SKB

The role of the Geological Survey of Sweden (SGU) in
the work to find, investigate and produce 3D geological
models for a site suitable for the disposal of highly
radioactive, spent nuclear fuel in Sweden
Michael B.
Stephens, SGU
Forsmark, south-central Sweden.
Site finally selected by SKB
SKB, SGU and SSM – their roles
SKB = Swedish Nuclear Fuel and Waste Mangement
Company, SGU = Geological Survey of Sweden, SSM =
Swedish Radiation Safety Authority
• SKB has the responsibility to propose a method and a site for the disposal
of highly radioactive, spent nuclear fuel (www.skb.se).
• The Geological Survey of Sweden (SGU) is the central governmental
agency responsible for questions relating to bedrock, Quaternary deposits
(soil) and groundwater in Sweden (www.sgu.se).
• SGU is financed by an annual governmental grant (c. 80-85%) and by
commissioned work from external customers (c. 15-20%), for example SKB.
• SGU colleagues here today are Erika Ingvald (communications
officer), Kaj Lax (newly appointed manager for the Bedrock and mineral
resource division at SGU).
• SSM (formerly SKi and SSI) not SGU is the governmental regulatory
authority with national collective responsibility within the areas of radiation
protection and nuclear safety (www.ssm.se).
SGU´s general policy for commission work financed
by external customers (for example, SKB)
• To meet society s need of and specific request for geological
information and knowledge
• To provide an increased knowledge at SGU of society s needs
and use of geological information
• To contribute to a more effective use of SGU s competence
and resources
• To retain and to develop geological competence at SGU
SGU´s role in connection with commission work for SKB
concerned with the identification and investigation of a
suitable site
• To provide the necessary geological information that is required to select a
site suitable for the following, more detailed step in the investigations
• To identify alternative areas at the ground surface suitable for the
following, more detailed step in the investigations
• To provide necessary expertise, along with other geoscientists, in the
investigation and modelling work at the two sites selected for detailed study
SKB selected during 2000 Forsmark and Oskarshamn (Laxemar-Simpevarp) as the sites for the
detailed investigation work that started 2002. Factors other than geology (e.g. infrastructure, land
use, land protection) influenced this decision.
SKB selected Forsmark as the site for the repository during June 2009
Governmental review of SKB work by SSM and predecessor
SKi/SSI.
SGU on the contact list
Is there a conflict of interest?
SKB hours
20000
SGU
committment
to
commission
work for SKB
2002 to 2009
18000
16000
14000
12000
10000
8000
6000
4000
2000
0
2002
2003
2004
2005
2006
2007
2008
Total cost c. 5-6 million euros
2009
100%
90%
80%
70%
60%
Remaining commission work
SKB commission work
50%
40%
30%
20%
10%
0%
2002
2003
2004
2005
2006
2007
2008
2009
1977-1985. Variable amount
of detailed surface and drill
core investigations in type
areas throughout the
country
• To develop methodology and to
learn about rock properties and
rock suitability
• SGU highly active in the
completion of the work on
commission
basis up to 1982
Source of image: SKB FUD report 2000
Type
area, e.g.
Stripa
Äspö
Stockholm
1997-1999. Systematic
regional screening based on
available geological and
geophysical data. No new
data acquisition
Three critical geological factors (SKBSGU):
• Homogeneous crystalline bedrock
• No potential for ore deposits
• Absence of regionally important (>10 km
length at the ground surface) deformation
zones
SGU fully responsible for the completion of
the work on a commission basis for SKB
Source of image: SKB FUD report 2000
Green = Areas
probably suitable for
more detailed
investigations, based
on geological
information
Red = Areas
probably not suitable
for more detailed
investigations, based
on geological
information
1992-2000. Feasibility studies
in municipalities based on available
geological and geophysical data.
Field check
Identify areas suitable for more detailed site
investigations based on the same three
geological criteria used in the systematic
regional screening study
SKB responsible for the choice of muncipality.
