Effects of Thermal Creep on Blister Behavior in UMo/Zr Monolithic Fuel Plates

For a UMo/Zr monolithic fuel plate with a gas space, a method is developed to simulate the macroscale blister behavior considering the thermal creep effects of the cladding, in which the calculation of cladding deformation is coupled with the gas space pressure. Based on the developed simulation method, the effects of thermal creep strain of cladding and the internal fission gas atom number on the blister behavior are analyzed. The research results indicate that with the thermal creep of cladding considered, if the fission gas atom number is 4.0×1017, the predicted blister threshold temperature will be 100℃ lower than the case without considering the thermal creep of cladding, with the blister threshold temperature set as the temperature at which the blister height reaches 0.1 mm, with the fission gas atom number increasing from 2.5×1017 to 4.0×1017, the blister threshold temperature might decrease by 40℃. The blister threshold temperature of the fuel plates could be improved by using a cladding material with low thermal creep rate.