First Data on the Efficiency of the Conservation of the Near-Surface Radioactive Waste Repository at the Former Radium Extraction Plant

Resumo

The efficiency of the conservation of the radioactive waste (RW) repository at the former radium extraction plant in Komi Republic was confirmed by comparative analysis of the dynamics of the ²²⁶Ra release into the river and groundwater. High mineralization of the surface and ground waters on the territory of the RW repository favored the dissolution of contaminant compounds present in RW. Owing to the supply of ²²⁶Ra dissolved in water and incorporated in suspended particles of 0.45–3.5 and >3.5 µm size, the activity concentration of ²²⁶Ra in water bodies under the impact of the plant increased by a factor of 1.3–3 relative to the background values. The RW isolation by making physical and geochemical (based on bentonite clays) barriers on the radionuclide migration pathway reduced the release of ²²⁶Ra into the hydrographic network. After the RW conservation, a tendency toward improvement of the groundwater quality with respect to the content of ²²⁶Ra and its chemical analogs is observed in the region of the study, which is confirmed by the results of the ecotoxicological evaluation of drainage waters from the object. Increased content of ²²⁶Ra is observed on the sites of discharge of melioration trenches from other industrial sites of the plant into the river.