ITERトカマク本体の組立方法と組立手順の検討

Study on assembly techniques and procedures for ITER tokamak device

小原 建治郎; 角舘 聡; 柴沼 清; 佐郷 ひろみ*; 上 弘一*; 清水 克祐*; 小野塚 正紀*

Obara, Kenjiro; Kakudate, Satoshi; Shibanuma, Kiyoshi; Sago, Hiromi*; Ue, Koichi*; Shimizu, Katsusuke*; Onozuka, Masanori*

核融合炉心の実証と核融合発電炉に必要な炉工学技術の開発を目的とした国際熱核融合実験炉(ITER)は、単体寸法と重量が十数メートル,数百トンもの大型・大重量の各種機器によって構成され、組立後のトカマク本体の概略形状寸法は直径26m,高さ18m,総重量は16,500tにもなる。一方、トカマク本体の位置・組立精度については3mm程度の高精度が要求されている。このため、大型・大重量機器としての取扱いはもとより、高度な組立精度を考慮したトカマク本体の組立手順と組立技術について検討する必要がある。本報告では、ITER国際チーム(IT)が中心となってまとめた従来設計をより実現可能な方法に改善するために、これまでの大型・大重量機器の組立・据付の知見をもとに、次に示す各作業ごとに必要な冶工具,専用ツール,計測方法を含めた組立方法・手順について検討した。(1)トロイダルコイルの組立・芯出し作業,(2)組立作業の簡易化と誤差を少なくするための手順と組立ツールの検討,(3)真空容器の溶接歪を小さくするための手順の検討,(4)作業中、トロイダルコイルに変形を与えない真空容器の支持方法,(5)要求位置・組立精度を確保するために必要な基準点・基準線の設定・検討。その結果、大型で大重量機器から構成されるITERトカマク本体の高精度な組立について現実的な組立方法・手順を提示することができた。

The International Thermonuclear Experimental Reactor (ITER) tokamak is composed of many kinds of components. The dimensions and weight of the respective components are around a few ten-meters and several hundred-tons. In addition, the whole tokamak assembly, which are composed of these components, are roughly estimated, 26 m in diameter, 18 m in height and over 16,500 tons in total weight. On the other hand, as for positioning and assembly tolerances of these components are required to be a high accuracy of 3mm in spite of large size and heavy weight. The assembly procedures and techniques of the ITER tokamak are therefore studied, taking account of the tolerance requirements. Based on the above background, the assembly procedures and techniques, which are able to assemble the tokamak with high accuracy, are described in the present report. The following newly developed tokamak assembly procedures and techniques, jigs and tools for assembly and metrology concept based on the available knowledge and experiences of the installation of the large components, in order to improve the IT (International Team) design toward the more realistic one. As a result, we show the realistic tokamak assembly procedures and techniques to be able to assemble the large and heavy ITER tokamak with high accuracy. (1)Assembly and alignment of the toroidal field coil with high accuracy. (2)Simplification of the assembly procedures, and the jigs/tools and procedures to reduce the misalignment. (3)Assembly procedures and techniques for the vacuum vessel to reduce the weld distortion. (4)Supporting procedures and techniques of the vacuum vessel sector to prevent the toridal field coil from the deformation due to the dead weight of the vacuum vessel sector. (5)Datum points and lines for the required positions and assembly tolerances during tokamak assembly.