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I-98-2 January 7, 1998
NRC PROPOSES TO FINE DUQUESNE LIGHT COMPANY $55,000 FOR VIOLATION AT BEAVER VALLEY INVOLVING EMERGENCY COOLING SYSTEM
The Nuclear Regulatory Commission staff has proposed a $55,000 fine against Duquesne Light Company for a violation of agency regulations at the utility's Beaver Valley nuclear power plant. The infraction at Beaver Valley, which is located in Shippingport, Pa., stems from a failure to adequately address a potentially significant problem involving one of the facility's emergency core cooling systems.
NRC staff and Duquesne Light discussed the violation at a predecisional enforcement conference on Dec. 10 at the NRC Region 1 office in King of Prussia, Pa.
Specifically, the problem centers on gas accumulation in the High Head Safety Injection (HHSI) System, one of the plant's lines of defense in the event of a loss-of-coolant accident. The system could be used to pump water into the reactor core to keep it covered and cooled if a small- to intermediate-size rupture were to occur in the Reactor Coolant System. However, if too much gas built up in the system, and was not properly vented, it could cause the binding of the system's pumps and render them inoperable.
Such a condition was identified at Beaver Valley's Unit 2 on September 12, when operators observed that one of the High Head Safety Injection pumps was not working properly and was below its required differential pressure limits. It was subsequently determined by the NRC that even though plant staff had encountered instances of gas binding between 1988 and last September, adequate corrective actions had not been implemented.
For instance, a gas accumulation occurred in March 1988 in one of the pumps that was large enough to prohibit its operation. Another pump experienced gas binding in June 1993, in November 1996 and again last August. The last event occurred even after the lines had been vented for over three hours -- much longer than the normal venting period of less than 10 minutes.
"This finding is significant because the gas binding of the pump created the potential for interruption of HHSI flow to the reactor during design basis accident conditions," NRC Region 1 Administrator Hubert J. Miller wrote to Duquesne Light in a letter notifying the utility of the enforcement action. "The violation is particularly risk significant because the issue affected both units over a long duration and affected the only safety-related high pressure source of injection to the reactor vessel for several accident scenarios. ...
"This finding is also significant because the prior indications of gas binding of this pump provided clear opportunities to correct this condition sooner," Mr. Miller stated.
Duquesne Light has 30 days to pay the fine or request in writing that all or part be withdrawn.
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