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Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay. Nuclear fission was discovered by chemists Otto Hahn and Fritz Strassmann and physicists Lise ...
The Chernobyl sarcophagus, built to contain the effects of the 1986 disaster. A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. When a fissile nucleus like uranium-235 or plutonium-239 absorbs ...
A molten-salt reactor (MSR) is a class of nuclear fission reactor in which the primary nuclear reactor coolant and/or the fuel is a mixture of molten salt with a fissile material. Two research MSRs operated in the United States in the mid-20th century. The 1950s Aircraft Reactor Experiment (ARE) was primarily motivated by the technology's ...
Small modular reactors (SMR s) are a class of small nuclear fission reactors, designed to be built in a factory, shipped to operational sites for installation and then used to power buildings or other commercial operations. The term SMR refers to the size, capacity and modular construction. Reactor type and the nuclear processes may vary.
A possible nuclear fission chain reaction: 1) A uranium-235 atom absorbs a neutron and fissions into two fission fragments, releasing three new neutrons and a large amount of binding energy. 2) One of those neutrons is absorbed by an atom of uranium-238, and does not continue the reaction. Another neutron leaves the system without being absorbed.
If k = 1, the chain reaction is critical and the neutron population will remain constant. In an infinite medium, neutrons cannot leak out of the system and the multiplication factor becomes the infinite multiplication factor, k = k ∞ {\displaystyle k=k_{\infty }} , which is approximated by the four-factor formula.
General Electric 's BWR product line of boiling water reactors represents the designs of a relatively large (~18%) [1] percentage of the commercial fission reactors around the world. The progenitor of the BWR line was the 5 MW Vallecitos Boiling Water Reactor (VBWR), brought online in October 1957. Six design iterations, BWR-1 through BWR-6 ...
A nuclear reactor core is composed of a few hundred "assemblies", arranged in a regular array of cells, each cell being formed by a fuel or control rod surrounded, in most designs, by a moderator and coolant, which is water in most reactors. Because of the fission process that consumes the fuels, the old fuel rods must be replaced periodically ...