Coarse-mesh thermal-hydraulics and neutronics coupling for the ALFRED reactor

Among the six advanced reactor systems identified by the Generation IV International Forum, the lead fast reactor (LFR) has been considered as one of the most promising future nuclear power plants. Among the LFR designs, Ansaldo Nucleare, as coordinator of the Lead-cooled European Advanced DEmonstration Reactor project, proposes Advanced Lead Fast Reactor European Demonstrator (ALFRED) as LFR demonstrator, which is the study object of the present paper. A multiphysics model for the ALFRED core is developed and presented in this paper, which couples neutronics and thermal hydraulics. The first physics is solved with neutron transport Monte Carlo simulations, while temperatures and the lead density are updated with coarse-mesh-based finite volume method CFD runs. The proposed model focuses on the adoption of spatially non-uniform temperature distributions of materials to compute better on-the-fly estimations of nuclides cross sections and thence a more accurate neutron physics description.