Pulsed operation test results of the ITER-CS model coil and CS insert

The ITER-Central Solenoid (CS) model coil, which was wound with forced cooled Nb₃Sn cable-in-conduit conductors, was fabricated and tested to demonstrate the justification of CS design for ITER. The CS model coil, whose magnetic stored energy at generation of 13 T is 640 MJ, is the largest one among superconducting pulsed coils constructed so far. The target of pulsed operation is to generate 13 T with ramp rate of 0.4 T/s. The CS model coil and also CS insert were achieved the target without quench. One of the most interesting test items for these coils is to know the dependence of quench current on ramp up rate in pulsed operation. Another is to investigate temperature margin to the target, which was made by changing ramp up rate and inlet temperature. In case of inlet temperature of 4.5 K, the CS model coil and CS insert were operated up to 13 T without quench with a rate of 0.6 T/s and 1.2 T/s, respectively. In case of 6.5 K, however, quench current of the coils was decreased as ramp rate was increased. These results are discussed in comparison with the critical current and the limiting current.