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.
Page Last Reviewed/Updated Wednesday, March 24, 2021