[2C16-21] Nuclear Materials

[2C16] Phase separation and recombinaison in U_1−yPu_yO_2−x with y = 0.30, 0.45, and 1.00

*Romain Jean-Marie Vauchy¹, Masahiro Ogasawara², Tadahisa Yamada², Takeo Sunaoshi², Tetsuya Tamura², Yuta Horii¹, Shun Hirooka¹, Masato Kato¹, Tatsutoshi Murakami¹ (1. Japan Atomic Energy Agency, 2. Inspection Development Company)

Keywords:Uranium-plutonium mixed oxide, MOX fuel, Nuclear fuel, Stoichiometry, Phase separation

The locus of U_1−yPu_yO_2−x and PuO_2−x fluorite’s phase separation/recombination into two structures was investigated using a combination of differential scanning calorimetry (DSC) and differential thermal analysis (DTA) at the Plutonium Fuel Development Center of JAEA, Tokai-mura, Japan. The systematic cross-experiment procedure allowed refining the limits of the solvus existing in hypostoichiometric U_1−yPu_yO_2−x and PuO_2−x dioxides. This allows to better understand the redox behavior of MOX fuel for fast reactors during manufacturing, and its subsequent storage.