Separative work units

Separative Work Units (SWUs) are a measure used in the field of nuclear engineering and enrichment of uranium. They quantify the effort required to separate isotopes in a mixture of uranium isotopes, particularly when enriching uranium for use in nuclear reactors or weapons. In the context of uranium enrichment, the most common isotopes are U-238 and U-235. Natural uranium is primarily composed of U-238, with only about 0.7% being U-235.