Thousands of Tubes Damaged at Calif Nuclear Plant
Over 1,300 tubes containing radioactive water inside San Onofre nuclear plant's steam generators in California has been reportedly damaged enough that they need to be taken out of service.
To date, the safety of tubing that snakes around the plant's 4 steam generators were installed in a multimillion-dollar upgrade three years ago.
According to the company's official statement on Monday, 807 tubes in Unit 3 and 510 tubes from Unit 2 reactors were retired. Every generator has almost 10,000 tubes and the total number of plugged tubes would not affect a proper operation of the plant.
Their statement came just days after an executive from Edison International announced that the firm plans to restart at least one of the reactors in the coming months. They are apparently planning which reactor will run at reduced energy for several months at least, because engineers are of the opinion that it will solve the problem of vibration -- something that the firm suspects is causing the unexpected wear in the alloy tubes.
The chairman of Edison, SCE's parent company, reportedly called investors to notify them of the premature wear found in around 1% of 39,000 tubes in the generators.
A nuclear watchdog Norton Medical and Scientific Research & Biotechnology issued a warning, saying in effect that it seems «the new steam generators are falling apart and Edison doesn't know why. It would be foolhardy to restart, even at reduced power, under the current circumstances.»
The nuclear plant is owned by the Riverside City together with San Diego Gas and Electric and SCE. A joint statement released last week by the California Independent System Operator and Edison gave possible dates this June for planning. However, government regulators were quick to assert that there is no timetable for a restart -- something that would still need a federal approval.
The alert concerns stemmed from an incident in January when the third reactor was shut off after a tube broke. But although radiation has escaped during that time, officials were quick to assure residents and workers that there was no imminent danger. Earlier that month, the second unit was shut down for its regular maintenance but investigators discovered instead of premature wear on hundreds of tubes that were only installed 2 years ago by Mitsubishi Heavy Industries. (The first unit operated on 1968 was dismantled in 1992.)
The tubes stand for a crucial safety barrier, that is, if a tube breaks then there is considerable chance for radioactivity to escape onto the atmosphere. Serious leaks could also use up the protective cooling water employed in a reactor.
SCE estimates that the repair expenses could cost about USD 55 to 65 million, aside from the initial USD 30 million it has spent to replace the output from the 2 reactors earlier this year.