05000267/LER-1981-019, Forwards LER 81-019/03L-0.Detailed Event Analysis Encl

Forwards LER 81-019/03L-0.Detailed Event Analysis Encl

ML20008F630
Person / Time
Site:	Fort Saint Vrain
Issue date:	03/19/1981
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20008F631	List: 05000267/LER-1981-019, Forwards LER 81-019/03L-0.Detailed Event Analysis Encl 05000267/LER-1981-019-03, /03L-0:on 810220,plant Operated in Degraded Mode to Repair Pressure Control Valve PV-21243-1.Caused by Excessive Leakage Through 1/2-inch Masoneilan Pressure Control Valve.Valve Stroke Lengthened.Seat & Stem Replaced
References
NUDOCS 8104210407
Download: ML20008F630 (6)

LER-1981-019, Forwards LER 81-019/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2671981019R00 - NRC Website

text

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1 puhuc service company oe cono m so 4

16805 ROAD 19%

PLATTEVILLE, COLORADO 80651 e

March 19, 1981 Fort St. Vrain

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Unit No. 1 j. :.

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Mr. Karl V. Seyfrit, Director

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.6. 4r Nuclear Regulatory Commission e,

D Region IV Office of Inspection and Enforcecent 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 Reference: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/

81-019, Final, submitted per the requirements of Technical Specification AC 7.5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/81-019.

Very truly yours, W<s.:

Don Warembourg Manager, Nuclear Production DW/cis Enclosure Q

3 cc: Director, MIPC l

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REPORI DATE:

March 19, 1931 P.E?ORTABLE OCCURRE';CE 81-019

^

ISSUI O CCCURRENCE DATE:

Feb ruarv 20, 1931 Page 1 of 4 i

FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE CCMPA',"i 0F COLORADO 16305 VELO COU'.7Y ROAD 19 1/2 PLAITEVILLE, COLO?Ato 8C651 REPORT NO. SC-267/dl-019/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

On two separate occcsions, the energency feedwater supply to Loop 1 hellun circulators was isolated. These events constitute operation in a degraded node allowed by LCO 4.2.2.a) and are reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

1 i

EVENT 4

DESCRIPTION

On February 20, 1981, and again on Fchruary 25, 1981, erracic operatien of i

PV-21243 necessitated isolation of energency feedwater to Loop 1 hellun circulator water turbine drives to repair PV-21243-1. Fort St. Vrain Tech-nical Specification LCO 4.2.2 specifies the conditions which must be met for circulator operability. I:e= a) of LCO 4.2.2 specifies that a supply of energency f eedwater be available to drive the circulater water turbines, and further, allows for isolation of the energency feedwater supply for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> without the affected circulators being considered inoperable.

l Refer to Figure 1 for si=plified diagras of this systen. A pressure control

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systen is provided to control energe feedwater flow to each of the cir-culator pelton wheel supply headers an under flow and no-flow con-ditions. Under flow cenditions, ?V. 243 ontrols supply header pres-sure. Under no-flow conditions, PV-21243-1 is provided to relieve ex-cess header pressure to the turbine water drain tank in the event PV-21243 leaks through. In both of these events, PV-21243-1 was allowing too nuch pressure to be bled off the header, thereby, causing PV-21243 to cycle er-ratically. This would not, in itself, render the energency feedwa:er to Loop 1 circulators inoperable.

Event 1 On February 20 at 1130 hours0.0131 days <br />0.314 hours <br />0.00187 weeks <br />4.29965e-4 months <br />, with the plant operatir at 69% thermal power, energency feedwater was isolated ahead of PV-21243 5 to lengthen the valve s:roke on PV-21243-1.

E=ergency feedwater was restored by 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br /> on February 20 within the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> allowed by LC0 4.2.2.a), thus restoring the requirements for circulator operability. Lengthening the valve stroke slowed, but did no: stop, PV-21243-1 excess leakage.

REPORTA3LE OCCT RRENCE SI-019

' ISSUE O Page'2 of 4 EVENT

DESCRIPTION

(Cont'd) i Event 2 On February 25 at 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br />,' with the plant operacia at 69% thermal power, emergency feedwater was isolated ahead of PV-21243 5 - to remove PV-21243-1.

The valve was repaired and re-installed. Emergency feedwater was restored at 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br /> en February 25 within the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> allowed by LCO 4.2.2.a),

thus restoring the requirements for circulator operability. '

Had it been necessary during either of the periods that a=ergency feedwater was isolated, the af fected helius circulators could ~ have been operated or.

water turbine drive at reduced speed utilizing a water supply from the emergency condensate or firewster syste=s.

CAUSE

DESCRIPTION:

In both events, excess flow through PV-21243-1 caused erratic cycling of PV-21243, necessitating manual isolation of emer6ency feed rater to Loop 1 circulators to effect repairs.

CORRECTIVE i

ACTION:

Event 1 PV-21243-1 valve stroke was lengthened and the system returned to service.

j Event 2 i

.V-21243-1 was removed for repair. The valve seat and stem were. replaced, 3

the valve re-installed, and the systen returned to service.

No further corrective action is anticipated or required.

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I Prepared By:

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