Development of the first ITER gyrotron in QST

This paper presents a summary of recent progress pertaining to the manufacturing and inspection of ITER gyrotrons and the operation system in QST. Major achievements are as follows. (i) The final design of the ITER gyrotron was accomplished and manufacturing of two ITER gyrotrons was completed. Then operation test in QST prior the shipment to ITER has started with ITER relevant high voltage power supply configuration. The 1st ITER gyrotron has achieved 1.05 MW operation for 300 s with 51% efficiency. Measured cooling channel waveform of 300s pulse demonstrated thermally stable condition representing sufficient cooling performance for 1 MW CW operation; (ii) 5 kHz modulation operation was demonstrated up to 200s at with >0.8 MW at flat top of pulses; (iii) 300s/1 MW operation was repeated for 20 shots with successful 19 shots which demonstrating >95% of reliability requirement. These results lead to success of ITER EC H&CD system construction and commissioning toward first plasma.