Japan's commitment to plutonium recycling has been explicitly stated in its long-term program since 1956. Despite the clear cost disadvantage compared with direct disposal or storage of spent fuel, the Rokkasho reprocessing plant started active testing in 2006. Japan's cumulative consumption of plutonium has been only 5 tons to date and its future consumption rate is still uncertain. But once the Rokkasho reprocessing plant starts its full operation, Japan will separate about 8 tons of plutonium annually. Our analysis shows that, with optimum use of available at-reactor and away-from-reactor storage capacity, there would be no need for reprocessing until the mid-2020s. With an additional 30,000 tons of away-from-reactor (AFR) spent-fuel storage capacity reprocessing could be avoided until 2050. Deferring operation of the Rokkasho plant, at least until the plutonium stockpile had been worked down to the minimum required level, would also minimize international concern about Japan's plutonium stockpile. The authors are happy to acknowledge Frank von Hippel, Harold Feiveson, Jungming Kang, Zia Mian, M.V. Ramana, and other IPFM members, as well as the generous grant from the MacArthur Foundation for helping make this research possible. (C) 2009 Elsevier Ltd. All rights reserved.