Operational characteristics of the experimental test facility for the passive cooling system of spent fuel pools

Ensuring reliable removal of residual heat from spent fuel pools is a key safety requirement for nuclear facilities, particularly for research reactors where the safe storage of spent fuel assemblies must be maintained under both normal and accident conditions. This paper presents the results of experimental studies of a test facility for a passive residual heat removal system designed for spent fuel assemblies in the spent fuel pool of a research nuclear reactor. The study employed both theoretical and empirical methods. The article describes the main thermal-hydraulic parameters and design features of the test facility and provides a description of the experimental methodology. The results of tests carried out under various operating modes of the facility are presented, including operation with full and partial filling of the circuit with the working fluid and operation in an annular thermosyphon mode. The experimental results confirm the operability of the proposed design and demonstrate the capability of the system to provide effective heat removal under different thermal conditions. In addition, three-dimensional modeling of the test facility was performed, which made it possible to identify design characteristics of components not accessible to visual inspection and to optimize the configuration of the evaporator module to ensure a more uniform distribution of the working fluid flow. A theoretical assessment of the impact of using this facility as part of a passive heat removal system on nuclear safety when installed in a spent fuel pool is also provided. The obtained results indicate that the installation of the proposed system does not lead to a violation of nuclear safety requirements and can serve as a basis for the development of a full-scale passive cooling system for spent fuel pools of research reactors.