Incorporation and structural investigations of dismantling nuclear waste in an alkali-rich borosilicate glass

International audienceIn this work, we firstly studied the ability of an alkali-rich glass matrix belonging to the SiO$_2$-B2O$_3$-Al$_2$O$_3$-Fe$_2$O$_3$-Na$_2$O-Li$_2$O-CaO complex system (Na$_2$O + Li$_2$O = 33 mol% (28.5 wt%)) to solubilize P$_2$O$_5$, MoO$_3$, ZrO$_2$ and Cs$_2$O that are present in a dismantling waste. Due to their high field strength, P$^{5+}$, Mo$^{6+}$ and Zr$^{4+}$ ions may exhibit a high tendency to separate from the silicate network in glass structure. To determine the capacity of this matrix to accept a wide range of waste composition, several glass series were prepared by increasing the total amount of oxides representing the waste (10-30 wt% waste loading) and by varying the relative proportions of P$_2$O$_5$, MoO$_3$ and ZrO$_2$ within the waste from 0 to 50 wt% in order to take into account the potential variability of the waste composition.To complete this work on the complex glass, XRD, Raman and multinuclear ($^{31}$P, $^{29}$Si, $^{23}$Na, $^{27}$Al, $^{11}$B) MAS NMR studies have been performed on a simplified glass belonging to the SiO$_2$-B$_2$O$_3$-Al$_2$O$_3$-Na$_2$O-CaO system derived from the complex composition by adding increasing P$_2$O$_5$ content (0 - 10 mol%), to investigate the crystallization of phosphate phases and the evolution of glass structure