Cost of San Onofre nuclear plant outage exceeds $400 million

The parent company of Southern California Edison, operator of the troubled San Onofre nuclear plant, reported that the costs of the yearlong outage at the plant had ballooned to more than $400 million by the end of 2012.

The hefty price tag for the darkened plant includes inspections, repairs and purchasing replacement power.

Edison International officials fielded questions Tuesday from analysts about the plant’s extended shutdown and the possibility that federal regulators will require the plant to go through a lengthy license amendment process before returning to service.

The utility also indicated Tuesday that the company has looked into what repairs could be done to restore both units to full power, and was told by the steam generator manufacturer, Mitsubishi Heavy Industries, that the job of replacing “significant portions” of the system could take more than five years to complete.

The seaside facility, one of only two nuclear power plants in California, has been shut down for just over a year because of unusual wear on steam generator tubes that carry radioactive water. One tube leaked in January 2012, releasing a small amount of radioactive steam.

Edison and San Diego Gas & Electric — which has a 20% stake in the plant — spent more than $780 million replacing the steam generators, which ratepayers are now repaying.

Edison officials also took a shot Tuesday at elected officials who have accused the company of knowingly installing defective equipment.

Edison has proposed restarting the less-damaged of the plant’s two units and operating it at 70% power, which the company argued would alleviate the conditions that led to the wear. The U.S. Nuclear Regulatory Commission is reviewing the proposal.

The plant powered about 1.4 million households in Southern California before the outage.

The report also heralded a potentially protracted dispute between Edison and Mitsubishi over the warranty on the equipment that limited payouts to $138 million, of which the company has paid out $45 million to date. Edison contends that the warranty cap should not apply because of unusual circumstances at San Onofre — Mitsubishi disagrees.

Edison Chief Executive Ted Craver said the company “bristles” at allegations made publicly by Sen. Barbara Boxer (D-Calif.) and U.S. Rep. Ed Markey (D-Mass.) that the company was aware of design flaws in the steam generators before installation and did not make fixes to avoid triggering a time-consuming license amendment.

“This is just not accurate, and it injects politics into a process that should be free from it,” Craver said during Tuesday’s earnings call.

The lawmakers cited a leaked confidential report written by Mitsubishi when they made their claims. The NRC has said it will make a redacted version of the report public, but has not yet done so.

Environmental group Friends of the Earth contends that Edison should be required to go through a license amendment process, including public hearings, before the plant can restart.

The NRC has yet to decide on that question, but agency staff asked Edison to demonstrate that the unit proposed for restart can operate safely at its full licensed power, raising the possibility that the commission would require a license amendment for it to operate at 70% power.

In a response submitted Monday, Edison argued that 70% power is, in fact “normal steady state full power,” drawing indignation from activists who are pushing for a license amendment.

The company said that the “clear purpose” of the technical specification governing tube integrity is “to ensure that the … tubes will retain their integrity over the range of operating conditions to which they will be subjected. In this case, that range is limited to 70% power.”

But the response also promised to provide an analysis by March 15 showing that the unit could operate at 100% power without danger of a tube rupture.

Edison officials were scheduled to meet with NRC staff Wednesday.

abby.sewell@latimes.com