To combat accusations that Southern California Edison sidestepped review of design changes made at the San Onofre nuclear plant, the U.S. Nuclear Regulatory Commission yesterday released a report showing the utility informed the agency before replacing the plant's four steam generators.

The new steam generators, which have been installed in the last couple of years, have become a major source of problems in recent months. The plant was forced offline in January after a tube carrying radioactive water briefly leaked. Since then, inspectors have found hundreds of other tubes wearing out more quickly than expected, apparently because they were vibrating and rubbing against support structures.

In a report commissioned by environmental group Friends of the Earth, consultant Arnie Gundersen argued that the plant's problems stemmed from design changes and that Edison had avoided a thorough review of the project by misleading NRC about the extent of the alterations. Edison officials said they fully informed NRC.

The document released yesterday is part of a presentation made at a June 2006 meeting between Edison and regulators about the project. It outlines several design changes, including the increased number of tubes and the use of a different metal to make the tubes.

But Gunderson said the report omitted several key aspects of the project.

"It looks like from the slide [Edison] mentioned all the good news and weren't telling the bad news," he said (Abby Sewell, Los Angeles Times, May 14). -- AS