Fission Energy for War and Peace 1 Fearing of fission bomb for Hitler first, the U.S. started the...
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Transcript of Fission Energy for War and Peace 1 Fearing of fission bomb for Hitler first, the U.S. started the...
Fission Energy for War and Peace 1
Fission Energy for War and Peace
Fearing of fission bomb for Hitler first, the U.S. started the Manhattan Project in 1942.
Atomic Committee of the Office of Scientific Research and Development (OSRD) was responsible.
OSRD members: E. Lawrence, A.H. Compton, H. Urey (all three were Nobel laureates), L. Briggs, E. Murphree J.B. Conant (director)
September 23, 1942, the Uranium Committee met with Secretary of War Henry L. Stimson, Chief of Staff General George C. Marshall and other top military officers including Major General Leslie R. Groves (Executive Officer of Manhattan Project)
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Fission Energy for War and Peace 2
Fission Bomb Project of U.S. and Canada
Grove and Chadwick’s talk brought cooperation between Britain and America.
Britain and Canada started a large establishment in Montreal under the National Research Council (NRC) of Canada
British-Canadian-American joint venture built a heavy-water nuclear reactor in Petawawa, Ontario, to produce both 239Pu and 233U.
The first zero-energy experimental pile (ZEEP) started operation on September 7, 1945.
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Fission Energy for War and Peace 3
Producing Bomb Materials
235U239Pu
Separate 235U (0.7%) from natural uranium:
gas diffusion of UF6
centrifuge of UF6 gasthermal diffusion of UF6 gas electromagnetic separation
Production of 239Pu by the reaction238U(n, 2)239Pu
Fission Energy for War and Peace 4
Bomb Material: Separating 235U by gas Diffusion
One diffusion unit
and
the diffusion plant
The blue spot is a personhttp://www.npp.hu/uran/3diff-e.htm
Fission Energy for War and Peace 5
Bomb Material: Separating 235U by Electromagnetic meth
Uranium Isotope Enrichment by theElectromagnetic Method.
From aparticleaccelerator
235UF6
collector
238UF6
collector
Bomb Material: Separating 235U by Electromagnetic method
The principle of this method is the same as the mass spectrometry for chemical analysis.
This is still a very important method for chemical analysis today.
Fission Energy for War and Peace 7
Isotope Separation by Plasma CentrifugeA vacuum arc produces a plasma column which rotates by action of an applied magnetic field. The heavier isotopes concentrate in the outer edge of the plasma column resulting in an enriched mixture that can be selectively extracted
Fission Energy for War and Peace 8
New Methods of Isotope Separation1. In the cyclotron resonance method a
radiofrequency field selectively energizes one of the ionized isotopes in magnetically confined plasma; isotopes are differentiated and the more energetic atoms are collected.
2. In the laser induced selective ionization method, the laser is tuned to selectively to ionize U235, but not U238. An electric field extracts the ions from the weakly ionized plasma and guides them up to collecting plates.
Fission Energy for War and Peace 9
Critical Masses for Chain Reactions
The minimum quantity for a sustained chain reaction to take place is called the critical mass or critical size, which depends on the moderator, chemical and physical states, shape etc.
The Idea of a Guillotine for Critical MassDetermination
Neutronmonitoring
devices
Releasingmechanism
235U or239Pu
Fission Energy for War and Peace 10
Reducing Critical Masses by Implosion
The Implosion Arrangement
Ignitionpoints
Chemicalexplosive
239Pu
Fission material is surrounded by chemical explosivewhich is ignited at many points simultaneously. Theexplosion forces pieces of 239Pu together and evenreduces the volume to reduce the critical mass.
Fission Energy for War and Peace 11
The First Fission Bomb Explosion
Major work sites:Oak Ridge 59,000-acre Hanford Engineer Work 450,000-acreProject Y (Los Alamos Laboratory) Chicago, Berkley, Montreal, New York
July 16, 1945, a plutonium (Fat Man) bomb was tested in Journey of Death. Two hemispheres of 239Pu were forced together to reach criticality. The bomb was attached to a 30-meter steel tower, which disappeared after the explosion.
Fission Energy for War and Peace 12
Fission Energy For War
At 8:15 am August 6, 1945, Little Boy (235U) was dropped on Hiroshima by a modified B-29 bomber.
On the 9th, a 239Pu-fuelled bomb exploded over Nagasaki
Destruction by atomic bomb Light and energy (heat) Shock wave Secondary fire Radioactive fission products
in the fallout
Fission Energy for War and Peace 13
The Nuclear Arms Race
During 1945-1991
Stalin competed with the U.S. and Britain for military superiority during WWII
Science is for everyone to discover, but research is costly, and atomic secret invite spy activities.
Development of hydrogen bomb intensified the cold war. Nuclear fusion leads to hydrogen bomb.
The world is facing a mutually assured destruction (mad) till 1991
Fission Energy for War and Peace 14
Nuclear Reactors
Basic Elements of Fission Reactors
ReactorCore
Control rods
Monitoringdevices
moderator
Energy transfer system
devices operating at steady-state chain reaction for research and power generation.
