Thermal conductivity of (U,Pu,Np)O solid solutions

Morimoto, Kyoichi ; Kato, Masato   ; Ogasawara, Masahiro*; Kashimura, Motoaki

Recently, the MOX fuel containing MA has attracted attention as a fuel of FBR which has profit in the high proliferation resistance and low environmental impact. The addition of MA into MOX fuel has an effect on the thermal conductivity of MOX fuel. In the development of MOX fuel containing MA like americium and neptunium, thermal conductivity is one of the important properties for fuel design and performance analyses. In this study, two MOX fuels containing 6 and 12% NpO were prepared, and their thermal conductivities were measured in the temperature range from 900 to 1770 K by the laser flash method. The results obtained in this method were compared with the data on the MOX fuel containing AmO obtained in the previous our study. In addition, our results were compared with the data of UO containing 50% NpO by Schmidt et al. and those of pure NpO by Nishi et al.. From these comparisons, the effect of Np addition into MOX fuel was discussed.