ISO DIS 16793

Description / Abstract: This International Standard describes the ceramographic preparation of uranium dioxide (UO₂) sintered pellets for qualitative and quantitative microstructure examinations.

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

They enable

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

— measurement of pore and grain size and measurement of pore and grain size distributions. The measurement of average grain size may be carried out using a classical counting method as described in ISO 2624[1] or ASTM E112,[2] 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.