Citations Pending For San Onofre Nuclear Plant Flaw

Monday, September 23, 2013
Associated Press

LOS ANGELES (AP) — The manufacturer of steam generators at California's shuttered San Onofre nuclear power plant and the utility that runs the facility will be cited by federal regulators for a flawed design.

Southern California Edison said it was told Friday by the Nuclear Regulatory Commission to expect a citation for failing to make sure computer modeling and analysis were adequate for the design of the steam generators.

The commission also plans to issue a notice of nonconformance against the manufacturer of the steam generators, Mitsubishi Heavy Industries.

The Southern California plant was shut down last year because of excessive wear caused by vibration in tubes that carry radioactive water. The facility has since been formally retired.

Nuclear Regulatory Commission inspectors found a computer code used to model the movement of heat and steam through the generators was flawed.

Edison's chief nuclear officer, Pete Dietrich, pointed out that it is not unusual for regulators to cite a plant's licensed operator for problems caused by a vendor or contractor.

"Mitsubishi designed the system," Dietrich said. "Mitsubishi built the system. Mitsubishi's system failed. They are the experts. SCE was the customer."

A statement from Mitsubishi obtained by the Orange County Register said the failure described in the NRC's notice of nonconformance "had no impact on the root cause" of the "unprecedented" vibration problems that occurred in the nuclear plant's steam generators.

An Nuclear Regulatory Commission spokeswoman told the newspaper Sunday that the agency would make a report available to the public Monday but declined to comment further.