Chemical stability of simulated waste forms SrZr_xTi_(1-x)O_3

Background: 90 Zr is a decay product of 90 Sr, which may induce structural changes of radioactive waster forms. Purpose: In order to study the influence of decay product on the stability of perovskite-type Sr Ti O3 used for immobilizing 90 Zr, C4H6O4Sr?0.5H2 O, Ti O2 and Zr OCl2?8H2O are used as the starting materials. Methods: The Zr-doped Sr Ti O3 synthesized can be generally represented as Sr ZrxTi1-xO3(0≤x1) with the high temperature solid reaction. The phases, structure and microcosmic shape of synthetic condensates were characterized by the X-ray Diffraction(XRD), Scanning Electron Microscope(SEM) and Fourier Transform Infrared(FT-IR), and long-term chemical stability was studied at constant temperature of 90 oC. Results: The results indicate that the second phase of compounds is observed when the value of x is more than 0.5. The leaching rate of Sr2+ and Zr4+ in waste forms increase with the immersion time, while the highest leaching ratios for 42 d are no more than 0.006 5 μg?m L-1 and 0.01 μg?m L-1, respectively. The crystalline phase and morphology of solidified Sr ZrxTi1-xO3 waste form are influenced by electron beam irradiation. Conclusion: This study results may provide technical support for long-time immobilization of the 90 Sr.