ML20137K768
| ML20137K768 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 01/13/1986 |
| From: | Mangan C NIAGARA MOHAWK POWER CORP. |
| To: | Starostecki R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| (55(E)-85-29), (NMP2L-0581), (NMP2L-581), NMP2L-581, NUDOCS 8601240214 | |
| Download: ML20137K768 (2) | |
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Y NIAGARA NUMOHAWK NIAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARP WEST. SYRACUSE. N '.13202/ TELEPHONE (315) 4741511 January 13, 1986 (NMP2L 0581)
Mr. R. W. Starostecki, Director U.S. Nuclear Regulatory Commission Region I Division of Reactor Projects 631 Park Avenue King of Prussia, PA 19406 Re: Nine Mile Point - Unit 2 Docket No. 50-410
Dear fir. Starostecki:
Enclosed is a final report in accordance with 10CFR50.55(e) for the problem concerning incorrect ohmic and wattage rating of excitation circuit matching resistor for the High Pressure Core Spray System diesel generator.
Very truly yours,
\\ O % f tt C. V. Mangan v Senior Vice President CVM/GG/cla (1377H) xc: Director of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 20555 R. A. Gramm, NRC Senior Resident Inspector i/
8601240214 860113ADOCK 05000410 PDR PDR S
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a NIAGARA M0 HAWK POWER CORPORATION NINE MILE P0 INT - UNIT 2 DOCKET N0. 50-410 Final Report for a Problem Concerning Incorrect Ohmic and Wattage Rating of Excitation Circuit Matching Resistor for High Pressure Core Spray System Diesel Generator (55(e)-85-29)
Description of the Problem It was discovered during testing of the High Pressure Core Spray System diesel generator that the matching resistor af its exciter field circuit was incorrectly sized for both resistance and wattage.
The incorrect rating would result in degraded generator output and failure of the resistor itself.
Analysis of Safety Implications 1.
Incorrect impedance rating of resistor:
A resistor rating of 50 ohms is not adequate to produce enough exciter field current to meet the rated power output of the diesel generator, thereby degrading the High Pressure Core Spray system during generator and main pump motor starting.
However, this incorrect resistance would have been discovered during testing because it is required that generator output rating be verified as part of preoperational testing and prior to cammercial operation.
2.
Incorrect wattage rating of resistor:
The resistor wattage rating of 225 watts is not adequate for the resistor to sustain the normal exciter field current during normal operation. The f ailure mechanism of this resistor would probably be an open circuit.
This failure of the resistor would render the High Pressure Core System diesel generator inoperative.
Had the above conditions remained uncorrected, it could have adversely affected the safety of operations of the plant.
Corrective Actions The incorrectly sized resistor will be replaced with a 25 ohm /5.1 amp resistor in accordance with Engineering and Design Coordination Report No. C46,134 and associated Field Deviation Disposition Request No. KGI-4636, Revision 0.
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