A Complex Method for Purification of Radioactively Contaminated Waters the Object «Ukryttya» of the Chernobyl Nuclear Power Plant

The paper considers the method of treatment of radioactively contaminated water of the “Ukryttya” facility of the Chernobyl nuclear power plant (after installation of a new safe confinement), formed mainly as a result of leakage of process solutions (dust suppressants) and trap water (after decontamination of surfaces). Taking into account heterogeneity, multiphase and multicomponent nature of radioactively contaminated water, an integrated method of its purification is proposed. At the pretreatment stage, a heterocoagulation process was applied and used to separate dispersions of micro- and nanoplastics. The use of nanocomposite based on magnetically sensitive thermally expanded graphite and smectites allows to reduce the activity of radiocesium and radiostrontium by 2–3 orders of magnitude. Application of the previously developed sorbent based on iron hydroxide nanoparticles, the surface of which is modified with nickel-potassium ferrocyanides, makes it possible to achieve the degree of purification from 137Cs and 90Sr – 99.99%.