More than 1,300 tubes that carry radioactive water are so damaged that they will need to be retired from service at the San Onofre nuclear plant in Southern California.

Southern California Edison, the utility that runs the plant, said that as of Monday, 510 tubes had been plugged or retired in the Unit 2 reactor, and 807 tubes had been plugged in the Unit 3 reactor. Each generator has nearly 10,000 tubes, so power generation could resume at the plant.

While reports said Edison wanted to restart one of the twin reactors next month and the other soon after, Nuclear Regulatory Commission Chairman Gregory Jaczko said earlier this week there is no timetable for restarting the generators. The commission has not yet received a report from the utility on safety issues concerning the reactors (E&ENews PM, May 7).

Unit 3 went offline in January after a radioactive leak was discovered in one of its tubes. Unit 2 was shut down for routine maintenance later that month. Investigators found that both reactors had severely worn tubes and have been looking into what caused the damage.

Engineers believe running the reactors at a reduced power level will lessen vibration to the tubes, which may have caused some of the wear (Michael Blood, AP/Boston Globe, May 8). -- JE