High-Fidelity Modelling of the Molten Salt Fast Reactor

TL;DR

This paper develops a comprehensive multiphysics model of the Molten Salt Fast Reactor using Cardinal, integrating neutronic and thermal-hydraulic feedback with transport of decay heat and delayed neutron precursors, highlighting current capabilities and limitations.

Contribution

It introduces a detailed multiphysics simulation framework for MSFRs combining OpenMC, NekRS, and Cardinal, with novel modeling of DNPs and DHPs transport and feedback mechanisms.

Findings

Model shows reasonable temperature and heat source behavior.

Current OpenMC limitations restrict delayed neutron source location modifications.

Framework sets groundwork for future MSFR simulations with enhanced feedback modeling.

Abstract

The Molten Salt Fast Reactor (MSFR) is one of the six GEN-IV reactor designs. In the MSFR, the liquid fuel is the coolant, which moves throughout the primary circuit. This complex phenomenology requires multiphysics modeling. In the present paper, a model of the MSFR is developed in the multiphysics code Cardinal, considering neutronic-thermal hydraulic feedback and the transport of delayed neutron precursors (DNPs) and decay heat precursors (DHPs). OpenMC is used to solve neutronic equations, and NekRS is used to solve mass, momentum, energy, DNPs, and DHPs distribution. A RANS k-t turbulence model is used in NekRS. DNPs and DHPs are modeled using a convective-diffusion equation with modified source terms considering radioactive decay. Cardinal results showed a reasonable behavior for temperature, heat source, velocity, DNPs, and DHPs. However, the current limitations in OpenMC do not allow the modification of delayed neutron source locations. Ongoing efforts look to include this feature in future work to introduce DNP feedback in OpenMC.