The Electrochemical Study of Dy2O3 Doped UO2 in Slightly Alkaline Sodium Carbonate/bicarbonate and Phosphate Solutions

Thermodynamic and Structural Modelling of Non-Stoichiometric Ln-Doped UO2 Solid Solutions,Ln = {La, Pr, Nd, Gd}

“…The similarity of stabilizing effects due to the doping observed in electrochemical oxidation (He et al, 2007;Razdan and Shoesmith, 2013;Kim et al, 2017;Liu et al, 2017), in oxidative dissolution (Trummer et al, 2010;Casella et al, 2016;Barreiro Fidalgo and Jonsson, 2019) and in air oxidation experiments (Kim et al, 2001) suggests that all these phenomena might be linked to a common thermodynamic factor.…”

“…Effects of oxidative dissolution have been recently measured in aqueous (typically with H 2 O 2 added) and in electrochemical systems both at corrosive (rest) potentials and at potentials promoting the conversion of U +4 to higher oxidation states. Such experiments applied to Gd-, Dy-, and Y-bearing samples have shown that the doping reduces dissolution yields and oxidative (anodic) currents relative to those measured for pure UO 2 ( Trummer et al, 2010 ; Razdan and Shoesmith, 2013 ; Casella et al, 2016 ; Kim et al, 2017 ; Liu et al, 2017 ; Barreiro Fidalgo and Jonsson, 2019 ). Similar reductions of oxidation rates have been measured for simulated fuels (SIMFUELs) that in addition to lanthanides contain a variety of other dopants ( He et al, 2007 ; Nilsson and Jonsson, 2011 ; Razdan and Shoesmith, 2013 ; Liu et al, 2017 ).…”

“…Despite this effort, mechanisms of resistance to oxidation in Ln - or Y-doped systems and in chemically more complex simulated fuels remain unclear. In several studies the stabilizing effect was linked to the formation of Ln -V O clusters (V O denotes an oxygen vacancy), which are thought to reduce the number of vacant sites that could host oxygen anions ( Razdan and Shoesmith, 2013 ; Kim et al, 2017 ; Liu et al, 2017 ). The formation of these clusters has been discussed in the frame of a point-defect model of Ln -doped UO 2 by Park and Olander ( Park and Olander, 1992 ).…”

DataSheet1.docx

“…Effects of oxidative dissolution have been recently measured in aqueous (typically with H 2 O 2 added) and in electrochemical systems both at corrosive (rest) potentials and at potentials promoting the conversion of U +4 to higher oxidation states. Such experiments applied to Gd-, Dy-, and Y-bearing samples have shown that the doping reduces dissolution yields and oxidative (anodic) currents relative to those measured for pure UO 2 (Trummer et al, 2010;Razdan and Shoesmith, 2013;Casella et al, 2016;Kim et al, 2017;Liu et al, 2017;Barreiro Fidalgo and Jonsson, 2019). Similar reductions of oxidation rates have been measured for simulated fuels (SIMFUELs) that in addition to lanthanides contain a variety of other dopants (He et al, 2007;Nilsson and Jonsson, 2011;Razdan and Shoesmith, 2013;Liu et al, 2017).…”

An Atomic-Scale Understanding of UO2 Surface Evolution during Anoxic Dissolution

“…Developing an understanding of surface interactions on UO 2 is the starting point to understand the behavior of the matrix dissolution of spent nuclear fuel. Sample characterization techniques commonly reported in the literature for dissolution studies related to nuclear fuel − are either not surface sensitive, or if they are surface sensitive, they sample over large areas. Techniques that provide high-resolution structural information, such as crystal truncation rod (CTR) X-ray diffraction (XRD), , Raman spectroscopy, − and X-ray absorption spectroscopy (XAS), − probe sample volumes several micrometers in size, whereas highly surface sensitive methods such as X-ray photoelectron spectroscopy (XPS) ,− probe over areas hundreds of micrometers in lateral and transverse dimensions.…”