ITERニオブアルミ・インサート・コイルのAE特性

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 2002, we carried out several kinds of tests using a CS model coil and Nb3Al insert coil (Nb3Al Insert). In the experiments, we measured the acoustic emission (AE) signals emitted from these coils. In this paper, we focus our discussion on the AE signals emitted from the coils. Two kinds of data acquisition methods for the AE signals were adopted during the series of excitations: whole waveform recording and AE envelope recording. Furthermore, two kind of measuring methods for AE envelope recording were selected: full-time recording and constant interval recording. In this paper, we mainly discuss the AE signals emitted from these coils using envelope recording at a constant interval. Observation of the AE signals showed that disturbances in both coils decreased within a few times of excitation iteration. Even though the Nb3Al Insert fully quenched at the time of inductive heating, we confirmed that the coil returned to an unaltered stable condition after removal of the heat. Furthermore, we confirmed that the average AE voltage kept a constant distribution pattern during the 1,000-time cycle test under a background field of 13 T using the CS model coil.