Microstructural development in irradiated U-7Mo/6061 Al alloy matrix dispersion fuel

A U-7Mo alloy/6061 Al alloy matrix mini-dispersion fuel plate was irradiated in the Advanced Test Reactor and then examined using optical metallography and scanning electron microscopy to characterize the developed microstructure. Results were compared to the microstructure of the as-fabricated dispersion fuel to identify changes that occurred during irradiation. The layer that formed on the surface of the fuel U-7Mo particles during fuel plate fabrication exhibits stable irradiation performance as a result of the ∼0.88 wt% Si present in the fuel meat matrix. During irradiation, the pre-formed interaction layer changed very little in thickness and composition. The overall irradiation performance of the fuel plate to moderate power and burnup was considered excellent.