ML20058K776

Ro:On 750209,smoke Was Observed Coming from Motor Starter for Reactor Water Cleanup Discharge Isolation Valve Caused by Shorted Relay Coil Resulting in Overheating of Control Transformer

ML20058K776
Person / Time
Site:	Monticello
Issue date:	02/10/1975
From:	Larson C NORTHERN STATES POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20058K782	List: ML20058K776 ML20058L245
References
NUDOCS 9102140382
Download: ML20058K776 (1)

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i i NORTHERM STATES POWER COMPANY

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Hunticello, Minnesota 55362 s

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7 February 10, 1975 I

i Mr. J. G. Keppler, Director Regim TII

.tOffice of Inspection and Enforceury2r t

United States Nuclear Regulatory C==hsion o

7 799 Ibosevelt Road Glen Ellyn, Illinois 60137

Dear Mr. - Keppler:

MONTF'PT Tn MKLEAR GD EP.ATEXi PIET

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Docket Ib. 50-263 License Ib. LFR-22 Ort February 9,1975, s:cke was observed erm%g from the motor starter for reactor water cicam:p discharge isolatica. valve, ID 2339.

Investi-gation revealed that a shorted relay coil resulted in overheating of the control tr=nsformer in the r:otor starter.

Failure of the centrol transformer caused the isolatica valve to be in per:ble.

Neither this i

. valve nor another valve in the discharge line was placed in the c1csed

'3he f:liled position as required by Techlical Specificatien 3.7.D.2.

relay and notor starter were repicced anti the systesa was returned to norcal cperation within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

Further investigation of this mience is continuing.

Yours very :nly, 1,:

C

.x2 Plant !hnaget l

CEL/m en 6

cc: A Giambusso G Charnoff i

Minnesota Pollutien Control Agency Attn:

E A Pry:ina File f

1 7102140382 750210 t

CF ADDCK 05000263 CF g,

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