Such interactions at the boundary of several phases affecting the properties of the main EBS component (bentonite) are called boundary transformations. In other countries, the experience in the design and operation of DGRs of radioactive waste includes a wide range of concrete applications that have been proposed for constructing engineering safety barriers to prevent the migration of radionuclides into the environment, such as a concrete lining of storage tunnels; a concrete buffer (backfill) located both inside and outside of the containers of radioactive waste; concrete plugs and seals in tunnels [3; 15; 16; 17]. To create a concrete buffer, cement can be used both individually and in a mixture with bentonite clay and hydrotalcite (a low-alkaline cement composition used in the Cigeo DGR project, France) [18], and slaked lime and ground limestone (cement composition NRVB, UK) [19]. In the scenarios described above, the use of concrete is mainly due to its easy availability, the low cost of raw materials for its manufacture, high strength, low water permeability, resistance to radiation, and the ability to screen ionizing radiation [2,20]. In the DGR project at the Yeniseisky site, at the moment, various options of engineered barriers are being considered in which bentonite can be in contact with concrete. First of all, this involves concreting the walls and waterproofing water-conducting cracks in the tunnels, where it is planned to place materials based on bentonite as a buffer and backfill in the immediate vicinity while considering the setup of a multi-container with a concrete and bentonite buffer, and so forth. [21]. The interaction of concrete and bentonite engineering barrier systems in the conditions of a DGR will lead to phase changes at the site of their contact, as well as the mutual redistribution of ions (Na\({}^{+}\), K\({}^{+}\), Ca\({}^{2+}\), Mg\({}^{2+}\), SO\({}_{4}\)\({}^{2-}\), Cl\({}^{-}\)) under the influence of groundwater [16,17]. The study by [22] dealt with changes in concrete engineering barriers under the continuous influence of the maximum design temperature loads typical for DGR, 300 \({}^{\circ}\)C. Under these conditions, the ultimate compressive strength of concrete decreases by about 25%, and its value will continue to decrease further at temperatures exceeding the maximum limit of 300 \({}^{\circ}\)C. When the cement slurry solidifies, this tendency is more pronounced. The hydraulic permeability of concrete also increases under the influence of elevated temperatures, which leads to an increase in porosity. This can lead to an increase in the rate of flow of groundwater through the barriers of the DGR, despite the fact that the effect of change in concrete would be relatively small and comparable to their cracking [22]. When groundwater enters a DGR with a cement backfill, its active components, such as calcium hydroxide, dissolve, and a C-S-H gel is formed due to the hydration of the OPC [21]. As a result, there is a slight increase in the hydraulic permeability of concrete (from \(10^{-11}\) to \(10^{-10}\) m/s) due to an increase in porosity [23], which, in turn, leads to a decrease in the mechanical strength of the concrete [24]. The diffusion of sulfate anions from bentonite into concrete and Ca\({}^{2+}\) cations from concrete into bentonite leads to the precipitation of calcite and gypsum on the surface of their contact [16,17]. The increased gypsum content in this area promotes the formation of ettringle crystals in the pores of the concrete. Calcite precipitates as a result of the interaction of the carbonate anion of granite groundwater with the calcium hydroxide dissolved from concrete. The saturation of Ca-bentonite with groundwater leads to the diffusion of Ca\({}^{2+}\) and Mg\({}^{2+}\) ions towards the surface of contact with concrete. Dissolved by groundwater, chloride and sulfate anions from bentonite diffuse into concrete [16,17].