Jocassee Dam (left) plugs the Keowee River in South Carolina about 10 miles upstream from Oconee
Nuclear Power Station (right) and its three nuclear reactors. (Duke Energy photos)

A quarter of the 104 nuclear power reactors in the United States may be at risk to a newly identified safety hazard. It’s a concern has generated eerie comparisons with the tsunami that crippled reactors at Fukushima, Japan.

The issue is whether the crumbling conditions at many of the nation’s dams pose unacceptably high risks to nuclear reactors located downstream.

A nuclear engineer at the federal Nuclear Regulatory Commission says the agency has completed a study which says they might. If so, the study undermines the NRC’s longstanding claim that nuclear plants across the United States are being operated in a safe manner. Concerned that the report contains information that might trigger alarms under the Patriot Act, the NRC is refusing to make the report public, repeatedly rejecting efforts by Cascadia Times to obtain it via the federal Freedom of Information Act.

As we approach the one-year anniversary of the nuclear accident at Fukushima, the NRC’s refusal to release the report is sending engineers at the agency into a tizzy.

About a quarter of the industry is potentially affected by upstream dam failures,” an NRC safety engineer, who has a copy of the report, said in an email to Cascadia Times. The engineer, who asked not to be identified, works in the NRC’s nuclear safety division at its headquarters in Rockville, Md.

In January, Cascadia Times filed a request under the Freedom of Information Act for a copy of the report, and since has been told not to expect to receive a clean copy. An NRC spokesman said the agency would release only a “heavily redacted” version.

Evaluations to this point have not identified any immediate safety concerns,” was all NRC press spokesman Scott Burnell would say about the report. He declined to comment on whether the agency has any long term concerns about the nation’s nuclear plants, and made clear the agency was not prepared to release the report to the public. The report is entitled, “Screening Review for Generic Issue 204.”

When the NRC issues the report we expect to put out a press release which will explain the situation in more detail,” he said.

If the potential hazards faced by US nuclear plants at this point are speculative, the dangers of collapse at many of the nation’s 85,000 dams are not. Since 2000, 80 dams and levees worldwide (and 7 in the US) have collapsed, including structures in New Orleans during Hurricane Katrina.

A recent report by the Association of State Dam Safety Officials says the number of “deficient” dams – those at high risk of collapse – has tripled in recent years, increasing from 1,348 in 2001 to 4,095 in 2007. That group believes that maintenance at many crumbling dams has been delayed as a result of too little funding for repairs from Congress.

The view that dams are in worse shape today than 10 years ago may be, in part, an illusion. Officials have better information today about dam conditions than ever before. But the crumbling conditions may also be a result of inevitable aging of the concrete structures. The average age of a dam in the US is 51 years.

The US Army Corps of Engineers keeps a online database of all dams in the United States, but access to that database is limited to only government employees.

The possibility that a dam failure may impact nuclear safety has existed as long as both nuclear plants and dams coexisted near each other in the same watershed – possibly as long as 50 years when the first nuclear plants were built. But there’s no evidence that the NRC acknowledged the threat during the planning, construction and licensing of nuclear plants.

The NRC’s refusal to release the report or notify populations living near the plants has drawn criticism.

I think it is a disservice to the communities that are in peril,” said Edwin Lyman, a senior scientist with the Union of Concerned Scientists, an anti-nuclear advocacy group.

How could a dam collapse threaten a nuclear power plant? All nuclear plants are located on rivers, lakes or bays – putting them close to the water they need to cool their reactors, but potentially in harm’s way if a surge of water comes through or over an upstream dam. The meltdowns at Fukushima a year ago in March demonstrated that too much water all at once can be a very bad thing.

The onset of global warming appears to increase the likelihood of a dam failure. Storms of today are more intense than ever before, climatologists say, and the occurrence of extreme weather and flooding events are becoming more common. Floods in the Missouri River basin in June 2011 partially inundated the Fort Calhoun and Cooper nuclear plants in eastern Nebraska.

However, the rising waters did not trigger a catastrophic event, as they did earlier in the year at Fukushima. Nor did they cause a dam to collapse. But there’s no assurance we won’t be so lucky the next time major flooding occurs upstream from a nuclear plant.

Though the NRC’s dam safety report was finished in June 2011, an engineer at the NRC said it was being withheld for “homeland security” reasons.

The NRC engineer, who works at the agency headquarters in Rockville, Md., said in an email to Cascadia Times that he was “not directly” involved with the writing of the Generic Issue 204 report. “However I work with people who are. Some of the team members are thoroughly disgusted by the fact that, after over two years, (the report) has not been released yet.” The engineer asked not to be identified.

It is possible, however, to pry some information out of the NRC about dam safety hazards facing nuclear power plants. A query using the NRC’s online search engine, ADAM, reveals the name of one dam that has recently been on the NRC’s watch list: Jocassee Dam, a hydroelectric facility owned by Duke Energy on the Keowee River in the northwest corner of South Carolina.

Jocassee Dam sits about 10 miles upstream from Duke Energy’s 2500 megawatt Oconee Nuclear Station and its three reactors.

The concern is that a dam breach at Jocassee Dam would send a tsunami-like wall of water towards the three reactors at the Oconee site,” the NRC safety engineer said.

The NRC’s concerns about Jocassee Dam go back at least as far as 1992, when an NRC study predicted that a dam failure at Jocassee “could result in flood waters of approximately 12.5 to 16.8 feet deep at the Oconee Nuclear Site.” At the time, the flood protection barrier at the nuclear plant, which the NRC described as “deficient,” was unable to protect against floodwaters above 4.6 feet.

Sandra Magee, an Oconee Nuclear Station spokeswoman, said Sunday in an email that “Duke dams are safe.”

Our hydro fleet dams are routinely inspected by Duke Energy personnel. (This includes, at least every two weeks for earthen dams like Keowee and Jocassee) The dams are also inspected annually by our regulators and every five years by an independent engineering consultant,” she said.

To view Magee’s entire statement, click here.

A May 2009 document revealed that Duke Power and the NRC were still discussing a “a postulated failure of Jocassee Dam and potential flooding at Oconee Nuclear Station.” NRC and Duke Energy officials had a “closed door” meeting to discuss the issue on May 11, 2009 at NRC headquarters. Cascadia Times has submitted a FOIA request for documents describing that and other meetings but has yet to receive a response from the NRC.

Just like at Fukushima, this wall of water could disable the safety systems of three reactor plants, the NRC engineer told me in email. “This could easily lead to a three-reactor accident if the plant is not prepared to handle it.”

First in a series on dam and nuclear plant safety in the US in a post-Fukushima world. Cascadia Times will post a copy of the redacted report online if and when it is released.