Fusion ceramic materials and components

Present-day approach for the radiation hardness assurance of components and materials for the International Thermonuclear Experimental Reactor ITER is based on extensive testing under representative conditions. Those conditions include radiation, temperature and vacuum and the possibility of in-situ monitoring of radiation-induced changes in characteristics of interest. The resistive bolometers are an example of an ITER component currently tested at SCK-CEN. Bolometers will be used for the plasma emission monitoring in high-radiation and high-temperature locations such as the divertor region. Previous tests with bolometers having gold strips on mica substrates were performed in the JMTR (Japan) and revealed problems of adhesion of the strips on the mica surface, which naturally has a very low roughness. A new type of the resistive bolometer based on platinum meander on alumina or aluminum-nitride (AlN) substrates have to be tested at a high neutron flux (0.01 dpa), high temperature (400 C) and in vacuum (10-3 mBar)- conditions appropriate for the ITER. Another illustration of on-going radiation testing for the ITER is the investigation of the Radiation-Induced Electrical Degradation (RIED). RIED is degradation of electrical insulation under the combined effect of radiation, temperature, vacuum and a strong electric field. It may be an issue to be dealt with in the design phase. Our objective is to develop instrumentation capabilities, which can provide in-situ data on the radiation hardness of materials and components intended for the use in the ITER. These capabilities will allow assessment of the performance parameters under conditions representative in terms of radiation load, temperature and vacuum, and will include on-line electric measurements