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

大型螺旋装置、温德斯坦7-X装置和国际热核实验堆等大型等离子体装置已经规划并开始制造。这些大型设备需要大规模超导磁体来产生强磁场。由于超导磁体在运行过程中会受到巨大的电磁力的作用，在制造之前必须对其机械变形行为进行估计。为此，本研究进行了几种形变评价方法的研究。1.铜比为1.0~2.0的NbTi超导体在室温下局部形变，然后冷却成液氦。在这种情况下，由于铜的电阻增加，导致淬火后的恢复延迟。另一方面，当超导体在低温下形变时，回复发生在正常情况下。从这些结果可以看出，稳定器的电学性质的变化受机械变形的影响，这在磁体的设计和制造中是值得注意的。2.用于大型螺旋器件的超导体对机械变形具有较高的稳定性。对大型螺旋装置内立式线圈进行了励磁试验，并成功地测量了冷却过程中的变形和励磁试验。在变形测量中，应考虑电缆线不受磁场的影响。

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.