LOS ANGELES (AP) Four more tubes that carry radioactive water at a Southern California nuclear power plant failed pressure tests, bringing the number to seven and prompting new safety concerns, authorities disclosed.
The four tubes failed Thursday at the San Onofre coastal plant in northern San Diego County, Southern California Edison announced. Three had failed Wednesday.
The utility shut down the plant's Unit 3 reactor and began testing samples from thousands of tubes in its steam generators on Jan. 31 after a leak was found. Traces of radiation escaped during the leak, but officials said there was no danger to workers or neighbors.
The Nuclear Regulatory Commission said Thursday it was sending a special team of inspectors to try to determine why the metal tubes, which were installed only a few years ago, have become frail enough to pose a risk of leaks.
``This is a significant issue,'' said NRC spokeswoman Lara Uselding. ``A tube rupture is really the concern.''