USA is littered with nuclear sites that could face danger from natural disasters

The U.S. has more than 3,700 nuclear warheads stockpiled around the country and 54 nuclear power plants in 28 states. And while nuclear energy facilities and weapons sites have always been built with potential natural disasters in mind — whether it was earthquakes, hurricanes, tornadoes or floods — those disasters stress their support systems and create new worries for safety experts.