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Natural uranium is made weapons-grade through isotopic enrichment. Initially only about 0.7% of it is fissile U-235, with the rest being almost entirely uranium-238 (U-238). They are separated by their differing masses. Highly enriched uranium is considered weapons-grade when it has been enriched to about 90% U-235. [citation needed]
Uranium-236 is not fertile, as three more neutron captures are required to produce fissile 239 Pu, and is not itself fissile; as such, it is considered long-lived radioactive waste. [115] Uranium-234 is a member of the uranium series and occurs in equilibrium with its progenitor, 238 U; it undergoes alpha decay with a half-life of 245,500 years ...
Uranium is a silvery-gray, weakly radioactive metallic chemical element.It has the chemical symbol U and atomic number 92. The most common isotopes in natural uranium are 238 U (99.274%) and 235 U (0.711%).
Uraninite, also known as pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO 2 but because of oxidation typically contains variable proportions of U 3 O 8. Radioactive decay of the uranium causes the mineral to contain oxides of lead and trace amounts of helium.
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235 U) has been increased through the process of isotope separation.Naturally occurring uranium is composed of three major isotopes: uranium-238 (238 U with 99.2732–99.2752% natural abundance), uranium-235 (235 U, 0.7198–0.7210%), and uranium-234 (234 U, 0.0049–0.0059%).
Uranium's radioactivity can present health and environmental issues in the case of nuclear waste produced by nuclear power plants or weapons manufacturing. Uranium is weakly radioactive and remains so because of its long physical half-life (4.468 billion years for uranium-238).
Natural uranium (NU or U nat [1]) is uranium with the same isotopic ratio as found in nature. It contains 0.711% uranium-235 , 99.284% uranium-238 , and a trace of uranium-234 by weight (0.0055%). Approximately 2.2% of its radioactivity comes from uranium-235, 48.6% from uranium-238, and 49.2% from uranium-234.
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