What is the Diablo Canyon Independent Peer Review Panel (IPRP)? 

In 2006, the California legislature enacted Assembly Bill (AB) 1632 which directed the California Energy Commission (CEC) to assess the potential vulnerability of the state’s nuclear plants to major disruptions, including seismic events. The CEC’s resulting AB 1632 report recommended that the utilities perform enhanced seismic studies with two- and three-dimensional seismic surveys in the areas onshore and offshore from DCPP and SONGS. In D.10-08-003, the CPUC approved funding for DCPP seismic studies and established the Independent Peer Review Panel (IPRP) to review them. The IPRP is tasked with providing expertise to the Commission while also assuring the public that the studies are being performed in an appropriate manner. Passage of AB 361 in October 2015 extended funding for the IPRP through 2025, the last year of the current operating licenses.

The IPRP is comprised of technical experts from the CEC, California Geological Survey, California Coastal Commission, California Seismic Safety Commission, and the County of San Luis Obispo. PG&E submits its seismic studies to the IPRP for review, the most recent of which was its Central Coastal California Seismic Imaging Project (CCCSIP) report, submitted in September 2014. Following the submission of these studies, the IPRP convenes for public meetings to review and discuss the results, and ultimately submits an IPRP Report. Since the IPRP’s inception it has issued ten reports, each available by clicking the following links:

PG&E issues responses to these reports which are available below (NOTE: PG&E did not formally respond to Report Nos. 1 and 4):

The IPRP meets periodically. The date, time, and location of future meetings can be found by visiting the CPUC calendar.

May 5, 2023: IPRP Comments and Questions for the Fact Finding Reports approved at the DCISC's February 15-16, 2023 meeting.

May 5, 2023: PG&E IPRP Long-Term Seismic Update

As mentioned above, AB 1632 also recommended seismic studies for SONGS. In D.12-05-004, the CPUC approved funding for SONGS seismic studies and established the Independent Peer Review Group (IPRG), with similar responsibilities as the IPRP. With the closure of SONGS in 2013, the IPRG is no longer active.

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