ML19309G101

First Interim Deficiency Rept Re Defects in Rosemount Trip/Calibr Units.Switch Failed Due to Malfunction open- Ciruiting Logic.Capacitor in Pressure Transmitter Failed Above 175 F.Defective Components Under Investigation

ML19309G101
Person / Time
Site:	Hartsville, Phipps Bend
Issue date:	04/25/1980
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML19309G098	List: ML19309G097 ML19309G101
References
NUDOCS 8005020359
Download: ML19309G101 (2)

Text

.O 8005020 3 5 9

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ENCLOSURE i

HARTSVILLE AND PilIPPS BEND UUCLEAR PLANTS (ALL UNITS)

DEFECTS IN ROSEMOUNT TRIP / CALIBRATION UNITS AND PRESSURE TRANSMITTERS 10CFR50.55(e) REPORT NO. 1 (IUTERIM)

On March 28, 1980, TVA notified NRC-0IE Region II, Inspector R. W.

Wright, of a reportable deficiency under 10CFR50.55(e) regarding defects in Rosemount trip / calibration units and pressure transmitters being supplied by GE for use at the Hartsville Nuclear Plant. He was also notified on April 15, 1980, that the condition al.a exists for equipmedt being supplied for use at Phipps Bend Nuclear Plant.

These deficiencies were reported to NRC-0IE Region V, Inspector R. H.

Englehen, under 10CFR21 on March 21, 1980, by GE both ver, bally and by letter MFN 065-80. _.

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This is the first interim report on the subject reportable deficiency.

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The final report will be sent to you on or before June 20, 1980.

Description of Deficiency -

General Electric was advised by Rosemount that some of the model 510DU trip / calibration units and model 1152 pressure transmitters contain de fec ts . The trip unit is used in conjunction with the pressure transmitter to provide high or low trip signals. The pressure transmitter is used for direct pressure measurement transmission or as a level sensor in conjunction with a differential pressure measuring device.

The trip unit has a coc= ton mode failure of an essential switch that determines the trip output logic. The malfunction open-circuits the logic, thereby providing an inoperable signal. As an example, when used as an ECCS water level trip unit, this can result in failure to trip on low water level.

The transmitter has a common mode failure of a capacitor when the transmitter operating temperature is greater than 175 F or when the damping potentiometer is rotated clockwise. The failure is manifested as a drop in transaitter output current up to 10 percent of the correct current. Ac an example, when used as a pressure transmitter, this can result in transmitting reactor pressure 10 percent lower

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than actual. . _ _. __ _, _ ___

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i GE has initially identified 64 items of equipment which may contain j defective pressure transmitters and which have been shipped to Hartsville  !

and Phipps Bend (54 at Hartsville and 10 c.. Phipps Bend). f

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. I GE has also verbally indicated that no trip calibration units have been shipped to either unresville or Phipps pend. They indicated that these units are in control room panels which have not been shipped to either site.

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Corrective Actions GE has undertaken an investigation to determine the location of all equipment which has one or more of the subject defective components installed.

Rosemount will replace the defective switches'in the affect'ed trip units and the defective capacitors in the affected transmitter units tint have been shipped to GE', including those shipped on to utilities by GE.

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