Speaker
Yasuhisa Oda
(Japan Atomic Energy Agency)
Description
The Electron Cyclotron Heating and Current Drive system developed for ITER is made of 12 sets of High Voltage Power Supplies, 24 Gyrotrons, 24 Transmission Lines and 5 Launchers, 4 UL located in upper ports and 1 EL at the equatorial level. The ITER operation requires to switch operating launcher during the plasma operation with short interval, namely mid-pulse switch operation. To change the waveguide switch which directs RF power either to upper port or equatorial port launchers, the gyrotron has to stop RF power during the switch operation since the direction is changed by mechanical movement of mirror position which takes a few seconds. Since ITER EC system is based on multi-subsystem concept, each subsystem has its own subsystem control unit (SCU) and EC main controller supervises all subsystem controllers. Hence cooperative operation requires to share the information of both RF power status and switch status between gyrotron SCU and TL SCU via main controller. The design of inter-subsystem control scheme is a key issue for ITER EC system control and its evaluation is required.
In JAEA, gyrotron and ITER relevant TL test stand were utilized for demonstration of mid-pulse switch operation. For this purpose, SCUs for each subsystem and main controller were developed using ITER relevant control system.
The operation of mechanical switch during gyrotron pulse was demonstrated. During the 150 s operation of high power gyrotron at 400 kW level, waveguide switch in TL was operated to change the direction of RF power. The time duration for switch operation with inter subsystem control scheme took 1.5 s in total. The synchronizing of RF power suspend and resume with switch motion was succeeded and RF power direction control during the gyrotron operation was successfully demonstrated.
Co-authors
Caroline Darbos
(ITER Organization, St Paul Lez Durance, France)
Dharmesh Purohit
(Institute for Plasma Research, Gandhinagar, India)
Franco Gandini
(ITER Organization, St Paul Lez Durance, France)
Izuru Yonekawa
(Nippon Advanced Technology Co. Ltd., Tokai, Japan)
Katsumi Ohshima
(Japan Atomic Energy Agency, Naka, Japan)
Kazuo Hayashi
(Japan Atomic Energy Agency, Naka, Japan)
Keishi Sakamoto
(Japan Atomic Energy Agency, Naka, Japan)
Koji Takahashi
(Japan Atomic Energy Agency, Naka, Japan)
Mark Henderson
(ITER Organization, St Paul Lez Durance, France)
Ryosuka Ikeda
(Japan Atomic Energy Agency, Naka, Japan)
Yasuhisa Oda
(Japan Atomic Energy Agency, Naka, Japan)
