Iter In-Vessel Coil design and R&D

ITER will incorporate In Vessel Coils (IVCs) as a method of stabilizing “Edge Localized Modes” (ELM) and providing “Vertical Stabilization” (VS). To meet the ELM and VS Coil requirements strong coupling with the plasma is required so that it is necessary for the coils to be installed in the vessel just behind the blanket shield modules. Due to this close proximity to the plasma the radiation and temperature environment is severe and conventional electrical insulation materials and processes cannot be used. The development of mineral insulated conductor technology has been required in the IVC design to deal with this high radiation and high temperature environment. While mineral insulated conductor technology is not new, building a large magnet with high current carrying capability and a conductor diameter larger than the mineral insulated conductor currently manufactured requires R&D and the extension of existing technologies. A 59mm Stainless Steel Jacketed Mineral Insulated Conductor (SSMIC) using MgO is being developed for this application. The IVC ELM and VS coils design includes both the development of the fabrication techniques for the SSMIC and the design and analysis of the ELM and VS Coil assemblies. The ELM coil assemblies consist of nine toroidal sectors of three (upper, midplane, and lower) 6-turn rectangular "picture frame coils" for a total of 27 coils mounted to the vacuum vessel. The ELM coil structural design must provide enough flexibility to relieve the thermal stresses in the coil while providing the stiffness to resist the high Lorentz (magnetic) loads on the coil. To achieve the required fatigue lifetime the ELM SSMIC conductors use a water cooled CuCrZr conductor. The VS coils consist of one upper and one lower 4-turn solenoid "ring" coil connected in an anti-series "saddle" arrangement. Because it is less stressed than the ELM coil conductor the VS SSMIC conductor use water cooled Cu instead of CuCrZr. This paper summarizes the design, development, and testing to date of the SSMIC conductor as well as the design and analysis of the VS and ELM coil assemblies. Joining and assembly techniques for the SSMIC conductor are also discussed.