Vibration from an earthquake shaking the San Onofre Nuclear Generating Station (SONGS) could cause sensors to malfunction that would prevent back-up emergency power from kicking on, plant operators concede. The latest problem is unrelated to the steam-generator tube wear that has kept the facility shut down since Jan. 31.
The revelation about the sensor mechanism comes in a letter from Southern California Edison to the Nuclear Regulatory Commission. It states excessive vibration would indicate to the sensors mechanical engine damage in the emergency diesel generators.
Edison engineers are currently analyzing the vibration sensor mechanism, according to the power giant.
There is still no timeline on when the plant will be ready to go back online, Edison adds.