Changes in voids induced by ion irradiations in UO2: In situ TEM studies

Experimental study of the diffusion of Xe and Kr implanted at low concentrations in UO2 and determination of their trapping mechanisms

“…Also, it has been demonstrated that the density of each cluster decreases with their size [48], [52], meaning that di-vacancies concentration is higher than that of the bi-Schottky defect, which is higher than that of nanometer sized voids. Latest TEM observations agree with theoretical calculations since small voids are observed after ion implanted in UO2 samples from 0.03 dpa approximately [53]. Their density increases sharply with the damage and up to 0.2-0.3 dpa, the density reaches a saturated state at around 0.6-3.10 24 m -3 .…”

“…The size of those voids remains constant with damage. Their diameter lies between 0.56 ± 0.11 nm and 1.05 ± 0.21 nm depending on TEM settings, which are of a major importance to precisely determine the actual void size [53]. Depending on void size observed by TEM, we could identify the presence of either small vacancy defects (diameter of about 0.56 ± 0.11 nm) or nanometer sized cavities.…”

SUPERFACT: A Model Fuel for Studying the Evolution of the Microstructure of Spent Nuclear Fuel during Storage/Disposal

“…It should be noted that the size of the bubbles looks much larger under these conditions than they were, and their concentration correspondingly smaller. An analogy can be made with the recent study of Onofri et al [ 36 ] showing that, in the case of nano voids, their size and density can vary substantially as a function of the TEM settings.…”

“…The main microstructure characteristics of alpha-damaged actinide dioxides with a fluorite structure consist of the formation of dislocation loops as extended defects whose size distribution and density vary with the accumulated alpha dose [ 13 , 17 , 25 , 36 , 39 ].…”

A new thermo-desorption laser-heating setup for studying noble gas diffusion and release from materials at high temperatures

“…PLEASE CITE THIS ARTICLE AS DOI:10.1063/5.0068858 UO 2 pellet resulting in a higher x increase at the subsurface, i.e. where the Kr is implanted and/or 2) an interaction of the added oxygen with the structural defects produced along Kr ion implantation [16,[46][47][48][49][50][51]: if oxygen intake and diffusion by and through the implanted UO 2 surface promotes defects annihilation, then an acceleration in the apparent diffusion rate of Kr is indeed expected [16].…”