Analysis of Power Conversion System Options for ARC-like Tokamak Fusion Reactor Balance of Plant

In recent years, fusion energy has assumed an important role in the energy scenario, being a sustainable, environmentally friendly, and practically inexhaustible energy source. Fusion energy could play a crucial role in fully decarbonized electricity production in the second half of this century, helping to meet the increasing energy demand. One of the studied reactors is ARC, a tokamak fusion device characterized by a compact and high-field design initially conceived by researchers at the Massachusetts Institute of Technology, which the Commonwealth Fusion System (CFS) plans to construct in the next decade. This paper is focused on the analysis and development of different configurations for the ARC Balance of Plant Power Conversion System, with the aim of improving the thermodynamic efficiency, which is one of the pillars of sustainability. Three cycles were studied by using the General Electric GateCycleTM software: a supercritical steam Rankine cycle, a supercritical CO2 Brayton cycle, and a supercritical helium Brayton cycle. The thermal efficiency of the three options was compared to select the most promising solution. The results showed that the supercritical steam cycle is the best configuration in terms of cycle efficiency for the ARC FNSF Pilot phase.