A grapefruit-sized sphere of plutonium holds enough energy to wipe a city off the map. But how does that actually work? From chain reactions to hydrogen bombs, we’re breaking down the terrifying ...

Dec 23 (Reuters) - The United States and Iran traded barbs at the United Nations Security Council on Tuesday over conditions for reviving nuclear talks, with the U.S. saying it remains ready for ...

Atomic bomb survivors' groups and others have denounced a remark by a security official at the prime minister's office, who said before a pool of reporters that "Japan should possess nuclear weapons." ...