ML19211A170

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Responds to IE Bulletin 79-23, Potential Failure of Emergency Diesel Generator Field Exciter Transformer. Connections Between Low Kva Rated Transformers & High Kva Rated Emergency Generators Have Not Been Made
ML19211A170
Person / Time
Site: Arkansas Nuclear  Entergy icon.png
Issue date: 10/05/1979
From: Trimble D
ARKANSAS POWER & LIGHT CO.
To: Seyfrit K
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
IEB-79-23, NUDOCS 7912170134
Download: ML19211A170 (2)


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8 CENTRAL FILES PDR:HQ ARKANSAS POWER & LIGHT COMPANY POST OFFICE BOX 551 LITTLE ROCK, ARKANSAS 72203 (501) 371-4000 October 5, 1979 1-109-5 2-109-4 Mr- K. v. Seyfrit, Director Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011

Subject:

Arkansas Nuclear One-Units 1 & 2 Docket Nos. 50-313 and 50-368 License Nos. DPR-51 and NPF-6 IE Bulletin No. 79-23 (File: 1510 and 2-1510)

Gentlemen:

The following is provided in response to IE Bulletin 79-23.

Item No. 1 Determine whether nor not connections have been made between low KV rated transformers and high KVA rated EDGs 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 to Item 1 Connections have not been made between low KVA rated transformers and high KVA rated EDGs without adequate limitations on the flow of circulating currents. The action taken in making this determination consisted of draw-ing review and physical examination of Unit 1 and 2 installation.

Item No. 2 1594 189 Provide a schedule for the completion of a sustained full-load operation test of the EDGs 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 the results of the similar long duration, full-load test which has already been completed on the EDGs installed at your facility. The test should demonstrate 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 load 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 fre-quency requirements are maintained and that the cooling system functions within design limits.

MEMBEA MIDDLE SOUTH UTIUTIES S M

s' ' Mr. K. V. Seyfrit October 5, 1979 t Y Response to Item 2 Full-load tests have previously been completed on Unit 2 EDGs. This test demonstrated full-load carrying capability for a continuous inter-val of 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 /> was at 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 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.

Full-load tests have previously been completed on Unit 1 EDGs. This test demonstrated full-load carrying capability for a continuous interval of 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br /> at the continuous rating of the diesel generator. An additional test demonstrating full-load carrying capability for a continuous interval of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, of which 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> was at 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 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. Since a design error does not exist based on the review conducted per Item 1, an additional 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> full-load test will not be conducted since the above testing was satisfactorily completed.

The results of the full-load test on Unit 1 and 2 are available at the plant site for review.

Very truly yours, bWb 0 T David C. Trimble Manager, Licensing DCT:DEJ:nak cc: Mr. W. D. Johnson U.S. Nuclear Regulatory Commission P. O. Box 2090 -

Russellville, Arkansas 72801 Mr. N.C. Moseley Director, Division of Reactor Operations Inspection Nuclear Regulatory Commission 4350 East-West Highway Bethesda, Maryland 20555 1594 190