Development of ITER gyrotron and its preliminary test result

An electron cyclotron heating and current drive system in ITER is designed to inject RF power of 20 MW to control actively plasmas. The RF power is supplied by 24 gyrotrons. QST procures to supply 8 gyrotrons which produce 170 GHz / 1 MW each and 1 equatorial launcher for ITER.The short pulse test of the first ITER gyrotron has started since 2017 April after preparation of test stand. A new anode and body power supply system which has the same configuration with ITER high voltage power supply (HVPS) system was installed into the gyrotron test stand. The new power supply system consists of DC HVPS devices which generate high voltage and HV switch components which control HV injection into gyrotrons. The ITER gyrotron was installed into the test stand with ITER SCM. The conditioning for long pulse operation follows after short pulse test. As preliminary results of long pulse operation, the operation of 1 MW output power up to 10 s has been succeeded. Its operation parameter was compliant to the specification of HVPS in ITER. The operation of 300 s pulse under 200 kW was also demonstrated. The temperature of cooling channel water (CCW) and in-tube vacuum of the gyrotron reached the steady state and no significant heating of internal components of gyrotron were detected. The success of steady state operation indicates that the cooling performance was sufficient for 1 MW long pulse operation.日韓加熱電流駆動ワークショッ