Letters to the Editor

Up-to-date seismic data needed

Tonight, the Nuclear Regulatory Commission will present its assessment of the Shoreline Fault Report developed in 2011 by PG&E. The public is invited to listen and to make comments at this open meeting at the Embassy Suites in San Luis Obispo from 7 to 9 p.m.

The Hosgri Fault, three miles from Diablo Canyon, was discovered in 1969 and classified by the United States Geological Survey as a “major, active” fault. NRC rules prohibit nuclear plants being near active earthquake faults; nonetheless, PG&E was granted an operating license partly on the condition they continue investigating local seismology.

In 2008, an additional alarm was sounded when a geophysicist at the USGS unearthed the Shoreline Fault, which is only 600 meters from the Diablo Canyon plant. PG&E concluded in 2011 that the Shoreline Fault could not produce an earthquake over 6.7, reassuring the public that we need not worry about the possibility of a radioactive release from Diablo Canyon’s reactors or the 2,000 metric tons of highly radioactive waste that are stored onsite. The tone of PG&E’s Shoreline Fault Report is confident, assuring us that we are safe.

The technological basis upon which PG&E’s Shoreline report was predicated, however, has been superceded by several eminent geologists, seismologists and geodesists, who have been gathering data using new information and techniques to analyze seismic hazards to the nuclear power plant. The committee doing the independent research is the Senior Seismic Hazard Analysis Committee, and its conclusions will be presented to the public in 2013.

Geologists on this committee have indicated that there is a distinct possibility that the Shoreline Fault may be seismically linked to other major earthquake faults in our area, creating a rupture hundreds of kilometers in length. An earthquake on the Shoreline Fault could produce about 70 percent greater vibratory ground motion on certain critical safety components than allowed by the present standard.

Why is PG&E urging the NRC to accept the conclusions of its outdated Shoreline report before the SSHAC report has been filed? Mothers for Peace is convinced that PG&E would like to plead its case for relicensing of the Diablo plant relying on its own report. Mothers for Peace feels strongly that the most up-to-date, independently gathered, scientific data must be used as a basis for PG&E’s request for relicensing.

The Nuclear Regulatory Commission has a responsibility to our community to rely heavily on the more complete findings of the Senior Seismic Hazard Analysis Committee, rather than on PG&E’s in-house Shoreline Fault Report.

Sherry Lewis is a spokesperson for San Luis Obispo Mothers for Peace. For a more in-depth analysis, go to mothers http://forpeace.org .