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Nakajima, Kunihisa; Omichi, Toshihiko*; Arai, Yasuo
Journal of Nuclear Materials, 304(2-3), p.176 - 181, 2002/08
Times Cited Count：3 Percentile：22.77(Materials Science, Multidisciplinary)The oxygen potentials of two type urania-yttria solid solutions, one is the solid solution expressed as nearly U
Y
O
and the other is nearly stoichiometric solid solution, are investigated by use of a mass spectrometer combined with a Knudsen cell. The oxygen potentials for the nearly stoichiometric specimens are much higher than those for pure urania with similar stoichiometry. On the other hand, the oxygen potentials for fully reduced specimens almost agree with those for pure urania having the same oxygen deficiencis.
Ikeuchi, Hirotomo; Yano, Kimihiko; Ogino, Hideki; Matsunaga, Junji*
no journal, ,
Mechanical properties (micro-hardness, elastic modulus, and fracture toughness) of fuel debris are essential information for defueling work in the Fukushima Daiichi NPP. The Urania-Zirconia solid solution, (U,Zr)O
, is expected to be separated into cubic phase with low Zr contents and tetragonal or monoclinic phase with high Zr contents during cooling process. In this study, the properties of tetragonal and monoclinic phase are investigated. The (U
Zr
)O
samples (x=0.85 for tetragonal phase and 0.95 for monoclinic phase) were prepared by sintering the compacted mixture of UO and ZrO powders at maximum 2673 K. The micro-hardness of samples was lower than what has been expected from trend of cubic phase. The elastic modulus was comparable with cubic phase. The fracture toughness of the tetragonal phase was higher than the other two phases. The stress-induced martensitic transformation around the indent is expected to increase the fracture toughness.
