Japan will turn over hundreds of kilograms (pounds) of sensitive nuclear material of potential use in bombs to the United States to be downgraded and disposed of, the two countries' leaders said as a nuclear security summit began on Monday.

 

China had voiced concern earlier this year about regional rival Japan's holding of plutonium but Washington and the United Nations nuclear agency have made it clear they are not worried about the way Tokyo is handling the issue.

 

Still, U.S. President Barack Obama and Japanese Prime Minister Shinzo Abe said that all highly enriched uranium (HEU) and separated plutonium would be removed from the Fast Critical Assembly at the Japan Atomic Energy Agency, a facility used for studying the nuclear physics of so-called fast reactors.

 

The announcement followed what the White House said were technological advances since the 1960s launch of this type of research plant that would allow it to be converted to run on fuel not potentially usable for bombs, unlike HEU or plutonium.

 

Japan, the world's only target of atomic bombs, during the final stages of World War Two, does not have nuclear weapons and has long said it will not seek to obtain them.

 

Like uranium, plutonium is used to fuel nuclear power plants and for research purposes, but can also serve as the fissile material for the core of a nuclear bomb.

 

 

The announcement was made in The Hague shortly before leaders from 53 countries, including Obama and Abe, began a two-day summit aimed at agreeing steps to help prevent al Qaeda-style militant groups from obtaining nuclear bombs.