Structure and Chemical Durability of Actinide Nuclides Solidified by High-Entropy Pyrochlore (La1/6Pr1/6Nd1/6Sm1/6Eu1/6Gd1/6)2Zr2O7

Abstract

Abstract: High-entropy ceramics(HECs) are a potential target for high-level waste curing due to their excellent phase and chemical stability. In this work, a high-entropy rare-earth zirconate pyrochlore (La_1/6Pr_1/6Nd_1/6Sm_1/6Eu_1/6Gd_1/6)₂Zr₂O₇ was designed. And the lanthanide element Ce was used as simulated radioactive actinide nuclides. A series of ceramic solidifications (La_1/6Pr_1/6Nd_1/6Sm_1/6Eu_1/6Gd_1/6)₂(Zr_1-XCe_X)₂O₇(0≤X≤0.5) were prepared using a high temperature solid phase method to solidify Ce. The solidifying performances were evaluated by analyzing the physical phase composition, microstructure, microscopic morphology, and anti-leaching. The results show that all the nuclides are uniformly solidly dissolved into crystal structure. As the CeO₂ content increases, the crystal structure changes from an ordered pyrochlore phase to a defective fluorite phase. The normalized leaching rates of Ce range from 10^-7 g·m^-2·d^-1 to 10^-6 g·m^-2·d^-1, showing excellent chemical stability.

Key words: high-entropy ceramics, high-entropy pyrochlore, high-level waste, ceramic solidification, chemical durability

CLC Number:

TQ174.75

DU Zhanyuan, ZHU Yongchang, CUI Zhu, JIAO Yunjie, DONG Xuanjiang, WANG Dongyu, YANG Debo, WANG Hua. Structure and Chemical Durability of Actinide Nuclides Solidified by High-Entropy Pyrochlore (La_1/6Pr_1/6Nd_1/6Sm_1/6Eu_1/6Gd_1/6)₂Zr₂O₇[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2024, 43(9): 3399-3406.

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Structure and Chemical Durability of Actinide Nuclides Solidified by High-Entropy Pyrochlore (La_1/6Pr_1/6Nd_1/6Sm_1/6Eu_1/6Gd_1/6)₂Zr₂O₇

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