Transcript No Slide Title

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 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 heavywater 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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Producing Bomb Materials
Separate 235U (0.7%) from natural
uranium:
gas diffusion of UF6
centrifuge of UF6 gas
thermal diffusion of UF6 gas
electromagnetic separation
235
239
U
Pu
Production of 239Pu by the reaction
238U(n, 2b)239Pu
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Bomb Material:
Separating 235U by gas Diffusion
 One diffusion unit
and
the diffusion plant 
The blue spot is a person
http://www.npp.hu/uran/3diff-e.htm
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235U
Bomb
eparating
BombMaterial:
Material:SS
eparating235
Uby
byElectromagnetic
Electromagnetic method
meth
Uranium Isotope Enrichment by the
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.
From a
particle
accelerator
238
235
UF6
collector
UF6
collector
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Fission Energy for War and Peace
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Isotope Separation by Plasma Centrifuge
A 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
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New Methods of Isotope Separation
1. 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.
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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 Mass
Determination
Neutron
monitoring
devices
Fission Energy for War and Peace
Releasing
mechanism
235
U or
239
Pu
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The Implosion Arrangement
Ignition
points
Reducing
Critical
Masses by
Implosion
Chemical
explosive
239
Pu
Fission material is surrounded by chemical explosive
which is ignited at many points simultaneously. The
explosion forces pieces of 239Pu together and even
reduces the volume to reduce the critical mass.
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The First Fission
Bomb Explosion
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.
Major work sites:
Oak Ridge 59,000-acre
Hanford Engineer Work 450,000-acre
Project Y (Los Alamos Laboratory)
Chicago, Berkley, Montreal, New York
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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
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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
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Nuclear
Reactors
Basic Elements of Fission Reactors
Control rods
devices operating
at steady-state
chain reaction for
research and
power generation.
moderator
Reactor
Core
Energy transfer system
Monitoring
devices
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Key Components
of Nuclear
Reactors
Reactor core (fuel):
enriched or natural U, 239Pu
Moderators
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
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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)
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Fast Breeder Reactors for Fission Fuel Production
Basic Elements of a Fast Breeder Reactor
Fuel
loading
machine
Boron
graphite
shield
B
R
E
E
D
E
R
Cor
e
B
L
A
N
K
E
T
Fission Energy for War and Peace
Magnetic
pump
Heat
exchanger
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Reactions in Fast Breeder Reactors (FBR)
Fast Breeder Reactors produce more
fission fuel they consume.
Two types of product dependent FBR
The 239Pu or uranium cycle
238U ( fast n, 2b) 239Pu,  = 2.7 b
c
The thorium cycle
232Th (slow n, b) 233U,
c = 7.4 b, f = 5.6×10-5 b
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CANDU Reactors
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 horizontally
Replace fuel during operation
Use oxide of natural uranium as fuel and D2O as moderator
Generate large volumes of nuclear wastes
Produce 239Pu
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CANDU 9 (900 MW)
Reactors
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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.
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TMI-2 3000 MW PWR Power Reactor
Block Diagram of a Pressurized Water Reactor
Relief
valve
Reactor &
Pressurized
containment primary
building
cooling
loop
Heat
exchange
and steam
generator
Cooling
tower &
housing
Turbine & generator
Reactor
core
Pumps Auxiliary
pumps
&
valves
Secondary
cooling
loop
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The TMI-2 Reactor Design
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TMI-2 Reactor accidents
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
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The TMI-2 Core After the Accident
Four 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.
Fission Energy for War and Peace
http://washingtonpost.com/wp-srv/national/longterm/tmi/gallery/photo10.htm
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Fission Products in the Core After the Accident
Long-life Fission Products in the Core after TMI-2 Accident
Isotope Activity /Ci Half-life Amount*
85K
9.7104
10.7 y
4.71013
90Sr
7.5105
28.8 y
9.81014
129I
2.210–3
1.6107 y 1.61012
131I
7.0107
8.04 d
7.01013
133Xe
1.5108
5.25 d
9.81013
137Cs
8.4105
30.2 y
1.11015
* Amount = Activity  half-life (s)/0.693
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The Chernobyl Accident
RBMK 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.
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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.
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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.
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Natural Reactor Location
Fission Energy for War and Peace
From: http://www.curtin.edu.au/curtin/centre/waisrc/OKLO/Where/Where.html
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Additional Evidences for
Natural Nuclear Reactor
Isotope of Neodymium
The natural reactor
released 15,000 MWyear energy for
150,000 years 1.8e9
years ago.
mass
142
143
144
145
156
148
150
Natural
27.11
12.17
23.85
8.30
17.22
5.73
5.62
Fission Energy for War and Peace
Fission
0
28.8
26.5
18.9
14.4
8.26
3.12
Oklo
0
25.7
29.3
18.4
14.9
8.2
3.5
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Nuclear Fission - Summary
discovery 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
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Power Nuclear Reactors in the World
nucleartourist.com/world/wwide1.htm
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