Effect of microstructure on the critical thermal shock temperature difference of UO2-5wt%CeO2 pellets

The properties of UO2 and (U,Pu)O2 ceramic oxide nuclear fuel pellets are largely dependent on the density and microstructural characteristics which affect the performance of fuel in reactors. Since the microstructure of nuclear fuel pellets is related to the behavior of fission gas release due to the change of the thermo-mechanical properties by neutron irradiation, investigations of these properties has widely been carried out during the last several decades. Fuel behavior against thermal stress can be one important property that can give estimations not only for the behavior of the fuels in service operational condition but also for the thermo-mechanical properties of the fuel materials, which are affected by material characteristics such as density and microstructure. This paper describes the results of the analyses of the behavior of UO2-5wt%CeO2 with different micro-structures, simulating (U,Pu)O2 fuel, against thermal stress by measuring critical thermal shock temperature differenceΔTc