Separation of Fission Products from Irradiated Uranium Dioxide in Fused Nitrate Systems

抄録

The separation of fission products from irradiated UO₂ in fused nitrate systems was studied by the following procedure:
Dissolution of UO2 in fused NH₄NO₃; adsorption of fission products on glass powder; fused salt chromatography with γ-Al₂O₃; evaporation from fused nitrates; and precipitation of U-compound (probably alkali uranate, M₂U₂O₇) in a fused LiNO₃-KNO₃ mixture. Radiochemically pure Zr-Nb was selectively separated from the fused NH4NO3 melt by adsorption. Ru and I were completely evaporated from fused LiNO3-KNO3 mixture at above 280°C and from fused NH₄NO₃ at above 240°C, respectively. By means of chromatography with a γ-Al₂O₃ column, Zr-Nb and rare earths were completely separated from U in fused NH₄NO₃ or fused NH₄NO₃-LiNO₃ medium at 150°to 180°C, and further, Cs, Ba and Ru were also expected to be separable from U under suitable condition. When the U-compound was precipitated in fused LiNO₃-KNO₃ at 350°C, Cs, Sr, Ba and Ru were fairly well separated from U.