Fundamental and Applied Investigations of Thermal Hydraulics for Fast Reactors with Liquid-Metal Coolants

摘要

Abstract The results of investigations in the field of hydrodynamics and heat transfer in fast reactors and an accelerator-controlled system with liquid-metal coolants are presented. Physical phenomena, effects, regularities, and characteristics of the velocity and temperature fields in the flow path and core of fast reactors are analyzed. The data of investigations on a sodium model of a large-module steam generator and a fragmented lead model of a steam generator with twisted tubes are presented. The results of investigations on a model of a fast neutron reactor tank demonstrate the temperature stratification with stagnant and recirculation formations, internal waves at stratified interfaces, temperature fluctuations, thermal fatigue of structural materials, and a decrease in the service life of equipment. It is shown that the boiling process of liquid metals in fuel rod assemblies has a complex structure and is characterized by both stable (bubble, disperse-annular) and pulsating (slug) modes with significant parameter fluctuations, which cause a heat transfer crisis. The heat transfer is investigated, a cartogram of the flow regimes of a two-phase flow of liquid metals in fuel rod assemblies is constructed, the effect of fuel rod surface roughness on heat transfer and boiling regimes is investigated, and the possibility of long-term cooling of the core during sodium boiling in the case of a “sodium cavity” above the reactor core is substantiated. The characteristics of the process of degradation of the fuel assembly simulator of the core of fast reactors during the thermal interaction of uranium-containing fuel simulators with static sodium and their dependence on the parameters and design of the system are determined. The problems of thermophysical investigations for a high-temperature sodium reactor for hydrogen production are presented.