Development of Vacuum Pressure Impregnation for Central Solenoid of JT-60SA

The manufacturing of central solenoid (CS) for JT-60SA is in progress. Vacuum pressure impregnation (VPI) process is key technology for large scale magnet and is used for CS. The height of the CS module after vacuum impregnation process is reduced due to the shrinkage of insulation thickness. Large shrinkage results in difficulties in the VPI process because a moving system is required on the VPI jigs. We evaluated the amount of shrinkage by a VPI test of insulation samples. The test results show that the height of the CS module reduces about 15 mm during the VPI process. Improved jig was developed based on this shrinkage. VPI was well performed and validated by a visual check and impulse test. These results suggest that the VPI process and jig were successfully established. In this paper, the detailed procedure of VPI for CS module, VPI test, and developed jig for VPI are described.