ITER ECH transmission system test stand and prototype component development

Abstract

Initial results for high power testing at ORNL of prototype ECH components for ITER will be presented. The US ITER Project Office is responsible for providing the ITER ECH transmission line system. Evacuated 63.5 mm diameter corrugated waveguide will be used and a total of 24 lines are required. Each line is designed to handle 170 GHz power at 2 MW operating in the HE11 mode. The ITER Organization completed a conceptual design of the system and the USIPO has assumed the responsibility for completing the design. A number of prototype components have been procured from industrial suppliers and some testing of vacuum integrity and mechanical alignment have been performed. Techniques for measuring waveguide straightness, ovality, wall thickness, corrugation depth and other parameters for long sections have been developed. Prototype components including a 140° miter bend, 90° miter bends, waveguide switches, arc detectors, polarization rotators, waveguide pumpouts, DC breaks and others have been procured. A prototype waveguide support and cooling system has been designed and is being installed. Work on commissioning a power supply and interim 400 kW 140 GHz gyrotron system is nearly complete and initial testing is underway. Development of a 170 GHz 0.5–1 MW gyrotron is progressing at CPI. Low power testing of some corrugated waveguide components is being performed in collaboration with the ITER low field side reflectometer team. A resonant ring for very high power testing of components at the 2 MW level or higher is planned using a high power grating-type directional coupler and long loop of waveguide. Low power testing and analysis of waveguide components is also being performed at MIT1.