Millstone gets another NRC violation for feedwater pump
Waterford — The Nuclear Regulatory Commission has cited Millstone Power Station owner Dominion Resources for a violation of “very low safety significance” for failure of a critical backup pump that has had repeated problems in the past.
In an inspection report released Wednesday, the NRC said the turbine-driven auxiliary feedwater pump at Unit 3, which is needed to supply cooling water to the reactor if electricity is lost, failed during a test on Feb. 22. The test was being conducted to verify that the pump, which is powered by a generator, would be able to supply the needed volume of cooling water during an emergency shutdown.
“This is an important safety component,” said Neil Sheehan, spokesman for the NRC.
During the test, the pump malfunctioned when a bearing seized up, Sheehan said. Immediate corrective actions taken by the company included replacing the bearing, installing a shield to minimize moisture and reduce the potential for corrosion, and lubricating the bearing.
The NRC has directed Dominion to submit a written response describing its long-term corrective actions to fix the pump.
“The NRC will certainly follow up on it and can pursue enforcement actions if we’re not satisfied with the response,” Sheehan said.
Ken Holt, spokesman for Millstone, said the pump was successfully tested twice after repairs were made following the February failure. Additional testing and repairs have been made while Unit 3 has been shut down for a refueling outage, he said.
"It will be tested again before Unit 3 returns to service," Holt said. He said he is confident problems with the pump have been fully resolved.
In the inspection report, the NRC listed the four past failures of the pump in 2013 and 2014, which resulted in the agency issuing a violation of “low to moderate” safety significance. After that, the plant was subject to several special inspections on the pump and tested it repeatedly in 2015. The NRC closed out the violation in July after determining that the problems with the pump had been corrected.
The new inspection report, however, indicates that problems continued.
“The NRC considered that Dominion has, on two previous occasions, failed to appropriately correct this issue, which involves a safety-significant system,” the report states. “Therefore, the NRC is issuing the Notice of Violation and is requiring a response from Dominion regarding, in part, its planned long-term corrective actions.”
The report states that the pump “has little margin to inoperability” and that “Dominion did not pursue a thorough review of the potential interactions of different failure modes after correcting the obvious causes from past failures, which contributed to the Feb. 22 … event.”
The inspection report lists a second violation of “very low safety significance” regarding a feedwater isolation valve. Unlike the other finding, this was considered a “non-cited violation,” meaning that Dominion is expected to take corrective actions but does not have to respond to the NRC with a written report.
“Both violations have been entered into our corrective action program, and we are commited to ensuring these issues are not repeated,” Holt said.
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