Thermal analysis and configuration optimization of Organic Rankine Cycle for waste heat recovery from a steady state Chinese Fusion Engineering Testing Power Reactor

A promising steady state magnetic fusion reactor is the Chinese Fusion Engineering Testing Reactor (CFETR). This study presents, for first time, the coupling of an efficient and optimized Organic Rankine Cycle (ORC) with CFETR power reactor to recover low grade waste heat, tackling challenges in minimizing the heat loss and enhancing the thermal performance. To address these challenges, advanced simulation and thermodynamic models were developed using EES and lamp based model with MATLAB to achieve high thermal efficiency. A non-ORC system using steam extraction with reheating exhibits a thermal performance of 27.4 %, approximately 1.1 % higher than a conventional Rankine cycle configuration without reheating. In comparison, the proposed ORC system incorporating reheating and preheating stages was evaluated with Toluene and R245fa as working fluids. R245fa achieved superior thermal performance, with a thermal efficiency of 40.1 % and exergy efficiency of 57 %, outperforming both organic and conventional working fluids under the same thermal input of 300 kW and temperature range from 70 °C to 165 °C. The analysis identified R245fa, combined with reheating and preheating ORC configuration, as a promising candidate for CFETR waste heat recovery. The sensitivity studies were conducted on turbine isentropic efficiency, working fluid pressure, and partial load behavior to optimize system parameters such as turbine-generated power, net system power, pump power requirements, and condenser heat extraction. Also, exergy analysis was performed to determine the quality of heat and work done by the ORC. The developed thermodynamic model accuracy was validated through the back work ratio and heat rate trend of decreasing and increasing, thermal and exergy efficiency showed deviation about ±3 %, with the result reported in literature. At optimal conditions, the system generated net power 132.7 kW and rejected 156.2 kW of heat. This study demonstrates the viability of ORC technology, particularly with R245fa, in fusion reactor applications and provides a reference framework for the low grade heat recovery for nuclear power plants. It offers an effective approach to meeting energy demands, reducing heat rejection, and ensuring the safe and long-term operation of CFETR under controllable conditions.