05000267/LER-1979-005, Forwards LER 79-005/03L-0

Forwards LER 79-005/03L-0

ML19282C161
Person / Time
Site:	Fort Saint Vrain
Issue date:	03/09/1979
From:	Warembourg D PUBLIC SERVICE CO. OF COLORADO
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML19282C162	List: 05000267/LER-1979-005, Forwards LER 79-005/03L-0 05000267/LER-1979-005-03, /03L-0 on 790209:during Semiannual Loss of Outside Electrical Power Test,Output Circuit Breaker Did Not Close.Cause Unknown.Breaker Replaced W/Equivalent Spare
References
P-79059, NUDOCS 7903210120
Download: ML19282C161 (1)

LER-1979-005, Forwards LER 79-005/03L-0

Event date:
Report date:
2671979005R00 - NRC Website

text

.

k pubue service company or cenende P. O. Box 361, Platteville, Colorado 80651 March 9, 1979 Fo rt S t.

Vrain Unit No. 1 P-79059 Mr. Karl V. Seyfrit, Director Nuclear Regulatory Con: mission Region IV Office of Inspection and Enforcement 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76012 REF: Facility Operating License No. DPR-34 Docket No. 50-267

Dear Mr. Seyfrit:

Enclosed please find a copy of Reportable Occurrence Report No. 50-267/79-05/03-L-0, Preliminary, submitted per the requirements of Tech-nical Specification AC 7.5.2(b)2.

Also, please find enclosed one copy of the Licensee Event Report for Reportable Occurrence Report No. 50-267/79-05/03-L-0.

Very truly yours,

& %,a -. &

Don Warembourg Manager, Nuclear Production DW/alk cc: Director, MIPC 1/

8 790321012o g9 790321012o i

REPORT DATE:

March 9, 1979 REPORTABLE OCCURRENCE 79-05 ISSUE O OCCURRENCE DATE:

February 9, 1979 Page 1 of 4 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 PLATTEVILLE, COLORADO 80651 REPORT NO. 50-267/79-05/03-L-0 Preliminary IDENTIFICATION OF OCCURRENCE :

On February 9,1979, while performing the loss of outside electrical power surveillance test, one diesel generator output circuit breaker would not close.

This condition is in violation of Fort St. Vrain Technical Specification LCO 4.6.1(3) and is reportable per Fort St. Vrain Technical Specification AC

7. 5. 2 (b) 2.

EVENT

DESCRIPTION

While the plant was shutdown, the surveillance test was being run, which simu-lates the loss of outside electrical power and main turbine trip. Upon simu-lation of loss of outside electrical power and turbine trip, both diesel gen-erators started automatically. However, the diesel generator lA output breaker (252 DGlA) to the essential 480 volt Bus No.1 did not close (refer to Figure 1).

Diesel generator 1B had been interlocked to simulate that it would not be the first generator to reach operating conditions, as called for by the p ro cedure. Therefore diesel generator 1B correctly did not close in on 480 volt Bus No. 3, because diesel generator 1A had not closed in to supply 480 volt Bus No.1 first.

CAUSE

DESCRIPTION :

Undetermined. Bench testing of breaker was successful. No electrical or mechanical malfunction could be ascertained.

The breaker had operated just prior to this loss of outside electrical power test, when the diesel generator set had been loaded manually to verify proper operation and it operated satisfactorily just after the loss of outside elec-trical power test when closed manually to again test operation.

REPORTABLE OCCITdRDiCE 79-05 ISSUE O Page 2 of 4 DESCRIPTION (continued):

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There have been three previous reports on this type of problem with the auto-matic_ load. shedding, load programming, and automat __ic start of dies _el_ genera-tor sets. Two Reportable Occurrence Reports, 50-267T77-06(30) and 50-267/77-

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O&(141,_ delt_with mechanical damage to the breakers _or controls and_were_un-related non-recurring type events. The third report, Reportable Occurrence Report _Nou5_0-267/77-31(30) and Reportable Occurrence _ Report No._ _50-267/77-31(30)A, was similar to this event and after inspection and evaluation by the manufacturer...no mechanical or electrical malfunction could be foun_d..

_ _ _ _ _ _. _ ____ __ _ _ CO RRE CTIVE__ _.__.

ACTION:

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The faulty breaker was replaced with a spare and~1s currin~tif' beiWinspected~--

and tested. The results of the investigation will be reported in a supplement to this report.

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REPORTABLE OCCURRENCE 79-05 ISSUE O Page 4 of 4

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Prepared by:

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Asa B. Reed Technical Services Technician Reviewed by-

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chnical Services Supervisor Reviewed by:

Frank M. Mathio Operations Manager Approved by:

A Wm _Ac11 Don Warembourg 47 Manager, Nuclear Production