, Italy. Website: www. goldschmidt2013.org AHF Analysentechnik August 26–30 Meteoroids 2013, Poznan, Poland. Web page: www.astro. amu.edu.pl/Meteoroids2013/index.php CAMECA 169 Bruker 178 Inside front cover CrystalMaker 171 March 27–29 Volcanism, Impacts and Mass Extinctions: Causes and Effects, London, England. Web site: http://massextinction.princeton.edu September 2–10 10th International Eclogite Conference, Courmayeur, Aosta Valley, Italy. Web page: www. iec2013.unito.it Excalibur Mineral Corporation 220 April 1–5 MRS Spring Meeting & Exhibit, San Francisco, CA, USA. Web page: www.mrs.org/spring2013 September 8–12 246th American Chemical Society National Meeting & Exposition, Indianapolis, IN, USA. Web page: www.acs.org Geological Society of London 234 IMA 2014 220 April 7–11 245th American Chemical Society (ACS) National Meeting & Exposition, New Orleans, LA, USA. Web page: www.acs.org April 24–28 Basalt 2013 – Cenozoic Magmatism in Central Europe, Görlitz, Germany. E-mail: basalt2013@ senckenberg.de; web page: www. senckenberg.de/root/index.php?page_ id=15387&preview=true September 24–27 Whistler 2013: Geoscience for Discovery, Whistler, BC, Canada. Web site: www.seg2013.org May 22–24 Geological Association of Canada /Mineralogical Association of Canada Annual Meeting, Winnipeg, Manitoba, Canada. Web page: www. mineralogicalassociation.ca/index. php?p=35 IsoPrime 175 McCrone Microscopes and Accessories 178 167 Inside back cover SPECTRO 173 The Geochemist’s Workbench Back cover Thermo Scientific 179 job postings See www.elementsmagazine.org/jobpostings October 27–31 MS&T’13: Materials Science & Technology Conference and Exhibition, Montréal, QC, Canada. Web page: www.matscitech.org/about/futuremeetings You have a position to fill at your department or lab? Advertise it in Elements or on the Elements website. Looking for a job? November 18–21 26th International Applied Geochemistry Symposium 2013 Incorporating the New Zealand Geothermal Workshop, Rotorua, New Zealand. Web page: www.gns.cri.nz/iags Check our website www.elementmagazine.org December 1–6 MRS Fall Meeting & Exhibit, Boston, MA, USA. Web page: www.mrs.org/fall2013 E lements 220 Savillex October 27–30 Geological Society of America Annual Meeting, Denver, Colorado USA. E-mail: [email protected]; web page: www.geosociety. org/meetings May 19–22 AAPG 2013 Annual Convention & Exhibition, Pittsburgh, PA, USA. Web page: www.aapg.org 180 Geochemical Transactions Rigaku October 2013 CMM Autumn School: Moisture Measurement in Porous Mineral Materials, Karlsruhe Institute of Technology (KIT), Germany. Web page: www.cmm.kit.edu/english/index.php May 5–8 Canadian Institute of Mining, Metallurgy, and Petroleum 2013 Conference & Exhibition, Toronto, Ontario, Canada. Web page: www.cim.org/calendar/calender. cfm?Year=All FEI 239 J une 2012 PARTING SHOTS A Ruin and Two Earthquakes References Minoura K, Imamura F, Sugawara D, Kono Y, Iwashita T (2001) The 869 Jogan deposit and recurrence interval of large-scale tsunami on the Pacific coast of northeast Japan. Journal of Natural Disaster Science 23: 83-88 Satake K, Namegaya Y, Yamaki S (2008) Numerical simulation of the AD 869 Jogan tsunami in Ishinomaki and Sendai plains. Active Fault and Earthquake Center, Report No. 8: 71-89 (in Japanese with English abstract) Photo courtesy of Tohoku History Museum and Miyagi Prefectural Research Institute of the Tagajo site The photograph shows the ruin of a local government castle of the Jogan era at Tagajo, located just north of Sendai, approximately 5 km from the present coastline. It was damaged during the Jogan earthquake in 869 AD. This earthquake had an estimated magnitude of 8.3 and caused a tsunami that seriously damaged the northeastern coast of Japan. The record of this tsunami and its effects are not only evidenced by the tsunami deposits but are part of the historical record of that time (see Minoura et al. 2001). The Jogan tsunami sediments can be found up to four or even five kilometers inland from today’s coastline in the deposits of the Sendai and Ishinomaki plains (Satake et al. 2008). Tagajo is an old castle town and was one of the cities hit by the Jogan earthquake and tsunami; 1000 lives in the old town were lost due to the tsunami (Minoura et al. 2001). Board of Education Report No. 167, 1995, in Japanese), about 300 meters south of the ruin shown in the photo. Flood waters from the 2011 tsunami came within one kilometer of the southern edge of the district (Geospatial Information Authority of Japan, www.gsi.go.jp/common/000061572. pdf). As the coastline was 1 km inland from today’s coast during the Jogan era, we can conclude that the tsunamis of 869 and 2011 were comparable in size because the difference in their flood fronts corresponds to the difference in the coastline between 869 and today. And a bit of geography According to the Miyagi Prefectural Research Institute of the Tagajo site (www.thm.pref. miyagi.jp/kenkyusyo/explanation_tagajoato. html, in Japanese), buildings, including the ruined castle, of the local government of Tagajo were first constructed in 724 AD (first stage), repaired in 762 (second stage), and reconstructed in 780 after fire damage caused by a local war (third stage). In 869, the local government buildings were destroyed by the Jogan earthquake and possibly by the subsequent tsunami, but they were reconstructed afterwards (fourth stage). Finally, the local government district (about 1 km × 1 km) was destroyed in the middle of the 11th century. The photo, therefore, may not show the ruin after the Jogan earthquake. The ruin in the photo is almost in the center of the district. A road gutter that was probably destroyed by the Jogan tsunami can be observed near the south gate of the district (Miyagi Prefectural E lements Map showing the 47 prefectures of Japan. They are grouped into 9 regions, from north to south: Hokkaido, Tohoku (yellow), Kanto (green), Chubu (blue), Kansai (dark blue), Chugoku (brown), Shikoku (purple), Kyushu (grey), and Okinawa. Reproduced from Wikimedia Commons (http://en.wikipedia.org/wiki/File:Regions_and_Prefectures_ of_Japan_2.svg) 240 J une 2012