05000315/LER-1979-067-03, /03L-0:on 791221,after Update of Axial Power Distribution Monitoring Sys Fz Setpoints,Two of Four Thimbles Used Found Lacking Lowest Sigma.Caused by Personnel Error in Readout.Fz Recalculated Using Correct Thimbles

/03L-0:on 791221,after Update of Axial Power Distribution Monitoring Sys Fz Setpoints,Two of Four Thimbles Used Found Lacking Lowest Sigma.Caused by Personnel Error in Readout.Fz Recalculated Using Correct Thimbles

ML17326A464
Person / Time
Site:	Cook
Issue date:	01/16/1980
From:	Delong S INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML17318A570	List: 05000315/LER-1979-066-03, /03L-0:on 791218,glycol Containment Isolation Valve VCR-10 Did Not Close When Control Switch Turned to Closed Position.Cause Not Known.Valve Operated Properly When Manually Shut 05000315/LER-1979-067-03, /03L-0:on 791221,after Update of Axial Power Distribution Monitoring Sys Fz Setpoints,Two of Four Thimbles Used Found Lacking Lowest Sigma.Caused by Personnel Error in Readout.Fz Recalculated Using Correct Thimbles ML17318A569
References
LER-79-067-03L, LER-79-67-3L, NUDOCS 8001220547
Download: ML17326A464 (3)

LER-1979-067, /03L-0:on 791221,after Update of Axial Power Distribution Monitoring Sys Fz Setpoints,Two of Four Thimbles Used Found Lacking Lowest Sigma.Caused by Personnel Error in Readout.Fz Recalculated Using Correct Thimbles

Event date:
Report date:
3151979067R03 - NRC Website

text

U. S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT NRC FORM 366 t

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CONTROL BLOCK:

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{PLEASE PRINT OR TYPE ALLREQUIRED INFORMATION)

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LICENSEE CODE 14 15 LICENSE NUMBER 25 26 LICENSE TYPE 30 57 CAT 58 CON'T

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0 Qs DOCKET NUMBER 68 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES &IO AFTER THE APDMS F

SETPOINTS WERE UPJIATED IT WAS FOUND THAT TWO OUT OF THE FOUR THIMBLES USED WERE NOT THE ONES WITH THE LOWEST UNCERTAINTY (SIGMA)

FOR R

THIS CONDITION WAS INCONSISTENT WITH T.S. 3.3.3.6 ITEMS a AND b.

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10 11 12 13 18 19 20 SEQUENTIAL OCCURRENCE REPORT REVISION LERiRP EVENT YEAR REPORT NO.

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0 21 22 23 24 26 27 28 29 30 31 32 ACTION FUTURE EFFECT SHUTDOWN ATTACHMENT NPRDX PRIME COMP.

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SUPPLIER MANUFACTURER

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33 34 35 36 37 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS Q27 o

THE SELECTION OF THE WRONG THIMBLES WAS DUE TO THE PERSONNEL INVOLVED READING 7

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FACILITY STATUS BG POWER OTHER STATUS' E

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0 NA METHOD OF DISCOVERY DISCOVERY DESCRIPTION Q32 CK LJQ>> ~Q>>

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10 12 13 44 45 46 ACTIVITY CONTENT RELEASED OF RELEASE AMOUNTOF ACTIVITYQ LOCATIONOF RELEASE Q 6

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10 44 45 PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION Q39 CQ'00 0

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9 11 12 13 PERSONNEL INJURIES NUMBER DESCRIPTIONQ41 s

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Qso NA NA THE THIMBLE SIGMA DATA FROM THE WRONG COLUMN ON THE COMPUTER PRINTOUT.

A COLUMN OF SIGMA DATA WITH A LOWER BOUND OF 2

PERCENT WAS USED.

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THE THIMBLES THAT WERE INCORRECTLY SELECTED FOR DETECTORS 1

AND 2 HAD SIGMAS 4

OF 1.9 PERCENT.

THE LOW UNCERTAINTY THIMBLES THAT SHOULD HAVE (SEE SUPPLEMENT) 80 80 80 80 7

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11 12 LOSS OF OR DAMAGETO FACILITY Q43

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10 PUBLICITY ISSUED DESCRIPTION~

9 10 NAME OF PREPARER S.

D. DeLong NRC USE ONLY 68 69 616-465-5901 80 ssa r

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SUPPLEMENT TO LER ¹ 79-067/03L-0 SUPPLEMENT TO CAUSE DESCRIPTION BEEN USED FOR THESE DETECTORS HAD SIGMAS OF 0.6 PERCENT AND 1.1 PERCENT RESPECTIVELY.

DURING THIS TIME THE THIMBLES SELECTED FOR DETECTORS 3

AND 4 WERE CORRECT.

THEREFORE, ONE APPROPRIATE DETECTOR WAS ALWAYS BEING USED TO MONITOR CORE PERFORMANCE.

THE PROBLEM WAS DISCOVERED IN 2~~ HOURS AND F RECALCULATED USING THE CORRECT THIMBLES.

THE F MARGINS WERE REDUCED FROM +15.9 PERCENT TO +14.5 PERCENT Z

AND +17.4 PERCENT TO 15.5 PERCENT FOR DETECTORS 1

AND 2 RESPECTIVELY.

THIS ERROR WAS DISCUSSED WITH THE INDIVIDUAL INVOLVED AND A TRAINING SESSION WAS CONDUCTED WITH ALL SECTION PERSONNEL IN ORDER TO PREVENT A REOCCURRENCE.