The Preload Variation Analyses of CFETR CSMC Under Different Strategies

The Central Solenoid Model Coil is a preparatory stage towards the final fabrication of China Fusion Engineering Test Reactor central solenoid. Its analysis and manufacturing experience will be used for the design and fabrication of China fusion engineering test reactor central solenoid coil. The assembly scheme of low-field coil modules of the central solenoid model coil is vertical stacking, which include the top, middle and bottom modules. And the high-field coil adopts the coaxial surrounding structure, which include the inner and outer Nb3Sn modules. After the coil is charged, the high-field and low-field modules must maintain alignment, so it is necessary to apply appropriate preload to the coil by using the preload system. In order for CSMC to operate effectively, four strategies are proposed to ensure that the preload system possesses substantial remnant preload while maintaining a small preload difference between inner and outer tension rods. And the preload variation trend under each strategy is analyzed. The study fruition presented in the paper provides valuable theoretical guidance for optimizing the design of preload system and also helpful for adjusting the preload applying scheme.