Progress on design and testing of ITER ECH&CD transmission line components

The performance requirement of 1 (possibly 2) MW cw at 170 GHz for ITER Electron Cyclotron Heating and Current Drive transmission line components is much more demanding than the performance that has been demonstrated on present devices. The high ITER heat loads will require enhanced cooling and, for some components, new or modified designs. In addition to thermal management issues, the components must be designed to have very low losses in order to meet the ITER transmission line efficiency requirements. Testing at representative ITER conditions of some components (waveguide switch, waveguides, miter bends, gate valve, and waveguide window) has been initiated at the JAEA 170 GHz gyrotron test stand at Naka, Japan. Results obtained on additional tests of GA components at JAEA will be presented. These additional components include a DC break, polarizer miter bends, arc detector miter bend, very low loss miter bends, and a waveguide switch. In addition, the US ITER Project Office (USIPO) plans to test a complete prototype ITER transmission line in order to validate the designs for use on ITER, and GA is providing some components to the USIPO for initial tests.