ITER TFインサート・コイルのAE特性

抄録

The Central Solenoid Model Coil (CS model coil) program was established in 1992 as one of the projects for the Engineering Design Activities (EDA) of the International Thermonuclear Experimental Reactor (ITER). In the year 2001, we carried out several kinds of tests using a CS model coil and a Toroidal Field (TF) insert coil. In the experiments, we measured the acoustic emission (AE) signals emitted from these coils. This was the first attempt to measure AE from the insert coil directly, as AE sensors were not attached during the previous tests conducted in 2000. In this paper, we focus our discussion on the AE signals emitted from the TF insert coil. Two kinds of data acquisition methods for the AE signals were utilized during the series of excitations: full waveform recording and AE envelope recording. Observation of the AE signals showed that the disturbances in the TF insert coil decreased with the iteration number of excitation as judged from the instantaneous AE energies and AE event count. Furthermore, we confirmed that the AE had constant distributions during a 1, 000-time-cyclic test under a back-ground-field of 13T using the CS model coil. Therefore, we obtained an important experimental result in that the TF insert coil was highly stable throughout the series of experiments.