Electron Backscattered Diffraction in the Study of Matrices for High-Level Wastes

The possibilities of scanning electron microscopy and electron backscatter diffraction (EBSD) in the study of matrices for immobilization of high-level radioactive wastes are shown from the example of two samples with Th (a Pu imitator) and Nd (an imitator of the REE–actinide fraction). The samples were produced by melting-crystallization and are composed of murataite and zirconolite (sample with Th) or pyrochlore, zirconolite, and rutile (sample with Nd). Murataite is a polysome 8C, and zirconolite includes polytypes 3T (sample with Th) or 4M (sample with Nd). The formation of zirconolite in a sample with Nd is probably caused by partial reduction of Ti 4+ up to Ti 3+ upon the reaction of melt with a glassy carbon crucible. It is concluded with the efficiency of EBSD in a study of crystalline matrices for radioactive wastes.