05000346/LER-1979-024-03, /03L-0 on 790214:fire Alarm Panel C4706 Signaled, Indicating Laundry Room Detector DS8630 as Source.Detector Declared Inoperable as No Cause for Signal Found.Cause of Event Undetermined.Possibly Due to Gases or Dust

/03L-0 on 790214:fire Alarm Panel C4706 Signaled, Indicating Laundry Room Detector DS8630 as Source.Detector Declared Inoperable as No Cause for Signal Found.Cause of Event Undetermined.Possibly Due to Gases or Dust

ML19282B684
Person / Time
Site:	Davis Besse
Issue date:	03/12/1979
From:	Fulmer S TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19282B682	List: 05000346/LER-1979-024, Forwards LER 79-024/03L-0 05000346/LER-1979-024-03, /03L-0 on 790214:fire Alarm Panel C4706 Signaled, Indicating Laundry Room Detector DS8630 as Source.Detector Declared Inoperable as No Cause for Signal Found.Cause of Event Undetermined.Possibly Due to Gases or Dust
References
LER-79-024-03L, LER-79-24-3L, NUDOCS 7903160120
Download: ML19282B684 (2)

LER-1979-024, /03L-0 on 790214:fire Alarm Panel C4706 Signaled, Indicating Laundry Room Detector DS8630 as Source.Detector Declared Inoperable as No Cause for Signal Found.Cause of Event Undetermined.Possibly Due to Gases or Dust

Event date:
Report date:
3461979024R03 - NRC Website

text

NRC FORM 366 U. S. NUCLEAR REGULATORY COMMISSION (7 771 LICENSEE EVENT REPORT CONTFX)L BLOCK:

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8 60 61 DOCKET NUVBER 68 63 kVENT DATE 74 7b REPORT DATE 80 EVENT DESCRIPTIC,N ANC PROB ABLE CONSEQUENCES h l On 2/14/79, investigation of an alarm signal from fire alarm panel C4706 indicated thel o 2 j laundry room detector DS8630 as the source.

Continued investigation revealed no obscrt o 3 [o TTI Ivable cause for the alarm. Attempts to clear the alarm failed and at 2145 hours0.0248 days <br />0.596 hours <br />0.00355 weeks <br />8.161725e-4 months <br /> on l

IbE I 2/14/79, the detector DS8630 and associated panel C4706 were declared inoperable, I

o e l Placind the unit in the Action Statement of T.S. 3.3.3.8.

At 2235 hours0.0259 days <br />0.621 hours <br />0.0037 weeks <br />8.504175e-4 months <br /> on 2/14/79, l

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There was no danger to the public or unit personnel.

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TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-79-28 DATE OF EVENT: February 14, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Fire alarm panci C4706 inoperable due to erroneous detector The unit was in Mode 1, with Power (MWT) = 2375, Conditions Prior to Occurrence:

and Load (Gross MUE) = 795.

At 2141 hours0.0248 days <br />0.595 hours <br />0.00354 weeks <br />8.146505e-4 months <br /> on February 14, 1979, investigation of Description of Occurrence:

an alarm caused by a signal frem panci C4706 indicated detector DS8630 (laundry room detector) as the signal source.

Continued investigation revealed no observa-ble cause for the alarm condition. Several n':ccmpts to clear the apparently spuri-ous alarm f ailed, and at 2145 hours0.0248 days <br />0.596 hours <br />0.00355 weeks <br />8.161725e-4 months <br /> on February 14, 1979, the detector DS8630 and associated panel C4706 were declared inoperable. Although DS8630 is not a required detector per Technical Specifications, the fact that it was continuously alarming through panel C4706 rendered the panel incapable of alarming from any of its other This some of which are required by Technical Specifications.

associated detectors, placed the unit in the Action Statement of Technical Specification 3.3.3.8.

At 2235 hours0.0259 days <br />0.621 hours <br />0.0037 weeks <br />8.504175e-4 months <br /> on February 14, 1979, maintenance personnel successfully reset DS8630.

This removed the unit from the Action Statement of Technical Specification 3.3.3.8.

Designation of Apparent Cause of Occurrence:

The exact cause of this occurrence is undetermined. Investigation of the equipment and detector by maintenance personnel f ailed to find any equipment malfunction.

It is possible that gases or dust given of f during normal laundry operation may have caused the detector to alarm.

Attempts to substantiate this have proven inconclusive.

There was no danger to the health and safety of the public Analysis of Occurrence:

or to unit personnel. No fires occurred during this time.

Corrective Action

Upon declaring panel C4706 inoperable, an immediate search of all area monitored by the panel.was performed. Maintenance personnel were advised A fire of the probica, and the equipment was checked for possible malfunction.

watch was instituted 'n accordance with Technical Specification 3.3.3.8.

Detector DS8630 was replaced on February 22, 1979 under Maintenance Work Request URO 13-8-79.

There has been one previous reported occurrence of erroneous detector Failure Data:

operation, see Licensee Event Report NP-33-79-22.

LER #79-024