ML19319B741

RO NP-33-77-31:on 770726,chlorine Detector 5358B Failed to Isolate Control Room Ventilation Sys During Functional Test. Caused by Loose Wire Connections in Detector.Connections Tightened & Detector Declared Operable within 1-h

ML19319B741
Person / Time
Site:	Davis Besse
Issue date:	08/19/1977
From:	George T, Lingenfelter J TOLEDO EDISON CO.
To:
Shared Package
ML19319B615	List: ML19319B614 ML19319B741
References
NUDOCS 8001270196
Download: ML19319B741 (2)

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LICENSEE CVENT REPORT

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@gl Chlorine Detecto.,AE 5358B failed to isolate the Control Rooi: Ventilation! 2 r as .

,o gl System during the Chlorine Detection System Functional Test.' The a sa w gi,

, . station was placed in the Action Statement of Technis 1 Specification a l

@g[ 3.3.3.7. (NP-33-77-31) .

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CAust etscairticee l It is suspected _ p at electrical connc:Llwas were never tightened during l gg'initialinstallation. All chlorine detectors were inspected for loose ^j connections to prevent recurrence.

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TOLEDO EDISON CCMPANY

$ DAVIS-BESSE UNIT ONE NUCLEAR PCWER STATION SUPPLEMENTAL INF0F3ATION FOR LER "P-33-77-31 i

DATE OF EVENT: July 26, 1977 FACILITY: Davis-Besse Unit 1

- IDENTIFICATION OF OCCURRENCE: Chlorine Detector AE 5358B declared inoperable.

I Conditions Prior to Occurrence: The plant was in Mode 3, with Power (MWT) = 0 and Load (MWE) = 0.

Description of occurrence: At 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on July 26, 1977, during the perfor=ance cf ST 5037.02, Chlorine Detection System Functional Test, Chlorine Detector AE 5358B failed to isolate the Control Room Ventilation System. The Shift Fore =an was immediately notified and the Control Room Normal Ventilation System was placed in the recirculation mode. This failure placed the station in the Action State-ment of Technical Specification 3.3.3.7.

Designation of Apparent Cause of occurrence: After investigation, Instrument and Control personnel discovered several loose wire connections in the detector. These loose connections caused the detector to fail. It is suspected that these connec-tions were never tightened during initial installation.

Analysis of Occurrence: Since all backup chlorine detectors were still operable and there was no actual chlorine leakage, there was no threat tc the health anc safety of the public or station personnel.

Corrective Action: Under a maintenance work order, the loose connections were tightened and at 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br />, the detector was retested and declared operable.

This removed the station from the Action Statement of Technical Specification 3.3.3.7. .

To prevent recurrence, all of the chlorine detectors were inspected for loose connections and none were found.

Failure Data: No previous similar events have occurred.

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