Behavior of Fission Products in Sulfide Reprocessing Process

For the development of sulfide reprocessing process for spent nuclear fuel, behaviors of fission products (FP) in the sulfide reprocessing process was analyzed by the use of their radioactive tracers. First,the FP tracer doped U3O8 was prepared by two stage heat-treatments using 152Eu,141Ce,140Ba,137Cs,103Ru,95Zr and 90Zr tracers.Then the FP tracer doped U3O8 was sulfurized by CS2 at 573,673 and 773 K followed by dissolving the sample into nitric acid.The dissolution ratios were obtained from γ-ray spectrometry of the tracers.The results are summarized as follows; 1) Dissolution ratio of Eu was high compared with that of U,and it increased with increasing sulfurization temperature,2) Cerium and Zr showed very low dissolution ratios as well as that of U,3) Dissolution ratio of alkali and alkaline earth elements was very high for all temperatures,4) Ruthenium showed very low dissolution ratio (c.a.1%),because of the formation of very stable sulfide,5)The experimental results correspond well with the thermodynamic consideration.