Interaction of Cs and Sr with C–A–S–H and Carbonated C–A–S–H phases: Experimental study and thermodynamic modeling

IF 3.2 2区工程技术 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Journal of Nuclear Materials Pub Date : 2025-09-08 DOI:10.1016/j.jnucmat.2025.156156

Sayuri Tomita , Kazuo Yamada , Go Igarashi , Yoshifumi Hosokawa , Ippei Maruyama

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引用次数: 0

Abstract

Understanding the retention mechanisms of radioactive cesium and strontium in cementitious materials is crucial for predicting contamination spread and designing effective barriers. This study investigates the adsorption behavior of Cs and Sr on calcium aluminosilicate hydrate (C–A–S–H) and its carbonated forms, revealing distinct retention mechanisms in these phases.

We found that in C–A–S–H, Cs and Sr adsorption occurs primarily through ion exchange with interlayer cations, with adsorption capacity increasing at lower Ca/Si ratios. In contrast, carbonation transforms C–A–S–H into CaCO₃ and an aluminosilicate gel with a three-dimensional network structure, significantly enhancing Cs and Sr retention through multiple mechanisms: ion exchange within the aluminosilicate framework, incorporation into the gel structure, and Sr substitution for Ca in carbonates.

Based on these findings, we developed a comprehensive thermodynamic model that successfully reproduces Cs and Sr adsorption behavior across various conditions by explicitly incorporating the aluminosilicate gel phase—a critical component overlooked in conventional models. This model provides a valuable tool for predicting radionuclide behavior in aging concrete barriers and supports the development of more effective containment strategies for radioactive waste.

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Cs和Sr与C-A-S-H和碳化C-A-S-H相的相互作用：实验研究和热力学模型

了解放射性铯和锶在胶凝材料中的保留机制对于预测污染扩散和设计有效的屏障至关重要。本研究研究了Cs和Sr在水合铝硅酸钙（C-A-S-H）及其碳化形态上的吸附行为，揭示了这些相中不同的保留机制。我们发现，在C-A-S-H中，Cs和Sr的吸附主要通过与层间阳离子的离子交换发生，在较低的Ca/Si比下吸附容量增加。相反，碳化作用将C-A-S-H转化为CaCO3和具有三维网络结构的铝硅酸盐凝胶，通过铝硅酸盐框架内的离子交换、结合到凝胶结构中以及Sr在碳酸盐中取代Ca等多种机制显著增强Cs和Sr的保留。基于这些发现，我们开发了一个综合的热力学模型，通过明确地纳入铝硅酸盐凝胶相，成功地再现了在各种条件下Cs和Sr的吸附行为-这是传统模型中被忽视的关键成分。该模型为预测老化混凝土屏障中的放射性核素行为提供了有价值的工具，并支持制定更有效的放射性废物遏制战略。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Nuclear Materials 工程技术-材料科学：综合

CiteScore

5.70

自引率

25.80%

发文量

601

审稿时长

63 days

期刊介绍： The Journal of Nuclear Materials publishes high quality papers in materials research for nuclear applications, primarily fission reactors, fusion reactors, and similar environments including radiation areas of charged particle accelerators. Both original research and critical review papers covering experimental, theoretical, and computational aspects of either fundamental or applied nature are welcome. The breadth of the field is such that a wide range of processes and properties in the field of materials science and engineering is of interest to the readership, spanning atom-scale processes, microstructures, thermodynamics, mechanical properties, physical properties, and corrosion, for example. Topics covered by JNM Fission reactor materials, including fuels, cladding, core structures, pressure vessels, coolant interactions with materials, moderator and control components, fission product behavior. Materials aspects of the entire fuel cycle. Materials aspects of the actinides and their compounds. Performance of nuclear waste materials; materials aspects of the immobilization of wastes. Fusion reactor materials, including first walls, blankets, insulators and magnets. Neutron and charged particle radiation effects in materials, including defects, transmutations, microstructures, phase changes and macroscopic properties. Interaction of plasmas, ion beams, electron beams and electromagnetic radiation with materials relevant to nuclear systems.