[en] In 1977, the executive branch reversed its long-standing support for nuclear fuel reprocessing, primarily because of the rick of spreading nuclear weapons. GAO reviewed safeguards technology designed to reduce such risks in Federal reprocessing facilities and found that concerns are warranted. Material in sufficient quantities to construct a nuclear weapon could be diverted and go undetected for a long time. Effective international control and safeguards over the production, storage, and use of separated plutonium are lacking. The United States should increase its efforts to: develop and ensure the use of effective safeguards for reprocessing facilities; and establish, in conjunction with major nuclear fuel users, suppliers, and reprocessors, an international system to control the storage and use of excess plutonium