ML17266A192

LER 80-016/09T-0:on 800411,engineering Evaluation Determined That Application of Two Rosemount Model 1152 Pressure Transmitters Resulted in Reportable Situation.Caused by Design Problem.Transmitters to Be Replaced

ML17266A192
Person / Time
Site:	Saint Lucie
Issue date:	04/16/1980
From:	SCHOPPMANN M A FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML17208A502	List: ML17208A501 ML17266A192
References
LER-80-016-09T, LER-80-16-9T, NUDOCS 8004240375
Download: ML17266A192 (3)

Text

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REPORTABLE OCCURRENCE 33~-16 LIGENSEE EVENT REPORT PAGE TWO Additional Event Descri tion and Probable Conse uences On April ll, 1980, an engineering evaluation determined that the appli-cation of certain Rosemount Model 1152 pressure transmitters resulted in a reportable situation.

It has been observed by the manufacturer, and reported to the licensee on March 15, 1980 that in a'imited number of transmitters an input pressure either over or under the normal operating range causes an output within the normal range of 4 to 20 milliamps.

The transmitters affected are Rosemount Model 1152 pressure transmitters with output codes"A" or"D".The manufacturer observed that due to a unique condition in the transmitter electronics, an overrange condition exceeding 140%of the upper range limit can cause a discontinuity in the trans-mitter output, resulting in an output less than 20 millamps.Due to a different unique condition in the t'iansmitter electronics, an underrange condition exceeding 100%of the calibrated span can cause an output above 4 milliamps.

The overrange discontinuity was observed in 5%of a limited sample, the underrange discontiniuty being observed in 55%of the sample.The model transmitter in parallel with a second transmitter from a different manufacturer actuates Containment Vacuum Relief Valve FCV-25-7 on one vacuum relief line.An identical control arrangement exists for Containment Vacuum Relief Valve FCV-25-8 on a redundant vacuum.relief line.These valves also perform*containmere isolation function in the event of a LOCA.Each containment vacuum relief line contains a check valve to prevent flow out from the containment.

The range of the affected.t=ansmitters is-5" H20 to 0" H20 for a 4 to 20 milliamp output.With an overpressure condition exceeding 140%of the calibrated span, equivalent to a positive pressure of 2" H 0 in containment, the Rosemount transmitters could open valves FCV-25-7 and 3CV-25-8 even though the second transmitter functions properly.Assuming a failure of the check valve(s);containment isolation capability would be affected.This model-transmitter is also used to monitor reactor coolant flow.Four transmitters monitor the differential pressure across the reactor coolant pumps and four transmitters monitor the differential pressure across the reactor core.These transmitters are"Indication Only" instruments and have no control, protective, or safety function.Corporate Power Plant Engineering has directed that the containment vacuum relief transmitters be replaced with Class 1E, Seismic Category I qualified Rosemount Model 1153 pressure transmitters.

The St.Lucie Plant Maintenance Department coordinated by FP&L Power Resources Department will be responsible for the transmitter replacement.

This action is scheduled to be completed prior to the start-up of the unit (approximately April 30, 1980).St.Lucie Unit 1 has been engaged in refueling since March 15, 1980.The Licensee has determined that its other licensed facilities are not affected by this situation, and its Engineering Department will ensure that the unit under construction, St.Lucie Unit 2, will also not be affected.C