The U.S. Nuclear Regulatory Commission will not let Southern California Edison restart the San Onofre Nuclear Generating Station until problems with excessive wear on tubes is resolved, according to NRC Region IV Administrator Elmo E. Collins.
The Los Angeles Times reported that a letter from the NRC to Edison on Tuesday states the plant will remain closed until the problems are fixed and it is safe to operate.
“Until we are satisfied that has been done, the plant will not be permitted to restart,” Collins’ statement declares.
San Onofre has been shut down since January while regulators and Edison try to determine what caused the excessive wear on tubes in relatively new generators built by Mitsubishi Heavy Industries.
From the Times story:
Under the terms of the letter issued Tuesday, before the plant can return to service, Edison must determine what is causing the tubes in Unit 3 to rub against each other and ensure that the same thing does not happen in Unit 2. It also must complete pressure testing of tubes with possibly excessive wear and take those that show too much deterioration out of service, and it must develop a schedule of added inspections once the plant returns to service. … An advocacy group released a report alleging that design flaws in the newly installed steam generators contributed to the problems.
The report was commissioned by Friends of the Earth and prepared by consultant Arnie Gundersen of Fairewinds Associates, a former nuclear industry executive who is now a critic of the industry. The report alleges that design changes — including a different alloy used to make the tubes, a change in the flow rate, addition of more tubes and changes in the support structures that hold the tubes in place — probably caused the unexpected wear.
As it happened, the NRC’s call to shut down came on the same day that the issue came before the Irvine City Council. At the meeting, Councilman Larry Agran initiated the first step toward the city officially calling for the plant to be permanently shut down.
Agran said a disaster like the one that struck the nuclear plant in Fukushima, Japan, last year is just waiting to happen. He placed the odds of a catastrophe at “1 in 100.”
“I don’t like those odds, especially when in the case of San Onofre most of Southern California is being put at risk,” Agran said.
Council members differed on their level of opposition to the plant. Councilman Jeffrey Lalloway, who left before a vote was taken on drafting a letter, said only that it would be worthwhile to have more information. No council member, however, expressed support for San Onofre’s continued operation.
A few dozen people attended the meeting to oppose San Onofre and back Agran’s demands, including Nelson Mar, a former senior engineer for two containment vessels at the plant. Mar noted that San Onofre was built to withstand a 7.0 earthquake and had a 30 ft. seawall to defend the plant from a tsunami wave.
But, Mar said, the protections are not enough. Fukushima was the victim of a many times more powerful earthquake and tsunami 50 feet tall.
“We are in the same situation like Japan. If that happened in Japan, it’s going to happen here,” Mar said.
Council members appointed Agran and Councilman Steven Choi to a subcommittee to draft the letter. Choi said the letter should call for the removal of radioactive waste from San Onofre.
The drafted letter is scheduled to come before the council April 24.