* San Onofre nuclear units shut since January
* Station may need new generators to produce full power
* SCE says it has no timeline to respond to NRC letter
By Eileen O’Grady
HOUSTON, July 31 (Reuters) - The prospect for a return to service of the damaged San Onofre nuclear station in California grew more distant Tuesday as Edison International executives said they are not yet ready to take the first step needed to restart the plant.
The 2,150-megawatt San Onofre nuclear station operated by Edison’s Southern California Edison utility has been shut since January after the discovery of premature tube wear in the giant steam generators.
The U.S. Nuclear Regulatory Commission determined that the unprecedented damage was so serious that the utility must seek its approval to repair and restart the units.
The NRC in March issued a so-called “confirmatory action letter” to inform SCE that it could not restart the reactors without NRC approval.
Southern California Edison (SCE) officials said last month that they planned to respond to the NRC letter by the end of July on how they would repair at least one of the reactors, but that is no longer the case, said Edison Chief Executive Ted Craver on a call with analysts on Tuesday.
“We will not be forecasting specific timelines for a confirmatory action letter submittal or potential startup dates,” Craver said. “As we have said many times, there is no timeline for safety, and to forecast dates is inconsistent with prudent decision making.”
The California grid operator has warned that the prolonged shutdown of the nuclear plant, located in Orange County between Los Angeles and San Diego, will strain power supply to meet electric demand in Southern California as warmer summer weather boosts air conditioning use.
Craver confirmed that the two nuclear units may never produce at full power unless the giant steam generators - installed in 2010 and 2011 at a cost of $650 million - are replaced.
He said San Onofre Unit 2 may be able to restart ahead of Unit 3, which experienced more severe damage.
If it is determined that Unit 2 can be restarted safely, it is unlikely it would operate at full output and will likely shut between refueling outages for further inspection, Craver said.
Unit 3 will need more “extensive additional repairs” to prevent the tube-to-tube wear from happening again, Craver said.
“SCE is also looking longer-term at what repairs, if any, could allow the steam generators to operate safely at full power,” Craver said. “SCE has not determined what those repairs might be, or whether the generators will need to be replaced for the units to operate at full output.”
SCE said $48 million has been spent so far to inspect the units and to plug more than 1,300 damaged tubes. Another $25 million is expected to be spent before Unit 2 can be restarted.
About $117 million has been spent on power to replace the lost generation from San Onofre which is 78 percent owned by SCE. Sempra Energy’s San Diego utility also owns 20 percent.
If the units remain out of service for nine consecutive months, the California Public Utilities Commission may initiate a review to remove the unit’s $1.2 billion revenue from customer rates, Craver said.
SCE expects some of its San Onofre repair bill to be covered by its warranty from steam generator manufacturer Mitsubishi Heavy Industries and from the Nuclear Electric Insurance Limited, an industry-sponored insurance fund.