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A potential wasteform for Cs immobilization: synthesis, structure determination, and aqueous durability of Cs2TiNb6O18

DOI: 10.1021/acs.inorgchem.6b01826 DOI Help

Authors: Tzu-Yu Chen (School of Chemistry, University of Birmingham) , Ewan R. Maddrell (National Nuclear Laboratory) , Neil C. Hyatt (Department of Materials Science and Engineering, University of Sheffield) , Joseph A. Hriljac (School of Chemistry, University of Birmingham)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Inorganic Chemistry , VOL 55 , PAGES 12686 - 12695

State: Published (Approved)
Published: December 2016
Diamond Proposal Number(s): 11089

Open Access Open Access

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 P3̅m1 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, hollandite—the material in the multiphase titanate ceramics (Synroc) targeted for cesium sequestration.

Journal Keywords: Precursors; Physical and chemical processes; Ceramics; Cesium; Cations

Subject Areas: Chemistry, Materials


Instruments: I11-High Resolution Powder Diffraction

Added On: 05/01/2017 10:18

Documents:
acs.inorgchem.pdf

Discipline Tags:

Earth Sciences & Environment Radioactive Materials Ceramics Chemistry Materials Science Nuclear Waste Inorganic Chemistry

Technical Tags:

Diffraction X-ray Powder Diffraction