05000267/LER-1981-046, Forwards LER 81-046/03L-0.Detailed Event Analysis Encl

Forwards LER 81-046/03L-0.Detailed Event Analysis Encl

ML20010G264
Person / Time
Site:	Fort Saint Vrain
Issue date:	08/26/1981
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20010G265	List: 05000267/LER-1981-046, Forwards LER 81-046/03L-0.Detailed Event Analysis Encl 05000267/LER-1981-046-03, /03L-0:on 810728,emergency Feedwater Supply to Loop 1 Helium Circular Water Turbines Isolated to Repair Leaking 2-inch Consolidated Safety Relief Valves.Caused by Valve Leakage Downstream of Pressure Control Valve
References
P-81212, NUDOCS 8109150503
Download: ML20010G264 (5)

LER-1981-046, Forwards LER 81-046/03L-0.Detailed Event Analysis Encl

Event date:
Report date:
2671981046R00 - NRC Website

text

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16805 ROAD 19%

PLATTEVILLE, COLOR ADO 80651 Augus t 26, 1981 Fort S t. Vrain Unit No. 1 P-81212 o\\

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fir. Karl V. Seyfrit, Director Nuclear Regulatory Connission 9

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\\ N 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 Re fe rence : 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/

81-046, Final, submitted per the requirements of Technical Specif: cation AC 7. 5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/81-046.

l Very truly yours,

D Wa Manager, Nuclear Production DW/cis j

Enclos ure cc: Director, MIPC 6N s

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8109150503 810826 PDR ADOCK 05000267 l { }, &

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s REPORT DATE:

Aucust 26, 1981 REPORTABLE OCCURRENCE 81-046 ISSUE 0 OCCURRENCE DATE:

July 28. 1981 Page 1 of 4 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-267/81-046/03-L-0 Final IDENTIFICATION OF OCCURRENCE:

The emergency feedwater header supply to Loop 1 helium circulatar water turbine drives was isolated for repairs with the plant operating at power. This is a cegraded mode of LCO 4.2.2(a) and is reportable per Fort St. Vrain Technical Specification AC 7.5.2(b)2.

EVENT

DESCRIPTION

On July 28, 1981, with the plant cperating at 30% power and 83 MWe, operations personnel experienced pressure control difficulties on the emergency feedwater supply header to Loop 1 helium circulator water turbines.

Refer to Figure 1 for simplified diagram of this system.

Emergency feedwater is supplied to Loop 1 and loop 2 helium turbines via two separate flow p ths cirulator[) water

( A and(

1.

The main pressure control valves ( U1 and 2 )

are designed to control feedwater supply pressure unde flow conditions.

Additional pressure control vavies (

3 and 4 ) are provided to bleed off any leakage from the main control valves to the turbine water drain tank under the no-flow conditions which normally exist.

In this instanca under no-flow conditions, excessive leakage through relief valves 7 downstream of the main pressure control valve for Loop 1 caused erratic operation of the main pressure control valve.

A Plant Trouble Report was initi ted, and the emergency feedwater supply to Loop 1 was isolated 5 for repair of the relief valves at 0800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> on July 28, 1981. The relief valves were repaired, p.nd the system restored to service at 0140 nours on July 29, 1981, 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 without the affected helium circulators being considered inoperable.

Had it been necessary during this period, the Loop 1 circulators could have been operated on water turbine drive at recuced speed utilizing a supply from the emergency condensate or firewater systems.

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Eoergency Feedwater To llackup Ileade r Bearing Water

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V-21522

/$g V-21542 To I,oop 1 IIelium Circulator V-211615 PV-2124 3 Water Turbine Drives

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To Turbine Water

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V-211616 P V-21244

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To Loop 2 IIelium Circulator

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Emergency Feedwater Pressure Control T

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REPORTABLE OCCURRENCE S1-046 ISSUE 0 Page 3 of a

CAUSE

DESCRIPTION:

Relief valve leakage downstream of main pressure control valves necessitated isolation for repair.

The relief valve leakage is attributed to normal wear.

CORRECTIVE ACTION:

The relief valves were removed, rebuilt, bench tested, and re-installed. The emergency feedwater supply header to Loop 1 was restored to service.

No further corrective action is anticipated or required.

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REPORTABLE OCCURRENCE 81-046 ISSUE O Page 4 of 4 i

Prepared By:

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Paul Moore Technical Services Technician Reviewed By:

W2./'W.cjM M11't McBri'de Technical Services Manager s

Reviewed By:

E[ /M d M Edwin D. Hill f Station Manager Approved By:

Yd Don Waremoourg

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Manager, Nuclear Production s

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