Proliferation Risks of Japanese Plutonium Surpluses Troubled U.S. Officials for Decades

Japan’s long-standing aspirations to develop a «plutonium economy» troubled U.S. officials going back decades as early as the Jimmy Carter administration, according to documents posted today by the nongovernmental National Security Archive at The George Washington University and the Nuclear Nonproliferation International History Project at the Woodrow Wilson International Center for Scholars.

The Japanese government appealed repeatedly in the late 1970s for authority to utilize American spent fuel for reactor experiments and for acceptance of the country’s right to resource self-sufficiency. Tokyo’s position sparked intense debate within the Carter administration, between those who wanted to avoid damaging ties with Japan and those – including the president – who placed a high priority on curbing the availability of sensitive nuclear technologies. Among the newly declassified documents in this e-book is a National Security Council memo expressing concern that the inevitable surplus from Japan’s desired processing plans would “more than swamp” global requirements and create a significant proliferation risk involving tons of excess plutonium by the year 2000. Indeed, as a result of reprocessing activities since then, Japan possesses 48 tons of plutonium and could be producing more, with no clearly defined use, when a new reprocessing facility goes on line in 2018, unless Washington and Tokyo renegotiate a nuclear agreement that expires that same year.

Today’s posting is part of a growing body of records being compiled by the National Security Archive’s Nuclear Vault that flesh out largely unknown aspects of the history of Japan’s nuclear program, and more generally the inherent dangers of proliferation of nuclear materials.