Aqueous leaching of Cr2O3-doped UO2 spent nuclear fuel under oxidizing conditions

Understanding the leaching behavior of spent nuclear fuel is crucial for the safety assessment of deep geological repositories to dispose spent nuclear fuel. During the last decades, new types of nuclear fuel are being introduced in commercial reactors. These new fuels with additives such as chromium oxide (Cr2O3) have an impact on the UO2 microstructure and therefore might affect properties relevant to the safety assessment. The main goal of this investigation is to understand the effects of Cr-doping on the instant release fraction of fission products. A sample consisting of fuel fragments and separated cladding was leached in simplified groundwater under aerated conditions at Studsvik's Hot Cell Laboratory. Data from leaching experiments performed on Cr-doped fuel manufactured by Framatome are presented and compared to other commercial Cr-doped fuel manufactured by Westinghouse (Advanced DOped Pellet Technology, ADOPT) and standard UO2 fuel.