Development of ITER Equatorial EC Launcher Components Toward the Final Design

Abstract

Development of an electron cyclotron equatorial launcher has proceeded with a series of prototype tests and design enhancements intended to improve reliability and functionality of the launcher. The design enhancements include adaptation of the launcher steering angles such that one of three beam rows of the launcher is necessarily flipped to perform counter current drive to conform to a new ITER physics requirement. Also, the top and bottom steering rows have been tilted at an angle of 5 deg so that the top and bottom beam rows can be accessed from on-axis to near midradius. Furthermore, the position of the fixed focusing mirror that forms a quasi-optical in-vessel millimeter-wave (mm-wave) transmission line is modified to increase the nuclear shielding capability. A high-power experiment of the mm-wave launching system mock-up fabricated based on the design confirmed a successful steering capability of 20 to 40 deg. It was measured that some stray radio-frequency power propagated in the beam duct and generated some heat on the duct. Prototype tests also include the fabrication of the blanket shield module and partial port plug mock-up and have shown no serious technological issue regarding the fabrication and cooling functionality.