在性到高性pH下,无化和Gd2O3化UO2的氧化溶解机制
Sonia García-Gómez1, Javier Giménez1, Ignasi Casas1
1Department of Chemical Engineering, EEBE and Barcelona Research Center in Multiscale Science and Engineering, Universitat Politècnica de Catalunya (UPC), 08019 Barcelona, Spain. sonia.garcia.gomez@upc.edu.
Dalton transactions (Cambridge, England : 2003)
|July 4, 2023
概括
加多二氧化 (UO2) 在广泛的pH范围内表现出低溶解率,这表明它有可能用于核废物应用. 用加多氧化物 (Gd2O3) 兴奋剂UO2有效抑制溶解,特别是在高性条件下.
科学领域:
- 材料科学 材料科学 材料科学
- 核化学 核化学 核化学
- 地质化学 地质化学
背景情况:
- 了解二氧化 (UO) 溶解对于核燃料的行为和废物管理至关重要.
- 像pH,氧和二碳酸盐这样的环境因素显著影响UO的稳定性.
- 加多氧化物 (Gd2O3) 兴奋剂被探索为一种提高UO2耐用性的策略.
研究的目的:
- 为了确定无辐射UO2和Gd2O3-dopedUO2的溶解速率作为pH的函数.
- 研究氧和二碳酸盐对UO2溶解机制的影响.
- 评估Gd2O3兴奋剂在减少UO2溶解中的有效性.
主要方法:
- 流通溶解实验是在9-13的pH范围内进行的.
- 实验是在受控的大气条件下与氧气 (O2(g)) 和碳酸进行的.
- 使用X射线光电谱 (XPS) 来分析溶解后的固体表面.
主要成果:
- 无辐射UO2溶解随着pH值从13降至9显著增加.
- UO2溶解与涉及二碳酸盐复合的氧化机制一致.
- 在Gd2O3中合的UO2 (5重%和10重%) 在研究的pH范围 (9-13) 中表现出始终低的溶解率.
- 加多兴奋剂似乎减缓了U(V) 氧化到U(VI),有助于降低溶解速度.
结论:
- Gd2O3兴奋剂有效地降低了UO2的溶解速度,特别是在超的条件下.
- 碳酸的存在在加速低pH下UO2溶解中起着关键作用.
- Gd2O3被合的UO2对在地质存储库中需要增强长期稳定性的应用非常有希望.
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