"A 'pit' is the plutonium core of a nuclear weapon. Until 1989, the Rocky Flats Plant (CO) mass-produced pits. Since then, the United States has made at most 11 pits per year (ppy). U.S. policy is to maintain existing nuclear weapons. To do this, the Department of Defense states that it needs the Department of Energy (DOE), which maintains U.S. nuclear weapons, to produce 50-80 ppy by 2030. While some argue that few if any new pits are needed, at least for decades, this report focuses on options to reach 80 ppy. Pit production involves precisely forming plutonium--a hazardous, radioactive, physically quirky metal. Production requires supporting tasks, such as analytical chemistry (AC), which monitors the chemical composition of plutonium in each pit. With Rocky Flats closed, DOE established a small-scale pit manufacturing capability at PF-4, a building at Los Alamos National Laboratory (LANL). DOE also proposed higher-capacity facilities; none came to fruition. In 2005, Congress rejected the Modern Pit Facility, viewing as excessive the capacity range DOE studied, 125-450 ppy. In 2012, the Administration 'deferred' construction of the Chemistry and Metallurgy Research Replacement Nuclear Facility (CMRRNF) on grounds of availability of interim alternatives and affordability."
CRS Report for Congress, R43406
Federation of American Scientists: http://www.fas.org/