from: http://www.eia.doe.gov/kids/energyexplained/sources/non-renewable/nuclear.html
Did You Know?
Steam coming out of the nuclear cooling towers is just hot water.
Some canisters are designed to be placed vertically in robust above-ground concrete or steel structures.
Nuclear Power Plants Produce No Carbon Dioxide
The first sentence is questionable: is nuclear energy really "clean"?
Unlike fossil fuel-fired power plants, nuclear power plants produce no air pollution or carbon dioxide. However, a small amount of emissions result from processing the uranium that is used in nuclear reactors.
Nuclear Energy Produces Radioactive Waste
Like all industrial processes, nuclear power generation has by-product wastes: spent (used) fuels, other radioactive waste, and heat. Spent fuel and other radioactive wastes are the principal environmental concerns for nuclear power.
Most nuclear waste is low-level radioactive waste. It consists of ordinary tools, protective clothing, wiping cloths, and disposable items that have been contaminated with small amounts of radioactive dust or particles. These materials are subject to special regulation that govern their disposal so they will not come in contact with the outside environment.
Spent Fuel Must Be Stored
The spent fuel assemblies, on the other hand, are highly radioactive and must initially be stored in specially designed pools resembling large swimming pools (water cools the fuel and acts as a radiation shield) or in specially designed dry storage containers. An increasing number of reactor operators now store their older spent fuel in dry storage facilities using special outdoor concrete or steel containers with air cooling.