Isotope separation is the process of concentrating specific
isotopes of a
chemical element by removing other isotopes. The use of the
nuclides produced is various. The largest variety is used in research (e.g. in
chemistry where atoms of "marker" nuclide are used to figure out reaction mechanisms). By tonnage, separating
natural uranium into
enriched uranium and
depleted uranium is the largest application. In the following text, mainly the uranium enrichment is considered. This process is a crucial one in the manufacture of uranium fuel for nuclear power stations, and is also required for the creation of uranium based
nuclear weapons. Plutonium-based weapons use plutonium produced in a nuclear reactor, which must be operated in such a way as to produce plutonium already of suitable isotopic mix or
grade. While different chemical elements can be purified through
chemical processes, isotopes of the same element have nearly identical chemical properties, which makes this type of separation impractical, except for separation of
deuterium.