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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 ...
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.
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
However, small amounts exist as spontaneous fission products in uranium ores. A kilogram of uranium contains an estimated 1 nanogram (10 −9 g) equivalent to ten trillion atoms of technetium. [21] [61] [62] Some red giant stars with the spectral types S-, M-, and N display a spectral absorption line indicating the presence of technetium.
This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
Uranium-235 makes up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a fission chain reaction. It is the only fissile isotope that is a primordial nuclide or found in significant quantity in nature. Uranium-235 has a half-life of 703.8 million years.
Uranium is a highly soluble and radioactive heavy metal. It can be easily dissolved, transported and precipitated within groundwater by subtle changes in oxidation conditions. Uranium does not usually form very insoluble mineral species, which is a further factor in the wide variety of geological conditions and places in which uranium ...