ML19323D008

Forwards LER 79-055/03X-1

ML19323D008
Person / Time
Site:	Fort Saint Vrain
Issue date:	05/09/1980
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19323D010	List: ML19323D008 ML19323D016
References
P-80100, NUDOCS 8005190525
Download: ML19323D008 (5)

Text

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8005190525

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Public senice company ce odceado

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16805 Weld County Road 191/2, Platteville, Colorado 80651

. .s May 9, 1980 Fort St. Vrain Unit No . 1 ,

S-80100 Mr. Karl V. Seyf rit, Directo r Nuclear Regulatory Commission Region IV Office of Inspection and Enforce =ent 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/

79-55, 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. 50-267/79-55.

Very truly yours, h Yw Don Warembourg Manager, Nuclear Production DW/cls Enclosure cc: Director, MIPC Poo2 5

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REPORT DATE: May 9. 1980 REPORTABLE OCCURRENCE 79-55 ISSUE 1 OCCURRENCE DATE: October 26, 1979 Page 1 of 4 FORT ST. VRAIN NUCLEAR GENERATING STATION 4

PUBLIC SERVICE COMPANY OF COLORADO 16805 WELD COUNTY ROAD 19 1/2 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-267/79-55/03-X-1 Final IDENTIFICATION OF OCCURRENCE:

On October 26, 1979, during performance of a scheduled surveillance test, it was found that a stuck open check valve (V-22370) degraded the opera-bility of the firevater booster pumps (FWBP). The valve failure did not make the pumps incapable of meeting the intent of LCO 4.2.19, which re-quires one operable pump during power operation. The reactor was operated at power during the surveillance interval, and it must be assumed that the degraded condition existed during power operation.

This is being reported per Fort St. Vrain Technical Specification AC 7.5.2(b)2, which requires reporting conditions leading to operation in a degraded mode permitted by an LCO that were revealed by test results.

EVENT DESCRIPTION:

On October 26, 1979, a surveillance test required by the Fort St. Vrain Technical Specifications (SR 5.2.7a-A) was being performed. As part of this test, the helium circulators are operated with reduced pressure con-densate supplied to the suction of the firewater booster pumps to simulate-operation on firewater. Figure 1 is a simplified schematic of the piping arrangement of the emergency condensate header and the firewater booster pumps P-2109 and P-2110. With reference to Figure 1, the test portion being performed requires that the pressure of the condensate at the suction of P-2109/P-2110 is reduced to approximately 114 psig. The pump to be tested is then started and the speed of the circulator driven by the boosted water verified as sufficient to give the required helium flow. When this was done on October 26, 1979, the circulator speed was less than the required 7-.ue, and pressure gauges installed at the pump suction and discharge indicated the same pressure. Investigation by an operator revealed no problem with the pump. When V-22370 was rapped sharply, the valve was heard to close, and circulator speed immediately increased to above the required value.

Since the reactor had been operated at power since the last previous demon-stration of firewater booster pump operability, it must be assumed that the reactor was operated at power with the firewater booster pumps opera-bility degraded.

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REPORTABLE OCCURRENCE 79-55 ISSUE 1 Page 2 of 3 i

CAUSE DESCRIPTION:

The cause of this event was the failure of V-22370 to close when required to do so. The degradation of pump operability resulting from this valve failure may be seen by reference to Figure 1. The design function of the firewater booster pumps is to take suction from the firewater system and discharge firewater at a boosted pressure to the circulator water turbines.

Firewater can be supplied via ivo separate routes, and discharge can be made via two separate paths.

One supply route is from the firewater system to the emergency condensate line through HV-31122 then to the pump suction through V-211565. Discharge of the pumps may then be routed to the circulator water turbines through V-211567 or V-211571. However, with V-22370 stuck open, the discharge path through V-211567 is not available since V-211567 must be closed to prevent the pumps from simply recirculating.

The second firewater supply route is through V-211573 and V-211570 directly to the pump suction, and the same two discharge paths to the circulator water turbines are available. If this source is used, the approved oper-ating procedure calls for V-211565 to be closed. In this manner, the failure of V-22370 does not result in a recirculation path. Discharge of the pumps may be routed to the circulator water turbines via either path described above.

Of the four possible combinations of supply and discharge routes, three were available with V-22370 stuck open. That is, supply via V-211570 with discharge through V-211567 or V-211571 and supply through V-211565 and dis-charge through V-211571 were three operable flow paths. Only the route utilizing supply through V-211565 and discharge through V-211567 was in-operable. The firewater booster pumps were operable, but their operability was degraded.

CORRECTIVE ACTION:

The immediate corrective action was to free the disc by rapping the valve body sharply.

The valve was opened and inspected as soon as plant conditions permitted.

No specific problem or mechanical defect was found when the valve was in-spected. The valve shaf t was cleaned and lubricated, and the valve re-assembled.

No further corrective action is anticipated or required.

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REPORTABLE OCCURRENCE 79-55 ISSUE 1 HV-31122 Page 3 of 4 Er. erg ncy Condansate '

r Sy tem Supply L

V V V V V Loop 1 Loop 2 Loop 2 S team Loop 1 S team S team Cen- S team Cen- Gene ra to r Generator erator Re- erator Re- Economizer Econonizer heaters heate rs V-22370 t

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Loop 1 Circula-y tor Water Turbines Loop 2 V-211567 X NO Circulator Water Tur-bines NO

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N N M

V-211585

(] V-211586

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NO P-2109 N

V-211565 V-211568 [ NO Emergency Feed-water Header V.

V-211566 2 NO No V-211573 V-211570 V-211571 V-2115 4 NX XM~ 1 From Fire PM ster System

• NC N X V-211583 [) V-211584 NC t NC l

Y NC NO , Spool y Steam P-2 10 Piece To Circulator Generator V-211572 E NO M- 1834 Water Turbine Drives Tell-Tale Drain FIGURE 1 EMERCENCY CONDENSATE HEADER AND FIREWATER BOOSTER PIS!PS Norra11y Open - NO Norrally Closed - NC

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REPORTABLE OCCURRENCE 79-55 ISSUE 1 Page 4 of 4

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Prepared By: / c-  % / , 42Of Richard R. Frost Technical Services Technician

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Reviewed By: #

J. V. G6hm Technical Services Supervisor Reviewed By:

Franid M. Mathie Operations Manager Approved By: '77,*,- u d u Don Warembourg [

Manager, Nuclear Produ6 tion

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