Radiation swelling of SiC under neutron irradiation

Ceramic materials produced on the basis of SiC and SiC/SiC composites are considered due to their high temperature strength, pseudo-ductile fracture behavior and low-induced radioactivity as candidate materials for fusion reactors. The radiation resistance of ceramic materials under neutron irradiation is the key problem which determines the use of these materials in fusion reactor environment. In the present paper the general physical mechanisms of radiation swelling of SiC are investigated. Recent experimental results concerning the effect of neutron and charged particle irradiation on radiation swelling of SiC are presented. A new theoretical model is suggested for the description of radiation swelling in ceramic materials. Point defects in ceramic materials can have an effective charge (e.g., an F+ center, vacancy with a single trapped electron). The theoretical model is based on kinetic consideration of charged point defect accumulation and kinetic growth of dislocation loops in the matrix taking into account the effect of internal electric field formed under irradiation in the matrix on diffusion processes of charged point defects. The theoretical results for radiation swelling are compared with the existing experimental data for irradiated SiC material. (C) 2002 Elsevier Science B.V. All rights reserved.