This document discusses the key components and operation of nuclear reactors. It describes how fission reactions produce heat to generate electricity. The main components are fuel, control rods, coolant, and containment structures. The fuel undergoes fission when struck by neutrons. Control rods control the reaction rate. Coolants transfer heat from the core. Containment protects against radiation leakage. Common reactor types include pressurized water reactors, boiling water reactors, and liquid metal fast breeder reactors, which differ in how they generate steam and circulate coolant. Nuclear power debates center on environmental, safety, and political issues.
2. Background
• Fission: spontaneous radioactive decays of
atoms and releases energy
• Energy is converted into heat to produce
steam and generate electricity
• Original nuclear reactors were designed for
submarines and navy ships
3. Components of a nuclear reactor
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Fuel
Control rods
Coolant
Containment
4. Components: Fuel
• Fissionable: isotopes that undergo induced fission
when struck by a free neutron
• Fissile: isotopes that can sustain a fission chain
reactions when struck by a thermal neutron
U-233
U-235
P-239
• Alpha/Beta decays
• Neutron capture
• Critical mass
5. Components: Fuel
• Enriched uranium hexafluoride (UF6) is
converted into uranium oxide (UO2) powder
• The power is processed into pellets via heat
• Stacked pellets are placed into tubes of
corrosion-resistant metal alloy
6. Components: Control Rods
• Neutron-absorbing materials
– Elements with varying capture cross sections for
neutrons of varying energies.
– Boron, silver, indium, cadmium
• Can be inserted or withdrawn from the core
• Control the rate of reaction
• Rods are attached to the lifting machinery by
electromagnets
7. Components: Coolant
• Circulating fluid through the core to control
heat transfer
• Water is a primary coolant
• In fast reactors, liquid metals such as sodium
and lead are used
• Molten salts
• Gas – helium
• Hydrocarbons
8. Components: Containment
• Protective structure around the reactor
• Protection against intrusion and radiation
leakage
• Steel or reinforced concrete
9. Types of reactors
• Boiling water reactor
• Pressurized water reactors
• Liquid-metal fast-breeder reactor
10. Pressurized Water Reactors
• Operate with thermal neutrons
• Steam is generated outside the reactor in
a secondary heat transfer loop
11. Boiling Water Reactor
• water is converted to steam, and then recycled back into
water by a part called the condenser, to be used again in
the heat process.
• steam generated inside the reactor goes directly to the
turbine
12. Liquid-Metal Fast-Breeder Reactors
• breeder reactors are designed to produce more fissile
material than they consume
• the fission reaction produces heat to run the turbine
while at the same time breeding plutonium fuel for
the reactor.
13. Nuclear power plants in commercial
production
Sources: Nuclear Engineering Handbook 2011
14. The Nuclear Reactor Debate
• Environmentally less harmful than fossile fuels
• Potential radiation contamination in the event
of a meltdown
• Nuclear proliferation and terrorism concerns
• Health effect concerns of those living near
nuclear power plants
• Political implications preventing new
development of nuclear reactors