SAN ONOFRE, Calif., April 13 (UPI) -- An environmental group is alleging unusual wear in steam generator tubes at California's San Onofre nuclear power plant is the result of a design decision.
A report by The Friends of the Earth says the problems stem from a decision to change the design to fit more tubes into each steam generator, the Los Angeles Times reported Friday.
The group's report was released a day after plant operator Southern California Edison acknowledged some tubes in the plant's reactor units are showing wear apparently caused by tubes vibrating and rubbing against each other.
Because the tube wear is considered a safety issue, San Onofre has been shut down since Jan. 31.
The Friends of the Earth said "cascading design changes" resulted from the decision to add 377 more tubes into each steam generator.
The group alleges Edison avoided a full U.S. Nuclear Regulatory Commission review of the changes by representing the new steam generators as being like the ones being replaced, but Edison and Nuclear Regulatory Commission officials have said the design changes were disclosed.