The Department of Energy's Los Alamos National Laboratory (LANL) has a national security
mission that includes responsibility for the science, engineering and technology related to certain
radioactive materials supporting the Nation's nuclear weapons program. These include materials
such as plutonium, enriched uranium and depleted uranium.
LANL maintains inventories of Categories I, 11,111, and IV accountable nuclear material.
Categories I and I1 materials are those that would be most attractive to an adversary intent on
theft or diversion. Categories 111 and N materials are those that would be less attractive, because
they contain smaller quantities of plutonium, uranium or other materials.