ML19254F577

Responds to IE Bulletin 79-23, Potential Failure of Emergency Diesel Generator Field Exciter Transformer. No Connection Exists Between Low & High Kva Rated Transformers

ML19254F577
Person / Time
Site:	Hatch
Issue date:	10/24/1979
From:	Widner W GEORGIA POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-79-23, NUDOCS 7911120063
Download: ML19254F577 (2)

Text

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% Georgia Power Company /

/e 230 Peachtree Street I Post Othce Box 4S45 Atlanta, Georgia 3030' Tetcphone 404 522-6000

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Power Generation Department Georeia Power October 24'.[197 @S Ai! 06 ,, ,

United States Nuclear Regulatory Commission

Reference:

Office of Inspection rid Enforcement RII: JPO Region II - Suite " ' 50-321/50-366 101 Marietta Street I&E Bulletin 79-23 Atlanta, Georgia 30303 ATTENTION: Mr. James J. O'Reilly Gentlemen:

Georgia Power Company hereby submits the following information in response to your letter of September 12, 1979, which transmitted Bulletin 79-23, " Potential Failure of Emergency Diesel Generator Field Exciter Transformer".

This bulletin addressed possible deficiencies in the wiring of field exciter transformers such as those found during a test of the diesel generators at an operating facility. Spe ifically, two questions were raised and are answered herein:

QUESTION 1 Determine whether or not connections have been made between low KVA rated transformers and high KVA rated EDG's without adequate limitations on the flow of circulating currents. If applicable, provide a description of the corrective action being taken to address this problem.

RESPONSE 1 It was determined that no ground / neutral connections have been made between low KVA rated transformers and high KVA rated Emergency Diesel Generators. A review of applicable drawings indicated that this type of connection was not included in system design. A physical inspection of the circuits was made to ensure no unauthorized connections had been made.

QUESTION 2 Provide a schedule for the completion of a sustained full-load operation test of the EDG's for a duration of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, or provide

• ae results of the similar long duration, full-load test which has already been completed on the EDG's installed at your facility. The test should demonstrated full-load carrying capability for an interval of not less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, of which 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> should be at a load equivalent to the continuous rating of the diesel generator and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at a lead equivalent to the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> rating of the diesel generator. The test should also verify that voltage and frequency requirements are maintained and that the cooling system functions within design limits.

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w. b GeorgiaPower d United States Nucletr Regulatory Commission Office of Inspectior and Enforcement October 24, 1979 Page Two RESPONSE 2 A sustained 24 hour full-load test was successfully conpleted on the two Unit 2 dieuel generators on September 16, 1977. Unit 2 will again be performing this test as part of the Unit 2 Technical Specification surveillance requirement.

A sustained 24 hour full-load test will be performed on the three Unit 1 diesel generators by February 1, 1980. If there are further questions in this regard, please contact this . office. Sincerely, W. A. Widner Manager of Nuclear Operations WEB /mb xc: U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, D. C. 20555 R. F. Rogers, III kb\k .-}}