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Synthesis and characterisation of Ca1-xCexZrTi2-2xCr2xO7: Analogue zirconolite wasteform for the immobilisation of stockpiled UK plutonium

DOI: 10.1016/j.jeurceramsoc.2020.05.066 DOI Help

Authors: Lewis R. Blackburn (University of Sheffield) , Shi-Kuan Sun (University of Sheffield) , Sebastian M. Lawson (University of Sheffield) , Laura J. Gardner (University of Sheffield) , Hao Ding (University of Sheffield) , Claire L. Corkhill (University of Sheffield) , Ewan R. Maddrell (National Nuclear Laboratory) , Martin C. Stennett (University of Sheffield) , Neil C. Hyatt (University of Sheffield)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of The European Ceramic Society

State: Published (Approved)
Published: May 2020
Diamond Proposal Number(s): 24074

Open Access Open Access

Abstract: A series of Ca1-xCexZrTi2-2xCr2xO7 zirconolite ceramics (0 ≤ x ≤ 0.35) were reactively sintered in air at 1350 °C for 20 h. Single phase zirconolite-2 M was formed for x ≤ 0.15, with Cr2O3 and an undesirable Ce-bearing perovskite phase present above x = 0.20. Electron diffraction analysis confirmed that the zirconolite-2 M polytype was maintained over the solid solution. X-ray absorption near edge structure (XANES) data determined that between 10 – 20% Ce was speciated as Ce3+, and Cr was present uniformly as Cr3+ with near edge features consistent with occupation of octahedral sites within the zirconolite-2 M structure. A sample corresponding to x = 0.20 was processed by reactive spark plasma sintering (RSPS), with a rapid processing time of less than 1 h. XANES data confirmed complete reduction to Ce3+ during RSPS, promoting the formation of a Ce-bearing perovskite, comprising 19.3 ± 0.4 wt. % of the phase assemblage.

Journal Keywords: Zirconolite; Immobilisation; Plutonium; Surrogate; Wasteform

Subject Areas: Chemistry, Materials


Instruments: B18-Core EXAFS

Added On: 03/06/2020 10:04

Documents:
1-s2.0-S0955221920304325-main.pdf

Discipline Tags:

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

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) X-ray Absorption Near Edge Structure (XANES)