ML19253D009

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Responds to IE Bulletin 79-23.Exciter Power Transformer Neutral Is Not Connected to Generator Neutral.Generator Failure Described in Bulletin Will Not Occur
ML19253D009
Person / Time
Site: Limerick  Constellation icon.png
Issue date: 10/22/1979
From: Boyer V
PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To: Grier B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-79-23, NUDOCS 7912120511
Download: ML19253D009 (1)


Text

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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET PHILADELPHIA. PA.19101 V.S.BOYER vics.pnasicaNT s

Mr. Boyce H. Grier United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 ,

SUBJECT:

NRC Region 1 letter dated September 12, 1979 RE: I.E. Bulletin 79-23

" Potential Failure of Emergency Diesel Generator Field Exciter Transformer" Limerick Generating Station Units 1 and 2 Docket Nos. 50-352 and 50-353 File: GOVT l-1 (IE Bulletin 79-23)

Dear Mr. Grier:

Philadelphia Electric Company has reviewed IE Bulletin No. 79-23 submitted with the subject letter received on September 13, 1979.

The exciter power transformer used on the Limerick diesel units is manufactured by Basler Electric Company, and the primary winding is connected wye with floating neutral. No connection is made to the neutral of the wye connected generator, which is grounded through a resistor. Therefore, the problem addressed by IE Bulletin No. 79-23 will not occur on the Limerick units.

The Limerick diesel generators will be tested in accordance with Regulatory Guide 1.108. Tests will be conducted on Unit 1 diesel units as part of the preoperational start-up test phase. Tests on Unit 2 diesel units will be conducted similarly.

Sincerely, y,? S . L ,

. .% ,. - 7 -r Copy to: US Nuclear Regulatory Commission 1540 288 Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, DC 20555 7912120 N/