NRC preliminary assessment issued for Diablo Canyon seismic safety study

Pacific Gas and Electric (PG&E) said Feb. 1 that the Nuclear Regulatory Commission (NRC) has informed the company that it has completed its preliminary review of a new earthquake study for Diablo Canyon nuclear plant.

NRC has determined that the information is suitable to use in performing the next phase of the NRC’s regulatory process, the utility said.

Due to the robust seismic design of Diablo Canyon, and the safety margins built into the design, PG&E does not anticipate the need for any seismic-related enhancements at the nuclear station in Avila Beach, Calif.

PG&E submitted the study to the NRC in March of 2015 following years of analysis by independent experts. The study re-evaluated earthquake potential in the vicinity of Diablo Canyon, which PG&E then compared against the plant’s design to ensure it’s safe to operate.

In its communication to PG&E, the NRC stated that it will complete its evaluation of the study by September of this year. The NRC also confirmed that the utility is to use the updated seismic information in completing by September 2017 a risk evaluation that further examines how plant structures, systems and components could be affected by the revised seismic findings.

The NRC and PG&E announced last year that this work would take place, and similar efforts are being performed at other plants around the country. The NRC will review these efforts to determine if additional actions might be required to further enhance safety at plant sites.

As part of its response to the Fukushima event in Japan in 2011, the NRC directed all U.S. nuclear utilities to perform an updated seismic hazard evaluation for their plant sites. Plants located in the eastern and central U.S. completed such analyses and provided them to the NRC in 2014. Western plants submitted their assessments in March 2015.

The process to perform the Diablo Canyon seismic hazard re-evaluation involved the use of new regulatory guidance, the latest scientific methods and models, and independent experts who publicly re-examined existing and new seismic information.

The organization Friends of the Earth has raised questions about the seismic safety at the nuclear station in California.

Each of the two pressurized water reactors (PWRs) at Diablo Canyon can generate more than 1,100 MW.

Pacific Gas and Electric, a subsidiary of PG&E Corp. (NYSE:PCG), is one of the largest combined natural gas and electric utilities in the United States.

About Wayne Barber 4201 Articles
Wayne Barber, Chief Analyst for the GenerationHub, has been covering power generation, energy and natural resources issues at national publications for more than 20 years. Prior to joining PennWell he was editor of Generation Markets Week at SNL Financial for nine years. He has also worked as a business journalist at both McGraw-Hill and Financial Times Energy. Wayne also worked as a newspaper reporter for several years. During his career has visited nuclear reactors and coal mines as well as coal and natural gas power plants. Wayne can be reached at