Reply #19: Actually, it's Low Enriched Uranium (LEU) (less than 20%, suitable for a research reactor) [View All]

[leveymg]

Low-enriched uranium' (LEU) has a lower than 20% concentration of 235U. For use in commercial light water reactors (LWR), the most prevalent power reactors in the world, uranium is enriched to 3 to 5% 235U. Fresh LEU used in research reactors is usually enriched 12% to 19.75% U-235, the latter concentration being used to replace HEU fuels when converting to LEU.

Highly enriched uranium (HEU) has a greater than 20% concentration of 235U or 233U.

The fissile uranium in nuclear weapons usually contains 85% or more of 235U known as weapon(s)-grade.

The very first uranium bomb, Little Boy in 1945, used 64 kilograms of 80% enriched uranium.