05000315/LER-1980-004-03, While Performing Scan Sequence, One of Two Detectors in Use for Axial Power Distribution Monitoring Sys Became Inoperable.Caused by Stretched Helex in Detector & Damaged Drive Wheel

While Performing Scan Sequence, One of Two Detectors in Use for Axial Power Distribution Monitoring Sys Became Inoperable.Caused by Stretched Helex in Detector & Damaged Drive Wheel

ML17326A685
Person / Time
Site:	Cook
Issue date:	04/30/1980
From:	Delong S INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17318A723	List: 05000315/LER-1980-004-03, While Performing Scan Sequence, One of Two Detectors in Use for Axial Power Distribution Monitoring Sys Became Inoperable.Caused by Stretched Helex in Detector & Damaged Drive Wheel
References
LER-80-004-03X, LER-80-4-3X, NUDOCS 8005050272
Download: ML17326A685 (4)

LER-1980-004, While Performing Scan Sequence, One of Two Detectors in Use for Axial Power Distribution Monitoring Sys Became Inoperable.Caused by Stretched Helex in Detector & Damaged Drive Wheel

Event date:
Report date:
3151980004R03 - NRC Website

text

, NRC FORM 366 U. S. NUCLEAR REGUI.ATORY COMMISSION t7.77) ~

UPDATE REPORT PR 'OUS REPORT DATE 04-08-80 CENSEE EVENT REPORT

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60 61 DOCKET NUMBEII 68 69 EVENT DATE 74 75 REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES Q10

~o2 WHILE PERFORMING A SCAN SEQUENCE ONE OF THE TWO DETECTORS IN USE FOR APDMS

~o3 BECAME INOPERABLE AND COULD NOT COMPLETE ITS SCAN.

ALL OTHER DETECTORS WERE 4

UNAVAILABLEFOR USE AND THEREFOREt T~S.4. 2. 6. 2, REQUIRING AT LEAST 2 THIMBLES h

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A REEVALUATION OF THIS EVENT HAS REVEALED THAT THE INITIATING CAUSE WAS THE FAILURE OF ONE OF THE TWO DETECTORS IN USE FOR THE QPDMS SYSTEM.

THE FAILURE WAS DUE TO THE DETECTOR DEVELOPING A STRETCHED HELEX AND SUBSEQUENTLY A DAMAGED DRIVE WHEEL.

AT THE TIME OF THIS EVENT ALL OTHER DETECTORS IN THE FLUX MAPPING SYSTEM WERE 4

UNAVAILABLETHUS MAKING THE APDMS (SEE ATTACHED SUPPLEMENT 7

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FACILITY STATUS 88 POWER OTHER STATUS Q E

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NA 45 METHOD OF DISCOVERY DISCOVERY DESCRIPTION Q2

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10 12 13 44 45 46 ACTIVITY CONTENT RELEASED OF RELEASE AMOUNTOF ACTIVITYQ3 LOCATIONOF REI.EASE Q 6

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10 11 44 PERSONNEL EXPOSURES I

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A'KTACHMENT TO LER

¹80-'004/03X-1'UPPLEMENT TO CAUSE DESCRIPTION AND ALTERNATE P250 COMPUTER SYSTEMS UNAVAILABLEFOR USE.

WHEN IT WAS DETERMINED THAT THE REQUIRED SCANS COULD NOT BE COMPLETED REACTOR POWER WAS REDUCED TO 83 PER CENT IN COMPLIANCE WITH THE ACTION REQUIREMENTS, OF T.S. 3.2.6.

II THE DAMAGED DETECTOR AND DRIVE WHEEL WERE REPLACED AND-RETURNED, TO SERVICE.

NO FURTHER ACTION IS PLANNED AT THIS TIME.

INCORE FLUX PROBE WAS A WESTINGHOUSE MODEL NO. WL-23630.

THE DRIVE 'WHEEL WAS A TELEFLEX PART NO. 25495.

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