Unit 3 -Nuclear Power PlantUnit 3 -Nuclear Power Plant

• Principles of nuclear energyPrinciples of nuclear energy

• Fission reactionsFission reactions

• Nuclear reactorNuclear reactor

• Nuclear power plantsNuclear power plants

Nuclear reactionNuclear reaction

• Chain reaction occurs when a Chain reaction occurs when a Uranium atom splitsUranium atom splits

• Different reactionsDifferent reactions– Atomic Bomb in a split secondAtomic Bomb in a split second– Nuclear Power Reactor more controlled, Nuclear Power Reactor more controlled,

cannot explode like a bombcannot explode like a bomb

History of nuclear History of nuclear powerpower

1938– Scientists study Uranium nucleus1938– Scientists study Uranium nucleus1941 – Manhattan Project begins1941 – Manhattan Project begins1942 – Controlled nuclear chain 1942 – Controlled nuclear chain

reactionreaction1945 – U.S. uses two atomic bombs on 1945 – U.S. uses two atomic bombs on

JapanJapan1949 – Soviets develop atomic bomb1949 – Soviets develop atomic bomb1952 – U.S. tests hydrogen bomb1952 – U.S. tests hydrogen bomb1955 – First U.S. nuclear submarine1955 – First U.S. nuclear submarine

““Atoms for Peace”Atoms for Peace”

Program to justify nuclear technologyProgram to justify nuclear technology

Proposals for power, canal-building, Proposals for power, canal-building, exportsexports

First commercial power plant, Illinois First commercial power plant, Illinois 1960 1960

• The energy in one pound of highly The energy in one pound of highly enriched Uranium is comparable to enriched Uranium is comparable to that of one million gallons of gasoline.that of one million gallons of gasoline.

• One million times as much energy in One million times as much energy in one pound of Uranium as in one one pound of Uranium as in one pound of coal.pound of coal.

Economic advantagesEconomic advantages

Emissions FreeEmissions Free

• Nuclear energy annually preventsNuclear energy annually prevents– 5.1 million tons of sulfur5.1 million tons of sulfur– 2.4 million tons of nitrogen oxide2.4 million tons of nitrogen oxide– 164 metric tons of carbon164 metric tons of carbon

• Nuclear often pitted against fossil Nuclear often pitted against fossil fuelsfuels– Some coal contains radioactivitySome coal contains radioactivity– Nuclear plants have released low-level Nuclear plants have released low-level

radiationradiation

Early knowledge of risksEarly knowledge of risks

• 1964 Atomic Energy Commission 1964 Atomic Energy Commission reportreport

on possible reactor accidenton possible reactor accident

– 45,000 dead45,000 dead– 100,000 injured100,000 injured– $17 billion in damages$17 billion in damages– Area the size of Pennsylvania Area the size of Pennsylvania

contaminatedcontaminated

Nuclear power around the Nuclear power around the globeglobe

• 17% of world’s electricity from nuclear 17% of world’s electricity from nuclear power power – U.S. about 20% (2nd largest source)U.S. about 20% (2nd largest source)

• 431 nuclear plants in 31 countries 431 nuclear plants in 31 countries – 103 of them in the U.S.103 of them in the U.S.– Built none since 1970s (Wisconsin as leader). Built none since 1970s (Wisconsin as leader). – U.S. firms have exported nukes.U.S. firms have exported nukes.– Push from Bush/Cheney for new nukes.Push from Bush/Cheney for new nukes.

Nuclear fuel cycleNuclear fuel cycle

• Uranium mining and millingUranium mining and milling

• Conversion and enrichmentConversion and enrichment

• Fuel rod fabricationFuel rod fabrication

• POWER REACTORPOWER REACTOR

• Reprocessing, Reprocessing, oror

• Radioactive waste disposalRadioactive waste disposal– Low-level in commercial facilitiesLow-level in commercial facilities– High level at plants or underground High level at plants or underground

repositoryrepository

Front end: Front end: Uranium mining and millingUranium mining and milling

Uranium enrichmentUranium enrichment

• U-235 U-235 – Fissionable at 3%Fissionable at 3%– Weapons grade at 90%Weapons grade at 90%

• U-238 U-238 – More stableMore stable

• Plutonium-239 Plutonium-239 – Created from U-238; highly radioactiveCreated from U-238; highly radioactive

Radioactivity of plutoniumRadioactivity of plutonium

Life span of least Life span of least 240,000 years240,000 years

Last Ice Age glaciation Last Ice Age glaciation was 10,000 years agowas 10,000 years ago

Neanderthal Man died outNeanderthal Man died out30,000 years ago30,000 years ago

• Largest industrial users of water, electricityLargest industrial users of water, electricity– Paducah, KY, Oak Ridge, TN, Portsmouth, OHPaducah, KY, Oak Ridge, TN, Portsmouth, OH

• Cancers and leukemia among workersCancers and leukemia among workers– Fires and mass exposure.Fires and mass exposure.– Karen Silkwood at Oklahoma fabrication plant.Karen Silkwood at Oklahoma fabrication plant.

