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On September 2, 2001, the 2B Recirculation … On September 2, 2001, the 2B Recirculation Pump Discharge Valve, 2-0202-5B, did not close upon demand.</br></br>Troubleshooting revealed a normally closed auxiliary contact stuck open, which prevented the valve from closing.</br></br>In the event of a Loss Of Coolant Accident (LOCA), the Low Pressure Coolant Injection loop select logic determines the appropriate recirculation loop for injection based on differential pressure sensed between the "A" and "B" loops. If, during a LOCA, the "B" loop would be selected for injection, a signal would be sent to the "B" discharge valve to close, allowing the injection path to be completed through the jet pumps and into the core.</br></br>Thus, with the "B" discharge valve open, full injection into the core would not be achieved. Therefore, this event is being reported pursuant to 10 CFR 50.73 (a)(2)(v)(B) and (D), any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat or mitigate the consequences of an accident. Maintenance freed the stuck contact and the valve was subsequently stroked twice. During repair, an auxiliary contact plunger arm was found to be off its normal plastic stop, which caused the contact to bind. A new auxiliary contact assembly including the lock washer on the plunger arm was installed and successfully tested with no evidence of binding. The cause of the failed plunger arm was a loosened plunger post due to a missing lock washer.</br></br>The root cause of this event was determined to be inadequate procedural guidance, which led to equipment failure. The auxiliary contact plunger post was found not to have a lock washer installed. The station procedure does not clearly direct that the plunger post be verified tight or to check for the installation of a lock washer.</br></br>The safety significance of this event has been determined to be minimal.s event has been determined to be minimal. +
September 2, 2001 +
On September 2, 2001, the 2B Recirculation … On September 2, 2001, the 2B Recirculation Pump Discharge Valve, 2-0202-5B, did not close upon demand.</br></br>Troubleshooting revealed a normally closed auxiliary contact stuck open, which prevented the valve from closing.</br></br>In the event of a Loss Of Coolant Accident (LOCA), the Low Pressure Coolant Injection loop select logic determines the appropriate recirculation loop for injection based on differential pressure sensed between the "A" and "B" loops. If, during a LOCA, the "B" loop would be selected for injection, a signal would be sent to the "B" discharge valve to close, allowing the injection path to be completed through the jet pumps and into the core.</br></br>Thus, with the "B" discharge valve open, full injection into the core would not be achieved. Therefore, this event is being reported pursuant to 10 CFR 50.73 (a)(2)(v)(B) and (D), any event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat or mitigate the consequences of an accident. Maintenance freed the stuck contact and the valve was subsequently stroked twice. During repair, an auxiliary contact plunger arm was found to be off its normal plastic stop, which caused the contact to bind. A new auxiliary contact assembly including the lock washer on the plunger arm was installed and successfully tested with no evidence of binding. The cause of the failed plunger arm was a loosened plunger post due to a missing lock washer.</br></br>The root cause of this event was determined to be inadequate procedural guidance, which led to equipment failure. The auxiliary contact plunger post was found not to have a lock washer installed. The station procedure does not clearly direct that the plunger post be verified tight or to check for the installation of a lock washer.</br></br>The safety significance of this event has been determined to be minimal.s event has been determined to be minimal. +
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October 31, 2001 +
September 2, 2001 +
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