Physicochemical Interaction of EK-164 Steel with Uranium Dioxide During High-Temperature Irradiation

The aim of the investigations was to analyze the character and depth of the corrosion damage to EK-164 steel irradiated in contact with uranium dioxide at temperature 410–640°C, maximum damaging dose 66–94 dpa, and burnup 10–13% h.a. These investigations were performed by means of full-scale electropotential scanning of irradiated elements as well as optical and scanning electron microscopy of the selected segments. Fuel-side intercrystallite corrosion of the steel at depth to 55 μm was found at 450°C. At irradiation temperature 580°C in the presence of corrosive fission products, the damage acquired a mixed character involving continuous and intercrystallite corrosion to depth reaching 60 μm. At intermediate temperature and maximum damaging dose, the corrosion depth in steel does not exceed 20 μm.