NRC Cites Rule Violations in Accident at San Onofre
Three violations of federal regulations apparently led to a November accident that threatened the stability of a safety-related water coolant system at the San Onofre nuclear power plant, a Nuclear Regulatory Commission investigation of the accident has found.
The violations, if upheld by high-ranking commission officials, could lead to fines against Southern California Edison Co., the utility that operates the seaside plant in northern San Diego County.
The report, completed May 16, also will form the basis for any commission decision on Edison’s request to restart San Onofre’s Unit 1, which was shut down after the Nov. 21 accident and cannot be restarted without the NRC’s permission.
The “apparent violations” cited in the NRC report involved the lack of an adequate program for detecting problems in safety-related equipment, an inadequate response when a key safety problem was detected, and the failure to provide proper procedures for trouble-shooting electrical problems at the plant.
A top-ranking Edison official said Wednesday that the company would not dispute two of the report’s three findings. Ken Baskin, vice president for nuclear engineering, safety and licensing, said, however, that he differs with the NRC’s conclusions on the electrical problems that led to the accident.
Baskin conceded that a key decision by plant operators to postpone visual inspection of a faulty valve was “a bad one.” But Baskin said the utility employees who made the decision did their best with the information they had at the time.
As it turned out, the suspect valve and four others like it all failed in November, creating conditions that made possible what is known as a “water hammer"--the over-pressurization of a 10-inch pipe and a resultant shock wave that cracked the pipe, damaged several pipe supports and released non-radioactive steam into the atmosphere.
The incident ended with no injuries, no release of radioactivty and no danger to the public, NRC officials said.