San Onofre Nuclear Plant Problems Diagnosed, but List of Unknowns Remains

Wednesday, June 20, 2012
San Onofre Nuclear Generating Station


Nuclear Regulatory Commission (NRC) officials announced Monday that a faulty computer model led to problems that shut down the San Onofre nuclear plant  in January, but left unanswered a host of questions.

What was the precise nature of the “mistake” by the generators’ manufacturer, Mitshubishi Heavy Industries, that led to underestimating the velocity of steam and water coursing through the tubes by a factor of three or four? A math error? Faulty theoretical assumption? Bad cost-cutting decision? Mitsubishi was absent from the press conference announcing the NRC’s findings and was unavailable for comment afterward.

Assuming that activists are unsuccessful in permanently shutting down the facility between San Diego and Los Angeles, what will it take to fix it? New generators? New pipes? New computer model? And how long will the fix take?

What will be the cost of repairs and who will foot the bill? While Mitsubishi’s generator and computer program were blamed for the problem, NRC regional administrator Elmo Collins said the plant’s operator, Southern California Edison, is ultimately responsible. Of course, ultimate responsibility doesn’t necessarily mean Edison gets stuck with the bill. And Mitsubishi’s 20-year warranty doesn’t cover the cost of replacement power.  

Outlays could include replacement of the generators, replacement of tubes and other extensive plant work, in addition to the cost of securing replacement power contracts for a plant that will be offline for the foreseeable future. Before San Onofre shut down, it provided less than 7% of California’s energy supply.

Thousands of pipes are damaged and worn. The generators, which the NRC says may have to be replaced, are new, coming online in 2010 and 2011 after a project cap of $782 million was approved. Those costs were passed along to consumers through rate hikes. “We were told there was a cap on this project,” said Rochelle Becker, executive director of the Alliance for Nuclear Responsibility. “The minute Edison files to get one penny from ratepayers on this project, we will be at the PUC opposing it.”

Protests, however, didn’t stop utility companies from passing along devastating costs they incurred during the 2000 energy deregulation crisis.  

–Ken Broder

To Learn More:

San Onofre: Federal Investigators Determine that Design Flaws Led to Nuke Plant Woes (by Michael R. Blood, Associated Press)

Environmental Group Demands Full San Onofre Review (by Abby Sewell, Los Angeles Times)

Outage at San Onofre May Cost Hundreds of Millions (by Elizabeth Douglass, San Diego Union-Tribune)

California Has Excess Power (San Onofre Safety)

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