Oxidation and phase behaviour studies of the U-Ce-0 system

Oxidation behaviour of uranium in the internally gelated urania–ceria solid solutions – XRD and XPS studies

“…The XRD pattern of the oxidized product corresponding to the compositions of 8.5, 16.0 and 31.3 mol% Ce (100 AE Ce/(U + Ce)) was found to be a mixture of orthorhombic and cubic phases. The segregation of MO 2þx (M ¼ (U + Ce)) cubic phase observed during the oxidation of the mixed oxide containing 8.5 mol% Ce is in agreement with the results of Tagawa and Fujino [38] and is in contrast to the results reported by Nawada et al [32] wherein the limit of the M 3 O 8 singlephase region was found to be close to 12 mol% Ce. The phase separation observed in this study can be attributed to the long duration (24 h) of annealing of the sample in air as compared to 8-10 h reported in the earlier study [32].…”

“…The pellets sintered at 1100°C for 24 h in an atmosphere of Ar + 2% H 2 were heated in air at 600°C for 24 h and quenched. The O/M ratio of the oxidized samples was determined by using titrimetric method [32].…”

“…By employing O/M analysis, Nawada et al [32] studied the valency of U in the oxidized products of various compositions of urania-ceria mixed oxides at different temperatures. Even though sufficient literature is available on the oxidation behaviour of U in UO 2 , no reliable study is reported on the mixed oxides of U with Pu or Ce prepared through the soft chemistry routes.…”

“…Even though sufficient literature is available on the oxidation behaviour of U in UO 2 , no reliable study is reported on the mixed oxides of U with Pu or Ce prepared through the soft chemistry routes. In the present study ceria (CeO 2 ) is used to simulate plutonia (PuO 2 ) in the MOX fuel [32][33][34] and an attempt is made to understand the oxidation behaviour of U in the simulated (U,Ce)O 2þx MOX fuel with different compositions of Ce, prepared through the ammonia internal gelation route and oxidized in air at 600°C, using O/M, XRD and XPS analyses in the light of dry storage of MOX and light water reactor spent fuel.…”

Sol–gel synthesis and microwave assisted sintering of zirconia–ceria solid solution

“…The inert matrix fuel (IMF) consists of a solid solution of Pu in yttria-stabilized zirconia (YSZ) [4][5][6][7][8][9]. In IMF simulation studies, ceria is added as a surrogate for plutonia [10][11][12][13], since ceria and plutonia have similar physicochemical properties such as crystal structure, ionic size in octahedral and cubic coordination, standard enthalpies of formation, specific heats, melting points, etc. The synthesis of such oxide fuel is an art than science.…”