Test result of a full-size NbSn conductor developed for the ITER TF coils

ITER TFコイル用NbSn実規模超伝導導体の試験結果

布谷 嘉彦; 名原 啓博; 吉川 正敏*; 松井 邦浩; 辺見 努; 高橋 良和; 礒野 高明; 小泉 徳潔; 中嶋 秀夫; Stephanov, B.*; Bruzzone, P.*

Nunoya, Yoshihiko; Nabara, Yoshihiro; Yoshikawa, Masatoshi*; Matsui, Kunihiro; Hemmi, Tsutomu; Takahashi, Yoshikazu; Isono, Takaaki; Koizumi, Norikiyo; Nakajima, Hideo; Stephanov, B.*; Bruzzone, P.*

日本原子力研究開発機構(JAEA)は、ITERの要求性能を満たすITER TF NbSn超伝導導体を開発し、ITER TFコイル実機に使用する導体の製作を開始した。TFコイル導体の製作を継続するために、製作した導体が要求性能を満足することの実証を目的とし、製作手法の異なる2種類のNbSn素線より製作した導体を用いてサンプルを製作し性能評価試験をスイス・ローザンヌ工科大学のサルタン試験装置により行った。製作したサンプルの長さは各々約3mで、各導体の表面に取り付けた温度センサと電圧タップを用いて分流開始温度(Tcs)を10.78Tの外側磁場で計測し、性能評価を行った。その結果、Tcs値は通電回数とともに低下する傾向が初期に各々見られたが、最終的に落ち着き、それぞれ6.1Kと6.0Kであった。これらの値は、ITER TF導体の要求値5.7Kを満たし性能の実証を行うことができた。

Japan Atomic Energy Agency (JAEA) has developed ITER TF NbSn conductors that fulfill ITER requirements and then commenced fabricating conductors to be used for ITER TF coils. As a qualification of conductor fabrication, two full-size conductor samples named as JATF4 were prepared and tested by the SULTAN facility at CRPP in Switzerland. The length of the samples was about 3 m, and temperature sensors and voltage taps were attached on conductors to measure the current sharing temperature (Tcs). The measurement was performed at the beginning of the test campaign, during cyclic test, and at the end of the campaign that corresponded to after once warm up and cool down. The Tcs values electrically assessed by the agreed procedure at outer magnetic fields of 10.78 T were 6.5 K and 6.2 K at the beginning and 6.1 K and 6.0 K at the end of the campaign for each conductor, respectively. These values concluded that the conductors have enough Tcs margin to satisfy the criterion of 5.7 K as ITER TF conductor, and conductor fabrication is qualified. Detail of the test results will be presented and discussed.