Technology transfer from laboratory to industry for fabrication of large superconducting coil joints

The future magnetic thermonuclear fusion reactors will use superconducting magnets. The development during the last decade of the cable-in-conduit conductor (CICC) allows the transport of high current intensities. The construction of the winding pack is conceived, for manufacturing reasons, in double pancakes. Joints have to be implemented to connect electrically double pancakes with each other. These joints must fulfil electrical, mechanical, hydraulic and tightness requirements and their design must allow industrial feasibility. The twin-box concept, developed at CEA, was tested with 3 prototype joint samples, and applied to the joints of the ITER Toroidal Field Model Coil, manufactured in the European industry. The tests of this coil in 2001 showed that all these joints operated satisfactorily and in particular achieved low and reproducible resistances. The technique is now being developed with niobium-titanium conductors for the ITER PF Coils and will be tested with a full size prototype sample in 2002. (author)