PG&E commits to finishing 3-D seismic studies related to Diablo Canyon before seeking final issuance of renewed licenses

Utility seeks to address public concern regarding seismic safety

Release Date: April 11, 2011

AVILA BEACH, Calif. – Pacific Gas and Electric Company (PG&E) today announced that it plans to accelerate completion of advanced 3-D seismic studies related to the Diablo Canyon Nuclear Power Plant. PG&E also formally asked the Nuclear Regulatory Commission (NRC) today to delay final action on the utility’s on-going license renewal application until PG&E submits the findings to the commission.

"In the wake of the tragic accident at Japan's Fukushima Daiichi nuclear plant, we know that many of our customers and government partners are concerned and want to know more about the seismic characteristics surrounding the Diablo Canyon Nuclear Power Plant," said John Conway, PG&E's Senior Vice President of Energy Supply and Chief Nuclear Officer. "Because we live in a seismically active region, PG&E takes care in all its operations, especially at Diablo Canyon, to analyze and address seismic risks. In the aftermath of the Japanese earthquake and the resulting tsunami, we are working even more closely with various governmental permitting agencies to accelerate the plant's advanced seismic research."

Conway added, "As PG&E works toward this objective, we are asking the Nuclear Regulatory Commission to withhold issuance of PG&E's renewed operating licenses, if approved, until after this research is completed and the findings are submitted to the commission."

"We recognize that many in the public have called for this research to be completed before the NRC renews the plant’s licenses," said Conway. "We are being responsive to this concern by seeking to expeditiously complete the 3-D seismic studies and provide those findings to the commission and other interested parties so that they may have added assurance of the plant’s seismic integrity."

PG&E is the only utility in the country that employs a seismic department staffed with experts. The scientific staff continually studies earthquake faults in the region of the power plant and global seismic events as part of the plant's comprehensive safety program. In November 2008, the United States Geological Survey, working in partnership with PG&E's geosciences department, discovered the new shoreline fault zone and PG&E evaluated whether that new feature presented a safety risk to the plant. PG&E submitted its evaluation to the NRC under the commitment of its current operating licenses. PG&E's evaluation confirmed the plant has adequate safety margin to withstand maximum ground motions postulated to occur from faults in the region, including the shoreline fault.

PG&E plans to undertake high-energy offshore 3-D studies of the shoreline fault's deeper regions as soon as it obtains necessary permits from various regulatory agencies, including the State Lands Commission, California Coastal Commission and County of San Luis Obispo. To address public concern regarding the seismicity of the area surrounding Diablo Canyon, the utility seeks to expedite this permitting process so it can begin this phase of studies as soon as possible. PG&E also plans to conduct significant research along the Los Osos Valley and in the Irish Hills. The company will share the results with local jurisdictions in order to enhance their knowledge of the seismic characteristics of the region for their emergency planning and building standards requirements.

"Even after we have completed these advanced studies, our geoscientists will continue their ongoing seismic research to give us, our regulators and the public confidence that the plant remains safe," said Conway. "It is only by continuously demonstrating that public safety is our highest priority that we will continue to earn the right to supply clean, reliable and affordable power to millions of California homes and businesses."

Pacific Gas and Electric Company, a subsidiary of PG&E Corporation (NYSE:PCG), is one of the largest combined natural gas and electric utilities in the United States. Based in San Francisco, with 20,000 employees, the company delivers some of the nation's cleanest energy to 15 million people in Northern and Central California. For more information, visit