Kukhotskyi O. Safety Analysis for Research Nuclear Facilities with CFD Technologies

The thesis focuses on solving the actual scientific and technical problem of improving the safety of research nuclear facilities (RNF). The traditional deterministic safety analysis has been expanded of CFD technologies for the detailed analysis of local thermal-hydraulic phenomena (LTHP) at RNF critical elements. Based on deterministic safety analysis goals and spheres the areas of use the CFD methods as a part of the traditional deterministic analysis have been identified. The main stages of the RNF safety analysis with CFD methods have been defined and scientifically arranged to ensure the systematic application of CFD technologies as a part of deterministic safety analysis. The implementation of the methodology ensures the fulfillment of the “best estimate approach” recommended by the IAEA. Classification of methods for the study of thermohydraulic phenomena has been introduced and allows in the early stages of safety analysis to determine reasonable tools and models that meet the research objectives. Following the proposed methodology the neutron target and subcritical assembly segment thermal-hydraulic models of the accelerator-driven system "Neutron Source Based on Subcritical Assembly driven by Linear Electron Accelerator" (Neutron Source) were developed and the analysis of transients in the core of Neutron Source were performed. The results of the thesis have been implemented and used in the practice of the State Nuclear Regulatory Inspectorate of Ukraine and the National Scientific Center "Kharkiv Institute of Physics and Technology".