A Potential Wasteform for Cs Immobilization: Synthesis, Structure Determination, and Aqueous Durability of Cs₂TiNb₆O₁₈
Chen, T-Y., Maddrell, E.R., Hyatt, N.C. et al. (1 more author)
(2016)
A Potential Wasteform for Cs Immobilization: Synthesis, Structure Determination, and Aqueous Durability of Cs₂TiNb₆O₁₈.
Inorganic Chemistry, 55 (24).
pp. 12686-12695.
ISSN 0020-1669
Abstract
Cs2TiNb6O18 is a potential ceramic wasteform for the long-term immobilization
of radioactive cesium. Cs2TiNb6O18 was synthesized using the aqueous precursor
method and a solid-state reaction, and its crystal structure was determined from the
Rietveld refinement of synchrotron X-ray and neutron powder diffraction data. The
structure is a pyrochlore analogue, space group P3̅
m1 with Cs in 9-fold coordination.
The calculated bond valence sum from analysis of neutron diffraction data of 0.84 and
high coordination number suggest that Cs has a strong bonding environment. The
chemical aqueous durability was investigated using the MCC-1 and PCT-B standard test
methods. The measured Cs leach rates of 3.8 × 10−3 and 2.1 × 10−3 g m−2 day−1 obtained
via the MCC-1 and PCT-B methods, respectively, demonstrate good promise of a safe long-term immobilization material
comparable to, if not better than, hollanditethe material in the multiphase titanate ceramics (Synroc) targeted for cesium
sequestration.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)