The influence of fracture mechanical properties caused by fabrication on fuel behavior in the reactor

Abstract Fission gas, solid fission products, impurities and thermal gradients create stress induced crack propagation in the fuel. The resulting fracture may be of the brittle, semi-brittle or ductile mode. The corresponding fracture mechanisms are discussed for the description of the fuel type specific behavior under steady and non-steady state operation conditions. Fine grain fuel mainly undergoes semi-brittle fracture and therefore is poor in fission gas content. Coarse grain fuel has a more solid and stressed outer zone. The dominant fracture mode is brittle. The fuel behavior can be predetermined by the fuel fabrication process, in details, by the choice of an appropriate morphology.