Pyrochlore glass-ceramics for the immobilization of molybdenum-99 production wastes: demonstrating scalability and flexibility to waste stream variance
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Date
2021-11
Journal Title
Journal ISSN
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Publisher
Elsevier
Abstract
Pyrochlore glass ceramics have been fabricated via in-situ crystallization under reducing conditions by both sintering and hot isostatic pressing (HIPing) as candidate wasteforms for the acidic waste biproduct of Mo-99 radiopharmaceutical production. The tailored wasteform demonstrates flexibility in the wasteform design to receive the required waste variability, it also suitably passes high-level waste performance requirement, and successfully scales to 1 kg scale with 45 wt.% waste loading. U-rich pyrochlore as the major phase was confirmed by X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy, with residual glass and minor secondary phases. The presence of both U4+ and U5+ valences in the wasteforms was revealed by diffuse reflectance spectroscopy. Addition of glass content had little influence on the pyrochlore composition but facilitated minor perovskite formation. The up-scaled dense, HIPed sample showed elemental releases of < 2 g/L for all elements in durability experiments. © 2021 Elsevier Ltd
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Keywords
Pyrochlore, Glass, Ceramics, Waste forms, Molybdenum 99, Radioactive wastes, Hot pressing, Solidification, Crystallization
Citation
Farzana, R., Zhang, Y., Dayal, P., Aly, Z., Holmes, R., Triani, G., Vance, E. R., & Gregg, D. J. (2021). Pyrochlore glass-ceramics for the immobilization of molybdenum-99 production wastes: demonstrating scalability and flexibility to waste stream variance. Journal of the European Ceramic Society, 41(14), 7269-7281. doi:10.1016/j.jeurceramsoc.2021.06.056