SGU highly active in the completion of the
work on a commission basis for SKB
Storuman
Malå
Forsmark
Älvkarleby
Tierp
Östhammar
Nyköping
Hultsfred
Oskarshamn
Oskarshamn
Source of image: SKB FUD report 2000
Bedrock possibly
suitable for a
repository of spent
nuclear fuel in the
municipality of
Östhammar based on
geological and other
factors
Candidate area
selected by SKB for
site investigation
Source of image: SKB FUD report 2000
Site investigation, 2002-2008
Forsmark and
Oskarshamn
(LaxemarSimpevarp)
Source of map image:
SKB report R-08-19
Site characterization in
Sweden
•
•
•
Surface-based including several deep coredrilled holes
– Started 2002 finished during 2008
– For spent fuel repository of the KBS-3
type
Conducted in campaigns
– five “data freezes”
– Initial site investigation phase resulting in
preliminary site descriptive models used
to develop preliminary repository layouts
and input to a full safety assessment
SKB will prepare safety case and submit a
permit application for a deep repository
during 2010
Source of image: SKB (Anders Ström)
Data evaluation and site descriptive modelling
Method-specific
interpretation
Investigations
Database
Primary data (measured data, calculated values and conceptual assumptions)
Interpretation of geometries and properties
“Datawash”, computations
Integrative, discipline specific
interpretation
Sitedescriptive model
Geology
Hydrogeology
Geometry
Integrative, iterative
(Structural geology)
Hydrogeochemistry
Rockmechanics
Thermal
properties
Source of image:
SKB (Anders Ström)
Ecosystem
Transportation
properties
Site description
Cross disciplinary
interpretation
EIA
EIA = Environment impact assessment
Investigations
Site Modelling
Design
Information flow and
feedback during site
characterization
Source of image: SKB (Anders Ström)
SA
SA = Safety assessment
Documentation – Forsmark as an example
SDM-Site Forsmark - Main report (TR-08-05)
Main references (level II)
Geology (R-07-45)
Thermal properties (R-07-47)
Rock mechanics (R-07-31)
Hydrogeology (R-08-95)
Hydrogeochemistry (R-08-47)
Transport properties (R-08-48)
Surface system (R-08-11)
Evolutionary aspects (R-08-19)
Confidence statement (R-08-82)
Complementary stage 2.3 reports
Geology (R-08-64)
Thermal properties (R-08-65)
Rock mechanics (R-08-66)
References (level III)
Geology
Hydrogeology
Hydrogeochemistry
Transport
Surface system
• Fracture domain report
• Hydro DFN
modelling and DZ
hydraulic properties
• Fracture minerals and altered
rock
• Retardation model
• Surface hydrology
• Stochastic modelling of
fractures and minor DZ’s
• Background
complementary studies
• Bedrock geological map
at the surface
• Groundwater flow
modelling
• Conceptual model
development and
modelling
Source of image: SKB (Anders Ström)
• Explorative analysis of major
components and isotopes
• Microbes, colloids and gases
• Water-rock interaction
modelling
• Porewater chemistry
• Background complementary
studies
• Chemistry
Rock
mechanics
• Forsmark in situ
stress
• Regolith
• Ecosystems
(limnic, terrestrial,
marine)
SGU work in the site investigations at Forsmark and Oskarshamn
• Expert geologists at Forsmark and Oskarshamn (2002-2007). Investigation
managers for bedrock geology (2002-2004) and Quaternary deposits (20022007) at Forsmark.
• Acquisition of primarily surface geological data at both Forsmark and
Oskarshamn
• Responsible for the development of various 2D and 3D geological
models for Forsmark and Oskarshamn (surface geological maps at
both sites; rock domains in 3D space at both sites; deformation zones
and fracture domains in 3D space at Forsmark; thickness of the
Quaternary cover at both sites)
• Writing of key background reports and specific chapters in final reports
SDM-Site Forsmark and SDM-Site Laxemar. Writing of scientific papers.
Supervision of two Ph.D. studies at the University of Lund, Sweden
Site investigation data
• Surface investigations
– airborne photography, airborne and
surface geophysical
investigations, interpretation of
lineaments and seismic reflectors
– mapping of rock units and structural
characteristics
– investigations of Quaternary deposits
– meteorological and hydrological
monitoring, hydrochemical sampling
of precipitation, surface waters and
shallow groundwater investigations
Source of image: SKB (Anders Ström)
Site investigation data
Drilling and drill core/borehole measurements
– 14 (Forsmark site) and 20 (Laxemar site)
deep (800 to1,000 m) core-drilled
boreholes
– several more shallow core-drilled and
percussion-drilled boreholes
– mapping, testing and monitoring
boreholes and drill cores (geology
including single hole
interpretation, thermal properties, rock
mechanics, hydrogeology, hydrochemistr
y)
– many soil/rock boreholes
Geological models in the bedrock
• Rock domains. Local and regional model scales. Why? Thermal and
mechanical rock properties
• Spatial distribution of subordinate rock types with low thermal conductivity in
two critical rock domains. Statistical approach. Local model scale
• Deformation zones. Local and regional model scales. Why? Need to
eliminate from the volume to be used for the repository
• Discrete fracture network. Orientation, size and intensity of fractures and
minor deformation zones inside the parts of the rock domains NOT affected by
more significant deformation zones, so-called fracture domains. Statistical
approach. Local model scale. Why? Detailed planning of the repository
Bedrock at Forsmark. 2D model at ground
surface. Forsmark tectonic lens
Work completed by SGU
3D model for rock domains (regional
scale)
Work completed by SGU with support from SKB
Source of image: SKB reports R-07-45 and TR-08-05
3D model for deformation zones at Forsmark
Work completed by SGU with support from SKB
Source of image: SKB report TR-08-05
Feasibility studies
Älvkarleby
Hultsfred
Tierp
Oskarshamn
Östhammar
Nyköping
Malå
Storuman
2009-06-03
Forsmark selected by SKB
Site
investigations
Forsmark
Oskarshamn (Laxemar)
Detailed
underground
investigations
Forsmark
1992-2000
Source of image: SKB (Anders Ström)
2002-2008
2015?-
SGU-SKB collaboration today, 2010…...
What is happening?
• Geological excursion guides for Forsmark and Oskarshamn
(2009)
• Contribution to ongoing safety assessment of Forsmark (20092010)
• Control and review of ongoing geological modelling work in
connection with the extension of the SFR facility for low- and
medium-radioactive nuclear waste at Forsmark (2009-2010)
• 3D geological modelling at the Äspö underground laboratory
facility, Oskarshamn (2009-2010)
• Writing of papers for publication in international scientific journals
(2009-2010)
• Update of the local geological models for Forsmark (2010)
• Contribution to the planning for detailed underground
investigations (2009-2015)