Edison files to shut down San Onofre reactors

SAN ONOFRE, Calif. — Southern California Edison announced Thursday that it has taken the formal administrative step necessary to retire the two reactors at the troubled San Onofre Nuclear Generating Station.

The majority owner and operator of the plant said it filed a Certification of Permanent Cessation of Power Operations with the Nuclear Regulatory Commission Wednesday.

Edison announced last week that it would shutter the facility, which has been idle since January 2012 following a small, non-injury leak in one of the units. The other had been undergoing maintenance at the time.

An investigation determined that vibrations caused faster than expected deterioration in steam generator tubes. New generators had been installed in 2009 and 2010.

After a plan to restart the unit where the leak did not occur stalled before the NRC, Edison officials announced they would retire the reactors rather than impose further uncertainties on customers, investors and the region’s energy market.

Decommissioning is expected to take many years, according to the utility.

“Safety will remain our top priority as we transition to the decommissioning process,” SCE Senior Vice President and Chief Nuclear Officer Pete Dietrich said. “We take very seriously our obligation to protect the health and safety of the public and our employees as we take the regulatory and planning steps to decommission San Onofre.”

Dietrich said the NRC will continue to provide regulatory oversight of San Onofre.

Management will draw upon the expertise of staff who managed the decommissioning of Unit 1 at San Onofre, which ceased operation in 1992, he said.

San Diego Gas & Electric owns 20 percent of the plant and received 20 percent of its power when it was operational.

SDG&E said earlier this week that, thanks to last year’s opening of the Sunrise Powerlink transmission line in the East County, enough power should be available this summer in its service areas of San Diego and southern Orange counties.

However, utility officials said customers should be prepared to take conservation measures if any transmission lines are shut down by wildfires or other problems.