Combustion synthesis and thermal expansion measurements of the rare earth–uranium ternary oxides RE6UO12 (RE=La, Nd and Sm)

Thermal expansion and heat capacity of Gd6UO12(s)

“…The lattice parameters (a and c) of Gd 6 UO 12 (s) obtained in this study were compared with those reported in literature [6] for other RE 6 UO 12 (s) compounds (see Figs. 1 and 2).…”

“…Other properties such as thermal expansion of RE 6 UO 12 (s) (RE = La, Nd and Sm), heat capacities of RE 6 UO 12 (s) (RE = La, Sm and Eu) and thermal diffusivities of RE 6 UO 12 (s) (RE = La, Sm and Eu) have also been measured by Jena et al [6], Venkata Krishnan et al [7], and Krishnaiah et al [8], respectively. But there are no experimental data on heat capacity and thermal expansion coefficients of Gd 6 UO 12 (s).…”

“…Similarly percentage expansions in volume were calculated at different temperatures. The calculated percentage expansion values for Gd 6 UO 12 (s) were compared with those for other RE 6 UO 12 (RE = La, Nd and Sm) reported by Jena et al [6] and shown in Fig. 4.…”

“…Jena et al reported a lower percentage expansion along the c axis than that along the a axis for La, Nd and Sm compounds but our experiments with the Gd compound showed similar percentage expansion along both the axes. Jena et al [6] attributed the lower expansion along the c axis to the rigid configuration and edge sharing of the octahedral structures of UO 6 and REO 6 along the c axis. The slight increase in the elongation along the c axis for Nd and Sm compounds as compared to the La compound was attributed to increased coulombic repulsion between the two adjacent RE (Nd or Sm) cations along the c axis.…”

The effects of the physical states of a simulated fission product on the linear thermal expansion of (U0.924Ce0.076)O2

“…The thermal expansion is affected by the fission product as well as the fuel material itself. In this regard, the thermal expansions of UO 2 and various element doped-UO 2 have been intensively studied by many investigators [6][7][8][9][10].…”