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Possible leak causes San Onofre nuclear plant shutdown

A reactor at the San Onofre nuclear reactor in Southern California was being shut down after a possible leak was detected in one of the unit's steam generator tubes, the plant operator said Tuesday.

Southern California Edison said in a statement that "a precautionary shutdown of Unit 3" at the electricity generating plant was under way, but that there had been no release of radiation to the atmosphere and there was no danger to employees or the public.

The San Onofre plant is on the Pacific Ocean coast near San Clemente north of San Diego. It consists of two units, No. 2 and No. 3. No. 1 was shut down permanently in 1992. It is one of two nuclear plants that generate electricity in Southern California; the other is the Diablo Canyon plant in San Luis Obispo County.

Unit No. 2 at San Onofre was already offline for maintenance and refueling, but Southern California Edison said the shutdown of No. 3 would not affect the supply of electricity to customers.

In September, the failure of a major tranmission line between Arizona and California caused the Onofre reactors to go offline automatically.

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