Mechanical Properties Evaluation of Large Scale Superconductors in High Magnetic Field and Large Current under Cryogenic Temperatute.

大型等离子体装置，如大型螺旋装置，温德斯坦7-X和国际热核实验反应堆，已经计划并开始制造。这些大型装置需要大型超导磁体来产生高磁场。由于超导磁体在运行过程中会受到巨大的电磁力作用，因此在制作超导磁体之前必须对其机械变形行为进行估计。为此，本研究进行了几种变形评估的测量。将铜比为1.0比2.0的NbTi超导体在室温下局部变形，然后冷却到液氦中。在这种情况下，由于铜的电阻增加，淬火后的恢复被延迟。另一方面，当超导体在低温下变形时，恢复是正常的。从这些结果可以看出，稳定剂的电性能变化受机械变形的影响，在磁体的设计和制造中应引起注意。用于大型螺旋装置的超导体对机械变形具有相当的稳定性。线圈变形可通过使用线圈组进行机械试验来估计。对大型螺旋装置内垂直线圈进行了励磁试验，成功地测量了其在冷却和励磁试验期间的变形。在变形测量时，应考虑电缆导线不受磁场影响。

Large scale plasma devices, such as the Large Helical Device, the Wenderstein 7-X and the International Thermo-nuclear Experimental Reactor, have been planed and started to fabrication. These large devices require the large scale superconducting magnet to generate high magnetic fields. Since huge electro-magnetic forces will act on the superconducting magnet during the operation, the mechanical deformation behavior must estimate before fabrication. For this purpose, the several kinds of measurements for the deformation evaluation have been carried out in this study.1.NbTi superconductor which had a copper ratio of 1.0 to 2.0, was deformed locally at room temperature, and then was cooled into liquid helium. In this case, a recovery after quenching was delayd because of the increase of an electrical resistance of copper. On the other hand, when the superconductor was deformed at cryogenic temperature, the recovery occurred in a normal way. From these results, it was recognized that the changes of the electric property of a stabilizer were affected by the mechanical deformation and it should be noted on the magnet design and fabrication.2.The superconductors which was used for the Large Helical Device had a rather stability to mechanical deformation. The coil deformation would be estimated by the mechanical test using a coil pack.3.An excitation test of Inner Vertical coil of the Large Helical Device was carried out, and the deformation during cooling period and excitation test was measured successfully. In the deformation measurement, cable wires should be considered not to be affected by magnetic field.