Southern California Edison has not yet concluded what the cause of the problems are at San Onofre, but the company told investors this week it hopes to petition to restart the plant in June.
Victor Dricks of the federal Nuclear Regulatory Commission said the company cannot bring the plant back on line until it has established the cause of the problems and indicated how it will ensure they won't happen again. He said once the agency has that information it will do its own independent review and inspection.
“We will reach our own conclusions regarding the information they have submitted to us," Dricks said, “and only then will the NRC make a decision about restart.”
Meanwhile, Dricks said, the NRC is reviewing its own procedures when it checked Edison’s plans to install new steam generators.
The generators were installed in 2010 at a cost of about $700 million, but had to be shut down in less than two years when a small leak in the generator tubes released radiation. The leak is due to premature wear of the tubes in the generator. What remains to be established is why the tubes wore out so fast.
Victor Dricks of the NRC says regulators did examine Edison’s new steam generator design. But in view of what’s happened since then, the agency is taking another look at how it scrutinizes such applications.
“The system we’ve used has been effective up until now," he said. "We’re going to exercise due diligence and look at our own procedures and look and see do they need to be tweaked - do they need to be changed or improved upon?"
Edison presented the new design to the NRC as being equivalent to the old design, allowing them to proceed without changes to the license.
If it transpires the new design, which is unique to San Onofre, is responsible for the premature tube wear, critics say that could raise questions about the effectiveness of the NRC’s oversight.
