Thermal hydraulic studies of the temperature regimes of the fuel assemblies of fast reactor core (on the 50th anniversary of the start-up of the NPP with the BN-350 reactor)

The article presents the results of thermohydraulic studies of the fast reactor core with liquid metal coolants, as well as the problems and tasks of further research. The main attention is paid to the results of studies obtained in substantiation of the reactor core of the nuclear power plant with the BN-350 reactor, which was put into operation 50 years ago, in 1973. The features of the formation of velocity and temperature fields in the core of fast reactors with liquid metal coolants are outlined and commented, which are largely related to the features of the thermophysical properties of liquid metals, as well as the design, neutron physics of the core and the influence of inter channel mass and heat transfer. The results of experimental studies of hydrodynamics obtained on models of rod bundles in air and liquid metal using the electromagnetic measurement method are presented and analyzed, which became the basis for the development of computational methods for determining the hydrodynamic characteristics of rod bundles longitudinally flown by a turbulent coolant flow. The results of experimental studies of heat transfer and temperature fields in the central and peripheral regions of fuel assemblies are presented in a wide range of parameters of fast reactor fuel assemblies. The results of computational modeling of thermal hydraulics in fuel assemblies of the core for nominal and non-nominal regimes of operation of fuel assemblies are presented. The influence of inter channel exchange on the formation of the temperature field, the influence of shape change due to the effects of radiation swelling and creep of steels during the campaign, etc. are analyzed.