ML19210E808

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Responds to IE Bulletin 79-23, Potential Failure of EDG Field Exciter Transformer. Each Transformer to Be Inspected for Direct or Indirect Grounding Condition
ML19210E808
Person / Time
Site: Shoreham File:Long Island Lighting Company icon.png
Issue date: 11/01/1979
From: Novarro J
LONG ISLAND LIGHTING CO.
To: Grier B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-79-23, NUDOCS 7912130015
Download: ML19210E808 (2)


Text

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~~Yi LONG ISLAND LIGHTING COM PANY 7 FLCO Jwaypegg SHOREHAM NUCLEAR POWER STATION

_ . . P.O. BOX 618, NORTH COUNTRY ROAD e WADING RIVER, N.Y.11792 November 1, 1979 SNRC-442 Mr. Boyce H. Grier Office of Inspection and Enforcement Region 1 U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 Long Island Lighting Company Shoreham Nuclear Power Station - Unit 1 Docket No. 50-322

Dear Mr. Grier:

NRC Inspection and Snforcement Bulletin No. 79-23 addresses design errors in the connection of the emergency diesel generator control / excitation power (EPT) transformers and the neutral of the generator. A deliberate or inadvertant connection between the neutral of the EPT and the generator neutral will result in high circulating currents due to harmonics, which in turn can lead to transformer damage or failure. This condition can also lead to tripping of the emergency diesel generator via operation of the generator differential relaying. This relaying is not by-passed in the emergency or fast-start mode. (Ref. I&E Circular 77-16).

The bulletin also requires a schedule for the completion of a sustained full-load operation test 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 />.

A review of the design and construction drawings has revealed that the neutral of the primary winding of the EPT is not grounded to the generator output. However, to ensure that such a connection will not be made, each emergency diesel generator will be inspected for the direct or indirect ground-ing condition. This inspection will be performed at the completion of construction activities, as part of the on-site acceptance testing.

1550 043 7

912130 C) ( $

FC-893 5 l

November 1, 1979 Mr. Boyce Grier Page 2 Preoperational tests for the emergency diesel generators are currently scheduled for summer of 1980. Testing shall be in accordance with regulatory positions C.2.a and C.2.b of Regu-latory Guide 1.108 (Revision 1, August 1977). The Shoreham FSAR Section 14.1.3.7.24 is currently being modified to reflect this.

Very truly yours, J

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J. P- Novarro Project Manager Shorehem Nuclear Power Station MAG:jm cc: Mr. Victor Stello, Director Office of Inspection & Enforcement Washington, D.C.

Mr. J. Higgins Site NRC Trailer 1550 044