More than 1,300 tubes that carry radioactive water inside the San Onofre nuclear plant in Southern California are so damaged they will have to come out of service, plant officials said.
The figures released by Southern California Edison are the latest disclosure in a probe of equipment problems that have kept the coastal plant sidelined for more than three months.
At issue has been the integrity of tubing that snakes through the plant’s four steam generators, which underwent installation in a multimillion-dollar makeover in 2009 and 2010.
A company statement said as of Monday, they plugged or retired from use 510 tubes in the Unit 2 reactor, and 807 tubes in its sister, Unit 3. Each of the generators has nearly 10,000 tubes, and the number retired is well within the limit allowed to continue operation.
The statement comes just days after an Edison executive said the company hopes to restart at least one of the twin reactors next month. The company is drafting a plan under which the reactors would run at reduced power, at least for several months, because engineers believe that will solve a problem with vibration the company believes has been causing unusual wear in the alloy tubing.
Unit 2 went offline in January for routine maintenance, but investigators later confirmed accelerated wear on tubing in both units.
Federal regulators say there is no timetable for a restart.
In January a tube broke, which prompted Edison to shut down the Unit 3 reactor as a precaution. Traces of radiation escaped at the time, but officials said there was no danger to workers or neighbors.
Costs related to the long-running shutdown could climb over $100 million, company officials say, and state officials have warned about possible rotating blackouts in Southern California while the reactors are offline.
About 7.4 million Californians live within 50 miles of San Onofre, which can power 1.4 million homes.
SCE, San Diego Gas & Electric and the city of Riverside own the plant. The Unit 1 reactor operated from 1968 to 1992, when officials shut it down and dismantled it.