Effect of the ce content on a nuclear waste glassy matrix in the system SiO2-Al2O3-CaO-MgO-ZrO2-TiO2, synthesized at a low melting temperature

Abstract

Aluminosilicated glasses containing Zr and Ti metals have satisfactory properties, and may be suitable as nuclear glasses, dedicated for storage of radioactive waste solutions. This study summarizes the synthesis of a glassy matrix in the system: SiO2-Al2O3-CaO-MgO-ZrO2-TiO2. Ce element was added as an actinide surrogate. The effect of Ce addition on the glass structure is investigated, for Ce contents ranging between 0 and 15 wt.%. For the whole of glasses, a double melting at 1,350°C during 5 h gave monophasic homogeneous glasses. Both X-ray diffraction and scanning electron microscopy analyses reveal a pure amorphous structure. Most of the basic properties increase with the glass Ce content, the Archimedes density from 2.827 to 3.049 g/cm3, and Vickers indentations from 680 to 862 HV. Oxygen molar volumes are not affected by the glasses Ce contents. The differential thermal analysis show that the glass transformation temperature decreases with the Ce content, and with the heavy elements content. The optical absorption spectroscopy study shows that the Nd cations environment is not altered by the glasses Ce concentration. A preliminary corrosion test leads to low dissolutions of Si, Ca and Zr, estimated by ICP analyses to few ppms. Out coming investigations are in course for further glasses network characterizations