ML20128B956

Special Rept:On 930102,ST Procedure in Progress D21 EDG Kilowatt Output Was Erratic & Unstable.Caused by Loose Wire on D21 EDG Electronic Governor.Unit 1 EDGs Were Inspected & Verified Not to Have Same Conditions

ML20128B956
Person / Time
Site:	Limerick
Issue date:	01/28/1993
From:	Doering J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9302030237
Download: ML20128B956 (3)

Text

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'" T.S. 6.9.2 PIIILADELPIIIA ELECTRIC COMPANY.

LIMERICK GENERATING STATION P. O. BOX 2300 SANATOGA. PA 19464-2300 (215) 3271200 EXT. 2000 January 28,-1993 J. DoERING, JR.

g gr g f Docket No. 50-353 License No. NPF-85 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

Limerick Generating Station, Unit 2 Special Report for a Valid Emergency Diesel Generator Test Failure

REFERENCE:

Technical Specifications Sections 4.8.1.1.3 and 6.9.2 This Special Report is submitted pursuant to the requirements of Technical Specifications (TS) Section 6.9.2 as required by TS Surveillance Requirement 4.8.1.1.3. TS Surveillance Requirement 4.8.1.1.3 requires reporting of all diesel generator failures, valid or nonvalid, within 30 days. The report is required to include the information reccmmended in Regulatory Position C.3.b of Regulatory Guide (RG) 1.108, " Periodic Testing of Diesel Generator Units as Onsite Electric Power System at Nuclear Power Plants," Revision 1, August 1977.

On January 2, 1993, with Unit 2 at 68% power level, Operations personnel were performing Surveillance Test (ST) procedure ST-6-092-361-2, "D21 Diesel Generator Operability Verification." While the ST procedure was in progress, the D21 Emergency Diesel Generator (EDG) kilowatt output was erratic and unstable. Operations personnel immediately-responded to this event by reducing the D21 EDG load and opening the D21 EDG output breaker. Operations personnel then placed the D21 EDG handswitch to 'stop' to shutdown the diesel engine. The D21 EDG was declared inoperable at approximately 1003 hours0.0116 days <br />0.279 hours <br />0.00166 weeks <br />3.816415e-4 months <br /> on January 2, 1993.

An investigation on Jantory 2, 1993, determined that the cause of this event was a loose wire on the D21 EDG electronic governor. Che cause or time that the wire became loose cannot be conclusively determined. The D21 EDG was last successfully tested on December 23, 1992. With the wire on the electronic governor in this condition, the operability of the D21 EDG following a design basis eveat such as a safe shutdown earthquake ,

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could not be assured. As auch, the application of the safeguard p 430203On37 930128 PDR AEOCK 05000353 ,

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1oads for.the D21 EDG could not be assured during' load sequencing following a design basis accident coincident with a loss of' offsite power event.

The D21 EDG was declared inoperable for.arnroximately 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> as'a-result of this event. Because tha tire ~in the-EDG electronic governor was not analyzed for its .s-found condition, the operability of the D21 EDG following a design basis-event is uncertain. However, the D22 and.D24 EDGs were available (the:D23 EDG was inoperable for testing), and would have'provided adequate AC power to the Unit 2 Safety Related loads in the event of an actual loss of offsite power.

Operations personnel tightened the loose. wire on the D21 EDG electronic governor, and procedure ST-6-092-361-2 was completed satisfactorily at 2158 hours0.025 days <br />0.599 hours <br />0.00357 weeks <br />8.21119e-4 months <br /> on January 3,.1993. The electronic governors for the remaining three Unit 2 EDGs and all four Unit 1 EDGs were inspected and verified to not have the same condition.

The D21 EDG vas declared operable on January 3, 1993, at 2203'  ;

hours.  :

The D21 EDG failure was classified as a valid failure using the guidance of RG-1.108, Revision 1, August 1977, Section C.2.e(5). Since this D21 EDG valid failure is the first failure-in the last 20 valid demands, the ST procedure-monthly frequency-is not required to be changed in accordance with TS Section 4.8.1.1.2.a. ,

If you have any questions, please contact Mr. Gil-J. Madsen at (215) 327-1200.

Sincerely, l'

DMS:cah

, cc: T. T. Martin, Administrator, Region I, USNRC T. J. Kenny, USNRC Seniot Resident Irmpector, LGS-

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D. M. Smith.- 52C '

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D.:R. Helwig - SMB1-1 '

G. a. Rainey -'52A-6 J. D. Cotton - 53A-l' J. A. Muntz - SSB3-1  :

G. J.-Madsen - SMB2-4 E. W. Callan - SMB3-1 J. B. Cotton - 53A-1 .

J. J. McElwain - SSB4-3 R. N.-Charles - 51A-1 G. J. Beck, Jr., 52A-5 '

Secretary, NCB'- SlA-13 Correspondence Release Point - SMB1-2 Commitment Coordinator - 52A-5 PA DER.BRP Inspector - SMB2-4 4

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