Development of ITER Toroidal Field Coil Winding Packs

Synopsis: The National Institutes for Quantum and Radiological Science and Technology (QST) is responsible for manufacturing nine ITER TF coil winding packs (WPs). QST has been proceeding WP manufacturing, the procedure for which has been developed through qualification trials and the authors’ experiences. However, since the WP is a huge superconducting coil that has never been fabricated so far, technical challenges newly arose when manufacturing the first WP, such as tight WP dimension tolerance, current center line (CCL) position control and non-destructive examination (NDE) for joint performance. In addition, unexpected discharge happened at instrumentation wires going through the ground insulation layer after the WP cold test. The authors resolved these problems by clarifying the root causes and developing new techniques through additional qualification trials. As a result, WP fabrication is now in the series production phase. In fact, six WPs have been fabricated and manufacturing of the remaining three WPs is on-going.