Ed Bedford 1 p.m., Dec. 12
Shutdown at San Onofre no Longer "Precautionary"
A shutdown at San Onofre Nuclear Generating Station’s Unit 3 reactor due to leaks found in the cooling system that pumps radioactive water through the generator’s core is now officially mandated by the Nuclear Regulatory Commission. Nearing two months in duration, the shutdown had previously been referred to by plant operator Southern California Edison as “precautionary.”
Though operators first insisted that no contamination had been released into the atmosphere, it was later disclosed that radioactive gas from the leak had been vented to an auxiliary building without the same safety seals as the main reactor. Numerous tubes in the cooling system, replaced in 2009, besides those that failed were found to have high levels of wear.
A report by engineer Arnie Gunderson of the nuclear consultant group Fairewinds Associates found that untested equipment and changes in design to the generators “created a large risk of tube failure.” The report specifically says the tube alloy used was changed, bracing was redesigned, and more tubes were added, all without disclosure by SoCal Edison to the Nuclear Regulatory Commission.
The findings come in addition to other safety problems highlighted in another report issued shortly before the shutdown occurred.
SoCal Edison had already announced in previous weeks that the plant would remain shuttered indefinitely, with the company promising to resolve all safety concerns before resuming operations. “We don’t put a deadline on safety,” said Southern California Edison spokeswoman Jennifer Manfre at the time.
Environmental groups are taking the opportunity to push for the plant’s permanent closure, rallying earlier this month on the first anniversary of Japan’s Fukushima Daiichi nuclear disaster. Another rally, commemorating Russia’ Chernobyl meltdown, has been announced for late April.
SoCal Edison has already commenced the process of applying to extend the plant’s operating license beyond its current expiration in 2022.