Validation of NEPTUNE CFD Two Phase Flow Models Using the OECD/NRC BFBT Benchmark Database

Abstract

In this work the flow within a fuel assembly of a boiling water reactor was modeled using NEPTUNE-CFD. The most important parameters to define the flow like the incipient boiling condition, the heat flux partitioning and the heat transfer models are identified and tested against experimental data from BFBT bundle test. Different heat transfer models are applied for the water/steam interface. Additionally the heat conduction is solved for the insulator and cladding of the heater rods by coupling NEPTUNE-CFD with the SYRTHES package. The calculated average void fractions are in good agreement with the experimental data and the areas for future improvements are identified.