Japan possessed about 47.1 tons of plutonium in and outside the country as of the end of 2013, up some 2.9 tons from the year before, the Cabinet Office said Tuesday.
Newly added were 2.3 tons generated through the spent fuel reprocessing outsourced to Britain and 640 kilograms Japan had not reported to the global watchdog for being unused even though loaded into a commercial reactor and faced criticism.
Japan upholds a nuclear fuel recycle policy, under which plutonium extracted by reprocessing conventional uranium fuel is consumed by existing reactors in the form of plutonium-uranium mixed oxide fuel. But its feasibility remains uncertain as the 2011 Fukushima nuclear crisis heightened public concerns over the use of nuclear power.
A further increase in plutonium could raise concerns in the international community for its potential for diversion to nuclear weapons.
In June, Japan was found to have failed to include the 640 kg of unused plutonium in its annual report to the International Atomic Energy Agency in 2012 and 2013 in what experts said was an inappropriate omission.
The plutonium was contained in MOX fuel loaded in March 2011 into the No. 3 reactor of Kyushu Electric Power Co.’s Genkai nuclear plant in southwestern Japan during its regular checkup, but has been left there unused as the reactor could not restart following the disaster at Tokyo Electric Power Co.’s Fukushima Daiichi complex.
The Japan Atomic Energy Commission, which is in charge of the issue, insisted at that time that fuel inside reactors has been treated as “being used” and hence exempt from reporting to the IAEA.
Of the 47 tons of plutonium Japan owns, about 10.8 tons have been stored in the country and the remaining portion kept in Britain and France, where spent nuclear fuel from Japanese power plants has been reprocessed.