Transmission electron microscope procedures for characterising dislocation loops in neutron-irradiated zirconium and its alloys

Abstract

Complete characterisation of the dislocation loops in irradiated zirconium and its alloys present particular problems; these include unfavourable texture, the presence of thin foil artefacts; the non-edge character of the loops and their elliptical shape. The procedures adopted to deal with these problems are described and a number of precautionary measures are listed. After considering the possible confusion between thin foil artefacts and small defect clusters, the report outlines the characterisation procedure in the order; Burgers vector identification; loop geometry; loop nature; and quantitative measurements. A detailed analysis of the possible errors associated with loop ellipticity is given in Appendix A.