Master (Spark Plasma) Sintering Curve of UO2 and UO2-10 Vol. % Mo Fuel Material

Abstract UO2-molybdenum (Mo) composites are being considered for accident tolerant fuel (ATF) applications in commercial nuclear reactors. In this study, UO2-10 vol. % Mo was fabricated using spark plasma sintering (SPS), where the particle size of Mo was varied between 30 nm, 60 nm, 100 nm, and 150 μm, to study its effect on the densification of the UO2-10 vol. % Mo composite. A decrease in Mo particle size was identified to cause a shift in densification peaks in UO2-Mo toward higher temperature, due to the Mo particles coating the bigger UO2 particles. The in situ ram displacement data was used to construct a master sintering curve (MSC), which was validated using additional SPS trials. The accuracy of the MSC was measured by the standard deviation between prediction and experimentally observed data, which varied from 0.7% to 4.8%.