Exploration of power conversion thermodynamic cycles for ARC fusion reactor

In the worldwide energy industry, nuclear fusion could be a breakthrough in the medium-long term. One promising fusion machine under design at Massachusetts Institute of Technology is ARC reactor. It is likely that the first nuclear fusion plants will rely on a traditional thermodynamic cycle for the downstream power energy conversion. In this framework, one of the design aspects is to maximize the thermal efficiency. In the present paper the thermodynamic cycles, which could be adopted in ARC rector, are explored. Three cycles have been considered: the Rankine, the Brayton and a combined cycle. For the gas adopted in the Brayton and combined cycles, two options have been investigated: supercritical Helium and supercritical CO2. A comparison among thermal efficiency and preliminary considerations on component integrity's, plant feasibility and economics of each studied configurations has been discussed to identify the possible best option for ARC reactor. The results show that a regenerative CO2 Brayton cycle with intercooler and re-heating systems is the most promising one. Such configurations is able to reach a thermodynamic efficiency of up to 0.6.