The federal Nuclear Regulatory Commission says it does not have a timeline for when it will formally respond to a report by a former resident inspector at Diablo Canyon nuclear power plant who recommended that the plant be shut down until it can be proven that it can safely withstand an earthquake along the newly discovered Shoreline fault.
Michael Peck, former senior resident inspector at the plant, filed a differing professional opinion with the NRC, criticizing the agency’s 2009 review of the seismic safety implications of the Shoreline fault that runs just offshore of the plant. The agency refused to release the report, but a leaked copy was released Monday by the environmental group Friends of the Earth.
In light of the report, a U.S. Senate committee led by U.S. Sen. Barbara Boxer is planning hearings on earthquake risks at Diablo Canyon, according to The Associated Press. Boxer, who chairs the Environment and Public Works Committee, says that the NRC is failing to do its job to protect public safety. She also says she’s alarmed that the agency hasn’t acted even though Peck’s recommendation was made a year ago.
Peck, a senior technical training instructor with the NRC, filed the report in July 2013, and the agency has not made a formal response. Until the formal response is complete, the agency cannot comment on Peck’s report, said Lara Uselding, NRC spokeswoman.
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The NRC and plant owner Pacific Gas and Electric Co. continue to maintain that the plant can withstand even the most powerful quake that the Shoreline and other faults surrounding the plant can produce.
“The NRC has exhaustively analyzed and resolved this issue, concluding that PG&E’s ongoing analysis of nearby faults and our engineering assessment of the facility demonstrate that Diablo Canyon is seismically safe,” said Blair Jones, PG&E spokesman.
News of the leaked report was greeted with concern locally. San Luis Obispo County Supervisor Bruce Gibson, a seismologist by training, said he has not seen the report yet.
“Clearly there is some explaining and analysis to do,” he said. “This deserves to be very thoroughly reviewed and considered.”
Peck was senior resident inspector at the plant from 2008 to 2012 when he was transferred to the agency’s technical training center in Chattanooga, Tenn. Peck was unavailable Monday to comment on his report.
Peck first raised his concerns in September 2010 when he filed non-concurrence papers and later elevated them to differing professional opinion, the highest level of official dissent within the agency. His report said that pipes and other important plant equipment at the plant may not be able to withstand the maximum shaking that could be generated by the Shoreline fault, which runs 2,000 feet offshore of the plant.
“We find it completely disgraceful that the NRC hid these concerns for all these years,” said Jane Swanson, spokeswoman for the antinuclear group San Luis Obispo Mothers for Peace.
Peck recommended that Diablo Canyon be shut down until it can be proved that the plant could withstand a quake along the Shoreline fault, a process that could require an amendment to the plant’s current operating license.
“The new seismic information resulted in a condition outside the bounds of the existing Diablo Canyon design basis and safety analysis,” Peck wrote in his report. “Continued reactor operation outside the bounds of the NRC approved safety analyses challenges the presumption of nuclear safety.”
Earthquakes have long been the main safety concern at Diablo Canyon.
The plant is ringed by many faults including the Hosgri, Shoreline, Los Osos and San Luis Bay faults. The plant is engineered to withstand a 7.5-magnitude quake on the Hosgri fault, which is considered the biggest fault.
PG&E has filed a request to extend Diablo Canyon’s operating licenses for an additional 20 years. At the request of county supervisors and others, the utility put the license renewal application on hold while it conducted extensive seismic studies of the plant.
These included plans for high- and low-energy offshore seismic surveys. The low-energy surveys were complete, but the state Coastal Commission blocked the high-energy surveys over environmental concerns in 2012.
The utility’s geosciences team is expected to finish its analysis later this year. PG&E will decide whether it will continue pursuing license renewal after the seismic studies are reviewed by a state Public Utilities Commission peer-review panel.