Uranium

Uranium Isotopes
Uranium at Kvanefjeld
Radiation and the Environment
Uranium
 

 

Uranium Isotopes 

In nature the uranium isotope Uranium-238 is the most abundant (99.284% natural abundance), followed by Uranium-235 (0.711%) and a very small amount of Uranium-234.
Uranium-235 has the distinction of being the only naturally occurring fissile isotope, and when bombarded with slow neutrons, generates the heat in nuclear reactors used as a source of power. Uranium-238 is also important because it absorbs neutrons to produce a radioactive isotope that subsequently decays to the isotope Plutonium-239, which is also fissile.
Mined uranium ores require isotope separation to concentrate the fissionable Uranium-235 that is used in most nuclear power plants. Typically, the isotope Uranium-235 is enriched to concentrations of 3 to 5%. This process produces large quantities of depleted uranium with increased proportions of Uranium-238, and generally 0.2 to 0.3% Uranium-235.
Most uranium mines produce a uranium product referred to as “yellowcake”, which is a uranium oxide compound (U3O8). Additional treatment is then required before yellowcake can be used as a fuel for nuclear reactors.
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