LOS ANGELES (AP) -- The long-running blackout at the troubled San Onofre nuclear power plant in California has cost at least $317 million, and it's not clear if the plant's troubled steam generators can ever be repaired and operated at full power, the plant's operator said.
Edison International, the parent of plant operator Southern California Edison, said in records filed with federal regulators that the tab for repairs and inspections through Sept. 30 had climbed to $96 million — double the amount reported at midyear.
With the plant out of service since January, replacement power costs jumped to $221 million over that period, up from $117 million at the end of June.
Just weeks after SCE announced a proposal to restart one reactor at the twin-domed plant and run it at reduced power, company officials Thursday again left open the possibility that the steam generators might eventually be scrapped.
In a conference call with Wall Street analysts, Edison Chairman Ted Craver said SCE was continuing to work with Mitsubishi Heavy Industries, which built the generators, and other industry experts to determine if the troubled machines that control heat inside the reactors can return to full capacity.
"It's not clear at this time if the units can be repaired, and it appears complete replacement of the steam generators would take some years," Craver said.
The problems center on damage to alloy tubing in four steam generators that were installed during a $670 million overhaul in 2009 and 2010.
The Unit 3 reactor was shut down Jan. 31 as a precaution after a tube break. Traces of radiation escaped at the time, but officials said there was no danger to workers or neighbors.
Unit 2 had been taken offline earlier that month for maintenance, but investigators later found unexpected wear on hundreds of tubes inside generators in both units.
Later tests found some tubes were so badly corroded that they could fail and possibly release radiation.
A three-month federal probe blamed a botched computer analysis for generator design flaws that ultimately resulted in excessive wear to scores of tubes.
Last month, SCE asked federal regulators for permission to restart the Unit 2 reactor and run it at reduced power. A decision by the Nuclear Regulatory Commission is not expected for months.
Edison's proposal was denounced by environmentalists and anti-nuclear activists who have argued for months that restarting the plant would invite catastrophe. About 7.4 million Californians live within 50 miles of San Onofre, which can power 1.4 million homes
"The key remains their acknowledgment that both units need repair or replacement of their steam generators, but they want to run Unit 2 for a while without those repairs or replacement," said Daniel Hirsch, a lecturer on nuclear policy at the University of California, Santa Cruz, who is a critic of the nuclear power industry.
"It certainly isn't a sign that 'safety is our No. 1 priority' if they know the steam generators need repair or replacement and are going to run Unit 2 with the crippled steam generators anyway," Hirsch said in an email.
Company engineers suspect that running the unit at lower power will stop vibration that has caused excessive wear to scores of tubes that carry radioactive water.
The outlook for heavily damaged Unit 3 is murky, and no decision on its future is expected until at least next summer.
Last week, the California Public Utilities Commission opened an investigation to determine whether ratepayers should bear costs tied to a plant that has been shut down most of the year.