ML19263A859

LER 78-119/03L-0 on 781204:containment Radiation Monitor Re 2005 Was Declared Inoperable Because of Detector Module Component Failure.Module Replaced,Calibr,Tested & Declared Operable

ML19263A859
Person / Time
Site:	Davis Besse
Issue date:	12/27/1978
From:	Kavach S TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19263A860	List: ML19263A859
References
LER-78-119-03L, LER-78-119-3L, NUDOCS 7901030163
Download: ML19263A859 (2)

Text

U. S. NUCLE AR REGUL ATORY COMMISSION

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hE RCO" l Ll@l0 l 5 l0 l- l0 l3 l4 (6 @l1 l2 ( 0l 4l 7l 8@l1 l2 l2 l7 l7 l8 60 01 DOCKET NUMBER 68 69 EVENT oATE 34 75 REPORT D ATE 80 EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h I o 2 l On December 4,1978, Containment Radiation Monitor RE 2005 was declared inonerable.

'I o 3 The unit entered Action Statement 9 of Technical Specificat' ion 3.3.2.1. which _ allowed] ,

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l o 4 l continued operation provided the inoperabic unit was tripped within one hour and the l There was no danger to the health End I so s I other three radiation strings were operable.

RE 2005 was placed in the tripped (safe) I l o is ! I saf ety of the public or to unit personnel.

I o 7 l condition in approximately eight minutes with the other strines remainine operable.

I O e l (NP-33-78-140)

CON'PONENT CODE S BC dE SU E DE CODE S BC E g l Il Bl@ El@ lA @ 1 lN l S lT lR lU lh l El@ W h 18 19 20 12 13 REVISION 7 8 9 to 11 OCCURRENCE REPORT SE QUENTI AL TYPE NO.

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41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h The module l gg l The cause of the occurrence was component failure of the detector module.

I ji;i; jwas replaced. After calibration and operational testing of the unit. RE 2005 was I

g,,7, l declared operable, and the unit was removed f rom Action Statement 9 of Technical I

g l Specification 3.3.2.1.

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7 8 9 DISC RY DISCOVERY DESCRIPTION A S  % POWE R OTHER STATUS l

l 1 l 5 l dh l 0 l 9 ' 2 ,@l NA l l Al@l Operator Observation A TIVITY CO TENT LOCATION oF RELE ASE RELEASED OF RELE ASE AMOUNT OF ACTIVITY l 1 6 l NA l NA 80 44 45 7 8 9 10 11 PERSONNEL EXPOSURES '

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l TOLEDO EDISON COMPANY i DAVIS-BESSE UNIT ONE NUCLEAR POWER STATION SUPPLEMENTAL INFORMATION FOR LER NP-33-78-140 DATE OF EVENT: December 4,1978 33 FACILITY: Davis-Besse Unit 1 Safety Features Actuation System (SFAS) Channel 2 i IDENTIFICATION OF OCCURRENCE:

Containment Radiation Monitor RE 2005 was inoperable.

The unit was in Mode 1, with Power (MWT) = 2564, Conditions Prior to Occurrence:

and Load (Gross MWE) = 820.

Description of Occurrence: On December 4,1978, at 0712 hours0.00824 days <br />0.198 hours <br />0.00118 weeks <br />2.70916e-4 months <br />, Centainment Radia-tion Monitor RE 2005 was declared inoperable. The unit entered Action Statement 9 of Technical Specification 3.3.2.1. Technical Specification 3.3.2.1 requires the operability of all four containment high radiation instrument strings in all modes.

Action Statement 9 states that operation may proceed provided the inoperableradia-unit is placed in the tripped condition within an hour, and three other containment tion monitoring unit strings are operable. RE 2005 vss placed in the tripped condi-tion at 0720 hours0.00833 days <br />0.2 hours <br />0.00119 weeks <br />2.7396e-4 months <br />. The other three SFAS containment high radiation instrument strings were operable.

Designation of Apparent Cause of Occurrence: The apparent cause of the occurrence The module was replaced by Instrument was component f ailure of the detector module.

and Control technicians.

Analysis of Occurrence: There was no danger to the health and safety of the public or to unit personnel. Three other SFAS containment high radiation instrument strings were operable during the period that RE 2005 was inoperable. RE 2005 was placed in the tripped (safe) position.

Corrective Action: The detector module was replaced by Instrument and Control tech-nicians under Maintenance Work Order IC-631-78.

After calibration in accordance with Surveillance Test ST 5031.04, " Containment Radiation Monitor Input to SFAS Refueling Period Calibration", and perf ormance of ST 5031.01, "SFAS Monthly Tust",

RE 2005 was declared operable at 2200 hours0.0255 days <br />0.611 hours <br />0.00364 weeks <br />8.371e-4 months <br /> on December 7,1978. The unit was then removed from Action Statement 9 of Technical Specification 3.3.2.1.

Failure Data: There have been previously reported occurrences of component failures in the detector modules on SEAS Containment Radiation Monitors RE 2004, RE 2005, RE 2006 and RE 2007. These were reported in Licensee Event Reports NP-33-77-04, NP-33-77-86, NP-33-77-89, NP-33-77-97,.NP-33-78-35, and NP-33-78-65.

LER #78-119 .