This study determined the dissolution rate of studtite, (UO)O(HO), which can be formed by reaction between HO and UO that leaks from spent nuclear fuel (SNF) in deep geological repositories. The batch dissolution experiments were conducted using synthesized studtite under different solution conditions with varying pHs and concentrations of HCO and [HO] in synthetic groundwater. The experimental results suggested that carbonate ligand and HO in groundwater accelerated the dissolution of studtite and uranium (U) release. Above 10 M of HO initial concentration, the released uranium concentration in solution decreased, possibly as a result of reprecipitation of studtite due to reaction between uranium and HO. The results will be useful to assess the comprehensive transport of uranium from both nuclear waste and SNF stored in deep geological repositories.
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