IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, VOL. 28, NO. 4, JUNE 2018 4203705 Manufacturing the European Superconducting TF Winding Packs for the ITER Marc Cornelis , Piergiorgio Aprili, Boris Bellesia, Alessandro Bonito-Oliva, Eva Boter Rebollo, Paz Casas Lino, Jordi Cornella Medrano, Michele Damone, Robert Harrison, Angela Hernandez Sanchez, Marc Jimenez, Charalampos Kostopoulos, Ken Libens, Narcis Pellicer Sabadi, Lionel Poncet, Santiago Tarrago, Eduard Viladiu Martinez, Jacques Silva Ribeiro, Paolo Barbero, Andres Felipe, Stefano Pittaluga, and Oriano Dormicchi Abstract—The magnetic field, necessary for the plasma confine- ment in the International Thermonuclear Experimental Reactor (ITER), Cadarache, France, is provided by the 18 Toroidal Field Coils (TFC). In each coil, this magnetic field is produced by circu- lating a current of 68 kA through 4.5 km of Nb 3 Sn cable-in-conduit superconductor, which is assembled into a mechanical structure ca- pable of withstanding the huge Lorentz forces produced. The Fu- sion for Energy, the European Domestic Agency for the ITER, is responsible for the supply of 10 TFC. This article gives an overview of the manufacturing and test processes applied during the series production of all sub- and final assemblies, as well as the pro- duction status. Special emphasis will be put on some particular characteristics of the Nb 3 Sn superconductor and other problems faced during manufacturing and strategies applied to overcome them. Index Terms—Superconducting magnets, fusion magnets, mea- surements and techniques, Nb 3 Sn wire. I. INTRODUCTION R EPRESENTING the main stage of the TFC assembly, the Winding Pack (WP) manufacturing step consists of a series of processes where TF conductors and Radial Plates (RP) are assembled, together with insulating materials and other components, into a superconducting coil. The process can be split in two phases: the manufacturing of 70 Double Pancakes (DP) and their subsequent assembly into 10 WPs (see Fig. 1). The main operations of the DP assembly are the following: 1) Conductor winding 2) Helium-inlet and termination assembly 3) Nb3Sn heat treatment (HT) 4) Conductor transfer into the RP Manuscript received September 19, 2017; accepted January 8, 2018. Date of publication January 24, 2018; date of current version February 13, 2018. (Corresponding author: Marc Cornelis.) M. Cornelis, P. Aprili, B. Bellesia, A. Bonito-Oliva, E. Boter Rebollo, P. Casas Lino, J. Cornella Medrano, M. Damone, R. Harrison, A. Hernandez Sanchez, M. Jimenez, C. Kostopoulos, K. Libens, N. Pellicer Sabadi, L. Poncet, S. Tarrago, and E. Viladiu Martinez are with the Fusion for Energy, Barcelona E-08019, Spain (e-mail: marc.cornelis@f4e.europa.eu). J. Silva Ribeiro is with the CNIM, ZI de Br´ egaillon, La Seyne-sur-Mer F- 8350, France. P. Barbero is with the SIMIC, Camerana 12072, Italy. A. Felipe is with the Iberdrola IC, Madrid 28050, Spain. S. Pittaluga and O. Dormicchi are with the ASG Superconductors s.p.a, Genoa 16152, Italy. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org Digital Object Identifier 10.1109/TASC.2018.2797299 Fig. 1. Images of a completed Double Pancake (top), and a Winding Pack (bottom). 5) Conductor insulation 6) Cover Plate (CP) laser welding 7) DP ground insulation 8) DP Vacuum Pressure Impregnation (VPI) The remaining steps for the WP phase are: 1) DP stacking 2) WP ground insulation 3) WP VPI 4) He-piping assembly and instrumentation wiring Relevant inspections and tests, such as dimensional measure- ments, electrical tests, leak and pressure drop tests, weld in- spection, are carried out at all steps to ensure the compliance of the final product and detect anomalies at the earliest possible stage. Besides a brief explanation of the overall manufacturing process and status, this paper will focus on two critical aspects: how precise and repeatable conductor geometry is achieved af- ter winding and heat treatment of the superconductor, in order to allow its transfer to the RP groove; and how completed DPs are stacked, insulated and impregnated together to obtain a final 1051-8223 © 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications standards/publications/rights/index.html for more information.