Though geologic carbon storage (GCS) is widely recognized as a promising strategy to reduce emissions of greenhouse gas (GHG), the potential for mobilization of radioactive uranium (U) from U-bearing minerals in deep subsurface due to CO₂ injection remains a concern. In this study, supercritical CO₂ and brine flowing through a fracture surrounded by reservoir rock containing uranium is simulated so as to study the potential of uranium release as a result of CO₂ injection and the impact of various factors on total uranium release rate. Mineral compositions of the reservoir rock are from previously published literature, which mimics typical sandstone mineral compositions. The reservoir rock is assumed to have 2 × 10⁻⁴ vol% UO₂ in solid phase. Simulation results show that CO₂ injection induces UO₂ dissolution, and both CO₂ and mobilized uranium are able to migrate in both the fracture and the rock matrix surrounding the fracture. However, the released uranium concentration is quite low in a 60-day simulation period. Mineral dissolution causes a very small porosity increase surrounding the fracture in the simulation period. Sensitivity analysis shows that an increase of UO₂ specific surface area and UO₂ content in reservoir rock causes a significant increase in released uranium concentration. In other words, total uranium release rate is positively correlated with the specific surface area of UO₂ and UO₂ content in reservoir rock because the increase of specific surface area and UO₂ content increases the total area of UO₂ in contact with HCO₃⁻ and O₂, which raises total uranium release rate. In summary, uranium release in and surrounding the fracture is mainly controlled by uranium supply of the reservoir rock, and the risk of environmental contamination by CO₂-induced uranium release is quite low in the scenario reported.

尽管地质碳储量（GCS）被广泛认为是减少温室气体（GHG）排放的一种有前途的策略，但由于注入CO ₂而从深地下的含U矿物中调集放射性铀（U）的潜力仍然值得关注。在这项研究中，模拟了超临界CO ₂和盐水流过由含铀的储层岩石包围的裂缝的情况，以研究注入CO ₂后铀释放的潜力以及各种因素对总铀释放速率的影响。储层岩石的矿物成分来自先前发表的文献，这些文献模仿了典型的砂岩矿物成分。假定储集岩的 UO为2×10 ^-4 vol％₂在固相中。模拟结果表明，CO ₂注入引起UO ₂溶解，CO ₂和动员铀都能够在裂缝和裂缝周围的岩石基质中迁移。但是，在60天的模拟期内，释放出的铀浓度非常低。在模拟期间，矿物溶解会导致裂缝周围的孔隙率增加非常小。敏感性分析表明，储集岩中UO ₂比表面积和UO ₂含量的增加会导致铀释放浓度的显着增加。换句话说，总铀释放速率与UO ₂的比表面积呈正相关和UO ₂在储集岩中的内容，因为比表面积的增加和UO ₂含量增加UO的总面积₂接触HCO ₃ ^-和O ₂，这引起了总铀释放速率。总之，在裂缝中及其周围的铀释放主要受储层岩石的铀供应控制，在所报告的情景中，CO ₂诱导的铀释放对环境造成污染的风险非常低。