05000346/LER-1979-063-03, /03L-0 on 790523:containment Pressurizer Smoke Detector Ds 8635 Did Not Alarm When Tested.Caused by Broken Wire in Detector Fixed Base.Wire Repaired & Detector Successfully Tested

/03L-0 on 790523:containment Pressurizer Smoke Detector Ds 8635 Did Not Alarm When Tested.Caused by Broken Wire in Detector Fixed Base.Wire Repaired & Detector Successfully Tested

ML19270H216
Person / Time
Site:	Davis Besse
Issue date:	06/20/1979
From:	Chesko R TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19270H215	List: 05000346/LER-1979-063, Forwards LER 79-063/03L-0 05000346/LER-1979-063-03, /03L-0 on 790523:containment Pressurizer Smoke Detector Ds 8635 Did Not Alarm When Tested.Caused by Broken Wire in Detector Fixed Base.Wire Repaired & Detector Successfully Tested
References
LER-79-063-03L, LER-79-63-3L, NUDOCS 7906250258
Download: ML19270H216 (2)

LER-1979-063, /03L-0 on 790523:containment Pressurizer Smoke Detector Ds 8635 Did Not Alarm When Tested.Caused by Broken Wire in Detector Fixed Base.Wire Repaired & Detector Successfully Tested

Event date:
Report date:
3461979063R03 - NRC Website

text

U. S. NUCLE AR REGULATORY COMMISClON NRC FORM 3G6 (7 77)

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60 61 DOCKET NUVBE R 6d 69 EVENT DATE 74 75 HEPORT DATE 80 EVENT DESCRIPTION AND PROB AoLE CONSEQUENCES h o 2 l At 1815 hours0.021 days <br />0.504 hours <br />0.003 weeks <br />6.906075e-4 months <br /> on 5/23/79, the containment pressurizer smoka detector DS 8635 did not l o

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410c2_59-5000. Fvt. 274 Richard C. Chesko PHONE:

DVR 79-079 NAW OF PHEPAREH

TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-79-66_

DATE OF EVENT: May 23, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE:

Smoke detector DS 8635 did not alarm during test Conditions Prior to Occurrence:

The unit was in Mode 5, with Power (MWT) = 0, and

cad (Gross MWE) = 0.

Description of Occurrence: At 1815 hours0.021 days <br />0.504 hours <br />0.003 weeks <br />6.906075e-4 months <br /> on May 23, 1979, the containment pressurizer smoke detector DS 8635 did not alarm when tested per Surveillance Test ST 5016.06,

" Fire Detector Functional Test".

This placed the unit in the Action Statement of Technical Specification 3.3.3.8.a.

The technical specification requires the fire detection system to be operable in all modes.

The action statement requires a fire watch be established in the affected zone within one hour. A fire watch was estab-lished within one hour.

Designation of Apparent Cause of Occurrence: A broken wire in the detector fixed base was the cause of this occurrence. The wire may have been damaged during initial installation or a defect may have been present in the wire which did not separate prior to this occurrence or during previous testing.

Analysis of Occurrence: There was no danger to the health and s'afety of the public or to station personnel. The unit was in Mode 5 throughout the occurrence and the other smoke detectors in containment were all working, jorrective Action:

Investigation revealed a broken wire in the base of DS 8635 which was repaired under Work Request IC-013-16-79.

The detector was tested successfully at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on May 24, 1979, removing the unit from the action statement.

Failure Data: Although there have been no previous occurrences of broken wires in detectors, there has been one previous occurrence of a failed detector, see Licensee Event Report NP-33-79-02.

2238 213 LER #79-063