Oxygen chemical diffusion in hypo-stoichiometric MOX

Analysis of oxygen potential of (U0.7Pu0.3)O2±x and (U0.8Pu0.2)O2±x based on point defect chemistry

“…The data, however, are scattered with an error of more than ±100 kJ Á mol À1 in the near stoichiometric region. In previous works, Kato et al [19,20] measured oxygen potentials of (U 0.7 Pu 0.3 )O 2 À x and (U 0.8 Pu 0.2 )O 2 À x in the near stoichiometric region by a gas equilibrium method. The data were obtained with high repeatability, and the relation between their stoichiometry and oxygen partial pressure was discussed.…”

Measurement of oxygen chemical diffusion in PuO2‐x and analysis of oxygen diffusion in PuO2‐x and (Pu,U)O2‐x

“…Other process such as surface reaction, micro-crack generation and grain boundary diffusion might dominate the oxidation process. In previous work [7], the oxygen diffusion of [7] MOX [7] PuO (Resistivity) [5] PuO (Thermogravimetry) [6] PuO (Dilatometry) [6] D (cm Ref. [6] Ref.…”

“…Therefore, it was considered that the data reported previously were higher than the current data. The MOX data reported by Kato et al [7] were measured by the same method as the current work. Figure 3 shows the plutonium content dependence of D .…”

“…[6] Ref. [7] uranium and plutonium mixed oxide (MOX) was investigated by same method as this work, and the diffusion dominated only the reduction process in the hypostoichiometric composition. Therefore, the D values were obtained from reduction curves in this work, which were shown in Table 1.…”

“…In these studies, the oxygen chemical diffusion coefficients were determined from the measured data during the oxidation process to stoichiometric PuO 2 . Kato et al [7] measured the data of (U,Pu)O 2-x by thermogravimetry. They reported that the oxygen chemical diffusion coefficient was determined from the measured data during the reduction process, and the oxidation curve did not dominate the O/M change.…”