05000317/LER-1981-001-01, /01T-0:on 810114,feedwater Transmitter Out of Calibr,Resulting in Erroneous Adjustments to ex-core Nuclear Instrument Channels.Transmitter Failed to Maintain Calibr. Transmitter Replaced.Cause of Shift in Calibr Not Stated

/01T-0:on 810114,feedwater Transmitter Out of Calibr,Resulting in Erroneous Adjustments to ex-core Nuclear Instrument Channels.Transmitter Failed to Maintain Calibr. Transmitter Replaced.Cause of Shift in Calibr Not Stated

ML20004D739
Person / Time
Site:	Calvert Cliffs
Issue date:	01/28/1981
From:	Davis S, Rizzo P BALTIMORE GAS & ELECTRIC CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20004D737	List: 05000317/LER-1981-001, Forwards LER 81-001/01T-0 05000317/LER-1981-001-01, /01T-0:on 810114,feedwater Transmitter Out of Calibr,Resulting in Erroneous Adjustments to ex-core Nuclear Instrument Channels.Transmitter Failed to Maintain Calibr. Transmitter Replaced.Cause of Shift in Calibr Not Stated
References
LER-81-001-01T, LER-81-1-1T, NUDOCS 8106090703
Download: ML20004D739 (3)

LER-1981-001, /01T-0:on 810114,feedwater Transmitter Out of Calibr,Resulting in Erroneous Adjustments to ex-core Nuclear Instrument Channels.Transmitter Failed to Maintain Calibr. Transmitter Replaced.Cause of Shift in Calibr Not Stated

Event date:
Report date:
3171981001R01 - NRC Website

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LICENSEE EVENT REPORT

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8 60 61 OCCKET NUMBER 68 69 EVENT OATE 74 75 REPORT CATE 80 EVENT DESCRIPTION AND PRCBABLE CCNSECUENCES h 10121 l At 1050 the shif+ sucervisor was notified that a Sa6mter trans,i'ter I

lo tal I which is used in calculatinc caloriretric nower was out of calibration.

I lo tti l This resulted in erronecus adiustrents to all fcur excore nuclear in-1 10 l s 1 I strurent channels on 1-11-81 causinc cower to indicate acaroximately I

lo is I l d.5. nercent icw.

The nuclear instrurents 'rere ir'*ediatelv readiosted.

I lo l7] I This reecrt is at the recuest of the MRC oesident Insnector since no I

t o is i I LCO's were violated and all RPS trins were oeerable.

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I li 11 1i failed to raintain its calibration.

The tn ne-ittar cu t-o + me e-A I

i,l2; I to be low.

It was reolaced with a scare.

Bench-testion has nnt ehnwn a I

i ;3l l reason for the annarant shif t in caliSratinn ubich nccurrsd.

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81-01/lT DOCKET NO.

50-318 LICENSE NO.

OPR-69 EVENT DATE l-14-31 REPORT DATE l-23-81 ATTACHpENT EVENT DESCRIPTION AND PROBA9LE CONSEOUENCES (CONT'0)

At 1050 on 1-14-81 with Unit 1 at 50 nercent ro0er (indicated) for cost refueling physic tests, the shift su.nervisor uas notified by Instrument Maintenance and Fuel Manaoerent that a feedwater flow transnitter thich is used in calculating calorimetric rower was out of calibration.

This problem resulted in erroneous adjustments beino made to all fcur reactor crotective system nuclear instrument channels on 1-11-81, and causing rower to indicate acproximately 4.5 eercent low.

The nuclear instruments were immediately readjusted.

Since the unit was returning to service followino an eleven week schedulad refuelinc and raintenance outage, it can be conservatively assured that the flow transmitter was rendered out of calibration durina the idle time.

Therefore, it has been concluded that no license limits or limitinc con-dition for creration were violated since variable over nower and all other RPS, feeduater flow tr:nsmitter oroblentries t ere enerable and the unit did not exc i

the Nevertheless, this recort is being made at the recuest of the NPC Resident Insrectcr.

CAUSE DESCRIPTION AND CCRRECTIVE ACTIONS (CONT'0)

The olant was uncercoina startue testino after ccmeletion of a refuelina and maintenance cutape. After reaching 50 nercent cower, discrepancies were noted arcnc olant parameters, narticularly electrical outnut, excore nuclear instrurentation ecuer level, and crimary temeeratures used in calculatino Rx eir.

Feedriter flow loon F-illl was suscected to be in error due to low indi-catic n.

" Hand calorimetric" data was collected and cercared with crevious 50 m rcent test procrar data. The cornarison shewed the F-Illl signal leve' about 0.5 x 106 lbs./Hr. less than the exnected value for 50 cercent.

Othe' narameters were near normal. Several calculations based on other cara reters such as prirary flow, d5T and secondary caloriretric inouts showed that the normal caloriretric calculation from the clant comruter was between 4.2 and 4.5 cercent low. This annroximated the 0.5 x 10o lbs./Hr. error in the F-llll loon signal.

After consultation betteen the Instrument "aintenance sucervisor and the Nuclear Fuel ilanaceTent group's shift enqineer, a conservative correction of 6 rercent nower ras "ade to the excore nuclear instrument channels.

Subsecuent troubleshootinc and reolacerent of the feedwater flow trans-r.itter restored the caloriretric innut sicnal accuracy.

P00R ORlG K

e In the case at hand, no deficiency was at first known to exist.

Abno rmal high electrical outnut was attributed to turbine ard secondary.?aintenance during the recent outage.

Close inscection and comcarison of plant parameters revealed a potential problem existed.

The Operat'cas Section General Sucervisor has instructed plant ooerators to ensure any suspected out of tolerance conditions are oromotly brought to the attention of plant naintenance nersonnel.

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