@article {289, title = {An atomistic modelling of the porosity impact on UO2 matrix macroscopic properties}, journal = {Journal of Nuclear Materials}, volume = {415}, year = {2011}, month = {Aug-15-2011}, pages = {210 - 216}, abstract = {

The porosity impact on the UO2 matrix thermomechanical properties was investigated using atomistic simulation techniques. The porosity modifies the thermal expansion coefficient and this is attributed to pore surface effects. The elastic moduli at 0\ K and at finite temperature decrease with porosity, this variation being well approximated using affine functions. These results agree with other mesoscale model predictions and experimental data, showing the ability of the semiempirical potential atomistic simulations to give an overall good description of the porous UO2. However, the surface effects are incompletely described.

Fig. 1. The UO2 elementary cell contains 12 atoms: 4 uranium atoms (large spheres){\textellipsis}

fig.=

Fig. 3. Example of 6{\texttimes}6{\texttimes}6 one pore relaxed supercells of different pore radius (4, 6 and{\textellipsis}

Fig. 4. One layer of UO2 as considered in the present work: top {\textendash} the (100){\textellipsis}

Fig. 5. Variation of the UO2 thermal expansion coefficient versus temperature: top {\textendash}{\textellipsis}

Fig. 6. Variation of the shear modulus (G) and Young{\textquoteright}s modulus (E) versus porosity at 0K

}, issn = {00223115}, doi = {10.1016/j.jnucmat.2011.06.006}, author = {Andrei Jelea and Colbert, M. and F. Ribeiro and G. Tr{\'e}glia and Roland Jean-Marc Pellenq} }