Research on plutonium disposition by U.S. and Russia from the nonproliferation and nuclear security perspectives

Kokaji, Lisa; Suda, Kazunori ; Tamai, Hiroshi ; Tazaki, Makiko ; Shimizu, Ryo 

After the Cold War, the United States and Russia have been decreasing the number of nuclear warheads under the Strategic Arms Reduction Treaty and other agreements, with step-by step removal from nuclear military programs under the process of nuclear disarmament. In 2000, the two states signed the Plutonium Management and Disposition Agreement (PMDA), which prescribes each of them to dispose of at least 34 metric tons of plutonium. Recently, since the cost of constructing the Mixed Oxide (MOX) Fabrication Facility has increased significantly, the United States has been assessing alternatives. In the revised PMDA, which defines weapon-grade plutonium as "an isotopic ratio of plutonium 240 to plutonium 239 of no more than 0.10", Article VII states, "Each Party shall have the right to conduct and the obligation to receive and facilitate monitoring and inspection activities", and Article VIII prescribes, "Each Party shall be responsible...for...disposition plutonium...taking into account...INFCIRC/225/Rev.4...". In accordance with the revised PMDA's obligation to dispose of an excess of 34 metric tons of plutonium, irradiation in fast reactors, irradiation of MOX fuel in LWRs, immobilization, downblending, and deep borehole options have been considered by the United States. In this research, it is examined how these options could be implemented from the nuclear nonproliferation and nuclear security perspectives.