DESIGN PARAMETERS OF CERAMIC INSULATOR MATERIALS FOR FUSION-REACTORS

The parameters relevant to the use of ceramic insulator materials in resistive components for direct currents (dc) and in transmission components for electromagnetic (em) waves are discussed. In resistive components, radiation-induced conductivity and radiation-enhanced electrothermal breakdown are of major concern. The limits for em power transmission are considered for the different plasma heating concepts. Special attention is given to the dielectric loss tangent. In addition, the mechanical and thermophysical properties relevant to thermal crack formation are reviewed. For the particularly critical gyrotron window, the technical analysis is exemplified and the motivation of cryogenic cooling is presented.