260651 Multi-Domain Mixed Potential Model for Spent Fuel Dissolution

Thursday, November 1, 2012: 12:30 PM
305 (Convention Center )
Kurt Frey and James L. Jerden Jr., Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, IL

Rates of spent nuclear fuel corrosion and dissolution in an aqueous environment are controlled by the galvanic potential of the fuel surface. Radiolytic products present in the environment affect this potential and can enhance fuel degradation through oxidative means. However, varying degrees of fuel utilization give rise to secondary domains on the fuel matrix surface, such as micro- to nano- sized epsilon phases comprised of molybdenum, ruthenium, and various other noble metals. These secondary domains can maintain different potentials from the bulk fuel surface, and participate in reactions (specifically hydrogen oxidation) that compete with other fuel dissolution reactions. This work extends the mixed-potential model (MPM) developed by Shoesmith, Kolar, and King to incorporate additional fuel surface domains. Originally used to describe the oxidative dissolution of uranium dioxide fuel in the presence of radiolytically generated hydrogen peroxide, the additional MPM domains have been used to model the epsilon phase and its impact on the rates of spent fuel dissolution.

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