The variables to influence the temporal drift of stoichiometry in FBR mixed oxide fuel

Room-temperature oxidation of hypostoichiometric uranium–plutonium mixed oxides U1−yPuyO2−x – A depth-selective approach

“…Fig. 14 proposes a tentative oxidation mechanism of hypostoichiometric uranium-plutonium mixed oxides U 1-y Pu y O 2-x based on moisture reactivity with oxygen vacancies leading to H 2 (g) release which was recorded in [20,21]. Furthermore, the plutonium content, which directly drives the extent of hypostoichiometry [14], has a clear influence on this oxidation rate.…”

“…Samples with less Pu are less hypostoichiometric and therefore the time needed to reach the O/M = 2.000 stoichiometry will be longer [20,21].…”

“…Woodley [20] and Eichler [21] reported a spontaneous oxidation of hypostoichiometric mixed oxides at room temperature by thermogravimetric analysis. They both agree that water chemisorption is responsible for the stoichiometry drift observed in U 1-y Pu y O 2-x .…”

The oxidation rate of (U0.7Pu0.3)O2−x with two fcc phases

“…It was reported that MOX pellets of hypo-stoichiometric composition were oxidized at room temperature in an atmosphere of inert gas and air [1,2]. It is important for the fuel fabrication process to evaluate the kinetics of the oxidation around room temperature.…”

Fluoride-Conversion Synthesis of Homogeneous Actinide Oxide Solid Solutions

“…Two synthetic routes are commonly used for the synthesis of actinide oxide solid solutions: dry pyroprocessing and wet aqueous coprecipitation. In the dry method, the separate actinide oxides are mixed and heated to 1700 °C or higher under reducing atmospheric conditions , for 48 h or more. Even after this prolonged synthesis, the resulting products often fail to meet the required degree of homogeneity, requiring the product to be milled or ground and resintered, sometimes more than once, to produce a final product that meets the requirement.…”