A Minor Electrical Component Failure Predictable, but Ignored

On February 3, 2005, an electric component failure caused Unit 2 at the San Onofre Nuclear Generating Station to trip. Though the event was "minor" it is a troubling example of increasing component failures that challenge the safety of nuclear plants.

The emergency diesel generators are the "safety-related" source of electricity for emergency equipment. By terming these electrical components "non-safety" related, fewer tests and inspections are being performed on them. In essence, these infrequently tested electrical components are being used until they break, as occurred last week at SONGS-2.

Across the country, "non-safety" related transformers and electrical breakers are failing right and left. SONGS itself had an electrical breaker failure back during the California energy crisis. A 25-year old "non-safety" related electrical breaker failed. The resulting power outage severely damaged the main turbine, causing the plant to be out of service for months.

How does this event impact the steam generator replacement and license renewal? Not at all, although it should. PG&E and SCE blindly assume that they won't have to do extensive repairs/replacements of their "non-safety" related electrical equipment. The event last week, and dozens of similar events in recent years, strongly suggests this assumption is weak at best.

The Nuclear Regulatory Commission's license renewal process focuses using tunnel-vision, on aging management of "safety related" components. Thus, the NRCe misses the significance of aging electrical components failing more and more often and challenging the reliability of the aging "safety related" components.

Edison has applied to the CPUC for compensation from ratepayers to replace its aging steam generators. Several consumer and environmental organizations and SDG&E oppose the replacement as not in the best interest of consumers or the environment.