ML19208C693

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Forwards IE Bulletin 79-23, Potential Failure of Emergency Diesel Generator Field Exciter Transformer. Action Required
ML19208C693
Person / Time
Site: 05000580, 05000581
Issue date: 09/12/1979
From: James Keppler
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To: Mcwhorter R
OHIO EDISON CO.
References
NUDOCS 7909270241
Download: ML19208C693 (1)


Text

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  1. pn atcoq'o, UNITED STATES 8*

~ 7, NUCLEAR REGULATORY COMMISSION d

E REGION 111 b[

799 ROOSEVELT ROAD o,

o GLEN ELLYN. ILLINOIS 60137 SEP11 On Pre-CPP The Ohio Edison Company ATTN:

Mr. R. J. McWhorter Vice President Engineering 76 South Main Street Akron, OH 44308 Gentlemen:

Enclosed is IE Bulletin No. 79-23 which requires action by you with regard to your power reactor facility with an operating license or a construction permit.

Should you have questions regarding this Bulletin or the actions required of you, please contact this office.

Sincerely,

&genhw VJames G. KejEpfer Director

Enclosure:

IE Bulletin No. 79-23 cc w/ encl:

Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Harold W. Kohn, Power Siting Commission 1049 153 990917o

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Accession No. 7908220104 SSINS No.:

682D UNITED STATES HbuLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.

20555 September 12, 1379 IE Bulletin No. 79-23 POTENTIAL FAILURE OF EMERGENCY DIESEL GENERATOR FIELD EXCITER TRANSFORMER Description of Circumstances:

Florida Power and Light Company recently reported a problem encountered during a 24-hour full load test of the emergency diesel generators (EDG) at their Turkey Point facility.

Approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> into the test, the A-EDG tripped due to a differential-relay lockout on B and C phases; the B-EDG was manually stopped, thus interrupting the test at that point in time.

Subsequent investigation and testing by the licensee revealed a design error on both the A and B EDGs which resulted in overheating of the Exciter Power Transformers (EPTs) at sustained high load operation.

The following nameplate data applies to the equipment installed at Turkey Point:

Emergency Diesel Generator General Motors (Electro-Motive Division)

Model EMD-999-20 Engine-turbocharged, 2 cycle, EMD design 20-645E4 Generator-EMD-design Model A-20 Exciter Power Transformer GE-single phase Model-9T24Y1004 Serial-MD Cycles-60 KVA 15 Insulation-4160 V The manufacturer's findings and recommendations regarding the above problem are described below:

"A potential problem can exist if the na p

tife primary windings of the excitation i DUPLICATE DOCUMENT to as the control power transformer (CP' Entire document previously entered into system under:

ANO Md6226/6y 1049 154 No. or geges:

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