Tests and analysis of quench propagation in the ITER toroidal field conductor insert

The International Thermonuclear Experimental Reactor (ITER) Toroidal Field Conductor Insert (TFCI) has been tested at JAERI Naka, Japan, in 2001, in the background field of the Central Solenoid Model Coil. The TFCI, a well-instrumented ∼43 m long Nb₃Sn solenoid with a thin Ti jacket, wound inside a SS mandrel and cooled by supercritical helium (SHe) at 4.5 K and 0.6 MPa, was successfully operated up to 46 kA and 13 T. Among others, tests of quench propagation, with delay time of the current dump up to 7 s, were performed driven by an inductive heater. The experimental results of these tests are presented. The hot spot temperature reached in the TFCI during the quench is qualitatively assessed. A more quantitative quench analysis is then performed using the Mithrandir code, confirming the qualitative estimation of the hot spot temperature and showing the importance of heat loss to the mandrel in the slowing down of quench propagation. The computed results reproduce well the main experimental features of the quench transient up to the current dump.