Several people contacted by the Inspector General's Office of the Nuclear Regulatory Commission said they had been contacted in connection to an investigation as to whether the NRC colluded with Pacific Gas & Electric to downplay concerns that the Diablo Canyon nuclear power plant could be unsafe in the event of a serious earthquake occurring along recently discovered seismic fault lines.
PG&E has repeatedly asserted that the two-unit facility at San Luis Obispo in California is safe.
Critics of the plant point out that several potentially dangerous fault lines have been discovered in the area since 1968, the year construction on the power plant began. The major concern involves the Hosgri Fault, which is capable of rocking the ground with vibrations as violent as 0.75 times the force of gravity. The plant, however, was designed to withstand an earthquake force of up to 0.4 times the force of gravity.
That fault line, three miles offshore, was discovered in 1971. Another, the Shoreline Fault, was found in 2008 and it is less than half a mile from the power facility, which includes two Westinghouse four-loop 3,411 MWt pressurized water reactors enclosed in dry ambient pressure containment vessels .
Allegedly, concerns brought up by former NRC inspector Michael Peck were treated dismissively, the San Francisco Chronicle reported.
Allegedly, the NRC rejected a request from PG&E to amend its operating license to reflect the plant's ability to remain safe under earthquake tremors 0.75 times the force of gravity, but then allowed PG&E to alter its safety report without due process. In addition, new safety tests conducted by the utility were more lenient than the ones originally used to gauge the plant's ability to withstand an earthquake, according to challengers who have filed a lawsuit that says the original testing methods are the only ones that should be valid.
Friends of the Earth, which filed the lawsuit, also contends that the utility and the regulator colluded to allow the company to file the safety report using the lenient testing methodology.
Part of the evidence for that allegation hinges on a PG&E updated seismic safety report being released the same day that the NRC rejected former inspector Peck's assertion that the plant was in violation of its license.
The NRC declined to comment on the investigation. A spokeswoman for Friends of the Earth said the group was "heartened" that its concerns were being taken seriously.