Insulator applications in a tokamak reactor

Insulators and, among insulators, ceramics have large potential applications in fusion reactors. Graphite silicon carbide and titanium carbide are potential candidates for the first wall protection against disruptions. Alumina, spinel and magnesium oxyde should be used as insulating materials for windows that must be equipped with radio frequency heating antennas. To minimise eddy currents losses and to limit electromagnetic forces in the nuclear island, ceramic electrical current breakers have to be foreseen. Diagnostics must be, in general, separated from the plasma by ceramic windows. The future magnetic fusion devices which will make a large use of superconducting coils, organic insulator like epoxy resins and polyimides are largely present in such coils but are very sensitive to radiation effects, so ceramic insulators are candidates for this purpose. Other possible utilisations of ceramic insulators exist like for electrical insulation of the vacuum pump motors. Facing to these uses of insulators in fusion devices, their behaviour in a large neutron and gamma-ray field is of utmost importance. Large amounts of measurements have been taken in fission reactors for the largest part of candidate materials. However, effects of 14 MeV neutrons and high gamma-ray fields (> 107Gy) are unknown