ML19208C679

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Forwards IE Bulletin 79-23, Potential Failure of Emergency Diesel Generator Field Exciter Transformer. Action Required
ML19208C679
Person / Time
Site: Midland
Issue date: 09/12/1979
From: James Keppler
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To: Howell S
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
References
NUDOCS 7909270221
Download: ML19208C679 (1)


Text

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,,3 Docket No. 50-329 Docket No. 50-330 Consumers Power Company ATTN:

Mr. Stephen H. Howell Vice President 1945 West Parnall Road Jackson, MI 49201 Gentlemen:

Enclosed is IE Bulletin No. 79-23 which requires action by you with regard to your power reactor facilities 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, Wb 0

VJames G. k ^g Keppler Director

Enclosure:

IE Bulletin No. 79-23 cc w/ enc 1:

Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Ronald Callen, Michigan Public Service Commission Dr. Wayne E. North Myron M. Cherry, Chicago 1049 \\2\\

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Accession No. 7908220104 SSINS No.:

6820 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.

20555 September 12, 1979 IE Bulletin No. 79-23 4

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:

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