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核素在介质中的扩散系数是表征核素迁移能力的主要参数之一。本工作应用毛细管扩散法分别在大气和惰气条件下研究了Np在模拟地下水中的扩散行为;探讨了模拟地下水的pH值(5.0、6.0、7.0、8.0、8.5、9.6),Fe~(2+)离子(5.0×10~(-6)、1.0×10~(-5)、5.0×10~(-5)、1.O×10~(-4)、5.O×10~(-4)、1.O×10~(-3)mol/L),温度(35.0、40、45、50、55℃),粘度等因素对扩散系数的影响;测定了Np在模拟地下水中的扩散系数(1.32×10~(-10)m~2/s,35.0℃,pH=8.46)和扩散活化能49.795kJ/mol.实验结果表明:温度升高,Np在模拟地下水中的扩散能力增强;模拟地下水的粘度、pH值、Fe~(2+)离子浓度升高,NP在模拟地下水中的扩散能力减弱。
The diffusion coefficient of the nuclide in the medium is one of the main parameters to characterize the nuclide migration ability. In this work, capillary diffusion method was used to study the diffusion of Np in simulated groundwater under atmospheric and inert gas conditions respectively. The effects of simulated pH value (5.0,6.0,7.0,8.0,8.5,9.6), Fe ~ (2) (+) Ions (5.0 × 10 -6, 1.0 × 10 -5, 5.0 × 10 -5, 1.0 × 10 -4, 4), 1.O × 10 -3 mol / L), temperature (35.0,40,45,50,55 ℃), viscosity and other factors on the diffusion coefficient; measured in the simulated groundwater Np diffusion The experimental results show that the diffusion ability of Np increases in simulated groundwater under the condition of higher temperature, higher coefficient of variation (1.32 × 10 -10 m -2 / s, 35.0 ℃, pH = 8.46) and diffusion activation energy of 49.795 kJ / Simulation of groundwater viscosity, pH value, Fe2 + ion concentration increased, NP in simulated groundwater diffusion ability weakened.