Features of high-pressure water electrolysis in assessing the thermodynamic efficiency of combining nuclear power plants with a hydrogen complex

The Relevance of the study of combining nuclear power plants with the hydrogen complex is substantiated by the need to adapt nuclear power plants to variable energy consumption during the day in the conditions of their involvement in regulating the unevenness of daily schedules of electric load while maintaining the basic load. Purpose. Assessment of the thermodynamic efficiency of combining a nuclear power plant with a hydrogen complex to cover the peak load in the power system, taking into account the features of the process of water electrolysis under high pressure. Methods. Based on world experience, the mechanism of crosspenetration of hydrogen and oxygen, as well as solutions aimed at preventing this phenomenon, are analyzed. The assessment of the thermodynamic efficiency of combining NPPs with a hydrogen complex was carried out on the basis of a mathematical and thermodynamic model of the expanded thermal scheme of the NPP using the IAPWS-IF97 formulations. Results. On the basis of the generalized analysis, the authors established and explained the regularity of the decrease in the efficiency of electrolysis with an increase in pressure due to the phenomenon of cross-penetration. Complex nomograms of the regularities of the influence of working pressure on the main characteristics of electrolysis, in particular, efficiency, specific consumption of electricity for hydrogen production, operating voltage on the cell, have been developed. It was obtained that the hydrogen complex based on high-pressure electrolysis turns out to be more efficient than the system using compressors in terms of the criteria for converting the using power into the peak power and the efficiency of the nuclear power plant. Conclusions. The authors have developed and patented a new principle of combining nuclear power plants with a hydrogen complex based on high-pressure water electrolysis and shown its efficiency under the influence of crosspenetration of hydrogen and oxygen in comparison with the system when using compressor machines as part of a hydrogen complex.