POTENTIAL AND LIMITATIONS OF CERAMICS IN TERMS OF STRUCTURAL AND ELECTRICAL INTEGRITY IN FUSION ENVIRONMENTS

The characteristic behavior of the nucleation and growth process of de fect clusters in various ceramic materials irradiated with electrons, ions and neutrons is a good measure for evaluating their structural in tegrity in fusion energy devices. In order to provide insight on the o rigin of the structural integrity, this review treats the characterist ic difference in defect: cluster evolution in MgAl2O4, alpha-Al2O3 and MgO. This review also includes experimental results which show the im portance of irradiation with concurrent transmutation-produced gases a nd of irradiation spectrum. Further attention is focused on the dynami c effects of irradiation, such as radiation induced conductivity and r adiation induced electrical degradation (RIED) during irradiation with electrons, ions, fission neutrons and fusion neutrons, Since the phen omenon of RIED evokes serious technological problems for applications of ceramics in irradiation environments, this paper heavily emphasizes on the nature and possible mechanisms of RIED. Data obtained from rec ent experiments that used standardized procedures for in-situ measurem ents of electrical conductivity are discussed.