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 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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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


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


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.


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


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.


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


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.


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

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


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


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.


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


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)


Basic Elements of a Fast Breeder Reactor

Borongraphite

shield

Fuelloadingmachine

Heatexchanger

Core

BREEDER

BLANKET

Magneticpump

Fast Breeder Reactors for Fission Fuel Production


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)


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


CANDU 9 (900 MW) Reactors


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.


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


The TMI-2 Reactor Design


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


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


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


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.


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.


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.


Natural Reactor Location

From: http://www.curtin.edu.au/curtin/centre/waisrc/OKLO/Where/Where.html


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.


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


Power Nuclear Reactors in the World

nucleartourist.com/world/wwide1.htm

fission energy for war and peace 1 fearing of fission bomb for hitler first, the u.s. started the...

Documents

fission energy

fission bomb project

fearing of fission bomb

pu slide

implosion slide

secretary of war henry

gas diffusion of uf

electromagnetic method