LOS ANGELES - Operators of the San Onofre nuclear power plant said someone may have tampered with an emergency generator but there's no danger because both reactors at the Southern California plant are shut down.
Southern California Edison, which runs the power plant, said the problem was discovered in October and reported to the Nuclear Regulatory Commission. The utility said there's evidence of possible tampering but other causes haven't been ruled out.
Team 10 has learned Southern California Edison found coolant in a backup generator's oil. The oil is used to cool and lubricate the engine, which is a backup system designed to prevent a nuclear meltdown.
"Eventually, it would have caused more wear and ultimately the failure of the engine," nuclear engineer Murray Jennex said.
Jennex, who teaches at San Diego State University, spent 20 years as a manager at San Onofre. He said he's seen and been a part of investigations into potential sabotage.
"We found bolts that weren't tightened like they were supposed to be," Jennex said. "In one case, we even found what looked like a pipe bomb."
A Southern California Edison spokeswoman told Team 10 there was never any danger and that the backup generator was part of a reactor that had been shut down since February.
While the official investigation into how coolant got into the oil hasn't ruled out terrorism, Jennex pointed to hundreds of layoffs planned at San Onofre as a possible motive.
"It's not a surprise," Jennex said. "This happens when people are losing their jobs."
Team 10 found a letter from the utility workers union representing San Onofre employees dated November 14, 2012, sent to management. It questions the "significant reductions" saying, "San Onofre does not explain how it plans to safely operate the facility with the reduced staffing."
Jennex said the problem was likely found during a routine monthly oil check, which includes chemical analysis.
He said the odds of finding who did this are slim because most of San Onofre's cameras and security are on the perimeter of the property.
"I doubt they will find the person who did this," he said.
Plant security has been increased.
San Onofre's reactors have been offline since January after problems were found with steam tubes.
Edison and the NRC plan to hold a public meeting Friday to discuss restarting one unit at low power.
Early Friday evening, an FBI official released this statement regarding the San Onofre discovery:
"The FBI is aware of the alleged security incident that occurred at the San Onofre Nuclear Generating (SONGS) Station. The FBI is presently reviewing the facts and circumstances concerning this incident. At this time there is no indication that this incident is terrorism related."