ML20058L296
| ML20058L296 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 05/30/1974 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| AO-263-74-12, NUDOCS 9105140443 | |
| Download: ML20058L296 (3) | |
Text
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r Regulatory Docket File MSP NORTHERN STATES POWER COMPANY M I N N E A PQ t,,g S. M I N N E S OTA 55401 May 30, 1974
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Mr. J F O' Leary
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Y Directorate of Licensing JL1/L. b
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w United States Atomic Energy Commission
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Washington, DC 20545
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Dear Mr. O' Leary:
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MONTICELID NUCLEAR CENERATING PLINT
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Docket No. 50-263 License No. DPR-22 A0 263/74-12 Inoperability of HPCI Auxiliarv Oil Pumo o
r nerating Plant which we are A condition occurred at the Monticello Nuclee c
reporting to your office in accordance with '-
.on 6.7. B.1, Abnormal occurr-ance Reports, of the Technical Specification sr Provisional Operating License 1
On May 21, 1974, during testing of HPCI system modifications which were in-stalled during the recent refueling outage, the HPCI turbine auxiliary oil pump failed to start.
Investigation revealed that the pump motor acceleration relay auxilierv contact assembly (see attached figure) was partially dislocated, thus preventing the main morer contactor from energizing.
assembly was properly installed and the oil pump success-The i.xiliary contact All other DC motor control centers were inspected for dislocated fully tested.
auxiliary contacts; all were found in good condition.
Routine electrical maintenance was performed on this equipment during the It is believed that the auxiliary contact Spring 1974 refueling outage.
assembly was slightly dislocated when maintenance was performed and subsequent operations of the acceleration rela y resulted in further dislocation until the auxiliary contact failed to actuate. To prevent a recurrence, an inspection assembly will be incorporated into the electrical of the auxiliary contact maintenance procedure.
This occurrence did not affect safe operation of the plant since the RCIC i
and Automatic Pressure Relief systems were fully operable during the time that the auxiliary oil pump was inoperable.
9105140443 740530 CF ADDCK 05000263 CF 1
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NORTHt:.RN STATEC POWER COMF ANY Mr. J F O ' Le ary May 30, 1974 Page 2
- Co previous malfunctions of DC powered components have occurr nd due to dislocated auxiliary contacts.
It is felt that this is an iso.'.cted incident nd that the planned additions to the maintenance procedures will ensure reliable future performances.
Very truly yours, hr Y
L 0 Mayer, PE Director of Nuclear Support Services LOM/lh cc:
J G Keppler G Charnoff
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