Steam produced from nuclear power plants or the burning of fossil fuels rotates the iron bars, which generate electricity. 1 kWh is equal to about 860,000 calories. Uranium 235 is most often used as a fuel in nuclear power plants. In uranium ores only 1 out of 139 uranium atoms is the desirable 235. Therefore, the uranium ore must be processed to extract the 235 before it can be used as nuclear fuel.
Nuclear reactors produce heat through the controlled chain reactions of nuclear fission .
To increase fission efficiency, the neutrons emitted by radioactive decay must be slowed down so that they will split other atoms rather than pass by them. To prevent nuclear reactors from producing too much fission and melting down, the 235 U is commonly dispersed in other materials that absorb neutrons without fission. In American reactors, the concentration of 235 U in the fuel is too low to generate nuclear explosions. However, some European reactors use enriched fuel, which could potentially produce small nuclear explosions. Breeder reactors are used in Japan, France and some other countries.