ST-HL-AE-5538, Special Rept on 961204,nonvalid Failure of Sdg 11 Occurred. Caused by Lack of Knowledge of Indications Available to Verify Sdg Output Breaker Completely Rack In.Training Bulletin Was Issued to Operations Personnel

Special Rept on 961204,nonvalid Failure of Sdg 11 Occurred. Caused by Lack of Knowledge of Indications Available to Verify Sdg Output Breaker Completely Rack In.Training Bulletin Was Issued to Operations Personnel

ML20133C070
Person / Time
Site:	South Texas
Issue date:	12/31/1996
From:	Parkey G HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ST-HL-AE-5538, NUDOCS 9701070027
Download: ML20133C070 (4)

Text

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The Light company Houston Lighting & Power ut esas mject lectrc nerat og tat on . x289 Wmorth, Texas 77483 l

l December 31, 1996

! ST-HL-AE-5538 File No.: G02 l I

10CFR50 1

I i

U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 South Texas Project Unit 1 Docket No. STN 50-498 Special Report Regarding a Nonvalid Failure of Standbv Diesel Generator #11 on December 4.1996 l

Pursuant to South Texas Project Technical Specifications 4.8.1.1.3 and 6.9.2, the South Texas Project submits the attached Special Report regarding a nonvalid failure of Standby -

Diesel Generator #11 on December 4,1996. l If you should have any qt;estions on this matter, please contact either Mr. S. M. Head at (512) 972-7136 or me at (512) 972-7800.

G. L. Parkey Plant Manager, Unit 1 9701070027 961231 ,

l PDR ADOCK 05000498 S PDR J py g l DNB/

Attachment:

Special Report Regarding a Nonvalid Failure of Standby Diesel Generator #11 on December 4,1996 sREP-96\5538 000047 s u wis25i2 Project Manager on Behalf of the Participants in the South Texas Project

Houston Lighting & Power Company South Texas Project Electric Generating Station ST-HL-AE-5538 File No.:G02 Page 2 Leonard J. Callan Rufus S. Scott Regional Administrator, Region IV Associate General Counsel 4

U. S. Nuclear Regulatory Commission Houston Lighting & Power Company

611 Ryan Plaza Drive, Suite 400 P. O. Box 61067 Arlington, TX 76011-8064 Houston, TX 77208 Thomas W. Alexion Institute of Nuclear Power l Project Manager, Mail Code 13H3 Operations - Records Center l U. S. Nuclear Regulatory Commission 700 Galleris Parkway Washington, DC 20555-0001 Atlanta, GA 30339-5957 ,

l David P. Loveless Dr. Bertram Wolfe

Sr. Resident Inspector 15453 Via Vaquero c/o U. S. Nuclear Regulatory Comm. Monte Semno, CA 95030 P. O. Box 910

Bay City, TX 77404-0910 Richard A. Ratliff Bureau of Radiation Control J. R. Newman, Esquire Texas Department of Health Morgan, Lewis & Bockius 1100 West 49th Street  !

l800 M Stmet, N.W. Austin, TX 78756-3189 '

Washington, DC 20036-5869 J. R. Egan, Esquire M. T. Hardt/W. C. Gunst Egan & Associates, P.C.

City Public Service 2300 N Street, N.W.

P. O. Box 1771 Washington, D.C. 20037 San Antonio, TX 782%

J. C. Lanier/M. B. Lee U. S. Nuclear Regulatory Commission City of Austin Attention: Document Control Desk Electric Utility Depanment Washington, D.C. 20555-0001 721 Banon Springs Road Austin, TX 78704 Central Power and Light Company J. W. Beck A7TN: G. E. Vaughn/C. A. Johnson Little Harbor Consuhants, Inc.

P. O. Box 289, Mail Code: N5012 44 Nichols Road Wadswonh, TX 77483 Cohassett, MA 02025-1166

o .

i Attachment ST-HL-AE-5538 j Page 1 of 2 '

Special Report Regarding a Nonvalid Failure of ,

Standbv Diesel Generator #11 on December 4.1996 Description of Event:

At 1402 on December 4,1996, Unit I was at 100% power. Standby Diesel Generator (SDG)  :

1. 11 had been removed from service to adjust the field generator brushes. Upon completion of the brush adjustment, SDG #11 was being tested to demonstrate its operability. During the -

operability test, the output breaker for SDG #11 did not close as expected when the control ,

room handswitch was placed in the closed position. l 1

Personnel sent to inspect the breaker found that the breaker was not completely racked in to the " connected" position. The breaker was then racked in and at 1427, the breaker was j

closed, SDG #11 was loaded to 25%, and subsequently declared operable.

When this event occurred, SDG #1I was already considered inoperable due to maintenance.  ;

SDG #1I was retumed to service within the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed by the LCO action statement of l

the Technical Specifications. '

Cause of the Event:

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I This event occurred because the non-licensed operator did not completely rack in the output '

breaker for SDG #11 following maintenance. The root cause is the operator's lack of ,

knowledge of indications available to verify the SDG output breaker is completely racked in l

to the " connected" position.  :

Event Analysis:  ;

i This event occurred because the non-licensed operator did not completely rack in the output  !

breaker. Per the criteria in Regulatory Guide 1.108, this event has been classified as a non-valid failure.  !

Corrective Actions:

A Training Bulletin was issued to Operations personnel describing the event and the secondary indications available for ensuring Class IE 4160V breakers are racked completely -

in to the " connected" position. t Non-licensed operators will be trained on the intemal workings of the Class IE 4160V i breakers in initial and requalification training by June 30,1997.

I SREP-%\5538 sTI: 30152512

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Attachment 1 ST-HL-AE-5538 Page 2 of 2 i Additional Information:  !

A mechanical interlock prevented the breaker from closing during this event. When the l breaker is completely racked in, this interlock is disengaged. Closing the breaker for the  ;

operability test further demonstrates that the rechanical interlock has been disengaged.

There has been 1 valid failure in the last 20 valid tests and 3 valid faibres in the last 100 i valid tests of SDG #11. Therefore, the testing frequency of SDG #11 remains at once per 31 ,

days.

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sREP-96\5538 sTI: 30152512