Cement As a Waste Form for Nuclear Fission Products: The Case of 90Sr and Its Daughters

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• 作者：Lucile Dezerald ; Jorge J. Kohanoff ; Alfredo A. Correa ; Alfredo Caro ; Roland J.-M. Pellenq ; Franz J. Ulm ; Andr茅s Sa煤l
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：November 17, 2015
• 年：2015
• 卷：49
• 期：22
• 页码：13676-13683
• 全文大小：419K
• ISSN：1520-5851

文摘

One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Because it is inexpensive and easy to manufacture, cement is the material of choice to store large volumes of radioactive materials, in particular the low-level medium-lived fission products. It is therefore of utmost importance to assess the chemical and structural stability of cement containing radioactive species. Here, we use ab initio calculations based on density functional theory (DFT) to study the effects of ⁹⁰Sr insertion and decay in C鈥揝鈥揌 (calcium-silicate-hydrate) in order to test the ability of cement to trap and hold this radioactive fission product and to investigate the consequences of its 尾-decay on the cement paste structure. We show that ⁹⁰Sr is stable when it substitutes the Ca²⁺ ions in C鈥揝鈥揌, and so is its daughter nucleus ⁹⁰Y after 尾-decay. Interestingly, ⁹⁰Zr, daughter of ⁹⁰Y and final product in the decay sequence, is found to be unstable compared to the bulk phase of the element at zero K but stable when compared to the solvated ion in water. Therefore, cement appears as a suitable waste form for ⁹⁰Sr storage.