In this study, the long-term mobility of natural uranium in the KAERI Underground Research Tunnel (KURT) site was investigated using sequential chemical extraction and isotopic analyses of natural uranium in granite. It was found that uranium(VI) would be leached out due to preferential leaching of 234U relative 238U and concentrated by an uraniferous enrichment process through long-term interactions with the oxic KURT groundwater. Our results also suggest that the migration of the preferentially released uranium(VI) through fractured granite can be significantly retarded by secondary mineral phases formed by the weathering processes of granite.

中文翻译：

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铀在花岗岩 KURT 场地中的长期迁移率，使用同位素分析和顺序化学提取

在这项研究中，使用花岗岩中天然铀的连续化学提取和同位素分析，研究了 KAERI 地下研究隧道 (KURT) 站点中天然铀的长期流动性。发现铀 (VI) 会因 234U 相对于 238U 的优先浸出而被浸出，并通过与含氧 KURT 地下水的长期相互作用通过含铀浓缩过程进行浓缩。我们的研究结果还表明，花岗岩风化过程形成的次生矿物相可以显着延缓优先释放的铀 (VI) 通过断裂花岗岩的迁移。