Study of the cooling systems with S-CO2 for the DEMO fusion power reactor

The power conversion system is one of the key parts of the fusion power plant. The DEMO fusion power reactor features multiple heat sources, like the first wall, blanket, divertor and vacuum vessel, on different temperatures and power levels. The heat addition into a thermodynamic cycle from different heat sources is disadvantageous in terms of efficiency of steam Rankine or helium cycles. However, it is advantageous for the S-CO2 cycles as it resolves the real S-CO2 property issues. S-CO2 is thus an option for conversion of heat into electricity and might have overall better performance than the steam Rankine or helium Brayton cycles. Therefore, it should be considered as an option for the DEMO fusion power reactor. The paper focuses on the application of S-CO2 for the European DEMO fusion power plant. The higher net efficiency of the S-CO2 cycles for the DEMO fusion power plant in comparison with the Rankine steam cycles is presented.