Nuclear Regulatory Commission Sides with Environmental Groups to Review Seismic Risks at Diablo Canyon Nuclear Plant

By Mothers for Peace, posted on Independent.com
Published on Aug 30, 2024

Photo Credits: Flickr

San Luis Obispo, CA, August 29, 2024 — In a notable and unexpected move, the Nuclear Regulatory Commission’s (NRC) Petition Review Board (PRB) has agreed to reevaluate the seismic risks at Diablo Canyon Nuclear Power Plant. This action follows compelling testimony from seismic expert Peter Bird, Ph.D, prompting the board to prioritize safety concerns at the aging facility situated atop and adjacent to multiple thrust faults.

Mothers for Peace (MFP), Environmental Working Group (EWG), and Friends of the Earth (FoE) commend the NRC’s responsiveness, which aligns with the recommendations outlined in their March 4, 2024, petition. The NRC’s decision marks a critical advancement in ongoing efforts to ensure the safety and integrity of the nuclear plant on California’s Central Coast.

Dr. Peter Bird, Professor Emeritus of Geosciences at UCLA, provided pivotal testimony on behalf of the environmental groups during a July 17 meeting with the NRC’s PRB. He presented new data on the significant seismic risks posed by thrust faults near Diablo Canyon—risks largely overlooked by PG&E’s assessments. For a detailed explanation by Dr. Bird of the seismic dangers facing Diablo Canyon, please watch this video.

In an August 28 letter, the PRB confirmed its decision to review the seismic risks, stating that the PRB would investigate the following issues: 

• PG&E’s 2012 study fails to fully account for the threat posed by thrust faults beneath Diablo Canyon and the nearby Irish Hills. The study primarily focuses on other types of earthquakes, overlooking this significant hazard.

• PG&E’s 2018 estimate of the risk of core damage from an earthquake is too low. Updated seismic data suggest this risk is much higher than previously believed.

• A magnitude 7.5 earthquake in Japan in January 2024, similar to what could occur near Diablo Canyon, underscores the need for a reassessment. The faults in Irish Hills near the plant are capable of generating large earthquakes approximately every 715 years.

• PG&E’s study neglects the possibility of an offshore thrust fault that could trigger a magnitude 7.5 earthquake near Diablo Canyon, akin to the recent quake in Japan.

Diane Curran, legal counsel for Mothers for Peace, said: “This is a major step forward and a clear acknowledgment that our concerns are valid.” She added, “It’s rare for the PRB to review a petition of this nature, highlighting the significant expertise of Dr. Bird and the seriousness of the seismic risks involved.” 

Earthquake risks at Diablo Canyon have been a longstanding public concern since the reactors were constructed in the 1970s. The NRC’s recent decision to allow PG&E to continue operating the Diablo Canyon reactors for an indefinite period beyond their retirement dates of 2024 and 2025, until the agency decides whether to renew their operating licenses, was made without considering these risks. The validity of that decision is now called into question by the PRB’s acceptance of the groups’ concerns.  

Caroline Leary, general counsel for the Environmental Working Group, emphasized the significance of the NRC’s decision. “The NRC’s acceptance of our petition highlights the serious seismic risks at Diablo Canyon and questions the rationale behind extending the plant’s operation under Senate Bill 846, signed by Gov. Newsom,” she said. “This is a critical step in holding PG&E accountable for the plant’s safety and protecting Californians from potential disaster.”

“We are pleased with the NRC’s decision to take a closer look at the risks that an earthquake could pose at Diablo Canyon,” said Hallie Templeton, Legal Director for Friends of the Earth. “We will watch closely as NRC conducts this renewed analysis and will not shy away from continuing to fight for public engagement around the safety of this aging nuclear power plant.”

Linda Seeley, spokesperson for Mothers for Peace said, “No license extension should be granted until the earthquake faults are thoroughly analyzed.”