ML20008F630

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: ML20008F630 ML20008F634
References
NUDOCS 8104210407
Download: ML20008F630 (6)

Text

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4 1 puhuc service company oe cono m so 16805 ROAD 19%

e PLATTEVILLE, COLORADO 80651 March 19, 1981 Fort St. Vrain Unit No. 1

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Mr. Karl V. Seyfrit, Director }.,. e'.

Nuclear Regulatory Commission .6 D

. 4r e, 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 cc: Director, MIPC 3 l

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

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, CCCURRENCE DATE: Feb ruarv 20, 1931 Page 1 of 4 i

l 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 1 Specification AC 7.5.2(b)2.

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EVENT l DESCRIPTION:

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

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

3

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

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

No further corrective action is anticipated or required.

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ISSUE 0-Page 4 of 4 I

I Prepared By: d/ TW' -

Paul Moore-Technical Services Technician i

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