The goal of this study is to demonstrate and quantify the impact that the uncertainty in thermophysical properties has on key metrics of thermal hydraulic importance for MSRs, in particular on the heat transfer coefficient. In order to achieve this, computational fluid dynamics (CFD) simulations using the RANS k-ω SST model were compared to published experiment data on molten salt. | Influence of molten salt- FLiNaK thermophysical properties on a heated tube using CFD RANS turbulence modeling of an experimental testbed EPJ Nuclear Sci. Technol. 5 16 2019 Nuclear Sciences c R. Freile and M. Kimber published by EDP Sciences 2019 amp Technologies https epjn 2019027 Available online at https REGULAR ARTICLE Influence of molten salt- FLiNaK thermophysical properties on a heated tube using CFD RANS turbulence modeling of an experimental testbed Ramiro Freile 1 and Mark Kimber 1 2 1 Department of Nuclear Engineering Texas A amp M University College Station TX 77840 USA 2 Department of Mechanical Engineering Texas A amp M University College Station TX 77840 USA Received 4 April 2019 Received in final form 6 July 2019 Accepted 20 August 2019 Abstract. In a liquid fuel molten salt reactor MSR a key factor to consider upon its design is the strong coupling between different physics present such as neutronics thermo-mechanics and thermal-hydraulics. Focusing in the thermal-hydraulics aspect it is required that the heat transfer is well characterized. For this purpose turbulent models used for FLiNaK flow must be valid and its thermophysical properties must be accurately described. In the literature there are several expressions for each material property with differences that can be significant. The goal of this study is to demonstrate and quantify the impact that the uncertainty in thermophysical properties has on key metrics of thermal hydraulic importance for MSRs in particular on the heat transfer coefficient. In order to achieve this computational fluid dynamics CFD simulations using the RANS k-ω SST model were compared to published experiment data on molten salt. Various correlations for FLiNaK s material properties were used. It was observed that the uncertainty in FLiNaK s thermophysical properties lead to a significant variance in the heat coefficient. Motivated by this additional CFD simulations were done to obtain