Nuclear Plant Siren Wails a False Alarm

A powerful warning siren for the San Onofre nuclear power plant blared a false alarm for nearly 20 minutes early Saturday morning, jarring residents awake and prompting a spate of worried telephone calls to local police.

Authorities blamed the shrill dawn alarm on a malfunctioning siren that apparently was touched off when storm water seeped into the equipment. The siren is one of 52 within a 10-mile radius of the San Onofre nuclear power plant and one of 18 located about five miles north in the city of San Clemente.

The siren began wailing about 6 a.m. and continued for nearly 20 minutes before city officials were able to disconnect it. San Clemente police reported receiving dozens of telephone calls about the siren.

Steve Conroy, a spokesman for Southern California Edison Co., which operates the plant, said the nuclear power plant was operating smoothly and “there was no emergency.”

“We are investigating,” said Conroy, “but we believe it was related to the heavy rainstorm. Probably water getting inside the field equipment caused it to go off.”

Last July another siren mistakenly sounded a warning alarm, blasting for about five minutes.