Nuclear Power Plants

History of nuclear power 1938– Scientists study Uranium nucleus 1941 – Manhattan Project begins 1942 – Controlled nuclear chain reaction 1945 – U.S. uses two atomic bombs on Japan 1949 – Soviets develop atomic bomb 1952 – U.S. tests hydrogen bomb 1955 – First U.S. nuclear submarine

The energy in one pound of highly enriched Uranium is comparable to that of one million gallons of gasoline. 17,000 as much energy in one pound of Uranium as in one pound of coal. Economic advantages

Emissions Free Nuclear energy annually prevents –5.1 million tons of sulfur –2.4 million tons of nitrogen oxide –164 metric tons of carbon

Nuclear Energy Powers 1 in 5 U.S. Homes and Businesses

States with nuclear power plant(s)

Nuclear power around the globe 17% of world’s electricity from nuclear power –U.S. about 20% (2nd largest source) 431 nuclear plants in 31 countries –103 of them in the U.S. –Built none since 1970s (Wisconsin as leader).

Countries Generating Most Nuclear Power CountryTotal MW USA99,784 France58,493 Japan38,875 Germany22,657 Russia19,843 Canada15,755 Ukraine12,679 United Kingdom11,720 Sweden10,002 South Korea8,170

Nuclear Power Plant Turbine and Generator Spinning turbine blades and generator Boiling water Steam

Nuclear fuel cycle Uranium mining and milling Conversion and enrichment Fuel rod fabrication POWER REACTOR Reprocessing, or Radioactive waste disposal –Low-level in commercial facilities –High level at plants or underground repository

Uranium Is Mined and Refined

Front end: Uranium mining and milling

Uranium enrichment U-235 –Fissionable at 3% –Weapons grade at 90% U-238 –More stable Plutonium-239 –Created from U-238; highly radioactive

Radioactivity of plutonium Life span of least 240,000 years Last Ice Age glaciation was 10,000 years ago Neanderthal Man died out 30,000 years ago

Enrichment Concentrates the Uranium Isotope

Uranium Is Encased in Solid Ceramic Pellets

Fuel Rods Filled With Pellets Are Grouped Into Fuel Assemblies

Nuclear Energy Comes From Fission Uranium atom Neutrons Split atoms

Heat Splitting Atoms Releases Neutrons, Making Heat Neutrons

Heat Produces Steam, Generating Electricity Heat Steam produced Steam Turbine Generator Electricity

Controlling the Chain Reaction Control rods Fuel Assemblies Withdraw control rods, reaction increases Insert control rods, reaction decreases

Nuclear Reactor Process 3% enriched Uranium pellets formed into rods, which are formed into bundles Bundles submerged in water coolant inside pressure vessel, with control rods. Bundles must be SUPERCRITICAL; will overheat and melt if no control rods. Reaction converts water to steam, which powers steam turbine

Boiling Water Reactor

Steam Pressurized Water Reactor

Safety Is Engineered Into Reactor Designs Containment Vessel 1.5-inch thick steel Shield Building Wall 3 foot thick reinforced concrete Dry Well Wall 5 foot thick reinforced concrete Bio Shield 4 foot thick leaded concrete with 1.5-inch thick steel lining inside and out Reactor Vessel 4 to 8 inches thick steel Reactor Fuel Weir Wall 1.5 foot thick concrete

Early knowledge of risks 1964 Atomic Energy Commission report on possible reactor accident –45,000 dead –100,000 injured –$17 billion in damages –Area the size of Pennsylvania contaminated

Cancers and leukemia among workers –Fires and mass exposure. –Karen Silkwood at Oklahoma fabrication plant. Risk of theft of bomb material. Risks of enrichment and fuel fabrication

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