NRC file photo of triple reactor Oconee nuclear power plant in South CarolinaAs reported by the Huffington Post, two U.S. Nuclear Regulatory Commission (NRC) staff engineers have blown the whistle on a long lasting agency cover up of the catastrophic risk to atomic reactors posed by the failure of upstream dams:

"...[T]he [NRC] engineer is among several nuclear experts who remain particularly concerned about the Oconee plant in South Carolina [photo, left], which sits on Lake Keowee, 11 miles downstream from the Jocassee Reservoir. Among the redacted findings in the July 2011 report -- and what has been known at the NRC for years, the engineer said -- is that the Oconee facility, which is operated by Duke Energy, would suffer almost certain core damage if the Jocassee dam were to fail. And the odds of it failing sometime over the next 20 years, the engineer said, are far greater than the odds of a freak tsunami taking out the defenses of a nuclear plant in Japan.

"The probability of Jocassee Dam catastrophically failing is hundreds of times greater than a 51 foot wall of water hitting Fukushima Daiichi," the engineer said. "And, like the tsunami in Japan, the man‐made 'tsunami' resulting from the failure of the Jocassee Dam will –- with absolute certainty –- result in the failure of three reactor plants along with their containment structures.

"Although it is not a given that Jocassee Dam will fail in the next 20 years," the engineer added, "it is a given that if it does fail, the three reactor plants will melt down and release their radionuclides into the environment."

In addition to Oconee, other nuclear power plants in the U.S., including Fort Calhoun, NE, which was inundated by historic floods on the Missouri River in summer 2011, are at risk of upstream dam breaks causing "inland tsunamis" (a phrase coined by Arnie Gundersen of Fairewinds Associates over a year ago) and reactor meltdowns.