ИСТИНА

For now, managing of radioactive waste sources is the subject of work of many researchers. A lot of attention is paid to high and (middle) level radioactive waste. However, low level radioactive waste management is equally important, since its amount is much higher. U-contaminated soils of Angarsk Electrochemical Combine, Russia, are included in this group. Understanding of Uranium speciation in such systems is crucial for waste managing, remediation of the territory and preventing of U migration in environment. In this work with the use of both synchrotron-radiation based-methods (X-ray absorption spectroscopy, powder X-ray diffraction) and laboratory methods (radiography, μ-X-ray fluorescence spectroscopy, scanning electron microscopy) Uranium speciation in the most active fractions of soil was estimated. Based on the obtained data on the nature, interatomic distance, and coordination numbers of the atoms of the nearest surrounding of U, speciation models of U(VI) in studied objects were proposed. Obtained data will be helpful in the developing of remediation strategies and low active waste utilization. This work was financially supported by the Russian Science Foundation (grant number 19-73- 20051).