An Euler-Euler Multiphysics Solver for the Analysis of the Helium Bubbling System in the MSFR

In this work, a multi-physics OpenFOAM solver for the study of the Molten Salt Fast Reactor (MSFR) is presented. A particular focus is devoted to the analysis of the helium bubbling system of the MSFR and of its effect on the reactor dynamic behaviour. Neutronics is modelled with the multi-group diffusion equation, while thermal-hydraulics is described with an Eulerian-Eulerian approach. The void reactivity feedback coefficient is evaluated on the basis the bubble spatial distribution, pointing out differences with respect to simulations carried out with uniform void fractions. The outcomes of this analysis constitute the starting point for further research on the MSFR dynamics and transient analysis, with a particular focus on the design of the reactivity control systems and the optimization of the reactor as well.