U.S. regulators grill Edison on bid to restart part of San Onofre
Federal regulators grilled Southern California Edison publicly for the first time Friday on its proposal to restart part of the troubled San Onofre nuclear power plant.
San Onofre has been out of service for 10 months because of unusual wear on steam generator tubes. A small radiation leak developed as a result and prompted a shutdown in January. The steam generators had been replaced less than two years earlier, costing co-owners Edison and San Diego Gas & Electric a combined $771 million.
After months of inspections and testing, Edison presented a plan to the U.S. Nuclear Regulatory Commission in October to restart one of the two reactors at 70% power, for five months, before taking it offline for inspection. The company said that running the unit at reduced power would prevent the tube vibration that resulted in excessive wear.
The other unit, which had more serious issues, was not included in the restart proposal and will remain offline indefinitely.
Edison representatives sought to convince the commission that the units, although nearly identical in design, are different enough that Unit 2 can be run safely, while Unit 3 may not be able to operate again without extensive repairs. (Unit 1 of the plant has been permanently decommissioned.)
“Unit 2 is clearly different based on results,” Edison Vice President of Engineering Tom Palmisano told NRC representatives, pointing out that Unit 2 showed substantially less of the unusual tube wear although its new steam generators had been operating for a year longer than Unit 3’s.
Edison’s analysis has blamed computer modeling by steam generator manufacturer Mitsubishi Heavy Industries for failing to predict the behavior of steam within the generators, leading to the excessive vibration, as well as design changes made to support bars, which failed to stop the vibration, particularly in Unit 3. Mitsubishi had no one present at the meeting.
The meeting took place amid increasing debate over the fate of the plant, which once supplied enough power for 1.4 million homes.
Also, just one day earlier, Edison announced that it had found evidence of potential tampering with a backup generator connected to the reactor that Edison does not plan to activate.
Workers found coolant in the generator’s oil system in October, and Edison said in a statement Thursday that it had found evidence that the incident might have resulted from intentional tampering, although the evidence did not confirm that tampering had occurred. The company said that it has beefed up security and that the incident did not pose a safety risk. The reactor unit it is attached to has been defueled.
Activists and residents have demanded that San Onofre be decommissioned. Short of that, they have demanded that the NRC force Edison to go through a license amendment process, complete with a courtroom-like hearing, before deciding whether to allow the plant to restart its Unit 2 reactor.
Although Friday’s meeting was set up as a technical discussion between Edison and the NRC, anti-nuclear activists arrived en masse to express their opposition to restarting the plant, with some chanting “Shut down San Onofre” at the outset. They were joined by a group of four Buddhist monks and nuns who had planned to march to San Onofre from Dana Point on Friday and hold a six-day vigil by the plant to call for its decommissioning.
They changed plans, though, after a local activist took a radiation reading with his portable Geiger counter and claimed that an old steam generator being prepared for shipping had caused a spike in radiation. They took up their vigil at a pier in nearby San Clemente instead.
One of the monks, Senji Kanaeda, who lives in Seattle but is originally from Japan, said he was concerned about nuclear power in part because of the disaster at Fukushima.
“We would like to pass a safe world to the next generation,” he said.
San Onofre is dealing with other issues as well. Edison is embroiled in a spat with the union representing many of the plant employees over the company’s plans to lay off more than 700 workers. Daniel Dominguez, business manager of Utility Workers Union of America Local 246, wrote Edison executives expressing concerns that the layoffs could affect the plant’s safety if it does restart.
Dominguez said in an interview that he is not concerned about Edison’s restart plan from a technical perspective but is worried that the plant will not be able to safely operate with the reduced workforce, especially with cuts of highly skilled workers.
“We think it doesn’t make sense to be doing layoffs while you’re trying to restart a unit with significant challenges,” he said.
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