Theoretical and Experimental Research on the Single-Phase and Incipient Boiling Heat Transfer of Liquid Metal Sodium

Abstract

Sodium-cooled Fast Reactor (SFR) is the most promising reactor among the six Gen-IV nuclear reactor systems. The coolant of SFR is liquid metal which has very different heat transfer characteristics from conventional fluids. The study on heat transfer characteristics of the liquid metal sodium at single-phase and two-phase has not only great academic but also application meanings for SFRs design and safety analysis. Xi’an Jiaotong University (XJTU) performed comprehensive studies from the theoretical and experimental aspects. In the theoretical studies, the main focuses are paid on the sodium single-phase heat transfer flowing in rod bundles, incipient boiling, two-phase thermal-hydraulic and critical heat flux (CHF). The experimental research on the flow and heat transfer characteristics of sodium in annuli is performed on XJTU single-phase sodium loop and two-phase boiling sodium loop, in which the single-phase friction and Nu correlations, the incipient boiling superheat (IBS) correlations, the two-phase friction multiplier factor and the heat transfer coefficient of sodium boiling are obtained. In this paper, the established theoretical models and the experimental studies for the single-phase heat transfer and the IBS in the annuli or the pin bundles are presented. The theoretical models are validated by the experimental data, and the comparison shows good agreement.