Update on San Onofre Nuclear Plant – backup emergency generators also flawed

NRC OVERSIGHT HAS FAILED AT SAN ONOFRE

This letter was sent to U.S. Nuclear Regulatory Commission Chairman Gregory Jaczko, with a copy to The Orange County Register:

Dear Chairman,

We were stunned to learn recently that for nearly three decades, the San Onofre nuclear reactors have been operating with inherently flawed backup emergency diesel generators, flaws that could have caused these generators to shut down as a result of a major earthquake. According to documents submitted to the NRC on May 14 of this year by Southern California Edison, the operator of the San Onofre plant, the effect of a major seismic event on the high-frequency sensors that would trigger the shutdown of the backup generators had not been analyzed. Upon discovering this issue, the sensors were immediately turned off, indicating significant safety concerns.

Allowing the San Onofre nuclear reactors, located directly next to major fault lines, to operate with such a fundamental safety issue unexamined for three decades is a dramatic failure on the part of the commission. The loss of both offsite and onsite power, or station blackout, is the very condition that led to the nuclear catastrophe at Fukushima Daiichi (Japan). As you are aware, the seismic vulnerability of nuclear reactors has become an even more urgent issue in the aftermath of the Fukushima Daiichi accident. We are well aware of your particular concerns in this area. Tuesday’s news underscores the need for immediate and urgent action.

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