Evaluation of temperature rise caused by AC loss due to plasma disruption in joint of JT-60SA poloidal field coil

Nakamura, Kazuya*; Yamamoto, Yusuke*; Suzuki, K.*; Takao, Tomoaki*; Murakami, Haruyuki; Natsume, Kyohei; Yoshida, Kiyoshi

The JT-60 Super Advanced (JT-60SA) of Japan Atomic Energy Agency is a fusion experiment device designed to contribute to the early realization of fusion energy by providing support to the operation of ITER. The CS and EF coils are fabricated in Japan. In case of the butt joint for CS, two conductors are pressed onto each side of a copper sheet. As for the lap joint, two conductors are pressed by overlapping them with copper blocks for used EF pancake coils and between the CS and the current feeder. When a time-varying magnetic field is applied to the joints, an AC loss occurs, and temperature margin of the joint decreases due to the AC loss. It is necessary to understand the temperature margin of the joints to protect this coil system from quench. In this study, we fabricated the butt joint and lap joint, and measured the AC losses under the time varying field. Based on these experimental results, we analyzed the temperature rise caused by AC losses of the joints by using FEM under the standard plasma scenario and disruption scenario. The obtained results become fundamental data to estimate the temperature margin of the joints.