ML19329B918

RO NP-33-17-13:on 770607,seismic Trigger Failed to Operate During Surveillance Test.Cause Undetermined.Seismic Trigger Replaced W/Nondefective Unit

ML19329B918
Person / Time
Site:	Davis Besse
Issue date:	06/29/1977
From:	Batch S, Lingenfelter J TOLEDO EDISON CO.
To:
Shared Package
ML19329B913	List: ML19329B912 ML19329B918
References
NUDOCS 8002060907
Download: ML19329B918 (2)

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tvt4f of SCmiritone gg At approximately 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> on June 7, 1977, during Surveillahce Tes't

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DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-77-13 l

• y DATE OF EVENT:* June 7, 1977

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FACILITY: Davis-Besse Unit 1

. _ . .__ IDENTIFICATION OF OCCURRENCE: Seismic trigger, which is required to actuate -

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Conditions Prior to Occurrence: The station was in Mode 5 with Power (MWE)-0,

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Description of Occurrence: At approximately 1530 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.82165e-4 months <br /> on June 7, 1977, during Surveillance Test, ST 5034.01, it was found that the seismic trigger was not operating properly. The seismic trigger.vas firing spuriously. I L

Desianation of Apparent cause of Occurrence: The station Instrument and Control l l (I&C) Lab did not determine the cause of this defective behavior. The trigger

)' is being returned to the manufacturer for analysis. The unit was replaced with a non-defective seismic trigger on June 25, 1977, which removed the station from

, the Action Statement of Technical Specification 3.3.3.3.

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Analysis of Occurrence: Since there was no seismic event requiring seismic moni-toring during the period that the unit was not operating properly, no damage to the health and safety of the public or station personnel occurred.

Corrective Action

The seismic trigger was replaced with a non-defective unit by i station personnel.

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• l Failure Data: No previous similar events have occurred.

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