Recent advances in material properties and behavior of transuranium compounds for application to nuclear fuel cycle

Takano, Masahide ; Nishi, Tsuyoshi; Hayashi, Hirokazu ; Nakajima, Kunihisa  ; Otobe, Haruyoshi  

Transmutation of minor actinides (MA) is a realistic option for future nuclear fuel cycles. We have been studying on synthesis, thermophysical and thermochemical properties, and behavior of transuranium (TRU) compounds concerning the MA recycling. In this lecture, recent advances in the following fields are introduced: (1) Solid solubility of TRU nitrides into ZrN matrix, and thermal conductivity of the nitrides as a function of ZrN fraction for ADS, (2) New synthesis technique of TRU chlorides and measurement of their melting points for pyrochemical reprocessing, (3) Am vaporization behavior on U-Pu-Zr based alloy fuels, (4) Relation between oxygen potentials and O/M for Am-bearing oxides, especially the difference between fluorite-type and pyrochlore-type oxides, (5) Self-irradiation damage issues such as expansion and annealing behavior of both lattice and bulk, helium release, and thermal conductivity drop due to defect accumulation.