Cs_(3)Bi_(2)l_(9)-hydroxyapatite composite waste forms for cesium and iodine immobilization  

作　　者：Kun YANG Yachun WANG Junhua SHEN Spencer M.SCOTT Brian J.RILEY John D.VIENNA Jie LIAN 

机构地区：[1]Department of Mechanical,Aerospace,and Nuclear Engineering,Rensselaer Polytechnic Institute,Troy,USA [2]Department of Materials Science&Engineering,Rensselaer Polytechnic Institute,Troy,USA [3]Savannah River National Laboratory,Aiken,USA [4]Pacific Northwest National Laboratory,Richland,USA

出　　处：《Journal of Advanced Ceramics》2022年第5期712-728,共17页先进陶瓷（英文）

基　　金：supported as part of the Center for Performance and Design of Nuclear Waste Forms and Containers(WastePD),an Energy Frontier Research Center(EFRC)funded by the U.S.Department of Energy,Office of Science,Basic Energy Sciences under Award DE-SC0016584。

摘　　要：Perovskite-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 Cs_(3)Bi_(2)I_(9)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 Cs_(3)Bi_(2)I_(9)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 Cs_(3)Bi_(2)I_(9)and Cs_(3)Bi_(2)I_(9)-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 Cs_(3)Bi_(2)I_(9)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 Cs_(3)Bi_(2)I_(9).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.

关 键 词：cesium(Cs) iodine(Ⅰ) PEROVSKITE nuclear waste HYDROXYAPATITE 

分 类 号：X591[环境科学与工程—环境工程] X705