NF EN ISO 22765, M60-331 (01/2025)

ISO 18610:2016 describes the ceramographic procedure used to prepare sintered (U,Pu)O2 pellets in order to perform qualitative and quantitative examinations of their microstructure. These examinations are carried out before and after a heat treatment or a chemical attack. They allow: - the observation of possible cracks, inter- and intragranular pores or inclusions; and - the measurement of grain sizes, porosity and homogeneity of plutonium distribution. The average grain diameter is measured by one of the following classic methods: counting (intercept method), comparison to standardized grids or standard images, etc.[2]. Measuring grain dimensions requires the uniform revelation of the microstructure across the entire sample. The location and distribution of pores and plutonium agglomerates are generally analyzed by automatic image analysis systems. The distribution of plutonium is, as a general rule, demonstrated by chemical attack but it is also possible to use alpha autoradiography. The first technique avoids the tendency specific to autoradiography to exaggerate the size of plutonium-rich agglomerates due to the distance traveled by the alpha particles from the source.
(Automatic translation from French)