Numerical study on the characteristics of the LBE thermal stratification in a scaled-down hot pool

The thermal stratification in Lead-Based Reactors would pose a significant threat to safe operation. A numerical study is presented in this work to illustrate the effects of the Richardson number (Ri) and the Peclet number (Pe) on thermal stratification in a scaled-down hot pool of lead–bismuth eutectic (LBE). The results demonstrated the critical value of Ri for the emergence of thermal stratification was approximately 1. Moreover, when the flux Richardson number (Ri_f) was above 4, the temperature fluctuation at the thermal stratification interface was marginal. The interface ascending rate of thermal stratification was inversely proportional to Pe. Increasing Pe would intensify the temperature fluctuation. The dominant frequency of the temperature profile was 0.1 ∼ 1 Hz, implying a high possibility of thermal fatigue at the solid surface. The results of this work will be helpful for the design and optimization of thermohydraulic parameters in Lead-Based Reactors.