05000346/LER-1977-097-03, /03L-0:on 771129,radiation Monitor Re 2006 Tripped Safety Features Actuation Sys Channel 3 Containment Radiation Due to Sporadic Spiking.Caused by Component Failure in Radiation Detector.Detector Replaced

/03L-0:on 771129,radiation Monitor Re 2006 Tripped Safety Features Actuation Sys Channel 3 Containment Radiation Due to Sporadic Spiking.Caused by Component Failure in Radiation Detector.Detector Replaced

ML19326A468
Person / Time
Site:	Davis Besse
Issue date:	12/16/1977
From:	Nelson J TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19326A464	List: 05000346/LER-1977-097, Forwards LER 77-097/03L-0 05000346/LER-1977-097-03, /03L-0:on 771129,radiation Monitor Re 2006 Tripped Safety Features Actuation Sys Channel 3 Containment Radiation Due to Sporadic Spiking.Caused by Component Failure in Radiation Detector.Detector Replaced
References
LER-77-097-03L, LER-77-97-3L, NUDOCS 8002040638
Download: ML19326A468 (2)

LER-1977-097, /03L-0:on 771129,radiation Monitor Re 2006 Tripped Safety Features Actuation Sys Channel 3 Containment Radiation Due to Sporadic Spiking.Caused by Component Failure in Radiation Detector.Detector Replaced

Event date:
Report date:
3461977097R03 - NRC Website

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8 60 61 oOCKET NUMBER EVENT OESCRIPTION AND PROS ABLE CONSEQUENCES h Io i2l l On 11/29 /77 at 1650 hours0.0191 days <br />0.458 hours <br />0.00273 weeks <br />6.27825e-4 months <br />, Radiation Monitor RE 2006 trinned SFAs chnnnal

't enne,4n-I l o t a l Iment Radiation due to sporadic spiking. The channel was then declared inoperable and l Io 64l lleft in the tripped state. This placed the unit in the Action Statement of Technical l I o l s t I pecification 3.3.2.1.

There was no danger to the health and safety of the public or !

S Ioisl l unit personnel. No other systems besides SFAS Channel 3 Containment Radiation were I

l o 17 l laffected except that it was then a one out of three trip.

Plant operation was not l

laffected by the component failure.

(NF-33-77-97)

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36 37 do di 4a 43 44 47 33 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS

o;lThe apparent cause was a component failure in Radiation Detector, Victoreen Model I

l3 g,,,il Number 847-1.

The complete detector, Victoreen Model Number 847-1. was replaced and I

g goperability verified at 1905 hours0.022 days <br />0.529 hours <br />0.00315 weeks <br />7.248525e-4 months <br /> on December 2, 1977.

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NAME OF PREPARER

TOLEDO EDISCN COMPANY DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION s*

SUPPLEMENTAL INFOREATION FOR LER NP-33-77-97 l

DATE OF EVENT: November 29, 1977 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Failure of Radiation Monitor RE 2006 in Safety Features Actuation System (SFAS) Channel 3

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Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 1153 and Load (MWE) = 389.

, Description of Occurrence: On November 29,1977, at 1650 hours0.0191 days <br />0.458 hours <br />0.00273 weeks <br />6.27825e-4 months <br /> Radiation Monitor RE 2006 tripped SFAS Channel 3 Containment Radiation due to sporadic spiking.

This The channel was then declared inoperable and left in the tripped state.

placed the unit in the Action Statement of Technical Specification 3.3.2.1 which requires all four Containment Radiation Monitors in all modes.

Designation of Apparent Cause of Occurrence: The apparent cause was.a component failure in Radiation Detector, Victoreen Model Number 847-1.

Analysis of Occurrence: There was no danger to the health and safety of the public or to unit personnel. No other systems besides SFAS Channel 3 Containment Radia-tion were affected except that it was then a one out of three trip. Plant opera-tion was not affected by the component failure.

4

Corrective Action

On November 30, 1977 at 1730 hours0.02 days <br />0.481 hours <br />0.00286 weeks <br />6.58265e-4 months <br />, corrective action com-menced on RE 2006 with the aid of the Victoreen representative.

From testing it was decided to change the complete detector, Victoreen Model Number 847-1.

ST 5031.01, "SFAS Monthly Test" was completed'on December 2, 1977, at 1905 hours0.022 days <br />0.529 hours <br />0.00315 weeks <br />7.248525e-4 months <br /> which verified operability, thus removing the unit from the Action Statement of Technical Specification 3.3.2.1.

The defective detector was given to the Victoreen representative for further analysis by Victoreen.

Failure Data: Two previous incidents of sporadic spiking on SFAS Channel 3 Containment Radiation occurred on October 24, 1977 (NF-33-77-87) and November 7, 1977 (NP-33-77-91).

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