Research on Heat Transfer Characteristics of Corium Pool Under Oscillating Conditions

In order to obtain the heat transfer characteristics of corium pool under oscillating conditions, an experimental study was carried out on the two-layer corium pool of small marine reactors. Fluorinert liquid FC-40 and water were used respectively to simulate the oxide layer and metal layer of corium pool in the experiment, and the transient variations of temperature field and heat transfer capacity under different oscillating conditions were obtained. The experimental results show that the oscillating conditions exert the most intense influences in the early stage of movements, and as the oscillating motion continues, the corium pool will reach a quasi-steady state of thermal equilibrium. In general, the temperature stratification of corium pool is weakened under the condition of oscillation, and the overall temperature is lower than that under the static condition, together with the increased heat transfer capacity to the cooling wall. Under the same high-intensity oscillating conditions, the effect of oscillations in vertical direction is more intense than that of oscillations in lateral direction. However, under the condition of low-intensity oscillation, the effect of oscillations in vertical direction can be ignored. Additionally, a new dimensionless parameter Lo was proposed to characterize the oscillatory influence strength, which represents the ratio of the characteristic oscillatory force to the characteristic shear force of fluid under oscillating conditions. It can be used to quantify the influence of different oscillation intensities under the same oscillation direction. This research is supposed to offer valuable reference to the in-vessel retention (IVR) analysis and safety system design for small marine reactors. © 2024 Atomic Energy Press. All rights reserved.