• Risk of theft of bomb material.Risk of theft of bomb material.

Risks of enrichmentRisks of enrichmentand fuel fabricationand fuel fabrication

Nuclear Reactor ProcessNuclear Reactor Process

• 3% enriched Uranium pellets 3% enriched Uranium pellets formed into rods, which are formed formed into rods, which are formed into bundlesinto bundles

• Bundles submerged in water Bundles submerged in water coolant inside pressure vessel, with coolant inside pressure vessel, with control rods.control rods.

• Bundles must be SUPERCRITICAL; Bundles must be SUPERCRITICAL; will overheat and melt if no control will overheat and melt if no control rods.rods. Reaction converts water to Reaction converts water to steam, which powers steam turbinesteam, which powers steam turbine

Nuclear Reactor StructureNuclear Reactor Structure

• Reactor’s pressure vessel Reactor’s pressure vessel typically housed in 8” of typically housed in 8” of steelsteel

• 36” concrete shielding36” concrete shielding

• 45” steel reinforced 45” steel reinforced concreteconcrete

Breeder reactorBreeder reactor “Breeds” plutonium as it operates “Breeds” plutonium as it operates

Uses liquid sodium metal instead of water for Uses liquid sodium metal instead of water for coolantcoolant– Could explode if in contact with air or waterCould explode if in contact with air or water

• 1966 Fermi, Michigan 1966 Fermi, Michigan – Partial meltdown nearly causes evacuation of DetroitPartial meltdown nearly causes evacuation of Detroit

• 1973 Shevchenko, Russia1973 Shevchenko, Russia– Breeder caught fire and explodedBreeder caught fire and exploded

• Controversial proposals in Europe, U.S.Controversial proposals in Europe, U.S.

ReprocessingReprocessing

• Separates reusable fuel from wasteSeparates reusable fuel from waste– Large amounts of radioactivity releasedLarge amounts of radioactivity released

• 1960s West Valley, NY 1960s West Valley, NY – Radiation leaked into Lake OntarioRadiation leaked into Lake Ontario

• 1970s La Hague, France 1970s La Hague, France – Released plutonium plumes into airReleased plutonium plumes into air

Back end: Radioactive Back end: Radioactive wasteswastes• Low-level wastes in commercial facilitiesLow-level wastes in commercial facilities

• Spent fuel in pools or “dry casks” by plantsSpent fuel in pools or “dry casks” by plants

• Nuclear lab wastesNuclear lab wastes– Hanford wastes leaked radiation into Columbia RiverHanford wastes leaked radiation into Columbia River

• High-level underground repository High-level underground repository – Yucca Mountain in Nevada to 2037Yucca Mountain in Nevada to 2037– Wolf River Batholith in Wisconsin after 2037?Wolf River Batholith in Wisconsin after 2037?– Risks of cracks in bedrock, water seepageRisks of cracks in bedrock, water seepage

Radioactive Waste Radioactive Waste RecyclingRecycling• Disposal of radioactive waste from nuclear Disposal of radioactive waste from nuclear

power plants and weapons facilities by power plants and weapons facilities by recycling it into household products.recycling it into household products.

• In 1996, 15,000 tons of metal were received In 1996, 15,000 tons of metal were received by the Association of Radioactive Metal by the Association of Radioactive Metal Recyclers . Much was recycled into products Recyclers . Much was recycled into products without consumer knowledge.without consumer knowledge.

• Depleted Uranium munitions for military.Depleted Uranium munitions for military.

Nuclear power plant Nuclear power plant

• Nuclear energy has no typical pollutants or Nuclear energy has no typical pollutants or greenhouse gassesgreenhouse gasses

• Nuclear waste contains high levels of Nuclear waste contains high levels of radioactive waste, which are active for radioactive waste, which are active for hundreds of thousands of years.hundreds of thousands of years.

• The controversy around nuclear energy The controversy around nuclear energy stems from all parts of the nuclear chain.stems from all parts of the nuclear chain.

SummarySummary