Edison Con? San Onofre Nuclear Plant Owner Proposes Reactor Restart

de Wikileads | Firedoglake de Gregg Levine

Containment domes or shell game? (Aerial view of San Onofre Nuclear Generating Station by Jelson25 via wikipedia)

Southern California Edison (SCE), the operator of the troubled San Onofre Nuclear Generating Station (SONGS), has proposed to restart one of the facility’s two damaged reactors without repairing or replacing the parts at the root of January’s shutdown. The Thursday announcement came over eight months after a ruptured heat transfer tube leaked radioactive steam, scramming Unit 3 and taking the entire plant offline. (Unit 2, offline for maintenance, revealed similar tube wear in a subsequent inspection; Unit 1 was taken out of service in 1992.)
But perhaps more tellingly, Edison’s plan–which must be reviewed by the Nuclear Regulatory Commission–was issued just weeks before the mandated start of hearings on rate cuts. California law requires an investigation into ratepayer relief when a facility fails to deliver electricity for nine months. Support of the zombie San Onofre plant has cost California consumers $54 million a month since the shutdown. It has been widely believed since spring that Unit 3 would likely never be able to safely generate power, and that the almost identical Unit 2 was similarly handicapped and would require a complete overhaul for its restart to even be considered.
Yet, calls for more immediate rate rollbacks were rebuffed by Edison and ignored by members of the California Public Utilities Commission (CPUC). Despite studies that showed SONGS tube wear and failure was due to bad modeling and flawed design, and a company pledge to layoff of one-third of plant employees, San Onofre’s operators claimed they were still pursuing a restart.
Thursday’s proposal for that restart does not directly engage any of the concerns voiced by nuclear engineers andwatchdog groups.
When SONGS installed new turbines in 2010 and 2011, it did not replace “like with like”–that would have required a costly custom machining of parts no longer routinely manufactured. Instead, San Onofre’s owners moved to “uprate” their generators–cramming in more transfer tubes to increase output–with the nuclear industry equivalent of “off the shelf” parts. It was a transparently profit-driven decision, but more crucially, it was a major design change that should have required a lengthy license-amendment process at the NRC.
Federal regulators, however, took on faith industry assurances that changes were not that big a deal, and approved San Onofre’s massive retrofit without an extensive investigation into the plan.
What is now understood to have happened is that the design of new parts for San Onofre was based on flawed computer models that failed to anticipate new fluid dynamics, increased vibration, and more rapid wear in the numerous thin, metal, heat transfer tubes. It’s a flaw that presumably would have turned up in a more rigorous regulatory review, and, again, a problem not directly addressed by Edison’s restart plan.
Rather than repair or replace the tubes and turbines, San Onofre’s owners propose to simply plug the most severely degraded tubes in Unit 2 and then run that reactor at 70 percent power. After five months, Unit 2 would be shut down and inspected. (There was no plan offered for the future of Unit 3.)
Why 70 percent? Edison said it believes that would lessen vibration and decrease the rate of wear on the heat transfer tubes. Does that make any scientific sense? Not in the eyes of nuclear engineer Arnie Gundersen, who has produced three studies on San Onofre’s problems: [cont'd.]