Multiphysics Modelling of the Molten Salt Fast Reactor using NekRS and the Fission Matrix Method

TL;DR

This paper presents a multiphysics computational model for the Molten Salt Fast Reactor that integrates thermal hydraulics and neutronics using a reduced-order Fission Matrix method within a high-fidelity simulation framework.

Contribution

It introduces a novel multiphysics modeling approach combining NekRS, the Fission Matrix method, and the MOOSE framework for MSFR analysis, enhancing simulation speed and accuracy.

Findings

Fission Matrix method enables fast neutronics calculations.

The model effectively couples neutronics with thermal hydraulics.

High-fidelity simulations validate the approach.

Abstract

The Molten Salt Fast Reactor (MSFR) has the particularity that the coolant is also the fuel, which tightens the coupling between neutronics and thermal hydraulics as the fuel circulates through the primary system. Therefore, developing computational models to analyze the MSFR requires a multiphysics approach. In this paper, we propose developing a neutronic thermal-hydraulic computational model of the MSFR that uses a reduced-order model to solve the neutronics equations. The principal computational tool chosen for this purpose is the high-fidelity code Cardinal, a wrapping within the MOOSE framework that integrates the Computational Fluid Dynamics code NekRS and the Monte Carlo particle transport code OpenMC. However, we use the Fission Matrix (FM) Method to solve the neutronics equations instead of OpenMC. The FM method can perform fast and still accurate neutronics simulations. It relies on precalculated databases obtained through a Monte Carlo simulation.