Nuclear Power Plants

Nuclear Power PlantTurbine and Generator

Spinning turbine blades and generator

Boiling water

Steam

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

Nuclear Energy Comes From Fission

Uranium atom

NeutronsSpit atoms

Heat

Splitting Atoms Releases Neutrons, Making Heat

Neutrons

Heat Produces Steam, Generating Electricity

Heat

Steam produced

Steam

Turbine

Generator

Electricity

Nuclear Fission

• The process of splitting a larger atomic nucleus into two smaller nuclei by bombarding it with neutrons. This process releases energy that is stored in the nucleus.

n10 + U235

92 Kr9136 n1

0Ba14256+ +

+Energy

3

Uranium Is Mined and Refined

Uranium Ore Uranium hexafluoride Gas Solid

Enrichment Concentrates the Uranium Isotope

• Our current nuclear power plants run on fission They use theU-235 isotope of Uranium as fuel. Most uranium in natural ores exists in as U-238 Only U-235 is fissionable. Processed uranium must be “enriched” in centrifuges to concentrate the U-235. Uranium used in reactors is 4-5% U-235. Uranium used in nuclear weapons must be 90% U-235.

Uranium Is Encased in Solid Ceramic Pellets

Fuel Rods Filled With Pellets Are Grouped Into Fuel Assemblies

• The fission process can continue until all of the available “big atoms” are gone. This is a chain reaction. Reactions must be slowed down with neutron-absorbing control rods.

Controlling the Chain Reaction

Control rods

Fuel Assemblies

Withdraw control rods,reaction increases

Insert control rods,reaction decreases

Boiling Water Reactor

Steam

Pressurized Water Reactor

Safety Is Engineered Into Reactor Designs

Containment Vessel1.5-inch thick steel

Shield Building Wall3 foot thick reinforced concrete

Dry Well Wall5 foot thick reinforced concrete

Bio Shield4 foot thick leaded concrete with1.5-inch thick steel lining inside and out

Reactor Vessel4 to 8 inches thick steel

Reactor Fuel

Weir Wall1.5 foot thick concrete