铀在北山花岗岩中的吸附迁移影响因素研究

运用水文地球化学模拟软件PHREEQC-Ⅱ，对铀元素进入中国高放废物处置预选场研究区地下水后的状况进行了模拟和预测。模拟得到核素铀进入研究区地下水后的元素浓度分布和迁移情况及外界因素变化引起地下水中铀迁移的行为，同时采用批式法测定不同条件下铀在甘肃北山花岗岩中的分配系数，研究了岩石粒径、溶液初始浓度、水相pH和温度对分配系数的影响，实验结果表明花岗岩对铀的吸附能力较弱，其中溶液初始浓度、粒径、温度影响较小，pH值对岩石的吸附性能有较大影响，在接近中性条件下影响达到最大，这与采用模拟软件模拟结果基本吻合。通过模拟和实验对比，能更好地研究在北山预选区处置条件下地下水-废物-岩石的相互作用过程中核素的迁移行为,从而为处置库系统安全评价提供有关依据。

Investigation of Sorption and Migration Effect Factors of Uranium on Granites in Beishan

The paper simulates and predicts the conditions after the uranium entered into the groundwater in a disposal site of pre-selected high level radioactive waste in China by using hydrologic modeling software PHREEQC-Ⅱ.The paper also analyzes the different roles of the various influential factors such as pH,dispersity,diffusion coefficient and temperature in the simulation.The behaviors of sorption and migration of uranium on granites in Beishan have been investigated by using the batch method.The distribution coefficient of uranium is determined.The effects of granite particle size,pH,concentration and temperature of uranium in simulated groundwater are studied.The results show that the ability of granites in Beishan to adsorb uranium is rather weak and influenced by some influential factors.The results of simulation by software is similar to the experimental results.Therefore,the study will provide an important basis for the safety research on the site.