Tracing U Mobility in Deep Groundwater Using Ra Isotopes

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 hydrogeo...

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Bibliographic Details
Published inProcedia earth and planetary science Vol. 17; pp. 484 - 487
Main Authors Krall, L., Auqué, L., Tullborg, E.L., Suksi, J., Trezzi, G., Garcia-Orellana, J., Andersson, P., Porcelli, D.
Format Journal Article
LanguageEnglish
Published Elsevier B.V 2017
Subjects
Ca2UO2(CO3)30
crystalline bedrock
Ra isotopes
spent nuclear fuel
Uranium
Uranium
Ra isotopes
Ca2UO2(CO3)30
crystalline bedrock
spent nuclear fuel
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Summary: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.
ISSN:1878-5220
1878-5220
DOI:10.1016/j.proeps.2016.12.122