ML19262B030

Responds to IE Bulletin 79-23.Will Perform 24 Load Tests During Preoperational Testing of Emergency Load Generators. Problem Described in Item 1 Not Applicable

ML19262B030
Person / Time
Site:	Zimmer
Issue date:	10/25/1979
From:	Borgmann E CINCINNATI GAS & ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-79-23, NUDOCS 7912110439
Download: ML19262B030 (1)

Text

{{#Wiki_filter:~f / C - THE CINCINNATI GAS & ELECTRIC COMPANY ~ CIN CIN N ATI OHIO 4 5201 October 25, 1979 E. A. BO RG M AN N wc t *=r s'or NY 4 U.S. Nuclear Regulatory Cc:,.ission Region III 799 Roosevelt Road Glen Ellyn, Illinu _ 60137 ATIN: Mr. James C Ecp"ler Regional Director RE: hM. H. ZIMIER NUCLF>R PoliER STATION - UNIT 1 IE BULLETIN 79-23, POTENTIAL FAILURE OF DIERGENCY DIESEL GENERATORS FIELD EXCITER TRANSFORMERS DOCKET 50-358, W.O. 57322, JOB E-5590, ITBI # 2676 Gentlemen: This Ictter is in response to I.E. Bulletin #79-23 concerning potential failure of emergency diesel generator field exciter tnnsfomers. First, in response to item 1 of the referenced I.E. Bulletin, we have re-viewed this problem with the diesel generator vendor. The problem described by the bulletin does not exist at the Wm. H. Zimmer Nuclear Power Station - Unit 1. He excitation power transfomer primary winding does not have a neutral connection. The winding is connected phase to phase. In addition, 3 potential transfomer primary windings arc connected in wye with the neutral grounded. However, the generator neutral is grounded through a high resistance which provides adequate limitation on the flow of circulating currents induced by hamonic voltages. In response to item 2, the 24 hours load test described in the bulletin and in Regulatory Guide 1.108, revision 1 will be perfemed during preoperational testing of the emergency diesel generators. He test is tentatively scheduled for the first quarter of 1980. We believe this information provides a complete response to the subject I.E. Bulletin. Very truly yours, THE CINCINNATI GAS S ELECTRIC CCTIPANY [[ pW-E.A. BORGbteN, SENI0IVICE PRESIDENT WPC/kjd cc: U.S. Regulatory Commission Office of ISE R.F. Scheibel C.W. Beringhaus ) 32 030 R.E. Cotta B.K. Culver i:E:j$il " C 8'i" * "" 0CT 2 91979 J.R. Schott J.D. Flynn 7912110 )}}