RADIATION AND ENVIRONMENTAL ASSESSMENT OF DISPOSAL FACILITIES FOR SUBLIMATE PRODUCTION WASTE IN THE IRKUTSK REGION

The article presents the findings of an environmental assessment focused on the contaminated areas surrounding the sublimate production waste disposal site in the Angarsk city. The radiation situation there is characterized by background gamma radiation levels. Fluorogypsum deposits resulted from fluorine acid processing contain naturally occurring radionuclides at levels allowing for their use as construction materials (A_eff =9 Bq/kg). The radioecological situation investigated in the vicinity of watered sludge pits, into which the uranium enrichment waste had been discharged, revealed the presence of contaminated soils containing man-made radionuclides ¹³⁷Cs and ²⁴¹Am, as well as uranium isotopes. The study indicates the areas with ²⁴¹Am specific activity levels exceeding the criterion set to refer waste to the radioactive waste category. Bottom sediments in sludge-settling pits revealed notable spatial variations in the distribution of man-made radionuclides, in particular, the specific activity of ²⁴¹Am tuned out to be higher than the criteria set for RW categorization as very low-level waste (VLLW). Given that the waste disposal facilities were sited in highly permeable soils, the study demonstrates potential risk of man-made radionuclide transport and groundwater contamination. The paper argues that the isolation method providing for sludge pit backfilling with soil can be considered as a temporary measure seen to prevent groundwater contamination until the final decision regarding the sludge pit isolation is made.

Keywords: radioactive waste, very low-level waste, sublimate production, fluorogypsum deposits, sludge fields, isotopes of uranium, cesium-137, americium-241.

Zozul Yu. N., Shlygin V. V., Akhromeev S. V., Edomskaya M. A., Shavrina K. E., Markova M. V. Radiation and environmental assessment of disposal facilities for sublimate production waste in the Irkutsk region. Radioactive Waste, 2024, no. 3 (28), pp. 101—109. DOI: 10.25283/2587-9707-2024-3-101-109. (In Russian).