NRC chief promises tough probe at Cal nuke plant

By the Associated Press | April 6, 2012 | 7:25 PM EDT

FILE - This file photo taken June 30, 2011 shows beach-goers walking on the sand near the San Onofre nuclear power plant in San Clemente , Calif. The twin reactors at the plant have been idled while investigators determine why tubing carrying radioactive water is eroding at an unusual rate, and the Nuclear Regulatory Commission chairman will visit the plant Friday, April 6, 2012, to highlight the agency's concern over the ailing equipment. (AP Photo, Lenny Ignelzi, File)

DANA POINT, Calif. (AP) — Following a tour of the troubled San Onofre nuclear plant, the chairman of the Nuclear Regulatory Commission says the plant will remain offline indefinitely until the cause of unusual tube wear in the plant's steam generators is determined.

Gregory Jaczko promised a thorough probe of suspect tubing Friday and said there will have to be a "clear understanding" of the cause of the problem before either of the twin reactors is restarted.

The reactors at the plant located between San Diego and Los Angeles have been shut down for more than two months.

Jaczko says there is no timetable to restart the plants but left open the possibility that Unit 2 could be restarted more quickly.

He made his comments after a tour of the plant with Democratic Sen. Dianne Feinstein and Rep. Darrell Issa, R-Calif.