Simulation with RELAP5/MOD3.3 of an Integral-Effect Test on Loop-Seal Clearing in the Upper Plenum Test Facility During Test A5 (NUREG/IA-0520)

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Publication Information

Manuscript Completed: July 2019
Date Published: June 2020

Prepared by:
Richard Trewin

Framatome GmbH
Paul-Gossen-Str. 100
91058 Erlangen, Germany

K. Tien, NRC Project Manager

Division of Systems Analysis
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

Prepared as part of:
The Agreement on Research Participation and Technical Exchange
Under the Thermal-Hydraulic Code Applications and Maintenance Program (CAMP)

Published by:
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

Availability Notice


The RELAP5/MOD 3.3 computer code has been used to simulate an experiment on loop-seal clearing conducted in the Upper Plenum Test Facility. An assessment of this code version was performed by comparing the calculated results to the measured data from the experimental facility.

Loop-seal clearing in a pressurized-water reactor during an intermediate-break loss-of-coolant accident was investigated in the UPTF-TRAM experimental facility during a series of experiments designated Test A5. The phenomenon of loop-seal clearing was studied at 15 bar(a) during an integral-effects test designated ITRun2a.

This report presents assessments that demonstrate the suitability of the code for analyzing loop-seal clearing transients.

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