ML20084U789
| ML20084U789 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 12/19/1974 |
| From: | Kalivianakis N COMMONWEALTH EDISON CO. |
| To: | Oleary J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20084U792 | List: |
| References | |
| AO-50-265-74-27, NJK-74-410, NUDOCS 8306290262 | |
| Download: ML20084U789 (3) | |
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December 19, 1974 l'.r. John F. O' Leary, Di rector Directorate of Licensing Regulation U. S. Atomic Energy Cormission Vashington, D. C. 20545 RE FE REtlCE : Quad-Ci tics fluclear Power Station Docket No. 50-265, DPR-30 Appendix A, Sections 1.0.A.4 and 6.6.8.1.a.
Dear fir. O' Leary:
Enclosed please find Abnormal Occurrence Report flo. A0 50-265/74-27 for Quad-Citics Nuc1 car Power Station.
This occurrence was previously re-ported to Region ill, Directorate of Regulatory Operations by telephone on December 9,1974 and to you and Region Ill, Directorate of Regulatory Operations by telecopy on December 10, 1974.
This report is submitted to you in accordance with the regulrcments of Technical Specification 6.6.B.I.a.
Very truly yours, C0loiONWEALTH EDISON C0l;PAtJY QUAD-CITI ES NUCLEAR POWER,SIATION
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REPORT NUMBER: A0 50-265/74-27 REPORT DATE:
Decembe r 19, 1974 OCCURRENCE DATE:
December 9, 1974 IDENTI FI CATI ON OF OCCURRENCE :
Failure of the 28 Recirculation Pump suction valve to auto-close.
CONDITIONS PRIOR TO OCCURRENCE:
Unit Two was in the RUN mode at 535 tue and 1785 Mut.
DESCRIPTION OF OCCURRENCE:
On December 9, 1974 at 10:05 a.m. the 2B Reactor Reci rculation Pump suc-tion and discharge valves received an autonatic close signal, and the 2B M-G Set tripped.
The pump discharge valve closed, but the suction valve, designated M0-2-202-48, did not close completely.
The valve was fully closed by manually holding in the contactor at the breaker until the running current decreased to normal.
The recirculation pump was left in the tripped condition and the valves remained closed.
Since the pump suction valve is given a close signal under accident con-ditions as part of Low Pressure Coolant Injection loop-select logic, this failure has been identified t,s an abnormal occurrence in accordance with Techni cal Speci fi cati on 1.0. A.4.
DESIGNATION OF APPARENT CAUiE OF OCCURRENCE:
Component failure Since the 2B recirculation pump suction valve is located within the pri-mary containrent boundary, it has not been possible to physically inspect the valve.
This will be accomplished during the next extended unit out-age.
Measurements were taken on che current required to open and close the valve.
It was determined that 13.6 amps were needed to close the valve, as com-pared to only 5.5 amps to open it.
It is postulated that either insufficient lubrication or faulty packing may have been the cause of the failure to close.
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December 19, 1974
. Ao 50-265/74-27 NJALYSIS OF OCCURRE!!CE:
During the actuation of the LPCI Mode of the Residual ifeat Removal System (RHRS), the suctica and discharge valves for the recirculation pump in it is not injection get a close signal.
the loop which is to receive the required that ei ther of the valves be closed in the loop with the postu-is downstream of the lated line break.
Since the coolant injection point pump discharge valve, having the suction valve closed provides additional into the reactor core.
assurance that adequate LPCI flow will inject injection path for the LPCI loop is the preferred coolant The "B" LPCI Since the recirculation pump suction and diccharge valves loop select.
The re fore, failure are closed, no adverse safety inplications are created.
of the 23 suction valve does not cause either LPCI subsystem to be in-operable.
CORRECTIVE ACTIO!!:
The 23 recirculatica pump suction valve was fully closed by manually hold-ing in the contactor at tne circuit breaker. Plant operation has continued
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at a reduced power level with the 2A recirculation pump in operation.
Further The suction valve will be inspected during the next extended outage.
information with regard to the cause of the failure and the corrective action required will be provided at that time.
FAI LURE DATA:
fio previous failures of this type have been encountered at Quad-Ci ties fluclear Power Station.
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