05000261/LER-1981-015-03, /03L-0:on 810525,computer Box FM-475 Found to Be Out of Acceptable Tolerances & Several Checkpoints Showed Erratic Readings During Loop a Steam Flow Channel Investigation.Caused by Two Worn Electronic Components

/03L-0:on 810525,computer Box FM-475 Found to Be Out of Acceptable Tolerances & Several Checkpoints Showed Erratic Readings During Loop a Steam Flow Channel Investigation.Caused by Two Worn Electronic Components

ML20005A192
Person / Time
Site:	Robinson
Issue date:	06/24/1981
From:	Graham J CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20005A191	List: 05000261/LER-1981-015, Forwards LER 81-015/03L-0 05000261/LER-1981-015-03, /03L-0:on 810525,computer Box FM-475 Found to Be Out of Acceptable Tolerances & Several Checkpoints Showed Erratic Readings During Loop a Steam Flow Channel Investigation.Caused by Two Worn Electronic Components
References
LER-81-015-03L, LER-81-15-3L, NUDOCS 8106300026
Download: ML20005A192 (2)

LER-1981-015, /03L-0:on 810525,computer Box FM-475 Found to Be Out of Acceptable Tolerances & Several Checkpoints Showed Erratic Readings During Loop a Steam Flow Channel Investigation.Caused by Two Worn Electronic Components

Event date:
Report date:
2611981015R03 - NRC Website

text

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'W1 to EVENT DATE 14 75 REPOHT DATE 80 EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h I O t 2 t ton May 25, 1981, at 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br />, with the plant in cold shutdown, loop "A" steam l

io!.,,jflow channel was investigated for an erratic response observed during plant operation. !

in ia; l Computer box FM-475 was found to be out of acceptable tolerances and several check-l io;3j l points were found to be giving erratic readings.

The redundant channel was operational l [ojajiso there was no threat to the health and safety of the public. This incident is l

l011l { contrary to Technical Specification 3.5.1 which is reportable under Technical Speci-l l o;a ; ification 6.9.2.b.1.

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li li l Itwo transistors, a potentiometer, and a filter capacitor.

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2 play 26, 1981. Due to the similarity of this LER with LER 81-014, a generic review of l

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This review indicated no generic problems.

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Supplemental Information for 1.icensee Event Report 81-015 1.

Cause Description and Analysis on ?!ay 25,1981, at 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br />, with the plant in cold shutdown, loop "A" steam flow channel was investigated for an erratic response observed during plant operation. Upon troubleshooting the channel, computer box FM-475 was found to be out of acceptable tolerances and several checkpoints were found reading erratically.

This was due to the failure of two transistors, a potentiometer, and a filter capacitor.

This failure is believed to be the result of normal use resulting in the end of useful life of the electronic components. The redundant channel was operational so there was no threat to the health and safety of the public.

This incident is contrary to Technical Specification 3.5.1 which is reportable under Technical Specification 6.9.2.b.1.

2.

Co rrec t ive Ac t ion The entire computer box was replaced with a qualified r:udule f rom s tock. The new box was calibrated and le f t in proper working condition on May 26, 1981.

3.

Correct ive Act ion to Prevent Recurrence Due to the similarity in filter capacitor failures in this LER and LER 81-014, a further review of the issue was initiated.

The findings of this review indicate that the number of failures is very small compared to the total number of filter capacitors in use and, therefore, no generic problem is indicated.