Stability of uranium(VI) doped CSH phases in high saline water

To evaluate the long-term stability of U(VI) doped CSH phases at high saline conditions, leaching experiments with NaCl, NaCl/Na2SO4 and NaCl/NaHCO3 containing solutions were performed. Time-resolved laser-induced fluorescence spectroscopy (TRLFS), infrared spectroscopy (IR) and X-ray powder diffraction (XRD) were applied to study the U(VI) binding onto the CSH phases and to get a deeper understanding of structural changes due to leaching. Results indicate that neither NaCl nor Na2SO4 affect the structural stability of CSH phases and their retention potential for U(VI). However, carbonate containing solutions lead to a decomposition of CSH phases and thus, to a release of uranium.