Title :
R&D of steady state and high voltage ICRF transmission line and ceramic feedthrough for LHD
Author :
Mutoh, T. ; Kumazawa, R. ; Seki, T. ; Simpo, F. ; Nomura, G. ; Ido, T. ; Norterdaeme, J.M. ; Watari, T.
Author_Institution :
Nat. Inst. for Fusion Sci., Toki, Japan
Abstract :
The steady state and high voltage test was carried out successfully on ICRF coaxial transmission line and ceramic feedthrough for LHD ICRF heating. The transmission line has 240 mm diameter and water cooling channel inside. The Teflon insulator with small recess is used. The coaxial line can stand for the high RF voltage of over 10 kV for 30 minutes and of 60 kV for 10 seconds. Three kinds of insulation gas vias tested at 43 MHz. SF6 and N2 gas are usable for high voltage and steady state operation but CO2 gas can not stand for over 30 kV for several minutes. Various types of ceramic feedthrough were tested for steady state and high RF voltage in the test stand. The cone type alumina ceramic feedthrough having gas cooling system and cylinder type silicon nitride composite ceramic feedthrough worked very well. Ceramic temperature of the cone type was measured by IR thermometer. By using the enough gas flow rate, truly steady state operation was achieved
Keywords :
Tokamak devices; ceramic insulation; fusion reactor design; fusion reactor ignition; high-frequency transmission lines; plasma radiofrequency heating; 10 s; 240 mm; 30 kV; 30 min; 40 kV; 43 MHz; 60 kV; CO2; ICRF heating; LHD; N2; SF6; Si3N4; Teflon insulator; ceramic feedthrough; coaxial transmission line; cone type; fusion reactors; gas cooling system; high RF voltage; high voltage ICRF transmission line; insulation gas vias; steady state ICRF transmission line; water cooling channel; Ceramics; Coaxial components; Cooling; Heating; Insulation; Radio frequency; Steady-state; Testing; Transmission lines; Voltage;
Conference_Titel :
Fusion Engineering, 1997. 17th IEEE/NPSS Symposium
Conference_Location :
San Diego, CA
Print_ISBN :
0-7803-4226-7
DOI :
10.1109/FUSION.1997.687081
