Redox Processes affecting the spent fuel source-term

The source term from spent fuel dissolution is subject to considerable uncertainties, both with respect to the presence and extent of oxidative dissolution processes of the spent fuel itself and the coupling with processes associated with the iron canister. Related problems to be examined in this work package are the representativeness and reliability of laboratory data with respect to the impact of unavoidable minor concentrations of oxygen also in inert-gas boxes used, the potential reactivity and its outcome of hydrogen from container corrosion in combination with high burn-up spent fuel, possible galvanic coupling of spent fuel and container material and the retention of redox sensitive radionuclides by relevant minerals, especially by steel container corrosion products. A set of investigations has been conducted with the aim of getting better insight into redox processes determining spent fuel and iron canister corrosion. ITU reports on studies on spent fuel in presence of corroding Fe, on corrosion of spent fuel in presence of H2 and on fuel corrosion studies on thin film model systems. The redox reactivity of doped UO2 in view of effects on the reactivity towards H2O2 has been studied at KTH. The reductive trapping of actinides in container corrosion products during spent fuel corrosion is investigated by INE. Studsvik reports on the redox chemistry at the near field of repository and the influences of iron canister material and hydrogen. Redox conditions near waste packages were studied by NRI.JRC.E.5-Nuclear chemistr