MHD Capabilities in SAM and NekRS for Fusion Liquid Metal Blanket Applications

Liquid metals such as lithium and lead–lithium eutectics are leading candidates for use as breeder and coolant materials in fusion blankets, where they enable both tritium breeding and efficient heat removal. In the presence of strong magnetic fields, magnetohydrodynamic (MHD) effects significantly influence flow distribution, pressure drop, and heat transfer, posing major challenges for blanket design and performance assessment. While high-fidelity computational fluid dynamics (CFD) tools exist for MHD analysis, there remains a lack of modern system-level analysis codes that integrate MHD effects with thermal–hydraulic and systems modeling.This paper presents recent developments at Argonne National Laboratory to address this gap through the implementation of MHD modeling capabilities in the System Analysis Module (SAM), a modern system analysis code built on the MOOSE framework. A reduced-order MHD modeling approach applicable to high Hartmann number and high interaction parameter flows is adopted, enabling efficient system-level simulations relevant to fusion liquid metal blankets. In parallel, MHD capabilities are being implemented in the high-performance CFD code NekRS to provide high-fidelity simulations for verification and model development.Analytical verification, code-to-code comparisons, and validation against historical experimental data from the Argonne Liquid Metal Experiment (ALEX) facility are presented for both square and round duct configurations under applied magnetic fields. The results demonstrate good agreement between SAM and NekRS predictions with analytical solutions in uniform magnetic fields; good agreement between SAM predictions with legacy MHD codes, and experimental measurements in varying magnetic fields. Ongoing and future work includes extension to insulating duct configurations, further NekRS development, and application to conceptual fusion blanket designs and ITER test blanket modules.