An Experimental Basis for a Mixed Potential Model for Nuclear Fuel Corrosion within a Failed Waste Container

Abstract

A mixed-potential model to predict the corrosion behaviour of nuclear fuel inside a failed carbon steel-lined copper waste container in a granitic repository is briefly described. A number of experiments underway to improve the mechanistic form of the model and to provide the necessary input data are discussed. A primary emphasis is placed on the consequences of the accumulation of corrosion product deposits on the fuel surface on the development of aggressive local chemistries, the cathodic reduction of H 2 O 2 and potential for scavenging of H 2 O 2 by the products of carbon steel corrosion (in particular H 2 ).

Heterogeneous reduction of U6+ by structural Fe2+ from theory and experiment

“…U 5+ has been documented to occur in nature in various minerals (Burns et al, 1997;Burns and Finch, 1999;Schindler et al, 2009;Vance and Mackey, 1978), during oxidative dissolution of UO 2 (Ulrich et al, 2008(Ulrich et al, , 2009Shoesmith et al, 2004;Santos et al, 2004), and only fleetingly during bacterial respiration (Renshaw et al, 2005). Various U 5+ solids have been synthesized using solid-state techniques (e.g., Van den Berghe et al, 2000Liu et al, 2009) as well as hydrothermal routes (e.g., Belai et al, 2008).…”

Spent fuel radionuclide source term model for assessing spent fuel performance in geological disposal. Part II: Matrix alteration model and global performance

“…• Electrochemical studies: They use the electrochemical properties of UO 2 which allows to relate the corrosion potential to the corrosion rate [9,26]. This approach was in particular developed by the Canadian team [18,21,26].…”

“…This approach was in particular developed by the Canadian team [18,21,26]. They allow having specifically relevant information on the oxidation step.…”

“…(i) An electrochemical model based on description of the UO 2 oxidation at the anode and oxidants reduction reactions at the cathode [18,21,26,32]. (ii) A chemical model based on the formalism of the mineral/water interface description developed by Stumm and focusing on the kinetics of surface complexes [20]; this model succeeds in reproducing the results of UO 2 dissolution in carbonate medium, but fails to reproduce data at low carbonate and oxygen content.…”

The effect of pH on the anodic dissolution of SIMFUEL (UO2)

“…While prospects for containment in a granitic repository (Canada, Finland, Sweden) are very good [1], it is judicious to analyze the potential consequences of failure while the production of radiolytic oxidants within the ground water flooded container still exists. Under granitic conditions, an anoxic environment will be rapidly established, since oxidants, such as dissolved O 2 , will be scavenged by reaction with the Cu container material, oxidizable minerals, or organic matter present in the repository environment [2].…”