San Onofre Nuclear Plant: Possible 'Tampering' of Generator Discovered

NRC Chairman and Representative Darrell Issa visit with operators and SCE execs at San Onofre in April | Photo: Nuclear Regulatory Commission/Flickr/Creative Commons License

Southern California Edison (SCE), the primary owners of the San Onofre Nuclear Generating Station, announced Thursday that it has found what may be evidence of tampering in a diesel generator that makes up part of the safety system for Unit 3 of the troubled nuclear reactor complex. The company said it had found evidence of engine coolant in an oil system for an emergency backup diesel generator. The generator would have been used in an emergency to provide power to cool Unit 3, which has been offline since operators found a leak in a steam generator tube in January.

The evidence of tampering is not conclusive, and SCE's investigation of the findings is ongoing, the company reports. The company notified the Nuclear Regulatory Commission of the matter on October 30.

In a statement provided to ReWire by SCE, the utility states that it's leaving no stone unturned in finding out how the coolant got there. In a worst-case scenario, the coolant might have caused the generator to falter as plant operators were using it to help cool an overheating reactor. Fortunately, the problem was noted while Unit 3 is shut down and de-fueled.

SCE has stepped up security as a result of finding the misplaced engine coolant, and is poring over security logs and maintenance records to try to find out how and when the coolant might have gotten there. "SCE is committed to the safety of the public and its employees and takes this matter very seriously," said Pete Dietrich, SCE's senior vice president and chief nuclear officer.

San Onofre's Unit 2, which was also shut down in January in a planned outage, is being considered for restart by the Nuclear Regulatory Commission. Unit 3 will remain offline.

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