Edison International, owner of California’s second-largest electric utility, plans to have its San Onofre nuclear plant in Southern California online by June after being shut since January due to a radiation leak.
The plant’s reactors would be operated at reduced power for three to five months and then be inspected under a plan being developed by the company, Stephen Pickett, executive vice president at Edison’s Southern California Edison utility, said in a telephone interview.
The units, which produce about 2,200 megawatts, have been shut after inspectors found excessive wear on some steam generator tubes, networks of pipe that transfer heat from a nuclear reactor so it can be used to spin power-generating turbines.
Edison has “honed in” on the cause of the tube wear at both units, which is related to the amount of steam flowing through them and makes some longer pipes vibrate and rub together, Pickett said.
“The higher the power, the greater the flow and the more likely the tubes are to vibrate,” Pickett said. About 1 percent of the 39,000 tubes had unusual wear, which is within the margin of design error for the generators, Edison Chief Executive Officer Ted Craver said on a conference call.
As a result, Edison plans to plug the defective pieces and run the reactors at reduced output for a limited period of time, Pickett said. Edison is considering operating San Onofre at 50 percent to 80 percent capacity over the summer, he said.
Edison expects to submit its restart plan by mid-May to the U.S. Nuclear Regulatory Commission, which must sign off on it, Pickett said.
Edison has told California’s grid operator that it may have its Unit 2 reactor online by June 1 and its Unit 3 reactor back by June 12, the company’s utility president Ron Litzinger said today during a conference call with investors. Those dates could be delayed by a few weeks depending on final plans and regulatory approval, Pickett said.
Stephanie McCorkle, a spokeswoman for the state grid operator California ISO, didn’t return multiple telephone calls requesting comment on the planned restart.
Repair costs will be between $55 million and $65 million pretax, Edison’s Chief Financial Officer Jim Scilacci said today on a conference call with investors. The company will try to recover those costs under its warranty with Mitsubishi Heavy Industries Ltd., which built the generators, Scilacci said.
The utility will also seek state regulatory approval to recover costs to buy replacement power, Scilacci said. The company spent $20 million on repairs and $30 million on replacement power in the first quarter, he said. There will be no impact on 2012 earnings, he said.
Regulators may also review the $592 million the utility has spent to install the generators two years ago, Pickett said.
The radiation leak posed no threat to the public, the NRC and Edison have said.
San Onofre, located about 60 miles (97 kilometers) south of Los Angeles, can produce enough power for 1.76 million average homes, based on Energy Department statistics.