Progress on performance tests of ITER gyrotrons and design of dual-frequency gyrotrons for ITER staged operation plan

Abstract

This paper presents the progress of performance tests of ITER gyrotrons developed at QST and the design of dual-frequency (170 GHz and 104 GHz) gyrotrons to enhance various operation scenarios in ITER, such as characteristics studies of H-mode/ELM at low magnetic fields. The major achievements in developing the ITER gyrotrons are as follows: (i) manufacturing of eight ITER gyrotrons and their auxiliary components has been completed. Performance tests at QST have been progressing and four of the eight gyrotrons achieved the required test criteria-1 MW/300 s/50%, 5 kHz modulation with 0.8 MW. Excitation of LP 01 mode having a purity of 95% was also successfully demonstrated using a 50 mm-diameter waveguide transmission line, satisfying the specification. (ii) The design of dual-frequency gyrotrons capable of 1 MW continuous-wave operation, was successfully completed.

Concept design of the megawatt power level gyrotron stabilized by a low-power signal for DEMO project

“…multi-frequency gyrotron, working at 105-152 GHz [23], coaxial cavity gyrotron [24] and gyrotron with mode converter for co-and counterrotation operating modes [25]. The synthesis method is very flexible and allows to provide input and output of the microwave beams via the same window with a slight angle between them [4] or, e.g. via two diametrically opposite windows [26].…”

“…One of the key elements in the future thermonuclear reactors is the microwave system of plasma heating based on powerful (about 1 MW per unit or even more) gyrotrons [1]. At present, the successful experimental implementation of the 1 MW power level gyrotrons with the operating frequency 170 GHz working in the so-called 'free oscillation regime' for experimental reactor ITER has been shown [2][3][4]. The further most promising way to increase the stability and both the power and frequency of oscillations is to use frequency locking by an external highly stable source (so-called master oscillator with relatively low output power, about several percents of the main generator).…”

Multi-frequency, megawatt-power gyrotron to facilitate a wide range of operations at ITER

“…After completing gyrotron performance tests, eight sets of ITER gyrotrons having the same component design, including a magnetron injection gun, a cavity resonator, a built-in mode convertor, and four internal mirrors were manufactured. Currently, six ITER gyrotrons have demonstrated their performance in factory acceptance tests for ITER [12,13]. In the previous R&D phase of the ITER gyrotron prototype, it was discovered that the TE 31,11 mode is included in a unique mode group [14].…”

Experimental Testing of the European TH1509U 170-GHz 1-MW CW Industrial Gyrotron—Long Pulse Operation

“…TER is relying on twenty-four Continuous Wave (CW) 1 MW gyrotrons operating at 170 GHz to cover its electron cyclotron resonance heating and current drive needs [1]. Such tubes have been developed in Russia [2] and Japan [3] and a European gyrotron targeting the ITER gyrotron specifications has also been under development by the European Gyrotron Consortium (EGYC) in cooperation with the industrial partner THALES, France, and under the coordination of the European Joint Undertaking for ITER and the Development of Fusion Energy (F4E) [4].…”