from http://www.eia.doe.gov/kids/energyexplained/non-renewable/sources/nuclear.html
Nuclear Power Plants Generate About One-Fifth of U.S. Electricity
Nuclear power accounted for about 20% of the total net electricity generated in the United States in 2008, about as much as the electricity used in California, Texas, and New York, the three States with the most people. In 2008, there were 66 nuclear power plants (composed of 104 licensed nuclear reactors) throughout the United States. Most of the reactors are east of the Mississippi. The last new reactor to enter commercial service in the United States was the Tennessee Valley Authority’s Watts Bar 1 in Tennessee in 1996.
In 2008, TVA resumed construction on Watts Bar 2, which was about 80% complete when its construction was stopped in 1988. It is now expected to be completed in 2012.
Source: Stock photography (copyrighted)
By the end of February 2009, the Nuclear Regulatory Commission (NRC) had received applications for a total of 26 newly designed reactors. It is uncertain how many of these reactors will eventually be built, but the NRC estimates 42 months to complete the review of all the applications prior to a final decision. Construction typically requires another five to seven years for each reactor.
Nuclear Power Comes from Fission
Most power plants, including nuclear plants, use heat to produce electricity. They rely on steam from heated water to spin large turbines, which generate electricity. Instead of burning fossil fuels to produce the steam, nuclear plants use heat given off during fission.
In nuclear fission, atoms are split apart to form smaller atoms, releasing energy. Fission takes place inside the reactor of a nuclear power plant. At the center of the reactor is the core, which contains the uranium fuel.
The uranium fuel is formed into ceramic pellets. The pellets are about the size of your fingertip, but each one produces roughly the same amount of energy as 150 gallons of oil. These energy-rich pellets are stacked end-to-end in 12-foot metal fuel rods. A bundle of fuel rods, sometimes hundreds, is called a fuel assembly. A reactor core contains many fuel assemblies.
The heat given off during fission in the reactor core is used to boil water into steam, which turns the turbine blades. As they turn, they drive generators that make electricity. Afterward, the steam is cooled back into water in a separate structure at the power plant called a cooling tower. The water can be used again and again.
