The usage of heat from the nuclear cogeneration plant and hydrogen production technologies based on thermochemical water splitting was analyzed. Two most promising ones – copper-chlorine (Cu–Cl) and sulfur-iodine (S–I) cycles have been studied. The main advantage of the two analyzed thermochemical technologies is that they can be completely or partially independent from the electricity required for the process. The Cu–Cl method has a high ability to reduce the enthalpy of technological heat even to temperatures of up to 120 °C, enabling high output of the produced hydrogen. It is not demonstrated by the S–I technology, which can reduce the temperature of the working medium to approximately 380 °C, although it exhibits the limited demand for electricity. Considering the working conditions of the planned demonstration plant it is recommended to install Cu–Cl cycle due to its high level of utilization of the available heat and no requirement for additional medium heating.