In order to investigate phase change and chemical stability of pyrochlore Gd 2Zr 2O 7 used for immobilizing Pu(IV), tetravalent cerium is used as the simulacrumsforplutonium with tetravalence, and Gd 2Zr 2-xCe xO 7 (0 ≤ x ≤ 2.0) series samples are successfully synthesized by high temperature solid reaction and using Gd 2O 3 and ZrO 2 powders as starting materials. The experiments of long-term chemical stability are conducted in synthetic seawater at 40°C and 70°C separately. The XRD diffractive data and extraction ratio of as-gained samples are collected by the help of X-ray diffraction (XRD) instrument and inductively coupled plasma mass spectrometry. The results indicate that the phases of compounds change from pyrochlore to fluorite-type phase when the value of x is more than 0.08. Extraction ratios of Gd 3+, Zr 4+ and Ce 4+ in waste forms increase with the increase of immersion time in synthetic seawater. The extraction ratio of waste form at 70°C is higher than at 40°C. The highest extraction ratios of Gd 3+, Zr 4+ and Ce 4+ for 42 days are no more than 0.032, 0.003 and 0.032 μg·ml -1 respectively.
|Journal||Wuli Xuebao/Acta Physica Sinica|
|Publication status||Published - 2012 Aug 5|
- Chemical stability
- Pyrochlore Gd Zr O
- Waste forms
ASJC Scopus subject areas
- Physics and Astronomy(all)