San Onofre nuclear plant generator might have been tampered with, utility says

Mike Blake / Reuters

The San Onofre nuclear power plant lies along the coast between Los Angeles and San Diego.

By NBC News staff and wire reports

Security has been beefed up at the San Onofre nuclear power plant in Southern California after it was discovered that a generator there might have been tampered with, the plant operator said. The plant has been out of service since January due to a leak in a steam generator.

Southern California Edison said it discovered engine coolant in an oil system in the backup diesel generator in late October during routine monitoring. An internal probe found evidence of potential tampering, though it could not be confirmed.

The presence of coolant posed no safety risk, the company said.

The news is the latest blow to San Onofre's majority owner, which earlier this month said the cost of the prolonged outage at the damaged nuclear power plant has topped $317 million. San Onofre's Unit 2 and Unit 3 reactors have been shut down since January after operators discovered a leak in a steam generator tube in Unit 3.  More >>