Design of the ITER EC upper launcher nuclear shielding

Abstract ITER will be equipped with four EC (Electron Cyclotron) Upper Launchers (UL) of 8 MW microwave power each with the aim to counteract plasma instabilities during operation. These launcher antennas will be installed into four upper ports of the ITER vacuum vessel. Beside their functional purpose the port plugs which are the structural system of the launchers, have to provide as much shielding as possible in order to protect adjacent components from neutrons and photons and to minimize the shutdown dose rate in the port interspace and the port cell, being located further back in the ITER Tokamak building. Thus appropriate shielding blocks shall be installed at proper positions inside the plug. In addition several structural components will be dressed up geometrically in order to provide maximum shielding capability. This paper presents the general design of the shielding elements and their technical integration into the EC Upper Launcher.