Calculation and experimental substantiation of thermal-hydraulic characteristics for the emergency cooldown system of BN-800 reactor

The present paper considers thermal-hydraulic tests of an emergency cooldown system for the BN-800 reactor with forced circulation of sodium in the primary and secondary circuits. The operating range of changes in the flow rate of coolants in the system under various operating modes is determined. Heat transfer in the air heat exchangers of BN-600 and BN-800 reactors is examined. The established Nusselt number dependence is in satisfactory agreement with the RD 24.035.05-89 methodological guidelines. A simple relationship has been obtained using the results of tests and calculations for assessing the capacity of air heat exchangers. The possibility of increasing their capacity by 26% compared to the design value is demonstrated. The significance of the thermosiphon effect on the temperature state of fittings in the emergency cooldown system is demonstrated. The experimental models have revealed the effect of pipeline inclination on the intensity of heat transfer.