Impact of iron on nuclear glass alteration in geological repository conditions: A multiscale approach

Role of vein-phases in nanoscale sequestration of U, Nb, Ti, and Pb during the alteration of pyrochlore

“…% of Fe; the amount of Fe in the original glass was 2 wt. % (Burger et al, 2013). In the present study, the differences between the content of Fe in the Fe-rich veins and in the pyrochlore are of similar magnitude as the previous study, 65.4±8.1 wt.…”

“…By analogy, the alteration of borosilicate glasses in that study led to the precipitation of various secondary Fe-phases -mostly magnetite, minor silicates, and trace amounts of apatite and calcite as the alteration products. Although no porosity was observed in the amorphous Fe-rich veins, which is different from the experimental results by Burger et al (2013), that porosity could have been reduced or completely eradicated during the transformation of the amorphous phase into crystalline material like biotite, betafite, and uraninite (Figs. 6 and 10).…”

“…The Fe-rich, amorphous veins that host betafite NPs are similar, with respect to structure, texture and chemical composition, to the layers of amorphous gel formed during alteration of borosilicate waste glasses designed for the immobilization of actinides in Ferich environments (e.g., Burger et al, 2013). High concentrations of Fe, > 45 wt.…”

“…( Moyes et al, 2000;Dodge et al, 2002;Ilton et al, 2004;Scott et al, 2005;Féron et al, 2008;Ferriss et al, 2009;Singer et al, 2009;Skomurski et al, 2011;Burger et al, 2013).…”

“…1, 2, 8, 10); thus, it is evident that Fe in the Fe-rich veins is present as a mixture of Fe 2+ and Fe 3+ species. All of these phases are capable of sequestering uranium (Ilton et al, 2004;Singer et al, 2009 (Burger et al, 2013;and references therein). These experiments were conducted at temperatures below 50 o C, and led to the formation of amorphous, porous gel containing 35 wt.…”