Coupled Computational Fluid Dynamics and Computational Thermodynamics Simulations for Fission Product Retention and Release: A Molten Salt Fast Reactor Application

This study presents a computational capability for fission product retention and release in two-phase, multispecies systems representing Molten Salt Reactors (MSR) with coupled thermal-hydraulics and fuel coolant chemical behaviours. This is demonstrated through four simulated cases centred on the proposed Molten Salt Fast Reactor (MSFR). This is achieved by two-way coupling the Computational Fluid Dynamics (CFD) code OpenFOAM and the Computational Thermodynamics (CT) code Thermochimica, using the Joint Research Centre Molten Salt Database (JRCMSD). Local chemical equilibrium is assumed, implying that chemical kinetics are predominantly governed by mass transport. Four simulations address normal operating conditions, exploring: (i) dilution of fission products injected within the molten salt coolant, (ii) molten salt coolant evaporation rate, (iii) release of radioactive gaseous species, (iv) shifts in the UF4/UF3 ratio, and (v) comparison of vapour pressures of gaseous species. The influence of temperature-dependent viscosity on retaining fission products, compared to consistent values, is also discussed. The feasibility of integrating CFD with Thermochimica showed promising results, broadening insights into multiphysics systems and setting the stage for its application in more intricate scenarios.

SCURO Nikolas;  BENES Ondrej;  LORENZI S.;  KRSTOVIC M.;  KREPEL Jiri;  PIRO Markus; 

2025-02-27

PERGAMON-ELSEVIER SCIENCE LTD

JRC138594

1878-4224 (online),   

https://www.sciencedirect.com/science/article/pii/S0149197024004001?via%3Dihub,    https://publications.jrc.ec.europa.eu/repository/handle/JRC138594,   

10.1016/j.pnucene.2024.105450 (online),