San Onofre

Reactor 2 at the San Onofre Nuclear Generating Station resumed operation Thursday after shutting down for three days for minor repairs, officials said.

All three reactors were out of service from Tuesday to Thursday, but other power plants and purchases from other utility companies provided ample electricity to customers, said David Barron, a spokesman for Southern California Edison.

Unit 3 has been out of service since April for refueling and is scheduled to resume operation July 16, Barron said. Unit 1 was shut down Saturday to undergo five months of refueling and repairs to bolts that support the unit’s thermal heat shield, he said.

Unit 2, the only unscheduled shutdown, was shut down this week to repair a small leak in pipes that carry non-radioactive water, Barron said. The shutdown was to last until early next week, but the repair was completed ahead of schedule, Barron said.

The Unit 1 repairs will cost $12 million, but estimates for the other two reactors were not available. All repair and refueling expenses, however, are within the station’s maintenance budget and will not result in customer rate increases, Barron said.

Southern California Edison is the majority owner and operator of the plant, which began commercial operation on Jan. 1, 1968, making it the oldest licensed nuclear plant in the state.