Thermodynamic and exergoeconomic investigation of various SCO2 Brayton cycles for next generation nuclear reactors

•The calculation model of six SCO2 Brayton cycles used in nuclear reactors is built.•Parametric analysis is carried out from views of thermodynamics and economics.•A comparative study is conducted among six SCO2 Brayton cycles. In the present paper, a thermodynamic simulation platform has been established for investigating the thermodynamic and exergoeconomic behavior of six SCO2 Brayton cycle layouts used in nuclear reactors. A detailed parametric study was performed through a sensitivity analysis on the cycle efficiency and the unit cost of the total product with the fixed maximum system pressure of 20 MPa and the maximum system temperature of 550 °C. The results reveal that there exists an optimal pressure ratio corresponding to the highest cycle efficiency (thermal optimal design case) or lowest total product unit cost (cost optimal design case) for each SCO2 cycle. The intercooling cycle has highest cycle efficiency and comparable cost to the recompression cycle. Considering the exergoeconomic factors fk, it can be concluded that, for intercooling cycle, it is a more cost-effective way to reduce the capital investment of compressor at the expense of less component efficiency compared to other cycles. Whereas for the recompression cycle, it performs most outstanding in terms of total product unit cost among the studied cycles when the effectiveness of heat exchanger exceeds 0.86.