A postirradiation examination of two uranium aluminide (UAlx) fuel plates from the Advanced Test Reactor (ATR) was conducted. The two fuel plates failed due to pinhole corrosion during irradiation to ∼76% of the maximum burnup limit of 2.3 X 1021 fission/cm3. It is believed that the aluminum cladding failed due to pit corrosion initiated at an existing pit ∼0.0076 to 0.0102 cm (3 to 4 mil) deep at a hot spot. About 0.2 and 0.8 g of UAlx fuel was washed out of these plates through the pinholes due to aqueous corrosion and erosion of the UAlx under ATR primary coolant conditions. Aluminum cladding pit corrosion depth and UAlx fuel corrosion-erosion mass rates under the ATR primary coolant conditions were calculated to be 0.23 cm/yr and 14 g/yr, respectively.