Summary: With the end of the Cold War and the breakup of the Soviet Union, the Energy Department (DOE) is turning its attention to managing nuclear materials designated as excess to national security needs and to cleaning up the contamination arising from 50 years of nuclear weapons production. As part of this transition, the United States has divided its 99.5-metric-ton plutonium inventory into two major categories--that which is allocated for national security requirements and that designated as excess. This report reviews (1) how much plutonium the United States allocated for national security needs, how much it designated as excess, and how DOE determined these amounts; (2) DOE's estimates of the current and near-term costs to manage plutonium; and (3) DOE's estimates of the long-term costs to manage plutonium. GAO found that the United States has taken important steps to reduce the dangers of nuclear proliferation associated with holding excess plutonium. However, without a technical basis for its categorizations, the United States cannot be certain that it is retaining the correct amount of plutonium for national security purposes.
