ML19325D701

Special Rept:On 890919,nonvalid Failure of Standby Diesel Generator Occurred.Caused by Failure of Reactor Operator to Read Correct Instrument Prior to Synchronization of Diesel Generator.Synchronization Procedure Revised

ML19325D701
Person / Time
Site:	South Texas
Issue date:	10/19/1989
From:	Chewning R HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ST-HL-AE-3266, NUDOCS 8910250346
Download: ML19325D701 (4)

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,a P.O. Box 1700 liouston. Tbxas 77001 (713) 228 9211 Houston Ughting Ac Power. - , --

October 19, 1989 ST-HL- AE- 3266 File No.: G02

. S. Nuclear Regulatory Ccmmission .

Attention: Document Control Desk i Washington, DC 20555 -  !

$ South Texas Project Electric Generating Station t Unit 1 Docket No. STN 50-498 '

Special Report Regarding -

A Diesel Generator Nonvalid Failure on September 19 19H Pursuant to the South Texas Project Electric Generating Station Technical Specifications 4.8.1.1.3 and 6.9.2, Houston Lighting & Power submits the attached Special Report regarding a diesel generator nonvalid i failure which occurred on September 19, 1989.

If you should have any questions on this matter, please contact Mr. C. A. Ayala at. (512) 972-8628.

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' S w nw R. W. Chewning j l Vice President Nuclear Operations d

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Attachment:

Special Report Regarding a Diesel Generator Nonvalid Failure on September 19, 1989 I

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ST-HL- AE- 3266  !

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Regional Administrator, Region IV Rufus S. Scott f Nuclear Regulatory Camission Associate General Counsel  !

611 Ryan Plaza Drive, Suite 1000 Houston Lighting & Power Company l Arlington, TX 76011 P. O. Box 1700  :

Houston, TX 77001 George Dick, Project Manager i U. S. Nuclear Regulatory Commission INPO [

Washington, DC 20555 Records Center  ;

1100 Circle 75 Parkway '

Jack E. Bess Atlanta, GA 30339-3064 Senior Resident Inspector-Unit 1 3 f

c/o U. S. Nuclear Regulatory Commission Dr. Joseph M. Hendrie i P. O. Box 910 50 Be11 port Lane  :

Bay City, TX 77414 Be11 port, NY 11713

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J. I. Tapia D. K. Lacker .

Senior Resident Inspector-Unit 2 Bureau of Radiation Control 'I c/o U. S. Nuclear Regulatory Commission Texas Department of Health I P. O. Box 910 1100 West 49th Street [

2ay City, TX 77414 Austin, TX 78756-3189 '

J. R. Newman, Esquire I Newman & Holtzinger, P.C.

1615 L Street, N.W. i Washington, DC 20036 ,

R. L. Range /R. P. Verret Central Power & Light Company .;

P. O. Box 2121 ,

Corpus Christi, TX 78403  ;

R. John Miner (2 copies)  !

Chief Operating Officer City of Austin Electric Utility l 721 Barton Springs Road '

Austin, TX 78704 R. J. Costello/M. T. Hardt  !

City Public Service Board ,

P. O. Box 1771 San Antonio, TX 78296  ;

Revised 06/16/89 NL.DIST 1

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Attachment ST-HL-AE- 3266 fage 1 of 2 South Texas Project Electric Generating Station Unit J Docket No. STN 50-498 Special Report Regarding A Honvalid Failure of #13 Standby Diesel Generator on Septes_ber 19, 1989 DESCRIPTION OF EVENT:

On September 19, 1989, Unit I was in Mode 6 at 0% Reactor Power. At approximately 0100 houro Standby Diesel Generator (SDG) #13 was started for a slave relay surveillance test in conjunction with the SDG operability test.

The licensed Reactor Operator coordinating the test was utilizing two procedures simultaneously. When the operator arrived at the step which states

" parallel the diesel" a third procedure was entered. The operator established the conditions required to synchronize and turned to the Unit Supervisor for permission to close the SDG output breaker. Upon receiving permission, he turned back to the SDG control panel and observed the frequency meter to be at the 12:00 position. At approximately 0110 hours0.00127 days <br />0.0306 hours <br />1.818783e-4 weeks <br />4.1855e-5 months <br />, the operator closed the SDG output breaker with the SDG electrical output approximately 120 degrees out of phase in relation to the grid, mistaking the frequency meter for the synchronization scope. The output breaker immediately opened and the SDG tripped on reverse power.

Inspections were performed on the generator, the diesel engine and the generator breaker to identify suspected damage. The generator and the output breaker were inspected and electrical tests were performed with satisfactory results. The engine to generator coupling and the engine were inspected for loose fasteners, excessive bearing clearances and visual damage. No discrepancies were noted. The SDG was started at 0423 hours0.0049 days <br />0.118 hours <br />6.994048e-4 weeks <br />1.609515e-4 months <br /> on September 22, 1989, and the surveillance testing was successfully completed.

.CAUSE OF EVENT:

The cause of this event was failure of the Reactor Operator to read the correct instrument prior to synchronization the diesel generator. This operator had successfully synchronized diesel generator units on several previous occasions.

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[ ST-HL- AE- 3266 Page 2 of 2 CORRECTIVE ACTION: I

/; a. result ~of this event, the procedures whts control SDG synchrea12ation vill be revised to require that the synchronization task be perform d by one operator and that the procedure steps be read and checked of f by e-other operater.. This action will be completed by 2/9/90.

ADDITIONAL INFORMATION:

Per the criteria of' Regulatory Guide 2.108, the failure described in.

this report has been classified as a nonvalid failure. As such, the test interval for SDG #1.' remains 31 days. There have been 45 valid tests performed on SDG #13 since receipt of the Unit 1 Operating License. There have been no valid failuren.

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