Silent Reactor

The pigeons of California’s power crisis returned home to roost this week with the state‘s first rolling blackouts in two months, including the first in the Los Angeles area since World War II.

It is fair to blame the outages on last month’s accident at San Onofre nuclear power plant, which knocked out a reactor, depriving the state of sufficient power to avert blackouts. New details are emerging about the accident and its aftermath, raising questions about the maintenance procedures of the plant‘s main owner, Southern California Edison. It also became clear in Sacramento that Governor Gray Davis had underestimated the cost of replacement power by at least $100 million, which must now be paid by taxpayers.

“I remember protesting San Onofre 20 years ago,” says former state Senator Tom Hayden, “and thinking that soon enough we would be ending the nuclear-power age, and entering one arcing through natural gas to conservation and renewables. How splendidly naive we were in those days, not realizing that, thanks to public subsidies, the nuclear industry was going to be immortalized. That phrase about ’constant vigilance‘ must have anticipated this era.”

The reactor, at the plant north of San Diego, produces 1,120 megawatts of electricity, enough to power 1.1 million households, and was lost when an exploding electrical circuit breaker caused a 30-minute fire in early February. The fire, which did not affect radioactive materials, led to a power interruption and sudden system shutdown of San Onofre Unit 3. (Unit 1 was decommissioned in 1992; Unit 2 remains online.) Other factors also contributed to the power outages, including maintenance at other plants, less hydropower from a parched Pacific Northwest, a transformer fire at an Edison facility in the desert, and the withholding of several thousand megawatts by power generators who aren’t being paid by the utilities or by the state.

But the silence of Unit 3 looms largest. According to SCE spokesman Ray Golden, three backup power systems, two alternating-current power supplies and a direct-current battery, failed in the process. The power failure within the plant knocked out a lubricating oil pump, the loss of which caused serious damage to a massive turbine. One 200-ton generator rotor was so badly damaged that it had to be shipped by special railcar to Virginia for repair by its manufacturer.

The reactor had already been offline since the beginning of the year for maintenance and refueling, and was just being powered up when the accident occurred. According to the U.S. Nuclear Regulatory Commission, San Onofre Unit 3 will be offline until at least June. Other sources, who correctly advised that the accident was much more serious than initially indicated, suggest it may be longer.

Meanwhile, since the Edison utility -- though not the Edison holding company -- is nearly broke, the state must buy replacement power on the exorbitant spot market, where rates are turning out to be substantially higher than the Davis administration had reported. As a result, the conservative estimate of $400 million for San Onofre replacement power climbs to more than $500 million.

The U.S. Nuclear Regulatory Commission was to have produced a report last month on the accident, but that report has been delayed, according to an NRC spokesman, until April 21, due to “the complexity of the investigation.”

However, a source inside the NRC offers more insight into the San Onofre accident, raising questions about management and maintenance practices in the non-nuclear portions of the plant.

“The event started when a non-Class 1E [i.e. non-safety-related] electrical breaker exploded and started a fire. The plant‘s emergency diesel generators automatically started,” notes the NRC source, “but because the safety-related electrical buses” (or power connectors) were still on, current from the emergency generators was unable to flow.

Several other power connectors were knocked out by the explosion and fire. One of these “provided power to the main turbine-lubricating oil pumps.” At most plants, these pumps receive their power from the emergency diesel-generator-backed buses -- not because these pumps perform a safety function but because they are needed to protect the plant’s investment. “When the main turbine-lubricating oil pumps stopped running, oil stopped flowing to the main turbine bearings. But the main turbine was still spinning. Without lubricating oil, there was soon metal-on-metal rubbing between the bearings and the shaft. The bearings were totally damaged, and the shaft was damaged such that re-lathing is required.”

The NRC source points out that San Onofre had some, but not enough, replacement bearings on site, and that a two- to three-month lead time is required for the parts. This source agrees with Edison spokesman Golden that the shortening of the normal 45-day maintenance and refueling period to 32 days did not cause the accident. “The breaker that failed,” says the NRC source, “was a non-safety-related breaker that is not included in the periodic NRC inspection program.”

Edison spokesman Golden says the circuit breaker that failed was a $50,000 item, a pittance compared to the amount the State of California is having to pay to replace the lost power. Though he does not offer an explanation, he dismisses suggestions that Edison management and maintenance practices played a role in the accident, saying that the company followed the maintenance schedule laid out by the manufacturer.