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Nuclear fission is an extreme example of large-amplitude collective motion that results in the division of a parent nucleus into two or more fragment nuclei. The fission process can occur spontaneously, or it can be induced by an incident particle."
Nuclear fission was discovered in December 1938 by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Fission is a nuclear reaction or radioactive decay process in which the nucleus of an atom splits into two or more smaller, lighter nuclei and
In a normal thermal reactor, tin-121m has a very low fission product yield; thus, this isotope is not a significant contributor to nuclear waste. Fast fission or fission of some heavier actinides will produce 121m Sn at higher yields. For example, its yield from U-235 is 0.0007% per thermal fission and 0.002% per fast fission. [10]
Nuclear fission is a substantial part of the world’s energy mix, but out in the broader universe, fission is much harder to come by. Now, a new study from Los Alamos National Laboratory and ...
In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series or "positive feedback loop" of these reactions. The specific nuclear reaction may be the fission of heavy isotopes (e.g., uranium-235 ...
Commercial nuclear fission reactors are operated in the otherwise self-extinguishing prompt subcritical state. Certain fission products decay over seconds to minutes, producing additional delayed neutrons crucial to sustaining criticality. [7] [8] An example is bromine-87 with a half-life of about a minute. [9]
Nuclear fission is the reverse process to fusion. For nuclei heavier than nickel-62 the binding energy per nucleon decreases with the mass number. It is therefore possible for energy to be released if a heavy nucleus breaks apart into two lighter ones. The process of alpha decay is in essence a special type of spontaneous nuclear fission. It is ...
An example of an induced nuclear fission event. A neutron is absorbed by the nucleus of a uranium-235 atom, which in turn splits into fast-moving lighter elements (fission products) and free neutrons. Though both reactors and nuclear weapons rely on nuclear chain reactions, the rate of reactions in a reactor is much slower than in a bomb.