A feasibility study of using CeO2as a surrogate material during the investigation of UO2thermal conductivity enhancement

A possible substitution of UO2 for research purposes is the cerium dioxide (CeO2) owing to its chemical and physical properties. Neutronic properties are different and fission is absent in the case of CeO2; however, similarities were studied recently to have a possibility to compare the neutronic influence of secondary additives into the matrix. This paper deals with increasing the thermal conductivity of UO2 nuclear fuel on surrogate material (CeO2); the main focus of the research is given on the sintering behaviour of CeO2. The incorporation of highly thermally conductive material (SiC) is the investigated concept of thermal conductivity enhancement. Conventional sintering and spark plasma sintering (SPS) were applied to compare the behaviour of CeO2 and UO2 reported in the literature. High temperature thermal conductivity measurements did not confirm the positive influence of SiC additive inside the CeO2 matrix mainly due to grain boundary disruptions. Similar behaviour was also previously reported for UO2 pellets with SiC.