Development and validation of a thermal-hydraulic analysis code for dual cooled assemblies in molten salt reactors

BackgroundCompared with traditional components, novel dual cooled assemblies for liquid-fuel molten salt reactors demonstrate a lower graphite hot spot temperature owing to their increased heat transfer area and reduced graphite thermal conduction distance. However, owing to the distinct geometric characteristics and spontaneous heating of liquid fuel, unique heat division and flow distribution patterns occur between the internal and external channels in dual cooled assemblies.PurposeThis study aims to develop new computational analysis tools to estimate the thermal-hydraulic performance of these assemblies.MethodsThis study developed a one-dimensional steady-state thermal-hydraulic analysis code, namely Thermal-Hydraulic Analysis Code for Dual Cooled Assembly-Molten Salt Reactor (THDA-MSR) using the MATLAB platform. Considering the spontaneous heating of the fuel salt, a one-dimensional temperature distribution model for liquid fuel and a he at transfer model between the fuel salt and graphite were established. A flow distribution model was developed based on the principle of equal pressure drops in parallel channels. Additionally, numerical simulations were performed using computational fluid dynamics (CFD) software to validate the code results.ResultsThe study demonstrates a strong agreement between the THDA-MSR and CFD results, with a pressure drop deviation and maximum graphite temperature deviation below 4.84% and 0.15%, respectively. The analysis shows that the ratio of the external channel is the key parameter affecting the maximum outlet temperature of the fuel salt and the maximum temperature of graphite.ConclusionsThe model is applicable for thermal-hydraulic calculations and analysis of dual cooled assemblies in liquid-fuel molten salt reactors.