High-Enriched Uranium

Highly enriched uranium. Uranium in which the naturally occurring U235 isotope - 0.7 percent in natural uranium, 99.3 percent U238 - is increased to 20 percent U235 or above, but usually to 90 percent or more. HEU is used in nuclear weapons, and in some types of research and submarine propulsion reactors.

Highly Enriched Uranium. Uranium in which the percentage of uranium 235 is raised ("enriched") from a natural level of 0.71 percent to greater than 20 percent-usually 90 percent. All HEU can be raised to make nuclear explosives, although a very large quantity is required for HEU enriched to only 20 percent.

Highly enriched uranium. Any form of uranium with a U-235 concentration of 20% or higher

Highly enriched uranium. induced radioactivity: Radioactivity produced in any material as a result of nuclear reactions, especially by absorption of neutrons.