UNE-EN ISO 16793:2021

This document describes the ceramographic preparation of uranium dioxide (UO2) sintered pellets for

qualitative and quantitative microstructure examinations.

These examinations can be carried out before and after thermal or chemical etching.

They enable

observations of fissures, inter- or intra-granular pores and inclusions, and

measurement of pore and grain size and measurement of pore and grain size distributions.

The measurement of average grain size can be carried out using a classical counting method as

described in ISO 2624 or ASTM E112[3], i.e. intercept procedure, comparison with standard grids or

reference photographs.

The measurement of pore-size distributions is usually carried out by an automatic image analyser. If

the grain-size distributions are also measured with an image analyser, it is recommended that thermal

etching be used to reveal the grain structure uniformly throughout the whole sample.