Peak Temperature Prediction Method Based on A Theoretical Model of Equivalent Thermal Conductivity for Fully Ceramic Microencapsulated Fuel

In order to satisfy the engineering need for rapid prediction of peak temperatures of Fully Ceramic Microencapsulated (FCM) fuels, inverse calculations of peak fuel temperatures could be performed by substituting the equivalent thermal conductivity of the fuel into a simplified homogeneous thermal conductivity model. In this paper, based on the multi-annulus model developed in previous study, a theoretical model for calculating the equivalent thermal conductivity of FCM fuel is derived by starting from the basic thermal conductivity equation and taking the peak fuel temperature as a conserved quantity, and the multi-annulus model is further equivalent to a homogeneous model. Then the derived model is compared with some conventional equivalent thermal conductivity theoretical models. The results show that the developed theoretical model could be combined with the homogeneous model to effectively achieve the prediction of peak fuel temperatures. The developed theoretical method is suitable for predicting the peak temperature of FCM fuel elements with internal heat sources, because the deviation between the predicted peak temperature and the actual value is basically within 3%. The developed theoretical model prediction method based on equivalent thermal conductivity could realize the rapid prediction of the peak temperature of FCM fuel. © 2024 Atomic Energy Press. All rights reserved.