AC losses of the toroidal model pancake (hollow conductor type)

The conductors of the toroidal field (TF) coil are being developed for the tokamak fusion reactor ITER International Thermonuclear Experimental Reactor. While the TF coil will be operated in the DC mode, the reduction of AC losses is important from the viewpoint of the plasma disruption. The Toroidal Model Pancake (TMP) is a test coil for investigating the applicability of a hollow conductor for the TF coil. The TMP has a 90-m-long hollow conductor, and AC loss measurements were carried out. This pancake has an inner diameter of 1 m and an outer diameter of 1.5 m. The results show that the effective diameter of (NbTi)/sub 3/Sn and NbTi corresponds to the nominal filament diameter of 4 mu m and 39 mu m, respectively, and that the coupling losses depended on the direction of the applied magnetic field. The time constant of the coupling current was 1.6 s when a magnetic field was applied in the perpendicular direction.<
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