Potential and limitations of ceramics in terms of structural and electrical integrity in fusion environments

Abstract

The characteristic behavior of the nucleation and growth process of defect clusters in various ceramic materials irradiated with electrons, ions and neutrons is a good measure for evaluating their structural integrity in fusion energy devices. In order to provide insight on the origin of the structural integrity, this review treats the characteristic difference in defect cluster evolution in MgAl 2O 4, α-Al 2O 3 and MgO. This review also includes experimental results which show the importance of irradiation with concurrent transmutation-produced gases and of irradiation spectrum. Further attention is focused on the dynamic effects of irradiation, such as radiation induced conductivity and radiation induced electrical degradation (RIED) during irradiation with electrons, ions, fission neutrons and fusion neutrons. Since the phenomenon of RIED evokes serious technological problems for applications of ceramics in irradiation environments, this paper heavily emphasized on the nature and possible mechanisms of RIED. Data obtained from recent experiments that used standardized procedures for in-situ measurements of electrical conductivity are discussed.