ML20012B736

Special Rept:On 900202,discovered That Overspeed Fuel Shutoff & Governor Lever Valve Tripped.Caused by Operator Leaving Valve in Tripped Position While Performing Maint Activity on 900201.Valve Reset & Tested

ML20012B736
Person / Time
Site:	South Texas
Issue date:	03/05/1990
From:	Vaughn G HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ST-HL-AE-3392, NUDOCS 9003160200
Download: ML20012B736 (4)

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.Hounton comptingLig & PoweranySouth Texas Project Electric P.O.Bos289 Generating Wadsworth, Texas ??483 sta  ?

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March 5, 1990 ,

ST HL-AE 3392 File No.: G02 10CFR50 i

U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555  !

South Texas Project Electric Generating Station Unit 2 Docket No. STN 50-499 >

Special Report Regarding A Diesel Generater Ronvalid Failure on February 2. 1990 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 failure ,

which occurred on February 2, 1990.

If yott should have any questions on this matter, please contact  ;

Mr. C. A. Ayala at (512) 972-8628 or mycelf at (512) 97 -7921. '

/ c G. E, Vaug i Vice President Nuclear Operations GEV/BEM/nl .

Attachment:

Special Report R,garding a Diesel Generator Non Valid Failure on February 2, 1990 t Y**

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A1/016.N12 A Subsidiary of Houston Industries incorportted

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ST.HL. AE. 3392 4  :

. Ho6ston Lighting & Power Company File No. : CO2 South Texas Project Electric Generating Stat, ion Fase 2 cc:

Regional Administrator, Region IV Rufus S. Scott Nuclear Regulatory Commission Associate General Counsel 611 Ryan Plaza Drive, Suite 1000 Houston Lighting & Power Company J . Arlington'. TX- 76011 P. O. Box 61867 f ..

. Houston, TX 77208 L

Coorge Dick, Project Manager Pi U.S. Nuclear Regulatory Commission INPO

, Washington, DC 20555 Records Center 1100 circle 75 Parkway JJ 1.-Tapia- Atlanta, CA 30339 3064 Senior Resident Inspector 7 c/o U. S. Nuclear Regulatory Dr. Joseph M. Hendrie

[ -Commission- '50 Be11 port Lane

[' .P. O. Box 910 Be11 port, NY 11743 Bay City, TX 77414 D. K. Lacker

'J. R. Newman, Esquire Bureau of Radiation Control Newman & Holtzinger, P.C. Texas Department of Health 1615'L Street, N.W. 1100 West 49th Street

., Washington, DC. 20036 Austin, TX 78704 D. E. Ward /R. P.:Verret LCentral Power & Light Company

P. 0 ; Box 2121 Corpus Christi,-TX 78403 J. C. Lanier Director of Cenoration City of Austin Electric Utility 721 Barton Springs Road Austin, TX -78704

'R. J. Costello/M. T. Hardt

-City Public'Sarvice Board P. O. Box 1771

, San Antonio, TX 78206 yv Revised 12/15/89 L4/NRC/

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Attachment ST.HL. AE.3392 Page 1 of 2  !

South Texas Project Electric Generating Station 7 Unit 2 -

. Docket No. STN 50 499 Special Report Regarding A Diesel Generator Nonvalid Failure On February 2. 1990 ,

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b Descrintion of Event:

i t On February 2, 1990 Unit 2 was in Mode 3. At 2121 hours0.0245 days <br />0.589 hours <br />0.00351 weeks <br />8.070405e-4 months <br />, Standby L Diesel Generator (SDG) 23 was started in the Emergency Mode to satisfy o Technical Specification surveillance requirements following the completion of a maintenance activity. The engine turned on starting air; however, it failed' #

to start and reach rated speed. The test was secured and troubleshooting was i performed to determine the cause of the failure. 1 An additional start of the engine was attempted. It was noted that no fuel was being injected into the engine. It was subsequently discovered that  ;

the overspeed fuel shutoff and governor lever valve was tripped. This valve shuts off fuel to the engine when an overspeed condition is detected. The valve was reset and the SDG was successfully tested at 0228 hours0.00264 days <br />0.0633 hours <br />3.769841e-4 weeks <br />8.6754e-5 months <br />. SDG 23 was ;

returned to operability on February 3, 1990 at 2115 hours0.0245 days <br />0.588 hours <br />0.0035 weeks <br />8.047575e-4 months <br />.

On February 1,1990 a preventive maintenance activity was performed to  :

. lubricate the shutdown linkage from the overspeed governor to the intake air l butterfly-valve. During the lubrication activity, the shutdown linkage was required to be stroked several times by a nonlicensed Reactor Plant Operator. i The operator was not certain of the correct reset position of the overspeed fuel' shutoff and governor lever valve. The procedure for restoration of the

'SDG to the standby mode did not contain specific instructions for restoration '

of the overspeed fuel shutoff and governor lever valve or the overspeed trip linkage. It is believed that the overspeed fuel shutoff and governor lever valve were left in the tripped position following the maintenance activity.

The operator performing the surveillance was unaware that the trip was present due to failure of the overspeed trip annunciator, ,

r Cause of Event:

The following causes have been identified for this event:

1. The procedure for restoration of the SDG to the standby modo did not include specific steps for restoratioa of the overspeed fuel shutoff and governor lever valve to the corrret position, o

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, bi :,6 .i Attachment ST.HL-AE.3392 page 2 of 2 :l Cause of Event Cont'd.

2. The nonlicensed Reactor Plant Operator did not fully understand the operation of the overspeed fuel shutoff and governor lever valve.

3. The overspeed trip annunciator failed to operate correctly.

Corrective Action:

The following corrective actions have been or will be taken as a result of this event:

1. The operating procedures for placing the SDGs in the standby mode have been revised to include instructions for verifying the proper.

positioning of the overspeed fuel shutoff and governor lever valve.

2. Correct operation of the SDG overspeed governor will be emphasized in the nonlicensed operator training program and a discussion of-this. event will be included in the next requalification training cycle for nonlicensed operators by July 6, 1990,

3. The overspeed trip annunciator has been repaired.

Additional Information; r

Per the criteria of Regulatory Guide 1.108, the failure described in this report has been classified as a nonvalid failure. The overspeed trip which was actuated occurred as a result of an error in the restoration of the system-following maintenance. It was detected during post maintenance testing. .At no time was the SDG declared operable with this. condition-present. There have been 25 valid tests of SDG 23 since completion of the diesel generator reliability demonstration. There have been no valid failures in the latt 20 valid tests. As such, the test interval for SDG 23 remains at once per 31 days.

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