`` Given the catastrophic consequences of even a single attack , we can not be complacent . '' ` ` It has not just been talk , it has been action , '' he said of the nuclear summit . Ukraine : The U.S. is doing its part , too , with installation of more nuclear detection equipment . Ukraine gave up its highly radioactive uranium in 2010 .
` ` It has not just been talk , it has been action , '' he said of the nuclear summit . Ukraine : The U.S. is doing its part , too , with installation of more nuclear detection equipment . Ukraine gave up its highly radioactive uranium in 2010 .