Generator problems that have sidelined the San Onofre nuclear plant may point to weakness in safety regulations, the chairman of the Nuclear Regulatory Commission said Wednesday.
At a news conference in Charlotte, N.C., Chairman Gregory Jaczko, who submitted his resignation on Monday, said root causes and a solution to steam generator deterioration at the sidelined San Onofre Nuclear Generating Station still have not been identified by plant operator Southern California Edison.
The nation’s top nuclear safety official indicated that he would continue to serve out a term expiring in June 2013 or until a successor is confirmed by the Senate.
San Onofre, which supplies 20 percent of San Diego County’s power, has been offline since January as investigators look to alleviate rapid wear on steam generator tubes that are rubbing against supports and each other. The nuclear commission is looking into the approval of design changes to the recently replaced generators and whether Edison sidestepped a more lengthy review.
Jaczko said even some critics of the agency contend that design issues would have been caught by a higher-threshold review.
“If they (Edison) did it consistent with our regulations,” he said, “then maybe we need to take a look at changing our regulations.”
Jaczko said the onus still is on Edison to identify what has gone wrong at the plant and submit a plan for resolving those problems. Regulators must approve any restart plan.
“We’re still waiting on that,” he said. “We don’t have a time-certain on that.”
Jaczko has said only that he offered his resignation to make way for the confirmation of a qualified successor. He declined to comment further.
Fellow commissioners -- two Democrats and two Republicans -- have criticized Jaczko for fostering a tense and unsettled work environment at the agency, writing to the White House last year to express “grave concern.”
As chairman, Jaczko pushed for stricter U.S. guidelines related to the 2011 Japan earthquake and meltdown at the Fukushima Daiichi plant.
A Jan. 31 tube leak at the San Onofre plant set off atmospheric radiation alarms, although regulators say the tiny release posed no threat to workers or neighbors.
Generator tubes represent one crucial barrier to the plant's radioactive workings. They carry hot, radioactive water from the reactor core, transferring heat to a second non-radioactive steam loop that drives turbines to generate electricity.
Staff at the Senate environment committee, led by California Sen. Barbara Boxer, expect to be briefed by Edison and nuclear regulatory officials this week on alternations to the generators at San Onofre and how they were vetted.
A report this month commission by an environmental group asserts that Edison strategically avoided a license-amendment review of the new generators, which were installed starting in 2009.
Engineers for Edison and generator manufacturer Mitsubishi Heavy Industries outlined a number of intended design improvements in a trade magazine article published in the weeks before San Onofre was shut down.