Problems affecting a pump that is part of a reactor safety system will be the focus of a Nuclear Regulatory Commission (NRC) Special Inspection at the Millstone Unit 3 nuclear power plant. The Waterford, Conn., plant is operated by Dominion Nuclear (NYSE: D).
The Special Inspection team will have three members and will began its work on Sept. 15. The component of interest is the plant’s turbine-driven auxiliary, or back-up, feedwater pump. That pump is one of several that can be used to help cool down the reactor after a shutdown by pumping water into the secondary side of the plant’s steam generators. The steam generators are essentially large heat exchangers that convert heat generated by the reactor into steam, which in turn is used to spin the turbine and produce electricity.
The basis for this Special Inspection is the failure of the turbine-driven auxiliary feedwater pump to pass quarterly surveillance tests on July 15 and Sept. 10. During both tests, the pump started and then unexpectedly stopped. It then restarted without operator intervention and reached rated speed approximately 15 minutes later. The pump has since undergone repairs and been restored to service.
“A key objective of this inspection will be to learn more about this latest malfunctioning of this safety-related component,” NRC Region I Administrator Bill Dean said. “The repetitive problems affecting the pump continue to give the NRC concern.”
Areas to be reviewed during the Special Inspection will include the adequacy and completeness of testing on the pump and causal evaluations of the problems. The results of the Special Inspection will be discussed in a report expected to be issued within 45 days after the completion of the review.
The NRC conducted a Special Inspection earlier this year into what appear to be unrelated issues with the same pump. That inspection report was issued Aug. 28.