AbstractThe TF coils for ITER (ITER, Final Design Report, December 1997) will use the concept of a circular thin walled Nb3Sn cable in conduit superconductor completely enclosed in an insulated groove in steel plates to form the coil pancakes. These are then stacked together to form the winding pack supported by a steel case. The concept is being demonstrated by the fabrication of a TFMC (E. Salpietro et al., Construction of a Toroidal Field Model Coil (TFMC) for ITER, MT-15 Fifteenth International Conference on Magnet Technology, Oct 20–24, 1997, Beijing, China; R. Maix et al., Manufacture of the ITER TF model coil (TMFC), Poster P1-217) with a bore of 1.4×2.5 m, a peak field of 8.77 T and a total current of 7.8 MAT. The coil will be tested during 1999 in the TOSKA facility at FZK, Karlsruhe, using the EURATOM LCT coil to provide an external field system. The objectives of the TFMC are as follows:1.to develop and verify the full scale TF coil manufacturing techniques, in particular the following features:◦plate manufacturing (forming the grooves);◦fitting the conductor in the groove after heat treatment and insulation (i.e. predictable geometry change);◦closing the groove with a cover plate and plate insulation;◦fitting the winding into the case, gap filling and case closure;2.to establish realistic manufacturing tolerances;3.to bench-mark methods for the ITER TF coil acceptance tests, including insulation and impregnation process;4.to obtain information on the coil’s mechanical behaviour, operating margins and in-service monitoring techniques, particularly for the insulation quality over fatigue cycles.