Nuclear Energy
...s changed into uranium dioxide powder and pressed into small pellets. The pellets are placed into tubes of stainless steel to form fuel rods. The rods are sealed and assembled into clusters to make fuel assemblies for use in the core of the nuclear reactor. The fuel rods are then shipped in special casks to nuclear reactors around the country. The nuclear fuel assemblies must be handled by workmen in special protective clothing that shields them from the radiation. Several hundred fuel assemblies make up the core of a reactor. In the core, the U-235 isotope splits causing heat in a process called a chain reaction. The process depends on a moderator such as water or graphite and is full controlled. Some of the U-238 in the reactor core is turned into plutonium and about half of this is also fissioned, providing about one third of the reactor’s energy output. Just like in a coal burning electric generating plant, the heat is used to make steam and drive a turbine and an electric generator. To maintain efficient nuclear reactor performance, about one third of the spent fuel is removed every year and replaced with fresh fuel. Spent fuel rods taken from the reactor core are highly radioactive and give off a lot of heat. They must be stored in special ponds to allow their heat and radioactivity to decrease. The water in the ponds has two purposes to protect from radioactivity and to disperse heat from the spent fuel rods. The rods can be stored in the ponds for long periods but it is only an interim step before the spent fuel is reprocessed or sent to final disposal. Reprocessing is a good alternative for spent fuel. The material still contains about 96% of its original uranium, of which the fissionable U-235 content has been reduced to less than 1%. About 3% of the spent fuel is waste products and 1% is plutonium produced by the reactor but not fissioned. Reprocessing separates the uranium from the cladding of the casing. Recovered uranium is then returned to a conversion plant for conversion into uranium hexaflouride and reenrichment. The reactor grade plutonium can be blended with enriched uranium to create mixed oxide fuel, in a fuel fabrication plant. The fuel is returned to the nuclear reactor for reuse. The process can be completed over and over with very little loss of uranium content. This makes it seem like a very good method of generating electricity. It can create large amounts of energy with a limited amount of raw material. With fossil fuels being a non renewable resource it seems that nucl...