Energy, exergy and environmental analysis of Rankine cycle for a steady state CFETR power plant with divertor as preheater

Growing global energy demand and the urgent need to transition toward low-carbon and sustainable power systems have intensified interest in advanced energy conversion technologies. Fusion energy is a promising solution for large scale and carbon free power generation, yet its practical deployment is constrained by elevated coolant outlet temperatures and the lack of mature power conversion technologies. An advanced Rankine cycle integrated with a steady state Chinese Fusion Engineering Testing Reactor (CFETR) is proposed, in which divertor heat ∼ 60 MWth is utilized as a preheater to enhance thermal utilization. A lumped thermodynamic model is implemented in MATLAB and coupled with EES and REFPROP based on energy and exergy analyses to evaluate five Rankine cycle configurations under fusion relevant operating conditions, accounting for working fluid phase change effects, component irreversibility, along with parametric optimization of input parameters and thermal performance. The optimized configuration achieves a thermal performance ∼35.36 %, representing an improvement of approximately 3% compared with conventional blanket based Rankine cycles. Results indicate that incorporating divertor heat and a reheat stage significantly improves cycle performance. The optimal steam inlet temperature and turbine isentropic efficiency are identified as 490 °C and 92%, respectively, yielding a turbine exergy efficiency of 87.23%. By improving thermal utilization and reducing irreversibility, the proposed system supports low carbon electricity generation, contributing to long term environmental sustainability and economically viable fusion power deployment. Benchmarking against DEMO-scale fusion power plants demonstrates good agreement with a deviation of about ∼2 % and confirms the validity of the proposed approach. The findings provide practical guidance for adapting mature Rankine technology to future steady state fusion power plants and other high temperature energy systems.