Federal inspectors said Monday they will ratchet up scrutiny of the San Onofre nuclear power plant after discovering that a battery meant to power safety systems had been inoperative for four years.
Plant personnel discovered in March that bolts connecting an emergency battery to a circuit breaker were loose, a problem the Nuclear Regulatory Commission attributed to poor maintenance.
The commission said that the twin-reactor plant near San Clemente, run by Rosemead-based Southern California Edison, remains safe, and that other backup batteries are functioning. But the commission expressed concern that the battery problem had gone unnoticed from 2004 to 2008.
Apart from the battery, the commission discovered seven additional safety flaws that it described as minor in themselves -- including poor documentation and inconsistent follow-up on potential problems -- but that taken together formed a troubling picture.
As a result, the commission issued a "white finding," characterized as a low- to moderate-level safety concern, and said it will step up inspections at San Onofre until it sees improvements.
"San Onofre has a good deal of work to do," said commission spokesman Scott Burnell. "When we see a pattern of a plant maybe not picking up on things as quickly as they could, that gets our attention very quickly."
Until now, he said, the San Onofre plant had been earning a "one" ranking on a five-point safety scale -- one being safest, and five being so dangerous the commission shuts the plant down. The newest findings, Burnell said, are likely to damage the plant's ranking.
In a news release, Edison said it accepted the commission's findings and promised to ramp up "the rigor needed in problem identification and resolution." The company "has made significant leadership and organizational changes at San Onofre to ensure that plant performance keeps pace with continuously rising nuclear industry standards," the news release said.
Edison brought in new plant management in 2008 and launched a safety and ethics training program for plant personnel, management and suppliers, said company spokesman Gil Alexander.
The plant, one of 65 commercial nuclear plants across the country, has been under tight scrutiny in the last year, drawing repeated federal inspections in response to perceived problems.
In its 2007 annual report on the plant, the nuclear commission cited a host of problems it characterized as being of "very low safety significance," but which might lead to bigger problems. These included repeated instances of plant managers failing to give employees proper instructions and failing to quickly identify and fix flaws.
In January, the commission reported finding five regulatory violations at the plant, including the case of a fire protection specialist who falsified records for years to show he had made hourly safety rounds. In March, the commission notified plant managers that its steps to correct the problems had "not been effective."
"From the NRC's standpoint, being able to identify issues quickly and resolve them appropriately is far more important than adhering to a rigid production schedule," Burnell said. "Either San Onofre will improve and our inspections will dial back, or if by some chance it doesn't improve, our inspections will ratchet up. We're on a continuum here."