Engineering design of an RF vacuum window for the ITER ICRH antenna

The RF vacuum window design proposed for ITER is similar to the one in operation on JET. It uses titanium alloys for the outer and inner conductors and double conical ceramic insulators. However, unlike the JET window, beryllia is the dielectric material. The design is complicated considerably by the need for continuous RF operation, which necessitates active cooling. Residual stress after manufacture has been optimised with particular attention given to subcritical crack growth in the ceramic. In addition, finite element methods were used to model the steady state temperature gradient from the combined effects of volumetric heating of neutron irradiation, RF surface heating and dielectric loss heating. A scoping study is included in the modelling methodology of bonded joints and on the hydraulic requirements of the window cooling system.