Theoretical study of xenon adsorption in UO2nanoporous matrices

Mehdi Colbert , Guy Treglia (1) , Fabienne Ribeiro (2)

1 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille
2 IRSN - Institut de Radioprotection et de Sûreté Nucléaire

We present a theoretical study of xenon incorporation in UO 2 nanocavities, by means of Grand Canonical Monte Carlo calculations based on semi-empirical potentials. We first characterize the reconstruction of the matrix around an empty cavity which leads to a stoechiometry change from UO 2 to UO in this region. Then, we determine xenon adsorption isotherms which exhibit an abrupt transition from a dilute phase to a dense one and an increase in the density of the latter phase as a function of temperature. This last result is attributed to a vibrational entropy effect by means of a mean field analysis. Finally, the pressure calculation inside the bubble proves the limitations of the usual mesoscopic models based on gas state behaviour.

Mots clés: UO 2; xenon; adsorption; modeling; Monte Carlo; nanoporous; UO 2

Domaines: Physique [physics]

Mehdi Colbert, Guy Treglia, Fabienne Ribeiro. Theoretical study of xenon adsorption in UO2nanoporous matrices. Journal of Physics: Condensed Matter, 2014, 26, ⟨10.1088/0953-8984/26/48/485015⟩. ⟨hal-03040139⟩