This is comparable to the water in the cooling system of a car, which carries away the heat built up in the engine. In a reactor, as much as 330,000 gallons of water flow through the reactor core every minute to carry away the heat. A moderator, water, slows down the speed at which atoms travel. This reduction in speed actually increases the opportunity to split, thereby releasing energy. Because nuclear generated electricity does not emit carbon dioxide into the atmosphere, nuclear power plants in the U.S. prevent about as much greenhouse has emissions as taking 5 billion cars off our streets and highways.
Radioactive wastes are the principal environmental concern for nuclear power.
Most nuclear waste is low-level nuclear waste. It is ordinary trash, 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 storage so they will not come in contact with the outside environment. The older and less radioactive fuel is kept in the dry storage facility. It is sealed in special concrete reinforced containers.