Nuclear Regulatory Commission Engineers Charge Government Coverup: Reactor Meltdown “Absolute Certainty” If Dam Fails … 100s of Times More Likely than Tsunami that Hit Fukushima
Washington’s Blog 
September 18, 2012
Numerous American nuclear reactors are built within flood zones on the Mississippi and Missouri rivers (indicated in red):
No wonder, nuclear expert Arnie Gundersen said :
Sandbags and nuclear power shouldn’t be put in the same sentence.
And the Huntsville Times wrote  in an editorial last year:
A tornado or a ravaging flood could just as easily be like the tsunami that unleashed the final blow [at Fukushima as an earthquake].
The Hill notes  today:
An engineer with the Nuclear Regulatory Commission (NRC) says the agency has withheld documents showing reactor sites downstream of dams are vulnerable to flooding, and an elevated risk to the public’s safety.
Richard Perkins, an NRC reliability and risk engineer, was the lead author on a July 2011 NRC report detailing flood preparedness. He said the NRC blocked information from the public regarding the potential for upstream dam failures to damage nuclear sites.
Perkins, in a letter  submitted Friday with the NRC Office of Inspector General, said that the NRC “intentionally mischaracterized relevant and noteworthy safety information as sensitive, security information in an effort to conceal the information from the public.”The Huffington Post  first obtained the letter.
He added the NRC “may be motivated to prevent the disclosure of this safety information to the public because it will embarrass the agency.” He claimed redacted documents in a response to a Freedom of Information Act request showed the NRC possessed “relevant, notable, and derogatory safety information for an extended period but failed to properly act on it.”
The report  in question was completed four months after … Fukushima.
The report concluded that, “Failure of one or more dams upstream from a nuclear power plant may result in flood levels at a site that render essential safety systems inoperable.”
Eliot Brenner, an NRC spokesman, told The Hill on Monday that the flooding report has been rolled into the agency’s “very robust” body of work on lessons learned post-Fukushima. He declined to comment directly on the letter.
“We cannot discuss the reasons for the redactions,” Brenner said. “The NRC coordinated with the Department of Homeland Security, the Army Corps of Engineers and FERC on the necessary redactions.”
Huffington Post reported :
In a letter submitted Friday afternoon to internal investigators at the Nuclear Regulatory Commission, a whistleblower engineer within the agency accused regulators of deliberately covering up information relating to the vulnerability of U.S. nuclear power facilities that sit downstream from large dams and reservoirs.
These charges were echoed in separate conversations with another risk engineer inside the agency who suggested that the vulnerability at one plant in particular — the three-reactor Oconee Nuclear Station near Seneca, S.C. — put it at risk of a flood and subsequent systems failure, should an upstream dam completely fail, that would be similar to the tsunami that hobbled the Fukushima Daiichi nuclear facility in Japan last year.
The engineer is among several nuclear experts who remain particularly concerned about the Oconee plant in South Carolina, 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 the letter, a copy of which was obtained by The Huffington Post, Richard H. Perkins, a reliability and risk engineer with the agency’s division of risk analysis, alleged that NRC officials falsely invoked security concerns in redacting large portions of a report detailing the agency’s preliminary investigation into the potential for dangerous and damaging flooding at U.S. nuclear power plants due to upstream dam failure.
Perkins, along with at least one other employee inside NRC, also an engineer, suggested that the real motive for redacting certain information was to prevent the public from learning the full extent of these vulnerabilities, and to obscure just how much the NRC has known about the problem, and for how long.
“What I’ve seen,” Perkins said in a phone call, “is that the NRC is really struggling to come up with logic that allows this information to be withheld.”