Japan pledges to reduce plutonium, but doesn't say how

Japan's nuclear policy-setting panel today approved revised guidelines on plutonium use, putting a cap on its stockpile and pledging to eventually reduce it to address international concerns, but without giving a specific timeline or targets.

The Japan Atomic Energy Commission's guidelines call for some government oversight to carefully regulate operation of the Rokkasho reprocessing plant in northern Japan when it starts up in three years so the amount of extracted plutonium doesn't spike.

Despite security concerns raised by Washington and others, the stockpile isn't decreasing due to difficulties in achieving a full nuclear fuel recycling program and slow restarts of reactors amid setbacks from the 2011 Fukushima disaster.

The guidelines, updated for the first time in 15 years, also urge Japanese utility operators to steadily consume plutonium reprocessed overseas, but does not elaborate on how that works out with additional plutonium from Rokkasho.

The guidelines say Japan's stockpile should not exceed "the current level." Japan now has about 47 tons of separated plutonium 11 tons at home, and 36 tons in Britain and France, where spent fuel from Japanese nuclear plants has been reprocessed and stored because Japan is not able to reprocess it into MOX fuel at home.

The amount is enough to make about 6,000 atomic bombs. Japan reprocesses spent fuel, instead of disposing it as waste, to extract plutonium and uranium to make MOX fuel for reuse, while the U.S. discontinued the costly programme.

Allowed under international safeguard rules, Japan is the only non-nuclear weapons state that separates plutonium for peaceful uses, though the same technology can make atomic bombs.

The stockpile largely comes from overly optimistic projections that had relied on the Monju plutonium reactor, and its failure has forced Japan to resort to conventional light water reactors as the only realistic option to burn it.

Seven years after the Fukushima meltdown, five of the 38 workable reactors have restarted, but only three of them are approved as MOX compatible and together they consume just over 1 ton of plutonium annually.

Japan has long denied any possible misuse of the material and reprocessing technology, and has pledged to not possess plutonium that does not have a planned use. But its failure to reduce the stockpile of separated plutonium doesn't look good, especially as the U.S. wants North Korea to get rid of its nuclear weapons and abandon reprocessing capabilities.

China has announced plans to build a similar reprocessing plant with France, while South Korea has expressed interest in reprocessing, raising a concern over future plutonium concentration in the region, experts say.