Neighbours are right to worry about Japan's plutonium stockpile
If any nation could be expected to exercise restraint and responsibility over the handling of weapons-grade stocks of the plutonium by-product of nuclear power, it should be the one that has been the only target of atomic bombs - Japan. It says something about regional tensions, sensitivity about the resurgence of Japanese nationalism, revisionist attitudes towards the country's pacifist constitution and calls for a more proactive self-defence posture that its plutonium stocks have become a divisive issue at the International Atomic Energy Agency. Behind closed doors, China has expressed concern, echoed by fellow nuclear power Russia, about the size of the holdings.
The American representative dismissed worries that its ally was not handling the material properly or that there were no plans for disposing of it. Like uranium, plutonium is used to fuel nuclear power plants but can also provide material for nuclear weapons.
China's concerns were prompted by a Japanese news report that Tokyo had baulked before giving in to US demands for the return of 300kg of mostly weapons-grade plutonium, bought for research purposes in the 1960s, which could be used to make up to 50 nuclear bombs. That leaves at least 159 tonnes of plutonium contained in spent nuclear fuel that had accumulated at civil reactor and processing sites by the end of 2012, according to Japanese data posted on the IAEA website.
A bitter territorial dispute with China over islands in the East China Sea and a visit by far-right Prime Minister Shinzo Abe to a shrine to war dead including leading war criminals have done nothing to ease concerns among neighbours about pro-rearmament sentiment. There may be no reason for worries that Japan will exploit its undoubted capacity to put the plutonium to improper use. But past victims of Japanese aggression are entitled to expect the US to maintain rigorous verification of its unqualified assurances about its ally's transparency and understanding of the conditions of use and maintenance of a sensitive by-product of nuclear power.