FORCED COOLING TYPE SUPERCONDUCTIVE CABLE

摘要

PURPOSE:To increase critical current density of the title cable and prevent rupture and deterioration of the cable at the time of drawing process while retaining void ratio by using a seamless cupronickel pipe for a coolant flowing pipe for a forced cooling type superconductive cable. CONSTITUTION:A plurality of superconductive element wires 23 are twisted, a plurality of the twisted wires are further twisted, and after repeating the processes, a stainless tape 24 is wound on the twisted wires 22 which sums up to such as 324. The twisted wires 22 are increased into a leading pipe 21 of an annealed cupronickel (Cu-10wt.% Ni) prepared by drawing process. To insert the wires 22, a dummy plastic wire to which the superconductive element wires 23 are attached on the end is inserted into the pipe 21 and pulled so as to insert the element wires 23. The pipe is then drawn into a prescribed diameter. Since the pipe 21 is seamless, airtightness inspection of the cable is not needed and thus production efficiency is improved. Void ratio is retained by using a thin leading pipe by drawing and critical current density of the cable is increased. Rupture of the element wires is prevented owing to an extremely small difference of the lengths of the leading pipe and the element wires at the time of drawing.