Peach Bottom update

Peach Bottom

On April 28, 2010, the NRC issued a report of an inspection covering a two-week period to evaluate changes, tests or experiments and permanent plant modifications. The inspection, completed March 19, 2010, dealt with activities relating to safety and compliance with the NRC’s rules and regulations and with conditions of the plant operator’s license. No findings of significance were identified, the NRC said.

The NRC issued a report on May 12, 2010, covering the three-month period ending March 31, 2010. The report said a self-revealed finding of very low safety significance was identified, and a licensee-identified violation was determined to be of very low safety significance.

The self-revealed matter involved the identification of 21 slow control rods during a Unit 2 scram time testing conducted from Jan. 30 to Jan. 31, 2010. Positioning of control rods helps change reactor power and can help shut down the reactor.

In the report, the NRC said there was planned power curtailment at Unit 2 on Jan. 29, 2010. A performance review of control rods was conducted, resulting in the identification of 21 slow rods, or 11 percent, of the 185 tested. The NRC said the 21 rods contained “1995-vintage SSPV diaphragms of the Viton-A material type.” The NRC said issues with these components had been found at other boiling water reactors plants, and they were to be regularly monitored. The NRC said Peach Bottom officials determined that the “performance monitoring and trending of the scram times was not being performed as required by Exelon (the licensee) procedure.”

The NRC noted that the 21 slow control rods were promptly repaired with a Viton-AB diaphragm made available in 1997 by the vendor as a warranty exchange for the Viton-A diaphragms. The NRC said the repaired control rods were re-tested satisfactorily and returned to service.

The licensee-identified violation involved preventive maintenance practices for the MSIV oil dashpot needle control valve. “There were no actual safety consequence associated with this event” discovered in September 2009, the NRC said..