Keuzes voor electriciteitsopwekking

Keuzes voor electriciteitsopwekking
http://lectureonline.cl.msu.edu/~mmp/applist/chain/chain.htm
Concept critical mass
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Critical Mass
Although two to three neutrons are produced for every fission, not all of these
neutrons are available for continuing the fission reaction. If the conditions are such
that the neutrons are lost at a faster rate than they are formed by fission, the chain
reaction will not be self-sustaining.
At the point where the chain reaction can become self-sustaining, this is referred to
as critical mass.
In an atomic bomb, a mass of fissile material greater than the critical mass must be
assembled instantaneously and held together for about a millionth of a second to
permit the chain reaction to propagate before the bomb explodes
The amount of a fissionable material's critical mass depends on several factors; the
shape of the material, its composition and density, and the level of purity.
A sphere has the minimum possible surface area for a given mass, and hence
minimizes the leakage of neutrons. By surrounding the fissionable material with a
suitable neutron "reflector", the loss of neutrons can reduced and the critical mass
can be reduced.
By using a neutron reflector, only about 11 pounds (5 kilograms) of nearly pure or
weapon's grade plutonium 239 or about 33 pounds (15 kilograms) uranium 235 is
needed to achieve critical mass.
In a reactor critical mass should be near 1 and controlled.
Electricity Generation - Nuclear
Power Reactors
Over 16% of the world’s electricity is produced from nuclear energy, more
than from all sources worldwide in 1960
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Waar staan ze (1)
Waar staan ze (2)
Waar
staat-ie (3)
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Power consumption USA
Nuclear power has a small role in the Dutch electricity supply, with the Borssele
reactor providing about 4% of total generation - 3.8 billion kWh (GkWh=TWh) of the
97.5 billion kWh total in 2005. (eerste commerciele reactor (1973))
Natural gas provides about 63 TWh, and coal 22 TWh. Renewables (mostly
biomass) add 7 TWh. Another 16 TWh electricity is imported, and since some of
that is nuclear-generated, official statistics put the nuclear share of deliveries at
9.6%.
Tsernobyl reactor
Major Nuclear Power Plant Accidents
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December 12, 1952
A partial meltdown of a reactor'
s uranium core at the Chalk River plant near Ottawa, Canada, resulted
after the accidental removal of four control rods. Although millions of gallons of radioactive water poured
into the reactor, there were no injuries.
October 1957
Fire destroyed the core of a plutonium-producing reactor at Britain'
s Windscale nuclear complex - since
renamed Sellafield - sending clouds of radioactivity into the atmosphere. An official report said the
leaked radiation could have caused dozens of cancer deaths in the vicinity of Liverpool.
Winter 1957-’58
A serious accident occurred during the winter of 1957-58 near the town of Kyshtym in the Urals. A
Russian scientist who first reported the disaster estimated that hundreds died from radiation sickness.
January 3, 1961
Three technicians died at a U.S. plant in Idaho Falls in an accident at an experimental reactor.
July 4, 1961
The captain and seven crew members died when radiation spread through the Soviet Union'
s first
nuclear-powered submarine. A pipe in the control system of one of the two reactors had ruptured.
October 5, 1966
The core of an experimental reactor near Detroit, Mich., melted partially when a sodium cooling system
failed.
January 21, 1969
A coolant malfunction from an experimental underground reactor at Lucens Vad, Switzerland, releases
a large amount of radiation into a cave, which was then sealed.
December 7, 1975
At the Lubmin nuclear power complex on the Baltic coast in the former East Germany, a short-circuit
caused by an electrician'
s mistake started a fire. Some news reports said there was almost a meltdown
of the reactor core.
March 28, 1979
Near Harrisburg, Pennsylvania, America'
s worst nuclear accident occurred. A partial meltdown of one of
the reactors forced the evacuation of the residents after radioactive gas escaped into the atmosphere.
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February 11, 1981
Eight workers are contaminated when more than 100,000 gallons of radioactive coolant fluid
leaks into the contaminant building of the Tennessee Valley Authority'
s Sequoyah 1 plant in
Tennessee.
April 25, 1981
Officials said around 45 workers were exposed to radioactivity during repairs to a plant at
Tsuruga, Japan.
April 26, 1986
The world'
s worst nuclear accident occurred after an explosion and fire at the Chernobyl nuclear
power plant. It released radiation over much of Europe. Thirty-one people died iin the immediate
aftermath of the explosion. Hundreds of thousands of residents were moved from the area and a
similar number are belived to have suffered from the effects of radiation exposure.
