Design changes at the San Onofre Nuclear Generating Station, which an expert says led to a small radiation leak, could be a sign that safety rules are inadequate, the nation’s top nuclear safety official suggested this week.
“We really need to take a look at this process one way or another,” Gregory Jaczko, chairman of the Nuclear Regulatory Commission, said at a North Carolina news conference, according to the Associated Press.
The plant remains shut down while officials investigate unusual tube wear that caused the leak in January. Environmental groups have alleged that plant operator Southern California Edison misled the government about the design changes to avoid a thorough safety review.
The NRC chief apparently is also not satisfied with the level of scrutiny the changes received.
“If [Edison] did it consistent with our regulations,” Jaczko said, “then maybe we need to take a look at changing our regulations.”
Under federal law, a nuclear plant’s operator is responsible for determining whether proposed design changes cause an increased safety risk. A thorough review by the NRC, which regulates nuclear plant safety in the United States, typically isn’t required unless the company running the plant concludes that the changes create a safety risk.
In the case of San Onofre’s replacement steam generators, which were brought online in 2010 and 2011, Edison declared that the design changes posed no additional safety risk, according to the NRC.
The new generators, however, developed problems. Tubes vibrated and rubbed against one another, quickly wearing them down, according to Edison and the NRC. The tubes were supposed to last decades, but in just a year, tubes in Unit 3 had worn down so much that a break occurred, causing the small radioactive leak on Jan. 31.
The leak posed no threat to workers or the public, officials say.
Since then, questions have emerged over whether Edison misrepresented the changes to avoid an independent analysis of their safety risks.
In his third report on the issue, nuclear expert Arnie Gundersen, whose work was commissioned by an environmental group, details nearly 40 safety triggers the changes should have tripped, any one of which would require a thorough review of safety risks by the government.
A key presentation that Edison gave to regulators about the planned design changes didn’t include major design alterations. Some of the omitted changes, which include removal of a structural component, should have triggered a much more thorough review by the government, said Gundersen.
Last Tuesday, U.S. Sen. Barbara Boxer (D-Calif.) requested all of the NRC’s documentation on how it approved the design changes. She chairs the Senate Committee on Environment and Public Works, which oversees nuclear energy issues.
Edison is expected to brief Senate staff this week about the changes and how they came to be approved.
Edison insists it provided “open and transparent information” to the NRC “at all times” during the approval process, though it hasn’t disputed any of Gundersen’s specific allegations.
The nuclear safety agency, meanwhile, says Edison informed it of the generator changes “in accordance with NRC requirements.”
Jaczko visited San Onofre last month and promised accountability if the design changes indeed caused the tubes to quickly wear down.
Jaczko, who is seen as the top safety advocate among the NRC’s leadership, recently announced plans to resign from his post.