Speaker
Dr
Shuichi Yamada
(National Institute for Fusion Science)
Description
A superconducting (SC) current feeder system is used as the current transmission lines for the experimental fusion device, LHD. It consists of nine flexible SC bus-lines with total length of 497 m, and nine pairs of gas-cooled current leads. The rated current and withstand voltage of each SC bus-line are 32 kA and dc 5 kV, respectively. The first experimental campaign for the plasma confinement study on LHD started in 1998. Cryostable condition of the SC coils and SC current-feeder system have been kept for more than four months every year. Five-corrugated stainless-steel tubes with a thermal shielding channel were used for the SC bus-line. Liquid helium consumption of the innermost tube of the SC bus-line is negligible, because the liquid helium in the second inner channel absorbed the heat load of about 0.3 W/m. The cooling process is automatically switched from forced-flow of two-phase helium to pool boiling, when the faults happen. The allowable current carrying time on the fault protection mode is expected to be longer than 30 minutes of the design value. The total time of the coil excitations exceeds 10,000 hours. Total number of the plasma production exceeds 120,000 shots. We have demonstrated successfully that the SC current feeder system was stable and easy for handling, and was useful for the SC experimental fusion device.
Author
Dr
Shuichi Yamada
(National Institute for Fusion Science)
Co-authors
Dr
Shinji Hamaguchi
(National Institute for Fusion Science)
Prof.
Toshiyuki Mito
(National Institute for Fusion Science)
Mr
sadatomo Moriuchi
(National Institute for Fusion Science)
