Quench detection using pick-up coils for the ITER central solenoid

摘要

At least two independent methods for quench detection should be used for the magnets of the ITER size, because of the potential severe impact of a failure. The voltage tape method and the flow meter method, which were used in the CS model coil (CSMC), are both considered for the ITER Central Solenoid (CS). The voltage tap method is primary due to its quick response. The ITER CS consists of six pancake wound modules, which are operated with individual operating current patterns in ac mode. The induced voltage in the windings must be compensated to detect the voltage due to any normal transition during the pulse operation. We have investigated the optimum configuration for pick-up coils (PC) for compensation. The results of simulations show that the compensated voltages are very low (70 mV) compared with the inductive voltage and adequate normal voltage sensitivity is obtained. The hot spot temperature in the CS during the operation was estimated from the simulation and the experimental measurements of the CSMC quench. The hot spot temperature estimated is 128-144 K, lower than the ITER design criterion (150 K). It is shown that the detection system using the PCs could be designed with a high enough detection sensitivity.