05000346/LER-1979-101-03, /03L-0:on 791017,safety Features Actuation Sys Channel 2 Radiation Detector Re 2005 Spiked Tripping Channel 2 Containment Radiation Bistable.Caused by Component Failure of Detector.Failed Detector Replaced

/03L-0:on 791017,safety Features Actuation Sys Channel 2 Radiation Detector Re 2005 Spiked Tripping Channel 2 Containment Radiation Bistable.Caused by Component Failure of Detector.Failed Detector Replaced

ML19254F957
Person / Time
Site:	Davis Besse
Issue date:	11/13/1979
From:	Eldred D TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19254F953	List: 05000346/LER-1979-101, Forwards LER 79-101/03L-0 05000346/LER-1979-101-03, /03L-0:on 791017,safety Features Actuation Sys Channel 2 Radiation Detector Re 2005 Spiked Tripping Channel 2 Containment Radiation Bistable.Caused by Component Failure of Detector.Failed Detector Replaced
References
LER-79-101-03L, LER-79-101-3L, NUDOCS 7911190521
Download: ML19254F957 (2)

LER-1979-101, /03L-0:on 791017,safety Features Actuation Sys Channel 2 Radiation Detector Re 2005 Spiked Tripping Channel 2 Containment Radiation Bistable.Caused by Component Failure of Detector.Failed Detector Replaced

Event date:
Report date:
3461979101R03 - NRC Website

text

U. S. NUCLE AR REGULATORY COMMISSION 3C FORM 366 (7 77)

LICENSEE EVENT REPORT CONTROL BLOCK: l l

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60 61 DOCK ET NUMBER 63 63 EVENT DATE 74 15 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 lOn October 17, 1979 at 1410 hours0.0163 days <br />0.392 hours <br />0.00233 weeks <br />5.36505e-4 months <br />, Safety Features Actuation System (SFAS) Channel 2 l Radiation Detector RE 2005 spiked tripping SFAS Channel 2 containment radiation bi-l 0 3

[ stable. This placed the unit in the Action Statement of T.S. 3.3.3.1.b9 which requirej o

4 [TlT) l the f ailed section of the channel be lef t in the tripped state. There was no danger j

l 016 l l to the health and safety of the public or station personnel. The containment radia--

l l 0 l 7 l l tion instrument strings associated with the other three SFAS Channels acre operable

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40 41 42 43 44 47 33 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h lThe cause of the occurrence was component failure of the detector. Under Maintenance l i

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DVR 79-153 David T. Eldred PHONE:

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TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATI0M FOR LER NP-33-79-118 DATE OF EVENT: October 17, 1979 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE:

Safety Features Actuation System (SFAS) Channel 2 Con-tainmer.t Radiation Detector RE 2005 inoperable The unit was in Mode 3, with Power (MWT) = 0, and Conditions. Prior to Occurrence:

Load (Gross MWe) = 0.

On October 17,1979 at 1410 hours0.0163 days <br />0.392 hours <br />0.00233 weeks <br />5.36505e-4 months <br />, SFAS Channel 2 Radia-Description of Occurrence:

tion Detector RE 2005 spiked (tripping SFAS Channel 2 containment radiation bistable) and returned to normal. The spiking was over full range of the readout and RE 2005 was declared inoperable. This placed the unit in the Action Statement of Technical Specification 3.3.3.1.b9 which requires the operability of all four SFAS containment radiation instrument strings in all modes. The SFAS channel 2 containment radiation The in the tripped state as required by the Action Statement.

bistable was lef t containment radiation instrument strings associated with the other three SFAS channels were operable, meeting the minimum operational requirements.

Designation of Apparent Cause of Occurrence: The apparent cause of this occurrence is component failure of the detector. The failed detector is being examined by the Instrument and Control shop and as of this time the problem has not been pinpointed.

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

or to station personnel. The containment radiation monitoring instrument strings associated with the other three SFAS channels are opera 51e.

RE 2005 failed in the high (safe) direction.

Corrective Action

Under Maintenance Work Order IC-464-79, the detector was replaced.

The new detector was declared operable by the successful performance of ST 5031.01 at 0515 hours0.00596 days <br />0.143 hours <br />8.515212e-4 weeks <br />1.959575e-4 months <br /> on October 20, 1979. Maintenance Work Order IC-466-79 was issued to troubleshoot and repair the failed detector. The low range board and the auxiliary board in the detector were found to be defective. These boards were replaced and a detector calibration was accomplished. The detector was returned to stock as a The spare and the failed boards were returned to Victoreen Company for repair.

maintenance work order was completed on Urvember 5 and closed on November 7, 1979.

Failure Data: Previous failures of RE 2005 were reported in Licensee Event Reports NP-33-78-140, NP-33-79-92, and NP-33-79-103.

LER #79-101 1345 339