Part 21 Report - 1997-330

LICENSEE: DUQUESNE LIGHT CO. SITE: BEAVER VALLEY 2 EN NUMBER:32216 DOCKET: 05000412 EVENT DATE: 04-24-97 RX TYPE: PWR EVENT TIME: 00:00 VENDORS: W-3-LP NOTIFY DATE: 04-24-97 EMERGENCY CLASS: N/A REGION: 1 STATE: PA TIME: 14:03 OPS OFFICER: BOB STRANSKY 10 CFR SECTION: CDEG 21.21(c)(3)(i) DEFECTS/NONCOMPLIANCE UNIT SCRAM RX INIT INITIAL MODE CURR CURRENT MODE CODE CRIT PWR PWR 2 N Y 100 POWER OPERATION 100 POWER OPERATION 10 CFR PART 21 REPORT REGARDING AUXILIARY FEEDWATER (AFW) CHECK VALVE FAILURE THE LICENSEE HAS IDENTIFIED THAT NOZZLE CHECK VALVES MANUFACTURED BY ENERTECH AND USED IN THE AFW SYSTEM MAY BE SUSCEPTIBLE TO A FAILURE IN WHICH THE SEATING RING CAN BECOME LOOSENED AND BE SWEPT INTO THE FLOW STREAM. THIS COULD CAUSE A PARTIAL BLOCKAGE AND POTENTIALLY PREVENT THE AFW SYSTEM FROM PERFORMING ITS INTENDED FUNCTION. THE PHENOMENON DESCRIBED IS ONE IN WHICH THE HOT VALVE BODY AND SEAT EXPERIENCE DIFFERENT RATES OF THERMAL CONTRACTION DUE TO THE FLOW OF COOL AUXILIARY FEEDWATER CAUSING THE SEATING RING TO SHRINK TO THE POINT THAT THERE IS NO LONGER AN INTERFERENCE FIT BETWEEN THE RING AND THE VALVE BODY. THE RING COULD THEN BE SWEPT INTO THE FLOW STREAM. THE LICENSEE REPORTED THAT ENERTECH HAS BEEN NOTIFIED OF THIS PHENOMENON AND HAS MODIFIED THE VALVES AT BEAVER VALLEY TO PREVENT THIS CONDITION IN THE FUTURE.

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