## 3 Research Results and Discussion
### Radiogenic Heating  
The process of interaction between gamma radiation and reinforced concrete structures of concrete shields of buildings where radioactive materials are handled is primarily characterized by radiogenic heating. Hence, when passing through the material of protective walls or ceilings, the kinetic energy of gamma quanta is converted into heat, which raises the temperature of concrete and reinforcement or triggers radiogenic heating [70; 131; 132]. Nearly all absorbed radiation is converted into heat [133]. Such heating has an adverse effect on the mass, dimensionality, and mechanical properties of cement products [49; 72; 73], silicate minerals and filler rock (at 30 \({}^{\circ}\)C for a gamma flux with the energy of 5 MeV and an accumulated dose of \(10^{10}\)-\(10^{11}\) Gy, respectively [121]). Moreover, according to the author of [121], an increase in the absorbed dose boosts the total amount of changes, and an increase in temperature causes its considerable reduction. Moreover, temperature can also have a significant effect on the corrosion of steel elements [64; 133]. [PERSON], [PERSON] et al. [64] studied corrosion processes in irradiated carbon steel immersed in an alkaline solution (pH = 13.4) at a temperature of 25 \({}^{\circ}\)C and 80 \({}^{\circ}\)C and a gamma radiation dose rate of 25 Gy/h, with an exposure duration of up to 6000 h. They found that the initial corrosion rate was higher at 80 \({}^{\circ}\)C than at 25 \({}^{\circ}\)C [64]. In general, an increase in temperature contributes to an increase in the depth of cracks and, in general, to cracking, due to different values of the coefficient of linear thermal expansion of steel elements, aggregates, and the binder concrete composite, as well as possible \"pore cleaning\", which, in turn, contributes to greater penetration of CO\({}_{2}\), an increase in the depth of carbonation [59; 134], and to the penetration of chlorides from the external environment to the surface of reinforcement and, as a consequence, to the acceleration of corrosion of the reinforcement [135]. As a rule, concrete containers for high-activity radioactive waste are heated by gamma radiation during 5-10 years to 100 \({}^{\circ}\)C [136], which can be considered gamma heating. However, the effect of this temperature on some elements of buildings and structures, such as protective walls and ceilings (shields), may be insignificant. Hence, according to open-access materials on the license authorizing the extension of operation of NPP Braidwood (units 1 and 2), posted on the official U.S. NRC website, the effect of gamma-induced radiogenic heating for reinforced concrete structures of nuclear power plants is limited to a temperature change of approximately 1.12 \({}^{0}\)F [137]. In other words, it is insignificant, which is consistent with conclusions of the IAEA report [19]. When analyzing the deterioration of reinforced concrete structures due to corrosion, one should take into account an increase in temperature due to radiogenic heating, both for the purpose of strength analysis and analysis of acceleration of corrosion processes, while the contribution of gamma radiation to the heating of protective structures should be analyzed separately in each individual case, depending on the calculated parameters of the dose rate and, accordingly, the energy of gamma quanta. In this finite element model, temperature conditions were taken into account for the prognostic threshold of 10-45 \({}^{\circ}\)C, but different temperature values can be applied because the COMSOL software package allows for multi-physical computations needed to take into account the additional effect of temperature. Radiolysis  
Radiolysis has a great effect on the corrosion conditions of reinforcement since it facilitates the process of release and diffusion of oxygen.