Nuclear Power

Nuclear Power Nuclear energy in California has produced 36,186 million Kilowatt/hours of electricity in 1995. The total dependable capacity of California's nuclear-supplied power is 5,326 megawatts, including the two operating nuclear power plants in California and portions of nuclear plants in other states owned by California electric companies. There are two ways to release energy from nuclear reactions: fission and fusion of atomic nuclei. Electricity generating technologies are available, whereas fusion is still in the early stages of research and development. Nuclear fission is the process of splitting the nuclei of atoms, which releases energy from within those atoms. Nuclear fusion is the process of joining, rather than splitting, these atoms with similar releases of energy. There are several types of fission reactors in the United States but the most common is light water reactors. The reason they are called "light water reactors" is because normal (light) water is used to cool the reactor core; some reactors use heavy water, which contains hydrogen atoms with an additional neutron in the nucleus. Pressurized water reactors (PWR) and boiling water reactors (BWR) use uranium-235, a naturally occurring radioactive isotope of uranium, as a fuel. As the nucleus of a uranium-235 atom is hit by a neutron, it splits into smaller atoms of other elements, and releases energy and extra neutrons. Those neutrons hit more atoms of the original uranium-235 creating a fission chain reaction that releases more energy and neutrons. In a PWR, water passes through the nuclear core and is heated. The power plant's primary circulating system passes water through the reactor core, where the water is heated by the nuclear reaction. That water (under high temp and pressure to prevent boiling) is passed through a steam generator, where it releases its heat to the secondary circulating system. Water in secondary circulating system is allowed to boil, and the resulting steam is used to drive a steam turbine-generator. In a BWR, there is no need for a steam generator and a secondary circulating system, as the water in primary circulating system is allowed to boil before exiting the reactor and is then routed directly to a steam turbine-generator. There are only two nuclear power plants out of six that are still used in California. The first one is owned by PG&E named Diablo Canyon Nuclear Power Plant near San Luis Obispo. The Plant has two units; the first unit is a 1,073-megawatt PWR, which began operation in May 1985. The second unit is 1,087-megawatt PWR, which began operation in March 1986. The second plant is owned by Southern California Edison Co. and San Diego Gas & Electric named San Onofre Nuclear Generating Station. Unit two of that station is a 1,070-megawatt PWR that began operation in August