<p>Thermal analysis of non-irradiated and irradiated to doses of 100, 250 and 500&#xa0;kGy solutions of hydrazine nitrate in 3 and 7&#xa0;mol L⁻¹ HNO₃ has been carried out. The onset temperature of the exothermic reaction (<i>T</i>_st), its rate (HR) and duration (<i>τ</i>) have been determined; the self-heating value of the solution (<i>ΔT</i>), the specific thermal effect of the reaction (<i>Q</i>_sp), and the pressure change in the system during the reaction (<i>ΔP</i>) have been calculated. With an increase in the nitric acid concentration from 3 to 7&#xa0;mol L⁻¹, a decrease in <i>T</i>_st from 89 to 67&#xa0;°C was recorded. With an increase in the absorbed dose, the onset temperature of the exothermic reaction in the case of linear heating increases by 25–30&#xa0;°C, and in adiabatic conditions—by 9&#xa0;°C. In addition, an increase in the radiation dose contributes to reducing the <i>Q</i>_sp value. During irradiation up to 500&#xa0;kGy, the parameters of exothermic reactions (for example, the self-heating value, reaction duration, and pressure increase) are reduced by 70%, which is associated with the radiolytic decomposition of hydrazine nitrate. Mathematical extrapolation of the dependence of <i>Q</i>_sp on the absorbed dose allows us to conclude that complete decomposition of hydrazine nitrate will occur in the radiation dose range from 550 to 1000&#xa0;kGy, depending on the concentration of HNO₃ in the solution.</p>