05000254/LER-1981-007-03, /03L-0:on 810313,no Position Indication Found on Recirculation Pump 1A Discharge Valve MO-1-202-5A.Caused by Tripped Valve Motor Breaker Due to Several Shorted Conductors in Cable 12507 Leading to Valve Inside Drywell

/03L-0:on 810313,no Position Indication Found on Recirculation Pump 1A Discharge Valve MO-1-202-5A.Caused by Tripped Valve Motor Breaker Due to Several Shorted Conductors in Cable 12507 Leading to Valve Inside Drywell

ML20008F699
Person / Time
Site:	Quad Cities
Issue date:	04/01/1981
From:	Kaeppel F COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20008F697	List: 05000254/LER-1981-007, Forwards LER 81-007/03L-0 05000254/LER-1981-007-03, /03L-0:on 810313,no Position Indication Found on Recirculation Pump 1A Discharge Valve MO-1-202-5A.Caused by Tripped Valve Motor Breaker Due to Several Shorted Conductors in Cable 12507 Leading to Valve Inside Drywell
References
LER-81-007-03L-02, LER-81-7-3L-2, NUDOCS 8104210515
Download: ML20008F699 (3)

LER-1981-007, /03L-0:on 810313,no Position Indication Found on Recirculation Pump 1A Discharge Valve MO-1-202-5A.Caused by Tripped Valve Motor Breaker Due to Several Shorted Conductors in Cable 12507 Leading to Valve Inside Drywell

Event date:
Report date:
2541981007R03 - NRC Website

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U. S. NUCLEAR f.E!ULATORY COMP'.lSSloN NRC FORM 366 (7 77)

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3 EVENT DESCRIPTION AND PROB #3LE CONS"QUENCES h to :J l At 10:45 a.m. the unit operator observed that there was no position indication on I

1A Recirculation Pump discharge valve M0-1-202-5A.

The_ breaker for the valve motor l g;.gl was found tripped and it could not be reset. This caused LPCI mode of RHR to be l

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LER NUMBER: LER/R0 81-7/03L-0 11.

LICENSEE NAME:

Connonwealth Edison Company Quad-Cities Nuclear Power Station lit.

FACILITY NAME: Unit One IV.

DOCKET NUMBER:

050-254 V.

EVENT DESCRIPTION

At 10:45 a.m. on March 13, 1981, Unit One was in the RUN mode operating at a steady power level of 812 MWe and 2486 MWt.

At 10:45 a.m. the unit operator observed that the 1A Recirculation Pump discharge valve MO-1-202-SA showed no position indication. An equipment attendant, sent to investigate the problem, determined that the breaker, at notor control center 18/19-5, for the valve motor had tripped. The breaker was reset and it tripped again.

Technical Speci fication 3.5. A.3. requires the LPCI mode of the RHR system to be operable when irradiated fuel is in the reactor. Since the breaker tripped and the valve could not be operated, LPCI was declared inoperable.

This was due to the fact that LPCI loop-select depends on closure of valve MO-1-202-5A in the event of a recirc pipe break on the B recirc loop.

LPCI injection into the A loop with the SA valve remaining open would have likely resulted in water being injected into the shroud rather than into the core. Work Request Qll582 was written to investigate the cause and repair.

VI.

PROBABLE CONSEQUENCES OF THE CCCURRENCE:

Technical Specification 3.5 A.5. requires that both core spray subsysters, the containment cooling mode of RHR, two RHR pumps and two standby diesel generators be demonstrated to be operable at the time that LPCI is declared inoperable. Two RHR pumps used for containment cooling had been demonstrated to be operable on the previous day and remained operable thereafter. The renaining items were demonstrated to be operable per the Technical Specification at the time of declaring LPCI inoperable.

Safe plant operation was not affected by this occurrence.

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CAUSE

The 12 conductor control cable for the valve notor consists of cable #12506 from the notor control center to tne drywell, the drywell penetration itself, and cable #12507 within the drywell from the penetration to the valve motor. Several conductors of cable #12507 were shorted togetner, causing the breaker to trip and the position indication in the Control Room to be Icst.

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Vill. CORRECTIVE ACTION:

Cable #12507 runs through conduit and cable trays in the drywell and could not be visually inspected in its entirety. An electrical test revealed that several conductors of the cable had shorted. A temporary 5-conductor flexible cable was installed to replace the shorted conductors. The cable and hardware used to install it were approved under the Quality Assurance program. The ca'aie was run in open air and is routed away from heat sources within the drywell.

The cable was tested satisfactorily by stroking valve MO-1-202-5A and checking to see that the recirculation pump tripped when valve MO-1-202-SA was closed.

Work Request Qll606 was wr8 tten to permanently install cable #12507 at the time of the next convenient scheduled Unit One outage of sufficient length.

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