ML20058L167
| ML20058L167 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 03/25/1974 |
| From: | Larson C NORTHERN STATES POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 9105080339 | |
| Download: ML20058L167 (1) | |
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NORTHERN ETATER POWER COMPANY Monticello, Minnesota.55362
. March 25,.1974 51
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Mr. J. G. Keppler, Regional Director MAR Directorate of Regulatory Operations N
Regien III jf#Smn3 United States Atme w Energy e m issian pdu # p 799 Roosevelt Read g
x Glen Ellyn, Illinois 61073 D /L t \\g
Dear Mr. Keppler:
MNTI(mn NUCLEAR GENERATING PIANI Docket No. 50-263 License No. DPR-22 I
Reactor low Low Water Level-ECCS Initiating Switch Malfunction A condition occurred at the Monticello Nuclear Generating Plant which we are Icpuulng to your office in accordance with Section 6.7.B.1, Abnormal Occurrence Reports, of Appendix A, Technical Specifications, of Provisicnal Operating License DPR-22.
On March 22, 1974, while performing a routine surveillance test, one of two switches an one of the four " Reactor Im Im Level-ECS Initiation" instruments was found failed in the tmtripped state. At the time the switch malfunction was ddscovered, the plant was in a cold shutdown condition for reactor refueling operations. The cause of the malfunctim has not been id-ntified; however, as a precautionary measure, the switch was replaced, and the instrtment was calibrated. Satisfactory repeatable operation of the switch was denenstrated in subsequent testirg of the instrument. The instnment involved has been placed on an accelerated eight week surveillance test schedule.
The switch =a16-tim did not result in an unsafe plant condition since redundant instruments were found to trip at the desired trip setting and would have provided the required ECCS initiation function at the desired trip setting.
Yours very y,
C.
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Plant Manager
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cc: J F O'Imary, Directerate of Licensing
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G Charnoff Minnesota Pollution Control Agency Attn: E A Prvzina 9105080339 740325
-e CF ADOCK 05000263
$h File cF Copies sent by telecopier to Keppler and O'Imary
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