THE HAGUE - Japan will turn over hundreds of kilograms of sensitive atomic material of potential use in bombs to the United States to be downgraded and disposed of, the two countries' leaders said ahead of a nuclear security summit on Monday.
China had voiced concern earlier this year about Japan's holding of plutonium but Washington and the United Nations nuclear agency in Vienna have made it clear they are not worried about the way Tokyo is handling the issue.
US President Barack Obama and Japanese Prime Minister Shinzo Abe said in a joint statement that all highly enriched uranium (HEU) and separated plutonium would be removed from the Fast Critical Assembly at the Japan Atomic Energy Agency.
Like uranium, plutonium is used to fuel nuclear power plants and for research purposes, but can also provide material for nuclear weapons. A Fast Critical Assembly is used for studying the nuclear physics of so-called fast reactors.
"This effort involves the elimination of hundreds of kilograms of nuclear material, furthering our mutual goal of minimizing stocks of HEU and separated plutonium worldwide, which will help prevent unauthorized actors, criminals, or terrorists from acquiring such materials," said the joint statement released by the White House.
"This material, once securely transported to the United States, will be sent to a secure facility and fully converted into less sensitive forms."
The announcement was made in The Hague shortly before leaders from 53 countries, including Obama and Abe, were due to hold a two-day summit aimed at preventing al Qaeda-style militant groups from acquiring nuclear bombs.
It will be the third such summit since 2010, when it was held in Washington at Obama's initiative. Minimizing civilian uses of HEU or plutonium is seen as vital in reducing the threat of nuclear terrorism.
CHINESE "EXTREMELY CONCERNED"
The plutonium, the statement said, would be prepared for "final disposition" and the HEU would be downblended to low-enriched uranium for civilian purposes.
Last month, China said it was "extremely concerned" by a report that Japan has resisted returning to the United States more than 300 kg (660 lb) of mostly weapons-grade plutonium.
Japan's Kyodo news agency at the time said the United States had pressed Japan to give back the nuclear material, which could be used to make up to 50 nuclear bombs. Japan had balked, but finally given in to US demands, Kyodo said.