Japan and the US have extended their nuclear pact as Tokyo pledged to work to reduce its plutonium stockpile to address Washington's concern.
The 30-year pact agreed upon in 1988 has allowed Japan to extract plutonium and enrich uranium for peaceful uses even though the same technology can make atomic bombs.
Without either side requesting a review, the pact was extended Tuesday with an option by which it can be terminated by either side giving six months' notice.
The new condition, however, makes Japan's nuclear program more susceptible to US policy.
Foreign Minister Taro Kono told reporters Japan must reduce the stockpile to keep the pact in place stably.
Kono said the pact is the foundation of Japanese nuclear industry and Japan must make concrete efforts to "reduce the large amount of plutonium" to eliminate any doubts and concerns about Japan's plutonium program.
Japan has long denied any possible misuse of the material and reprocessing technology, but its failure to reduce the stockpile of weapons-grade plutonium is forcing the country to show it's taking concrete steps to do so, especially as the US wants North Korea to get rid of its nuclear weapons.
Japan's nuclear policy-setting body is compiling new guidelines to better manage and reduce the plutonium stockpile.
Japan reprocesses spent fuel, instead of disposing it as waste, to extract and recycle plutonium and uranium to make MOX fuel for reuse.
Japan now has 43kg of plutonium - most of it reprocessed and stored in France and Britain - the amount enough to make 6000 atomic bombs.
Despite security concerns and Washington's pressure, the amount isn't decreasing due to slow restarts of reactors that can burn plutonium amid setbacks from the 2011 Fukushima disaster.
Japan's plutonium stockpile largely comes from the failed plutonium-burning Monju reactor, now scrapped after hardly operating and forcing Japan to turn to conventional reactors to burn plutonium, but at a much slower pace.
Japan's key reprocessing plant at Rokkasho, northern Japan, is in final stages of safety approval ahead of its planned 2021 launch, though experts say it only adds to the stockpile.
