Evaluation of superconducting current feeder system for the Large Helical Device(LHD)

A superconducting (SC) current feeder system for LHD has been operated sinc e March of 1998, It consists of 9 SC bus-lines, 9 pairs of current leads an d 3 current lead cryostats. SC bus-lines have a total length of 497 m, rate d current of 32 kA and withstand voltage of 5 kV under 77 K helium gas cond ition. After 2 fears operation of this system it was demonstrated that the SC current feeder system is reliable and useful. On the basis of these oper ational experiences we have evaluated performance, reliability, and operati on cast of the SC current feeder system in comparison with non-SC type curr ent feeder system. We have concluded that the SC current feeder system with high current capacity is more suitable than other current feeder systems s uch as using water-cooled bus bar, especially for large-scale SC fusion exp erimental devices.