Thermal design of helium cooled divertor for reliable operation

Nuclear fusion is the promising energy sources because the fuels for power generation are abundant and by-products are eco-friendly rather than other power generations. However, there are several conundrums that must be solved for developing the nuclear fusion plants, including DEMO (DEMOnstration nuclear fusion reactors), such as superconducting system, blanket, cryostats and others. In particular, a divertor is one of essential components because of withstanding the excessive heat flux (∼10 MW/m²) from the high-temperature plasma. Therefore, it is necessary for thermal design of divertor module under tremendous heat flux to develop the nuclear fusion plants. We investigate thermophysical behavior by convective heat transfer and suggest principle operating variables to decide for appropriate thermal design for divertor module. Based on the simplified thermal circuit, we demonstrate that the observed correlation can predict thermophysical characteristics of the divertor module and present the prerequisites for reliable thermal design based on the thermal design maps in terms of principle operating variables of divertor module. Finally, we reveal that the safety factor of thimble is primary concern to establish thermal design of divertor module. The present study will contribute to the development of divertor in nuclear fusion plants and the applications for high heat flux and temperature devices.