Tracing U Mobility in Deep Groundwater Using Ra Isotopes

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• 关键词：Uranium ; Ca2UO2(CO3)30 ; crystalline bedrock ; Ra isotopes ; spent nuclear fuel
• 刊名：Procedia Earth and Planetary Science
• 出版年：2017
• 出版时间：2017
• 年：2017
• 卷：17
• 期：Complete
• 页码：484-487
• 全文大小：238 K
• 卷排序：17

文摘

The mobility of natural U is compared among four boreholes in a fractured granite using Ra isotopes and geochemical modelling. 222Rn/226Ra activity ratios (ARs) spanning an order of magnitude underline differences in reactive surface area. (224Ra/228Ra)ARs up to 9 indicate recent changes in hydrogeochemistry, and (226Ra/228Ra)ARs 0.6-30 indicate variable deposition of U. Dissolved U is related to dissolution of a solid U(VI) phase by groundwater with HCO3− >20 mg·L-1. U reduction is hindered by Ca2UO2(CO3)30.