Results of R&D on ITER-TF winding critical issues

Koizumi, Norikiyo; Nakajima, Hideo; Matsui, Kunihiro; Isono, Takaaki; Okuno, Kiyoshi; Takayanagi, Tadatoshi*; Kuno, Kazuo*; Senda, Ikuo*

ITER-TF coil is scaled up by about 3 times from TFMC, which was developed in ITER EDA and successfully tested in EU. New technical issues are initiated because of the scale-up. The major issues are feasibilities of high accuracy automatic winding, precise prediction of conductor elongation and/or shrinkage after heat treatment to transfer the conductor in narrow grove of radial plate. It is also necessary to develop insulation system, whose radiation resistance is enough to sustain irradiation in ITER TF coil and which enable vacuum impregnation in suitable duration, such as 24 h. The authors therefore develop one of major parts of automatic winding machine, bending roller head, and optimize TF winding shape to enable successive winding. In addition, the elongation of the TF conductors was evaluated in 200 ppm after the heat treatment. Moreover, impregnation test of the conductor was performed. The test results indicate that it will take a several ten hours to impregnate TF double-pancake by the method developed in EDA.