Development of the Turn Releasing Technology for the Nb3Sn Pancake Coil of CFETR CSMC

A central solenoid model coil (CSMC) is being developed to verify the large-scalar superconducting coil manufacture technology for China Fusion Engineering Test Reactor (CFETR) in Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). The turn insulation wrapping of the Nb
₃
Sn pancake coil is conducted after the coil heat treatment. The turn releasing technology is necessary to be developed and verified to insure there is no damage to Nb
₃
Sn conductor during the turn insulation wrapping of the Nb
₃
Sn pancake coil. This paper introduces the design, analysis and verification for the safe stretch distance, the design and debugging of the special equipment, and the process experiment with the 4 × 4 mockup coil.