Uranium-238

Uranium-238 (U-238) is the most common isotope of uranium found in nature. When hit by a neutron, it eventually becomes plutonium-239 (Pu-239). Around 99.284% of natural uranium is uranium-238, which has a half-life of 1.41 × 10 seconds (4.46 × 10 years, or 4.46 billion years). Depleted uranium consists mainly of the 238 isotope, and enriched uranium has a higher-than-natural quantity of the uranium-235 isotope. Reprocessed uranium is also mainly... more

Uranium-238 (U-238) is the most common isotope of uranium found in nature. When hit by a neutron, it eventually becomes plutonium-239 (Pu-239). Around 99.284% of natural uranium is uranium-238, which has a half-life of 1.41 × 10 seconds (4.46 × 10 years, or 4.46 billion years). Depleted uranium consists mainly of the 238 isotope, and enriched uranium has a higher-than-natural quantity of the uranium-235 isotope. Reprocessed uranium is also mainly U-238, but contains significant quantities of uranium-236, and in fact all the isotopes of uranium between uranium-232 and uranium-238 except uranium-237. In a fission nuclear reactor, uranium-238 can be used to breed plutonium-239, which itself can be used in a nuclear weapon or as a reactor fuel source. In fact, in a typical nuclear reactor, up to a third of the generated power does come from the fission of plutonium-239, which is not supplied as a fuel to the reactor, but transmuted from uranium-238. Breeder reactors use the waste uranium... less