BS EN ISO 16793:2021

This standard BS EN ISO 16793:2021 Nuclear fuel technology. Guidelines for ceramographic preparation of UO2 sintered pellets for microstructure examination is classified in these ICS categories:

• 27.120.30 Fissile materials and nuclear fuel technology

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.