Objective Controlled nuclear fusion energy is regarded as the ultimate energy source of mankind. Thermal power generation is one of the most important energy conversion and utilization methods for controlled nuclear fusion energy. Safe, efficient and flexible thermal power generation technologies are of great significance to the commercial application of fusion technology.

Method Focusing on the magnetic confinement fusion power generation of superconducting Tokamak reactors, supercritical carbon dioxide (S-CO₂) cycles matching the heat exported by the reactor blanket and divertor were constructed and analyzed with a design fusion power of 1000 MW. The investigated cycles included the simple regenerative cycle, the split recompression cycle, the simplified split recompression cycle, and the combined operation of different cycles. To improve the flexibility of controlled nuclear fusion power generation, thermal energy storage and cycle mode switching strategies were further adopted to enhance the peak shaving performance of the system.

Result The results show that, under base-load operating conditions, the combined scheme of a double-heat-source simple regenerative S-CO₂ cycle (blanket and divertor) and a divertor single-heat-source simplified split recompression S-CO₂ cycle is applicable. The system achieves a net power output of 176.6 MW and a power generation efficiency of 35.3%. For peak-shaving operating conditions, the cycles corresponding to valley, flat and peak periods are switched to a blanket single-heat-source split recompression S-CO₂ cycle, a double-heat-source simple regenerative S-CO₂ cycle, and a combined cycle of double-heat-source simple regenerative S-CO₂ cycle and divertor single-heat-source simplified split recompression S-CO₂ cycle, respectively. With the coordination of thermal energy storage, the system can realize three power levels of 147.4 MW, 168.0 MW and 209.9 MW, with a daily average power generation efficiency of 35.0%.

Conclusion The S-CO₂ cycle is suitable for the energy conversion system of Tokamak controlled nuclear fusion, and it can be flexibly regulated to adapt to the technological evolution of future Tokamak fusion systems.