Friday, March 16, 2012

San Onofre Nuclear Generating Station, California: US probes equipment failure at nuclear plant

LOS ANGELES (AP) -- A nuclear reactor on the California coast will remain shut down indefinitely while a team of U.S. inspectors determines why several relatively new tubes became so frail that tests found they could rupture and release radioactive water, a federal official said Thursday.

"This is a significant issue," said Nuclear Regulatory Commission spokeswoman Lara Uselding. "A tube rupture is really the concern. ... That's what we don't want to happen."

The Unit 3 reactor at the San Onofre Nuclear Generating Station, located about 45 miles (72 kilometers) north of San Diego, was shut down as a precaution on Jan. 31 after a water leak from another tube in a massive steam generator. Traces of radiation escaped, but officials say there was no danger to workers or neighbors.

Since then, investigators have been looking into excessive wear found on steam generator tubes in the seaside plant and its twin, Unit 2, which has been off line for maintenance and refueling. The two huge steam generators at Unit 2, each containing 9,700 tubes, were replaced in fall 2009, and a year later in Unit 3 as part of a $670 million overhaul.

The NRC dispatched a special team to Unit 3 on Thursday after pressure tests showed three of the metal-alloy tubes had become so degraded that they could rupture under some circumstances. Such ruptures can require a plant to shut down. Read More