Operators of the San Onofre Nuclear Generating Station, located north of Oceanside near Interstate 5, are investing $280 million in improvements taking place later this year.

Gil Alexander, spokesman for the plant’s majority owner, Southern California Edison, said by phone Jan. 5 that upgrades are geared to boosting the plant’s output by about 2 percent, improving worker safety and making operations more cost efficient.

Turbines and related systems at the plant’s Unit 2 reactor will be shut briefly for upgrades sometime in the next two months, with a similar transition planned for fall at its Unit 3 reactor. Alexander said operators have made arrangements for replacement power during the upgrades, and there will be no interruptions to customer service.

Utility customers are expected to see their bills rise by no more than one-half percent as a result of the improvements, he said. The facility is approximately 78 percent owned by SCE, 20 percent by San Diego Gas & Electric Co., and 1.7 percent by the City of Riverside.

― Lou Hirsh