Fission products stability in uranium dioxide

Linking atomic and mesoscopic scales for the modelling of the transport properties of uranium dioxide under irradiation

“…Combined with the analysis of the atomic displacements (see Fig. 15) and charge redistribution observed after incorporation, the results obtained prove that steric effects are the main contribution to the incorporation of these rare gas atoms in UO 2 as is expected because of their filled electron shell, as was also shown by Thompson and Wolverton [67] and Brillant et al [68]. Fig.…”

Solubility and clustering of ruthenium fission products in uranium dioxide as determined by density functional theory

“…However, as the reference state is adjusted to the bulk metal, the signs of the incorporation energies become positive. Regardless of the reference state, the U vacancy is the most energetically favorable trap-site for Ru incorporation, as it is for several other fission products 17,18 . 18 The calculated solution energies of Ru are given in Table 7.…”

“…Regardless of the reference state, the U vacancy is the most energetically favorable trap-site for Ru incorporation, as it is for several other fission products 17,18 . 18 The calculated solution energies of Ru are given in Table 7. Trap-site formation energies are determined using PDM at 0K (as described in Table 2).…”

“…On the other hand, using the bulk metal as the reference indicates that Ru is insoluble in UO 2±x unless the Ru is trapped at a U vacancy in UO 2+x . These quantities were also calculated by Brillant et al 18 and Busker et al 51 using DFT and empirical potentials respectively; their results are given in Table 7 for comparison. The calculation criteria Brillant used are different from ours and the empirical potential inherently lacks the capability of calculating single atom energy with proper reference state thus the magnitude of the solution energies from both the DFT and the empirical potentials is quite different.…”

“…In addition, over the last decade, the chemical stability of various fission products that exist in gaseous or oxide form in UO 2 -including He, I, Cs, Sr, Ba, Zr, Mo, and Xe -have been determined using DFT [13][14][15][16][17] . More recently, the stabilities of selected metallic fission products were also examined 18 . In most cases these studies focused on a single fission product atom and its solution or oxide formation at trap sites, the stabilities of which were also evaluated using DFT [19][20][21][22][23] .…”