These days we don't hear too much about the ailing nuclear reactors in Fukushima Japan, but make no mistake the situation at the Fukushima Daiichi power plant remains very serious.

Now the U.S. is dealing with it's own potentially serious nuclear situation in Nebraska.  The Nuclear Regulatory Commission (NRC) said the breach in the 2,000-foot inflatable berm around the Fort Calhoun station occurred around 1:25 a.m. local time.

More than 2 feet of water rushed in around containment buildings and electrical transformers at the 478-megawatt facility located 20 miles north of Omaha.  Reactor shutdown cooling and spent-fuel pool cooling were unaffected, the NRC said.

The plant, operated by the Omaha Public Power District, has been off line since April for refueling. Crews activated emergency diesel generators after the breach, but restored normal electrical power by Sunday afternoon, the NRC said.  Buildings at the Fort Calhoun plant are watertight, the agency said. It noted that the cause of the berm breach is under investigation.