Abstract The analysis of 41Ca in concrete generated from the nuclear facilities decommissioning is critical for ensuring the safe management of radioactive waste. An analytical method for the determination of 41Ca in concrete is described. 41Ca is a neutron-activated long radionuclide, and hence, for accurate analysis, it is necessary to completely extract Ca from the concrete sample where it exists as the predominant element. The decomposition methods employed were the acid leaching, microwave digestion, and alkali fusion. A comparison of the results indicated that the alkali fusion is the most suitable way for the separation of Ca from the concrete sample. Several processes of hydroxide and carbonate precipitation were employed to separate 41Ca from interferences. The method relies on the differences in the solubility of the generated products. The behavior of Ca and the interfering elements such as Fe, Ni, Co, Eu, Ba, and Sr is examined at each separation step. The purified 41Ca was measured by a liquid scintillation counter, and the quench curve and counting efficiency were determined by using a certified reference material of known 41Ca activity. The recoveries in this study ranged from 56 to 68%, and the minimum detectable activity was 50 mBq g−1 with 0.5 g of concrete sample.

中文翻译：

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放射性混凝土中41Ca的测定分析方法

摘要 核设施退役产生的混凝土中41Ca的分析对于确保放射性废物的安全管理至关重要。描述了一种测定混凝土中 41Ca 的分析方法。41Ca 是一种中子激活的长放射性核素，因此，为了准确分析，必须从作为主要元素存在的混凝土样品中完全提取 Ca。采用的分解方法是酸浸、微波消解和碱熔。结果的比较表明，碱熔是从混凝土样品中分离钙最合适的方法。使用了几种氢氧化物和碳酸盐沉淀过程来将 41Ca 与干扰物分离。该方法依赖于生成的产品溶解度的差异。在每个分离步骤中检查 Ca 和干扰元素（如 Fe、Ni、Co、Eu、Ba 和 Sr）的行为。纯化后的 41Ca 用液体闪烁计数器测定，淬灭曲线和计数效率用已知 41Ca 活性的有证标准物质测定。本研究中的回收率为 56% 至 68%，0.5 g 混凝土样品的最小可检测活性为 50 mBq g-1。