Progress of mock-up trials for ITER TF coil procurement in Japan

日本におけるITER TFコイル調達に向けた試作の進捗

松井 邦浩; 小泉 徳潔; 辺見 努; 高野 克敏; 中嶋 秀夫; 大勢持 光一*; Savary, F.*

Matsui, Kunihiro; Koizumi, Norikiyo; Hemmi, Tsutomu; Takano, Katsutoshi; Nakajima, Hideo; Osemochi, Koichi*; Savary, F.*

原子力機構は、国内機関として9個のITER TFコイルの調達を担当している。TFコイルの製作では、熱処理によって長さが変化する超伝導導体を、800kN/mの電磁力を支持する役割をするラジアル・プレート(RP)の溝に挿入する。導体のRP溝への挿入を可能とするためには、寸法公差が0.01%程度の高精度なRP及び巻線の製作技術の確立が重要となる。この高精度な製作技術を確立するとともにTFコイルの調達に向けた製作手順の決定と最適化を目的として、原子力機構は、実規模のRP製作及び中規模巻線の試作を実施する。また、これらの試作に向けて、一次製造計画書を作成し、その実現性を実証するために小規模試作を実施する。小規模試作では、レーザ溶接によるカバー・プレート溶接,アクリル及び金属モデルを用いた含浸試験,TF導体の機械試験と曲げ試作等を実施している。本件では、小規模試作の結果と中規模及び実規模試作の進捗を報告する。

The magnet system for ITER comprises 18 Toroidal Field (TF) Coils using NbSn cable-in-conduit superconductor, which operate at 4.5 K in supercritical helium. Japan Atomic Energy Agency (JAEA) is responsible for the procurement of 9 TF coils as Japanese Domestic Agency (JADA). Before launching the procurement of these coils, reduced and full-scale trials will be performed to determine and optimize the manufacturing process of a TF coil. During the manufacture of the TF coil, heat-treated superconducting cable-in-conduit conductor, whose length may vary during heat treatment, shall be inserted in the grooves of the radial plate (RP), which is part of the mechanical structure supporting the large electromagnetic forces that are of the order of 800 kN/m. The RP also enhance reliability of the electrical insulation that will be tested up to 19 kV DC and 2.5 kV AC for the winding pack to ground. Very accurate tolerances, of the order of 0.01% on the length of the RP grooves and of the wound conductor, are required to enable the insertion of the conductor. Therefore, the development of suitable manufacturing techniques for the RP and for the winding operation is essential to achieve this requirement. JAEA has contracted companies for fabrication trials of a full-scale RP and winding trials of a one-third scale double pancake to verify feasibility of the required tolerances from an industrial view point. Prior to these trials, JAEA developed a preliminary manufacturing plan and then, industry will carry out small-scale trials to demonstrate applicability of the preliminary manufacturing plan before making the reduced and full-scale trials. The small scale trials will include the cover plate welding with the laser welding, the impregnation using the acryl and metal models, and, the mechanical test and the trail bending of the TF conductor. The results of the small-scale trials and progress on the reduced and full-scale trials are presented in this paper.