ST-HL-AE-3937, Special Rept:On 911030,fuel Oil Leak Occurred at Cylinder 5R on High Pressure Fuel Oil Supply Line Connection to Fuel Oil Injector.Evaluation Underway to Determine Cause. Injector & Fuel Oil Line Replaced

Special Rept:On 911030,fuel Oil Leak Occurred at Cylinder 5R on High Pressure Fuel Oil Supply Line Connection to Fuel Oil Injector.Evaluation Underway to Determine Cause. Injector & Fuel Oil Line Replaced

ML20086F870
Person / Time
Site:	South Texas
Issue date:	11/27/1991
From:	Jump W HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
ST-HL-AE-3937, NUDOCS 9112040012
Download: ML20086F870 (4)

Text

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The Light co mp any .uniTna I'rojnt fluirk Gennaundiadun l'. a hos m Wadswouli Tnai 77m llouston Lighting & Power yt November 27, 1991 ST 1tL-AE-3937 File No.: G26 10CFR50 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DG 20555 i

South Texas Project Electric Generating Station l Unit 2 i l

Docket No. STN 50-499

! Special Report Regarding A Valid l L Failure of #22 Standby Diesel Generator on October 30. 1991 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 valid failure of the #22 Standby j Diesel Generator on October 30, 1991. '

If you should have any questions on this matter, please contact Mr. C. A. Ayala at (512) 972-8628 or myself at (512) 972-7205, i

W p,p William J. Jump i Manager, Nuclear Licensing JMP/ amp j

Attachment:

Special Report Regarding A Valid Failure of #22 Stanc" y Diesel Generator on October 30, 1991 l

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1. 9112 ^bo+

911127 PDR ADOCK 030'>O499 S PDR

Ilouston Lighting & Power Company South' Texas Project Electric Generating Station ST HL-AE 3937 File No.: C26 Page 2 cc:

Regional Administrator, Region IV Rufus S. Scott Nuclear Regulatory Commission Associate General Counsel 611 Ryan Plaza Drive, Suite 400 Houston Lighting 6 Power Company Arlington, TX 76011 P. O. Box 61867 Houston, TX 77208 George Dick, Project Manager U.S. Nuclear Regulatory Commission INPO Washington, DC 20555 Records Center 1100 circle 75 Parkway J. 1. Tapia Atlanta, GA 30339-3064 Senior Resident Inspector c/o U. S. Nuclear Regulatory Dr. Joseph M. Hendrie Commission 50 Be11 port Lane P. O. Box 910 Bellport, NY 11713 Bay City, TX 77414 D. R. lackor J. R. Newman, Esquire Bureau of Radiation Control Newman 6 Holtzinger, P.C, Texas Department of Health 1615 L Street, N.W. 1100 West 49th Street Washington, DC 20036 Austin, TX 78756-3189 D. E. Ward /T. M, Packett Central Power and Light Company P. O. Box 2121 Corpus Christi, TX 78403 J. C. Lanitr/M. B. Lee City of Austin Electric Utility Department P.O. Box 1088 Austin, TX 78767 K. J . Fiedler/M. T. Hardt City Public Service Board P. O. Box 1771 San Antonio, TX 78296 Revised 10/11/91

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-Attachment ST ilL AE 3937 Page 1 of 2 South Texas Project Electric Generating Station Unit 2 Docket-No. STN 50 499 i Special Report Regarding A Valid Failure of #22 Standby Diesel Generat:or on October 30. 1991 I. Descriotion of Event on October 30,1991, Unit 2 was in mode 6 and in a scheduled refueling outage.- At_approximately 1855 hours0.0215 days <br />0.515 hours <br />0.00307 weeks <br />7.058275e-4 months <br />, durint a preparatory 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> run

. for hot crankshaf t web deflection measurement, Standby Diesel Generator

-(SDG)'22 was secured due to a fuel oil leak at cylinder SR on the high  !

pressure fuel oilisupply'line connection to the fuel oil injector. The ,

- leak gradually developed into a spraying leak which became a potential-fire hazard due-to the. fuel oil spraying toward the exhaust header. As a result -the' engine run was terminated to protect the engine from damage.

The fuel injector 5R was removed on October 31, 1991 per the performance of the. Standby Diecel Generator Inspection (During Shutdown) procedure.

A visual inspection did not indicate any apparent cracks or thread damage; Some wear was observed on -the injector where the tubing ferrule seats. A dye penetrant test (PT) was performed on November 8, 1991; No indication of cracks were - found on the threaded area per _ the PT.

On November:19, 1991, the fuel; injector was- tested in the shop to attempt to duplicate.the fuel leakage. The high pressure fuel line was installed on the injector in the same configuration as in- the field. It.

was torqued l to '75 ft lbs at the' injection nozzle and at the testing a connection. Both connections were-observed to-leak when:the fuel line was pressurized up to.3600 psig. .The fuel line was disconnected and" u

!- re installed in.the reverse configuration. The connection at the -

injector did not leak but the connection at the testing connection was leaking. The results of this' test indicate that the seating surface in

-the high pressure fuel line may be the cause of the~ leaking.

II. Cause of Event i .A fuel 011= leak at the connection between the high pressure fuel oil-supply line and fuel injector created a potential _ fire hazard during an l

SDG 22 engine run. Additional evaluation 11s being performed to determine-the actual cause for the fuel oil leak.

R SREP)91-323,001

Attachment ST.HL AE 3937 Page 2 of 2 South Texas Project Electric Cencrating Station Unit 2 Docket No. STN 50 499 Special Report Regarding A Valid Failure of #22 Standby Diesel Generator on October 30. 1901 111. Annivsis of Event Due to the funi oil spraying toward the hot exhaust header, continued operation of SDG 22 would have constituted a fire hazard. SDG 22 would have responded to a test or emergency start signal, but the potential for a fire hazard caused this event to be classified as a valid failure.

In pcevious events, fuel leaks typically did not spray (atomize) toward hot surfaces and were judged to not be potential fire hazards.

Therefore, they were not classified as valid failures.

IV. Gorrective-Actions

1. The fuel injector was replaced on November 6, 1991.

2. The high pressure fuel line was replaced on November 9, 1991,

3. The high pressure fuel line was sent to a HL&P Materials Laboratory for Stereo Binocular Microscopic Examination to determine the cause of the event.

4. An evaluation of the results of the examination will be performed and further actions determined as needed. This will be addressed in a follow up report to be submitted by February 26, 1992.

V. Additional Information There have been two valid failures in the last 20 valid tests of SDG 22.

The number of valid failures in the last 100 valid tests is less than four. Therefore, the testing frequency for SDC 22 will be once per 7 days until seven consecutive failure free valid tests have been performed and the number of valid failures in the last 20 valid tests have been reduced to one.

SREPt91-323.001

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