05000346/LER-1979-108-03, /03L-0:on 791108,during Normal Plant Evaluation of Switching Decay Heat Removal Pumps,Pump 1 Failed to Start Remotely & Locally at Breaker.Caused by Faulty Cutout Switch.Switch Assembly Replaced

/03L-0:on 791108,during Normal Plant Evaluation of Switching Decay Heat Removal Pumps,Pump 1 Failed to Start Remotely & Locally at Breaker.Caused by Faulty Cutout Switch.Switch Assembly Replaced

ML19290B673
Person / Time
Site:	Davis Besse
Issue date:	12/06/1979
From:	Naylor R TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19290B666	List: 05000346/LER-1979-108, Forwards LER 79-108/03L-0 05000346/LER-1979-108-03, /03L-0:on 791108,during Normal Plant Evaluation of Switching Decay Heat Removal Pumps,Pump 1 Failed to Start Remotely & Locally at Breaker.Caused by Faulty Cutout Switch.Switch Assembly Replaced
References
LER-79-108-03L, LER-79-108-3L, NUDOCS 7912130486
Download: ML19290B673 (2)

LER-1979-108, /03L-0:on 791108,during Normal Plant Evaluation of Switching Decay Heat Removal Pumps,Pump 1 Failed to Start Remotely & Locally at Breaker.Caused by Faulty Cutout Switch.Switch Assembly Replaced

Event date:
Report date:
3461979108R03 - NRC Website

text

U.S. NUCLEAR REGUL ATORY COMMISSION NRC FORM 3GG (7-77)

LICENSEE EVENT REPORT CONTROL BLOCK: l l

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8 60 bl DOCKET NUMBER 66 69 EVEN T QATE 14 13 REPCRT DATE 63 5O R EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h l On 11/8/79 at 1845 hours0.0214 days <br />0.513 hours <br />0.00305 weeks <br />7.020225e-4 months <br /> during a normal plant evolution of switching decay heat re-

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f moval (DPR) pumps, DHR Pump 1 failed to start remotely and also failed to start local-l o

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4 l ly at the breaker. The unit was in Mode 5, and no reactivity changes were taking l

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supplying cooling water in the event that DHR was necessary.

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l Maintenance Uork Order 79-3511, the cutout switch assembly was replaced, and the unit l l was tested and returned to service at 1720 hours0.0199 days <br />0.478 hours <br />0.00284 weeks <br />6.5446e-4 months <br /> on November 13, 1979.

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Richard W. Naylor PHONE:

DVR 79-162 NAYE OF PREPARER

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TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-79-125 l

i DATE OF EVENT: November 8, 1979 FACILITY: Davis-Besse Unit 1 Decay Heat Pump 1 f ailed to start during a normal IDENTIFICATION OF OCCURRENCE:

evolution.

The unit was in Mode 5, with Power (MWT) = 0, and Conditions Prior to Occurrence:

Load (Gross MWE) = 0.

On November 8,1979 at 1845 hours0.0214 days <br />0.513 hours <br />0.00305 weeks <br />7.020225e-4 months <br /> during a normal plant Description of Occurrence:

evolution of switching decay heat removal pumps (DHR), DHR Pump 1 failed to start Several attempts were remotely and also f ailed to start locally at the breaker.

The unit was in made'to close the breaker without success by operations personnel. Technical Specification 3.1.2 Ibde 5, and no reactivity changes were taking place.

requires one boron injection flowpath from the concentrated boric acid storage system DHR Pump via a DHR Pump to the Reactor Coolant System to be operable while shutdown.

2 was operable during the period that DHR Pump 1 was inoperable.

The apparent cause of the occurrence was Designation of Apparent Cause of Occurrence: switch was replaced, and the original was disassem-switch. The cutout a faulty cutout the stem was slightly This showed that the bolted unit was gouged and that bled.

bent.

There was no danger to the health and safety of the public or Analysis of Occurrence:The unit was in Mode 5, and the redundant DHR Pump was operable to station personnel.

that DHR was necessary.

and capable of supplying cooling water in the event Under Maintenance Work Order (MWO) 79-3511, the cutout swit:h

Corrective Action

assembly was replaced, and the unit was tested and returned to service at 1720 hours0.0199 days <br />0.478 hours <br />0.00284 weeks <br />6.5446e-4 months <br /> The breaker was cycled several times from the control room on November 13, 1979.

A preventative maintenance program was established to check and the pump was run.

cutout switch operation and linkage at refueling outages during other breaker main-This MWO covers all breakers on C1 and D1 buses.

tenance.

switch There has been one previously reported occurrence of a cutout Failure Data:

failure, see Licensee Event Report NP-33-79-ll7.

1553 182 LER #79-108