Study on Systematic Application of Superconductivity and Cryogenic Technologies to Controlled Nuclear Fusion

为了实现可控的核聚变，需要低温工程来冷却大型超导线圈系统，以产生巨大的磁场并将其保持在低温下。作为聚变装置工程的一部分，要求低温工程系统化和系统化应用。本研究主要围绕以下几个方面展开研究：大型超导磁体系统、包括超流氦冷却在内的大规模氦冷却、高临界温度超导(HTS)在电流馈线和输电中的应用、超导线圈的功率控制、低温结构材料的力学性能。目前，德国文德斯坦7-X正在建设大型超导线圈系统。德国卡尔斯鲁厄科学研究院和法国萨克雷研究所将对所有线圈进行测试，以检查超导电性。结合大型螺旋器件项目的经验，构建了有效的冷却方案，并积极开展了Bi系、YBCO等高温超导材料的研究。镀银Bi2223焊丝供应稳定。高温超导线材的力学性能较差，在大型超导线圈中的应用并不容易，但高温超导线材在超导输电中具有广阔的应用前景。YBCO薄膜的制备难度较大，约3μm厚的薄膜有望在多个工程领域得到应用。高温超导将在聚变装置中用作电流馈送器和电力传输装置。

In order to realize the controlled nuclear fusion, cryogenic engineering is needed to cool down the large superconducting coil system to create huge magnetic field and keep it at cryogenic temperature. The systematization of the cryogenic engineering and the systematic application are desired as a part of the fusion device engineering. In this study, the investigation has been carried out mainly based on the following fields ; large scale superconducting magnet system, large-scale helium cooling including the super fluid helium cooling, applications of high critical temperature superconductors (HTS) to current feeders and electricity transmission, power control of superconducting coils, mechanical properties of cryogenic structural materials.The large-scale superconducting coil system is now under construction for Wenderstein 7-X in Germany. Forschungszentrum Karlsruhe in Germany and Saclay institute in France will test all the coils to check the superconductivity. The effective scenario of the cooling is constructing by taking account of the experience in the Large Helical Device project.The investigations on HTS, such as Bi system and YBCO, have been performed energetically. The wire of Ag-sheathed Bi2223 is supplied stably. The application to the large superconducting coil is not easy because of the poor mechanical properties, but it is promising to apply the HTS wires to superconducting electricity transmission. The production of the thin film of YBCO is rather hard and about 3 μ m thick films are expected to use in several engineering fields. The HTS will be used as current feeders and electricity transmission in the fusion devices.