Cheng Jianfeng, Gu Runqiu, He Panqing, Pan Yuelong, Leng Yangchun, Liu Yu, Wang Yanhui, Tuo Xianguo
School of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, China.
Nuclear Power Institute of China, Chengdu, 610005, China.
Appl Radiat Isot. 2022 Mar;181:110102. doi: 10.1016/j.apradiso.2022.110102. Epub 2022 Jan 8.
The Alxa region (Inner Mongolia, China) is one of the areas preselected for use as a geological repository of high-level radioactive waste in China. Radioactive waste produces radioactive rays during long-term storage, and the cumulative absorbed dose in 1000 years can significantly exceed the maximum of 0.7 MGy, thereby challenging the long-term adsorption stability of clay. This study employed Co gamma (γ)-rays to irradiate clay in air under a dose rate of 10 kGy/h. The changes in the internal structure and mechanisms of clay under different gamma radiation doses (1, 2, and 3 MGy) were investigated. Additionally, the adsorption properties of irradiated clay for U(Ⅵ) were tested under different conditions. The clay samples underwent minimal structural changes following high-dose irradiation, and the interlayer spacing was altered due to the fractured framework, dehydroxylation, and radiolysis of water. After irradiation, the Fe (Ⅱ) content in clay was significantly increased, unlike Fe (Ⅲ) content. The adsorption mechanisms of clay before and after the experiments were verified, revealing that the adsorption capacity of irradiated clay to U(Ⅵ) is reduced.
阿拉善地区（中国内蒙古）是中国预选作为高放废物地质处置库的地区之一。放射性废物在长期储存过程中会产生放射性射线，1000年内的累积吸收剂量会显著超过0.7毫戈瑞的最大值，从而对黏土的长期吸附稳定性构成挑战。本研究采用钴γ射线在剂量率为10千戈瑞/小时的条件下在空气中辐照黏土。研究了不同γ辐射剂量（1、2和3毫戈瑞）下黏土内部结构和机理的变化。此外，还测试了辐照黏土在不同条件下对U(Ⅵ)的吸附性能。高剂量辐照后黏土样品结构变化极小，层间距因骨架断裂、脱羟基作用和水的辐解作用而改变。辐照后，黏土中的Fe(Ⅱ)含量显著增加，与Fe(Ⅲ)含量不同。验证了实验前后黏土的吸附机理，结果表明辐照黏土对U(Ⅵ)的吸附能力降低。
