Author:
Yang Kun,Wang Yachun,Shen Junhua,Scott Spencer M.,Riley Brian J.,Vienna John D.,Lian Jie
Abstract
AbstractPerovskite-based ceramic composites were developed as potential waste form materials for immobilizing cesium (Cs) and iodine (I) with high waste loadings and chemical durability. The perovskite Cs3Bi2I9 has high Cs (22 wt%) and I (58 wt%) content, and thus can be used as a potential host phase to immobilize these critical radionuclides. In this work, the perovskite Cs3Bi2I9 phase was synthesized by a cost effective solution-based approach, and was embedded into a highly durable hydroxyapatite matrix by spark plasma sintering to form dense ceramic composite waste forms. The chemical durabilities of the monolithic Cs3Bi2I9 and Cs3Bi2I9-hydroxyapatite composite pellets were investigated by static and semi-dynamic leaching tests, respectively. Cs and I are incongruently released from the matrix for both pure Cs3Bi2I9 and composite structures. The normalized Cs release rate is faster than that of I, which can be explained by the difference in the strengths between Cs−I and Bi−I bonds as well as the formation of insoluble micrometer-sized BiOI precipitates. The activation energies of elemental releases based on dissolution and diffusion-controlled mechanisms are determined with significantly higher energy barriers for dissolution from the composite versus that of the monolithic Cs3Bi2I9. The ceramic-based composite waste forms exhibit excellent chemical durabilities and waste loadings, commensurate with the state-of-the-art glass-bonded perovskite composites for I and Cs immobilization.
Publisher
Tsinghua University Press
Subject
Ceramics and Composites,Electronic, Optical and Magnetic Materials
Reference62 articles.
1. Aiken SC. SRS completes first batch in waste removal pilot project. Nuclear News 2019, 62: 46–47.
2. Carter ML, Vance ER, Mitchell DRG, et al. Fabrication, characterization, and leach testing of hollandite, (Ba,Cs)(Al,Ti)2Ti6O16. J Mater Res 2002, 17: 2578–2589.
3. Den Exter MJ. Immobilisation of iodine. 2003. Available at https://ftp.nrg.eu/pub/www/nrg/nrglib/2004/immobilisation_of_iodine.pdf.
4. Morgan MT, Moore JG, Devaney HE, et al. The disposal of iodine-129. In: Proceedings of the Scientific Basis for Nuclear Waste Management, Boston, USA, 1979: 453–459.
5. Ojovan MI, Lee WE. An introduction to nuclear waste immobilisation. Mater Today 2006, 9: 55.
Cited by
13 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献