ML19208C681

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Forwards IE Bulletin 79-23, Potential Failure of Emergency Diesel Generator Field Exciter Transformer. Action Required
ML19208C681
Person / Time
Site: La Crosse File:Dairyland Power Cooperative icon.png
Issue date: 09/12/1979
From: James Keppler
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To: Linder F
DAIRYLAND POWER COOPERATIVE
References
NUDOCS 7909270224
Download: ML19208C681 (1)


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NUCLEAR REGULATORY COMMISSION

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GLEN ELLYN. ILLINOIS 60137 Docket No. 50-409

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eM' Dairyland Power Cooperative ATTN:

Mr. F. W. Linder General Manager 2615 East Avenue - South La Crosse, WI 54601 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,

(/ James G. k ier bul a v Kepp Director

Enclosure:

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

Mr. R. E. Shimshak, Plant Superintendent Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Anthony Roisman, Esq.,

Attorney 1049 125 27_3 7909270

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 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 nm prit h l

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

ANO 790$220/ON 1049 126 No. of pages:

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