Thermo-mechanical analyses of large ceramic rings during brazing process

The 1 MV bushing for the ITER Neutral Beam (NB) injector is composed of a stack of five large insulator rings made of ceramic material brazed to metal plates. The fabrication and qualification of such rings is a technological challenge to be faced up with test campaigns for material qualification, prototypes fabrication and thorough thermo-mechanical analyses. ures for failure probability assessment are presented in the paper and the results of thermo-mechanical analyses carried out on reference and alternative design solutions highlight the influence of many design parameters on failure probability and residual stresses at room temperature.