Fission Energy for War and Peace 15
Key Components of Nuclear
Reactors
Reactor core (fuel): enriched or natural U, 239PuModerators graphite, H2O, D2O He (100 Atm and 1273 K) Be (high temperature liquid metal). Na (773 to 873 K for breeder reactor) BeF2 + ZrF4 ( for GCR)Control rods Cadmium, Boron, Carbon, Cobalt, Silver, Hafnium, and Gadolinium, c =255 kb for 157Gd Monitoring devices Neutron and radioactivity detectors, T, etc Energy transfer system Moderator or liquid
Fission Energy for War and Peace 16
Types of Fission Reactors
Fast Breeder Reactors (FBR)
Aqueous Homogeneous Reactors (AHR) Heavy Water Moderated Reactors (HWR)
Pressurized Water Reactors (PWR) Boiling Water Reactors (BWR)
Organic-Cooled Power Reactors (OCPR)Sodium Graphite Reactors (SGR)
Gas-Cooled Reactors (GCR)
Fission Energy for War and Peace 17
Basic Elements of a Fast Breeder Reactor
Borongraphite
shield
Fuelloadingmachine
Heatexchanger
Core
BREEDER
BLANKET
Magneticpump
Fast Breeder Reactors for Fission Fuel Production
Fission Energy for War and Peace 18
Fast Breeder Reactors produce more fission fuel they consume.
Two types of product dependent FBR
The 239Pu or uranium cycle 238U ( fast n, 2) 239Pu, c = 2.7 b
The thorium cycle
232Th (slow n, ) 233U, c = 7.4 b, f = 5.6×10-5 b
Reactions in Fast Breeder Reactors (FBR)
Fission Energy for War and Peace 19
CANadian Deuterium Uranium (CANDU) Reactors employ natural uranium for fuel and heavy water as moderator.
Features:22 reactors supply 20% of electric power in Canada Bundles of fuel tubes loaded horizontallyReplace fuel during operation Use oxide of natural uranium as fuel and D2O as moderator Generate large volumes of nuclear wastesProduce 239Pu
CANDU Reactors
Fission Energy for War and Peace 21
Reactor accidents
An accident is a series of undesirable events that took place due to accumulated causes.
Costly Lessons comes from the understanding of full details of accidents.
Nuclear accidents attract more attention due to release of radioactive nuclides.
Radioactivity causes fear, because most people know little about it.
Many nuclear accidents have happened.
Fission Energy for War and Peace 22
TMI-2 3000 MW PWR Power ReactorBlock Diagram of a Pressurized Water Reactor
Pressurizedprimarycoolingloop
Heatexchangeand steamgenerator
Secondarycoolingloop
Turbine & generator
Coolingtower &housing
Reactorcore Pumps
&valves
Auxiliarypumps
Reactor &containmentbuilding
Reliefvalve
Fission Energy for War and Peace 24
Three Mile Island (TMI-2) was a pressurized water reactor (PWR) with a 3000 Mw capacity.
March 28, 1979, two pumps failed to supply feed water steam generator.
Valve of auxiliary pump was closed by error and auxiliary pump failed to operate.
Pressure increased and relieve valves opened.
Relieve valves failed to close resulting in a loss of coolant.
Zircaloy-4 oxidized by water, producing a large volume of hydrogen gas.
Core overheated resulting in meltdown
TMI-2 Reactor accidents
Fission Energy for War and Peace 25
The TMI-2 Core After the AccidentFour years later, photo image of TMI–2 core shows damage to its uranium fuel rods more extensive than originally thought just after he accident.Core meltdown shows the temperature reached 5000 K.
http://washingtonpost.com/wp-srv/national/longterm/tmi/gallery/photo10.htm
Fission Energy for War and Peace 26
Long-life Fission Products in the Core after TMI-2 Accident
Isotope Activity /Ci Half-life Amount*85K 9.7104 10.7 y 4.71013
90Sr 7.5105 28.8 y 9.81014
129I 2.210–3 1.6107 y 1.61012
131I 7.0107 8.04 d 7.01013
133Xe 1.5108 5.25 d 9.81013
137Cs 8.4105 30.2 y 1.11015
* Amount = Activity half-life (s)/0.693
Fission Products in the Core After the Accident
Fission Energy for War and Peace 27
The Chernobyl AccidentRBMK graphite-moderated, channel-tube-cooled reactors. Reactor 4 in Chernobyl had been in operation for 3 years prior to the accident.
April 26, 1986, Reactor 4 at Chernobyl was scheduled for a safety test to see if residual power is sufficient to operate the reactor safely in case of a sudden power failure.
Operators turned off cooling system and powered down. When power from the reactor failed to operate the reactor safely, they used power from the grid without notifying grid controller. Radioactivity of fission products overheat the core. When they turned up power with cooling system off, the core fragmented and exploded destroying the building.
Radioactivity (fallout) spread to north Europe.
Fission Energy for War and Peace 28
The Soviet RBMK Reactor Design
The Soviet RBMK reactor has individual fuel channels, using ordinary water as coolant and graphite as moderator. It evolved from reactors designed for 239Pu production.
Fission Energy for War and Peace 29
Natural Reactor
Bouziques found low 235U abundance in uranium from Oklo, Gabon, West Africa and interpreted as a result of a natural fission reactor a long time ago.
A large quantity of uranium ore concentrated and reached a critical size for a natural reactor.
Found additional supporting evidences shown in the next frame.
Fission Energy for War and Peace 30
Natural Reactor Location
From: http://www.curtin.edu.au/curtin/centre/waisrc/OKLO/Where/Where.html
Fission Energy for War and Peace 31
Additional Evidences for Natural Nuclear Reactor
Isotope of Neodymium
mass Natural Fission Oklo 142 27.11 0 0 143 12.17 28.8 25.7 144 23.85 26.5 29.3 145 8.30 18.9 18.4 156 17.22 14.4 14.9 148 5.73 8.26 8.2 150 5.62 3.12 3.5
The natural reactor released 15,000 MW-year energy for 150,000 years 1.8e9 years ago.
Fission Energy for War and Peace 32
Nuclear Fission - Summarydiscovery of neutron-induced fission
fission products, fission yields
fission cross sections
nuclear model for fission
estimate (calculate) fission energy
nuclear reactors, types, moderators, control rods
enrichment of uranium and energy production using fission
natural nuclear reactors
reactor accidents and their impacts