Thermal-hydraulic simulation of the CFETR TF coil operation during a plasma scenario: Gandalf-Fluent and 4C code-to-code comparison

Within the framework of the comprehensive research facility for fusion technology (CRAFT) activities, a prototype toroidal field (TF) coil has been designed and will be manufactured at the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP), in Hefei. The main purpose is to develop and validate the manufacturing technologies of the large-scale superconducting coils of the China Fusion Engineering Test Reactor (CFETR). To ensure the safe operation of the CFETR device, the Gandalf-Fluent tool and the 4C code are employed to evaluate the performance of the superconducting magnets, and their thermal-hydraulic simulation results are compared with each other. The comparison shows that the thermal coupling between turns and pancakes and the transient model of the thermal coupling to the casing structures, accounted for in 4C but neglected in Gandalf-Fluent, have a significant effect on the temperature profile. Then a detailed reassessment of the minimum temperature margin (Delta T-mar(min)) is carried out using the 4C code. The results show that the Delta T-mar(min) is similar to 1.0 K (if a realistic value for the inter-turn and inter-pancake coupling parameter is assumed), lower than the design requirement of 1.2 K, and it deserves the attention of the designers.