A Nuclear Regulatory Commission independent review panel has ruled against the opinion of NRC Senior Reactor Technical Instructor Michael Peck, who had argued that the Diablo Canyon nuclear power plant should be closed during a license amendment process.
As first detailed by the Associated Press, Peck filed a “differing professional opinion” with the prevailing opinions of the NRC and operator Pacific Gas & Electric that Diablo Canyon is properly licensed to withstand the largest jolt that could be delivered by a recently discovered seismic feature, known as the Shoreline fault. Peck, the former senior resident NRC inspector at Diablo Canyon, filed his opinion that the plant would require a license amendment to incorporate data from the Shoreline fault on July 19, 2013.
“The staff’s conclusion of a ‘reasonable assurance of safety’ does not provide an acceptable basis for not enforcing existing NRC quality assurance, safety analysis, and license requirements,” Peck wrote.
He further recommended that Diablo Canyon’s two reactors be shut down until PG&E successfully completed a license amendment.
The panel concluded that “an amendment to the license was not required because the Shoreline fault zone ground motions do not exceed the levels evaluated in the [Diablo Canyon] design and licensing.”
In a Sept. 9 memo to Peck, NRC Executive Director for Operations Mark Satorius said that he reviewed Peck’s opinion and appeal, but didn’t agree with the conclusions about Diablo Canyon’s licensing basis. Satorius said Peck “narrowly defined the licensing basis and approved methodology for seismic evaluations as being limited to the methodology associated with the [Double Design Earthquake] from the original license application.”
He said Peck didn’t include proper information about the previously known Hosgri fault, which is larger than the Shoreline.
“While I appreciate your concern with the clarity of the Final Safety Analysis Report Update, I am unable to arrive at the same conclusion whereby you exclude the Hosgri evaluation and associated methodologies from the licensing basis,” Satorius said.
Peck previously told New Times he was prohibited from commenting about NRC pre-decisional documents.
The same day the NRC released its decision on Peck’s differing opinion, PG&E announced that it had submitted a long-awaited report to the NRC after years of studying the seismic hazards at Diablo Canyon. As of press time, New Times was unable to review the report in its entirety.
In a company press release, PG&E said the report concluded that “Diablo Canyon Power Plant demonstrates the facility remains seismically safe and able to withstand the largest potential earthquakes in the region.”