Strategy and Initial Progress of Integrated Commissioning of Magnet Power Supply for Superconducting Tokamak JT-60SA

Abstract

JT-60SA is one of the largest superconducting tokamaks in the world, and its commissioning is ongoing to achieve the first plasma. The power supply (PS) for superconducting coils consists of ac/dc converter, switching network unit, and quench protection circuit. These subcomponents are required for each coil, and therefore, multiple subcomponents are used in JT-60SA. For plasma discharge, these many subcomponents need to be operated simultaneously, and this commissioning for system integration is an important issue. In the commissioning so far, the toroidal field (TF) coils were energized up to the rated current of 25.7 kA, and plasma was generated by the electron cyclotron range of frequency (ECRF) injection. In TF coils, fast discharge for quench protection was successfully achieved at a high current of 18 kA, which is 70% of the rated current. PF coils have been energized one by one up to ±5 kA, which is 25% of the rated current, and a high voltage of ±5 kV required for inductive plasma initiation was applied to the coils. The commissioning strategy for system integration of the coil PSs and these initial results are described in this article.