NRC chief heads to sickly Calif. nuke plant

[April 06, 2012]  LOS ANGELES (AP) -- The twin reactors at the San Onofre nuclear plant have been sidelined, more than 300 tubes that carry radioactive water will be scrapped because of excessive wear, and investigators are trying to figure out why tubing is rattling inside the lungs of the plant -- its massive steam generators.

How sickly is San Onofre?

The chief of the Nuclear Regulatory Commission will get a firsthand look Friday, at a time when some officials in nearby communities have been calling for the plant to shut down permanently because of safety concerns.

NRC Chairman Gregory Jaczko, joined by Democratic Sen. Dianne Feinstein and Republican Rep. Darrell Issa, will meet with plant managers and "they are going to be discussing the issues of the steam generators" where hundreds of tubes have shown unexpected wear, agency spokesman Victor Dricks said.

The visit to the seaside plant, located between San Diego and Los Angeles, comes 10 days after the NRC announced that San Onofre will remain dark until operator Southern California Edison fixes the widespread problem with tubing that carries radioactive water.

The high-profile trip also underscores the concern inside the federal agency tasked with ensuring the safe operation of the nation's commercial nuclear industry.

SCE has assured its customers that the reactors will not be restarted until that "it is safe to do so," and no date has been set.

State energy officials have warned of rotating blackouts in the power-hungry region if a heat wave hits while the plants are offline -- San Onofre can power 1.4 million homes.

The troubles began to unfold in late January, when the Unit 3 reactor was shut down as a precaution after a tube break in one of the generators. Traces of radiation escaped, but officials said there was no danger to workers or neighbors.

Unit 2 was taken offline earlier that month for routine maintenance and refueling. But investigators later found unusual wear on tubing in both units. The company has said 321 tubes that were heavily damaged will be plugged and taken out of service at the two reactors, well within the margin to allow them to keep operating.

Gradual wear is common in such tubing, but the rate of degradation at San Onofre has been unsettling to officials since the equipment is relatively new -- the generators were installed in a multimillion-dollar makeover in 2009 and 2010.

The plant's four steam generators each contain nearly 10,000 alloy tubes that carry hot, pressurized water from the reactors. The tubes are a critical safety barrier -- if one or more break, there is the potential that radioactivity could escape into the atmosphere. Also, serious leaks can drain cooling water from a reactor.

Two environmental groups, Friends of the Earth and San Clemente Green, issued a statement urging the chairman to make a "full determination" of problems at the plant before considering a restart. Last week, a report commissioned by Friends of the Earth claimed the utility misled the NRC about design changes that it said are the likely culprit in excessive tube wear.

The plant is owned by SCE, San Diego Gas & Electric and the City of Riverside. The Unit 1 reactor operated from 1968 to 1992, when it was shut down and dismantled.

[Associated Press; By MICHAEL R. BLOOD]

Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.