LOS ANGELES (AP) — An environmental group asked federal regulators Tuesday to idle California's last operating nuclear plant to review whether its reactors can withstand strong shaking from nearby earthquake faults.
Friends of the Earth, an advocacy group critical of the nuclear power industry, filed a petition with the Nuclear Regulatory Commission asking for a hearing on seismic risks at the Diablo Canyon plant. The group says the plant is violating its federal operating license.
Neighboring faults, one about 650 yards from the plant, pose "a serious safety risk to the public and the environment," the 92-page petition said.
The NRC, which oversees the nation's commercial nuclear power industry, and Diablo Canyon owner Pacific Gas and Electric Co., have said the nearly three-decade-old reactors, which produce enough electricity for more than 3 million people annually, are safe and that the facility complies with its operating license, including earthquake safety standards.
A statement from NRC spokeswoman Lara Uselding said the agency would review the petition. PG&E spokesman Blair Jones said the environmental group "is mischaracterizing the facts."
"The plant was built with seismic safety in mind ... and is designed to withstand the largest potential earthquakes that could occur in the region," Jones said. "Major components can continue to perform their safety functions during and after" a strong earthquake.
The petition was filed after The Associated Press disclosed Monday that a senior federal nuclear expert is urging the NRC to shut down the seaside plant until it can determine whether the twin reactors can withstand shaking from any of several nearby faults.
Michael Peck, who for five years was the NRC's lead inspector at the plant, says in a 42-page, confidential report that the NRC is not applying the safety rules it set out for the plant's operation.
The document, which was obtained and verified by AP, does not say the plant itself is unsafe. Instead, according to Peck's analysis, no one knows whether the facility's key equipment can withstand strong shaking from those faults — the potential for which was realized decades after the facility was built.
The petition echoes those concerns. The group argues the reactors located between Los Angeles and San Francisco should remain closed until a rigorous safety review is completed and PG&E amends its license.
Following the AP report, the Senate Environment and Public Works Committee announced it would hold hearings into how the NRC has handled Peck's recommendation, which was filed in July 2013.
The conflict between Peck and his superiors stems from the 2008 discovery of the Shoreline fault, which snakes offshore about 650 yards from the reactors. A larger crack, the Hosgri fault, had been discovered in the 1970s about 3 miles away, after the plant's construction permits had been issued and work was underway. Surveys have mapped a network of other faults north and south of the reactors.
According to Peck's filing, PG&E research in 2011 determined that any of three nearby faults — the Shoreline, Los Osos and San Luis Bay — is capable of producing significantly more ground motion during an earthquake than was accounted for in the design of important plant equipment.
The NRC says the Hosgri fault presents the greatest earthquake risk and that Diablo Canyon's reactors can withstand the largest projected quake on it. But Peck writes that after officials learned of the Hosgri fault's potential shaking power, the NRC never required changes in the structural strength of many systems and components in the plant.