March 24, 1992
At the Sosnovy Bor station near St. Petersburg, Russia, radioactive iodine escaped into the
atmosphere. A loss of pressure in a reactor channel was the source of the accident.
November 1992
In France'
s most serious nuclear accident, three workers were contaminated after entering a
nuclear particle accelerator in Forbach without protective clothing. Executives were jailed in
1993 for failing to take proper safety measures.
November 1995
Japan'
s Monju prototype fast-breeder nuclear reactor leaked two to three tons of sodium from
the reactor'
s secondary cooling system.
March 1997
The state-run Power Reactor and Nuclear Fuel Development Corporation reprocessing plant at
Tokaimura, Japan, contaminated at least 35 workers with minor radiation after a fire and
explosion occurred.
September 30, 1999
Another accident at the uranium processing plant at Tokaimura, Japan, plant exposed fifty-five
workers to radiation. More than 300,000 people living near the plant were ordered to stay
indoors. Workers had been mixing uranium with nitric acid to make nuclear fuel, but had used
too much uranium and set off the accidental uncontrolled reaction.
Light Water Reactor (LWR)
Reactor Type
Heavy Water Reactor (HWR)
a. Boiling Water Reactor
b. Pressurized Water Reactor
(PWR)
Purpose 1
electricity
electricity; nuclear powered ships
(U.S.)
electricity; plutonium production
Coolant
Type
water (H2O)
water
heavy water (deuterium oxide, D2O)
Moderator
Type
water
water
heavy water
uranium-dioxide (UO2)
uranium-dioxide
uranium-dioxide or metal
Fuel Enrichment
Level 3
low-enriched
low-enriched
natural uranium (not enriched)
Comments
steam generated inside the
reactor goes directly to the
turbine
steam is generated outside the
reactor in a secondary heat
transfer loop
used in Canada: called "CANDU" "Canadian Deuterium Uranium;" Also used
in Savannah River Site reactors (metal fuel
at SRS)
Fuel -Chemical
Composition
2
Graphite Moderated Reactor
Reactor Type
Fast Breeder Reactor (FBR)
Liquid Metal (LMFBR) (most common type
of breeder)
a. Gas Cooled
b. Water Cooled
Purpose 1
electricity; plutonium
production
electricity; plutonium production
electricity; plutonium production
Coolant
Type
gas (carbon dioxide or
helium)
water
molten, liquid sodium
Moderator
Type
graphite
graphite
not required
uranium dicarbide
(UC2) or uranium metal
uranium dioxide (RBMK) or metal (Nreactor)
plutonium dioxide and uranium dioxide in
various arrangements
Fuel Enrichment
Level3
slightly-enriched,
natural uranium
slightly-enriched
various mixtures of plutonium-239 and
uranium-235
Comments
used in Britain, and
France (e.g.: AGR,
MAGNOX)
used in former Soviet Union, e.g.
Chernobyl (RBMK); N-reactor at
Hanford.
breeder reactors are designed to produce
more fissile material than they consume.
Monju; Phenix
Fuel -Chemical
Composition
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Little Boy: A Gun-Type Bomb
Hiroshima, Japan on August 6, 1945
• trinty1a.mov
Fat Man: Implosion-Type Bomb
Nagasaki, Japan on August 9, 1945
• ngbomb1a.mov
Alternative to fission
Nuclear fusion for hydrogen bomb
Need to make tritons (?)
H-bomb (without H)
Inertial fusion
Tokamak
Design - Main Features
Central Solenoid
Outer Intercoil
Structure
Blanket
Module
Vacuum Vessel
Cryostat
Toroidal Field Coil
Port Plug (IC Heating)
Poloidal Field Coil
Diver
tor
Machine Gravity Supports
Torus Cryopump
Direct Capital Cost
Component s/ S ys t ems
Magnet Sy st ems
Ves s el, Blanket , Divert or, Pumping & Fuellin g
Cryo st at & T herm al S hield
As s embly
Auxili aries
Buildings
Heatin g & Cur rent Drive (7 3 MW)
Diagnos ti cs ( s t ar t -up s et)
To t al Dir ect Capit al Cos ts
Dir ect Cos t
( kIUA* )
762
505
105
93
586
380
206
118
2 7 55
% of
To t al
28
18
4
3
21
14
7
4
100
* 1 kI UA = $ 1 9 89 1 M - $ 2 0 00 1 .39 2 M - €2 0 00 1 .27 9 M - ¥ 2 0 00 1 4 8M