Aqueous Corrosion of Uranium Aluminide Fuel

A postirradiation examination of two uranium aluminide (UAl_x) 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 UAl_x fuel was washed out of these plates through the pinholes due to aqueous corrosion and erosion of the UAl_x under ATR primary coolant conditions. Aluminum cladding pit corrosion depth and UAl_x fuel corrosion-erosion mass rates under the ATR primary coolant conditions were calculated to be 0.23 cm/yr and 14 g/yr, respectively.