Moderator - The substance used to slow down neutrons, making them more likely to react with the fuel (usually uranium-235).This can be ordinary water, heavy water, helium, carbon dioxide, molten metals such as sodium, lead and lead-bismuth alloy, and even liquid salts of fluorine and chlorine. Coolant - The fluid that transfers the heat generated in the core to the electricity generation system.Here are some parameters that can be varied: There are very many ways to convert the heat from nuclear fission to create electricity with a turbine. The largest by count of operational reactors is Bruce Nuclear Generating Station in Kincardine, Ontario Lake Huron's northeast shore, with eight CANDU reactors each generating roughly 750 MW of electricity. The largest one by power-output, Kashiwazaki-Kariwa in Japan, has a gross total capacity of 8212 MW (Two 1,356 MW reactor cores with five 1,100 MW cores). A single reactor generates from 400 to 1400 MW, and a power station can contain multiple reactors. It was essentially a modified beached submarine reactor, generating 60 MW of electricity.Ī typical modern station is much more powerful than those early designs. The first electricity-only power station was started in 1957 in Shippingport, Pennsylvania. It had four Magnox reactors for plutonium production with cooling systems modified to include steam turbines to generate 50 MW of electricity each, for a total of 200 MW. The first commercial power plant, Calder Hall, was put into operation in 1956 in Windscale (now Sellafield) in the United Kingdom. The first power station was started in 1954 in Obninsk in the USSR. It used a pressurized water reactor, the most popular design used in power stations today. The first nuclear submarine, the USS Nautilus (SSN-571), was launched in 1954. The first nuclear bomb, known as "the gadget," exploded in 1945 in the Trinity test. Modern nuclear power is more or less a spin-off of the technology developed to power nuclear submarines, itself an offshoot of the Manhattan Project, the US effort to build the first nuclear bomb.
However, those conditions were more likely in the Proterozoic than they are today as the percentage of fissile U235 in naturally occurring Uranium has fallen below the amount needed for a water moderated reactor to work. The conditions under which a natural nuclear reactor could exist had been predicted in 1956 by Paul Kazuo Kuroda. Such a reactor was discovered in 1972 at Oklo in Gabon, Africa, by French physicist Francis Perrin. Natural nuclear fission reactors can form in uranium deposits where self-sustaining nuclear chain reactions have occurred.
0 kommentar(er)
