Validation of welding technology for ITER TF coil structures

Japan Atomic Energy Agency (JAEA), acting as the Japan Domestic Agency (JADA) in the ITER project is responsible for the procurement of 9 Toroidal Field (TF) coil winding packs (WPs), structures for 19 TF coils (including one spare), and assembly of the WPs and the coil structures for 9 TF coils [1]. The TF Coil structures which support large electromagnetic force generated in TF coils under the cryogenic temperature (about 4 K), are very large welded structures composed of a coil case and structural attachments made of high strength and high toughness stainless steel. JAEA has been performing welding trials for heavy thickness materials since 2008 and is planning fabrication of full-scale mock-ups of main sub-components (1 set for the inboard side and 1 set for the outboard side) in 2011 in order to investigate the technical issues for manufacturing the TF coil structures. This paper presents the results of welding trials and the status of full scale mock-ups fabrication to confirm the validity of welding technology and manufacturing design before fabricating the actual products.