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In a fission nuclear reactor, uranium-238 can be used to generate plutonium-239, which itself can be used in a nuclear weapon or as a nuclear-reactor fuel supply. In a typical nuclear reactor, up to one-third of the generated power comes from the fission of 239 Pu, which is not supplied as a fuel to the reactor, but rather, produced from 238 U. [5] A certain amount of production of 239
238 92 U + n → 239 92 U (23 minutes) → 239 93 ekaRe; Meitner was certain that these had to be (n, γ) reactions, as slow neutrons lacked the energy to chip off protons or alpha particles. She considered the possibility that the reactions were from different isotopes of uranium; three were known: uranium-238, uranium-235 and uranium-234.
Uranium appears in nature primarily in two isotopes: uranium-238 and uranium-235. When the nucleus of uranium-235 absorbs a neutron, it undergoes nuclear fission, releasing energy and, on average, 2.5 neutrons. Because uranium-235 releases more neutrons than it absorbs, it can support a chain reaction and so is described as fissile. Uranium-238 ...
The development of organouranium compounds started in World War II when the Manhattan Project required volatile uranium compounds for 235 U/ 238 U isotope separation. For example, Henry Gilman attempted to synthesize compounds like tetramethyluranium, and others worked on uranium metal carbonyls, but none of the efforts met success due to organouranium instability.
Uranium-238 (U-238 or 238 U), the most common isotope of uranium Topics referred to by the same term This disambiguation page lists articles associated with the same title formed as a letter–number combination.
They acknowledged Meitner's priority, and agreed to the name. The connection to uranium remained a mystery, as neither of the two known isotopes of uranium (uranium-234 and uranium-238) decayed into protactinium. It remained unsolved until uranium-235 was discovered by Arthur Jeffrey Dempster in 1935. [46] [48]
234 U occurs in natural uranium as an indirect decay product of uranium-238, but makes up only 55 parts per million of the uranium because its half-life of 245,500 years is only about 1/18,000 that of 238 U. The path of production of 234 U is this: 238 U alpha decays to thorium-234. Next, with a short half-life, 234 Th beta decays to ...
Unlike other isotopic dating methods, the "daughter" in fission track dating is an effect in the crystal rather than a daughter isotope.Uranium-238 undergoes spontaneous fission decay at a known rate, and it is the only isotope with a decay rate that is relevant to the significant production of natural fission tracks; other isotopes have fission decay rates too slow to be of consequence.