San Onofre reactors shut "into the summer" - CEO
* Company gives conflicting information on possible return date
* Outage at 2,150-MW plant enters fourth month
* Repair costs now estimated at $55 mln to $65 mln
HOUSTON, May 4 (Reuters) - Damaged reactors at the San Onofre nuclear station in California will likely remain shut into the summer, the chief executive officer of the plant's majority owner, Edison International, told investors this week.
Both units at the 2,150-megawatt plant halfway between Los Angeles and San Diego have been shut since January following the discovery of premature wear on tubes inside giant steam generators made by Mitsubishi Heavy Industries.
A prolonged shutdown of the nuclear plant could lead to reliability problems across southern California this summer when power demand rises to meet air conditioning demand, the state grid operator has warned.
A small number of damaged tubes in each reactor have been taken out of service after extensive inspections and tests being reviewed by the U.S. Nuclear Regulatory Commission. The significance of the tube degradation led the NRC to issue a letter in late March that requires the utility to seek its approval before restarting either reactor.
Southern California Edison (SCE), which operates the reactors for a group of owners, told the grid operator back in March that it hoped to restart the units in June, and local media reports this week quoted an SCE executive saying the company would seek to restart Unit 2 in mid-June and Unit 3 in July.
However, an NRC spokesman said Friday the utility has not responded to the NRC letter with a proposed timeline to restart the units. The NRC letter spells out specific action SCE must take to ensure that the cause of tube wear is understood and that the issue is addressed going forward. Continued...