The linear thermal expansion and the thermal diffusivity measurements for near-stoichiometric (U, Ce)O2 solid solutions

Synthesis, characterization and thermal expansion measurements on uranium–cerium mixed oxides

“…6, the lattice parameter decreases linearly with increase in CeO 2 content. Similar observation was reported in the literature [6]. The variation of lattice parameter with y in (U 1Ày Ce y )O 2 is given by the expression:…”

“…The thermal expansion coefficient of solid solution containing 15% CeO 2 was found to be less than that of pure UO 2 and mixed oxide containing 5% CeO 2 . In the contrary Kim et al [6] observed a uniform increase in percentage thermal expansion coefficient with increase in CeO 2 content [6]. Kim et al [6] used thermo-mechanical analyzer for the measurement, whereas Yamada et al [7] used high temperature XRD.…”

“…In the contrary Kim et al [6] observed a uniform increase in percentage thermal expansion coefficient with increase in CeO 2 content [6]. Kim et al [6] used thermo-mechanical analyzer for the measurement, whereas Yamada et al [7] used high temperature XRD. The present investigation on thermal expansion measurements on (U 1Ày Ce y )O 2 were aimed at clarification on the existing discrepancy in the literature.…”

“…CeO 2 owing to its structural similarity readily forms solid solutions with UO 2 and PuO 2 , the fuel constituents. Moreover, CeO 2 is also considered as an inactive surrogate for PuO 2 due its similar chemical/thermodynamic behavior [1][2][3][4][5][6]. In the cerium-uranium-oxygen system, as well as in the plutonium -uranium-oxygen system, it has been shown that there exists a homogeneous region of the solid solution with a fluorite structure and similar isomorphous phase diagram (U, Ce)O 2 and (U, Pu)O 2 system [7].…”

“…The existing thermophysical/chemical data for (U, Ce)O 2 system are heat capacity [8], electrical conductivity [9], oxidation behavior [5], oxygen potential [1,10], lattice parameter [1] and thermal conductivity [11][12][13][14][15][16][17][18]. Thermal expansion measurements on (U, Ce)O 2 available in the literature [2,6] are only up to 22 mol.% CeO 2 . There also exists discrepancy among the literature data on the variation of linear thermal expansion coefficient of (U 1Ày Ce y )O 2 with CeO 2 content.…”