Japan to US: Have Our Nuclear Cache

A big win for President Obama: Japan today announced it will hand over some 700 pounds of weapons-grade plutonium as well as an estimated 450 pounds of highly enriched uranium to the US, reports the New York Times, which calls it the "biggest single success in President Obama's five-year-long push to secure the world's most dangerous materials." Though the research stockpile, acquired in the '60s, amounts to only a sliver of the country's supply, it could be used to make dozens of nuclear weapons and had long been considered vulnerable; the Times recalls a reporter's 1990s visit to the Tokaimura storage facility, which was then staffed by unarmed guards.

The announcement comes as leaders gather today at the Hague for Obama's third nuclear security summit meeting; they'll discuss how to prevent outside hands from accessing countries' supplies, Bloomberg Businessweek notes. "This material, once securely transported to the United States, will be sent to a secure facility and fully converted into less sensitive forms," a joint statement from the two countries reads, per Reuters. The Times adds 13 nations have eliminated their nuclear arsenals since the talks began in 2010; many more have built up security. Japan certainly isn't eliminating its stockpiles though; it claims some nine tons of plutonium, and intends to open a nuclear plant capable of producing even more this fall. (More Japan stories.)