Geochemical analysis for long term effect and stability of engineering barrier

工程屏障长期效应和稳定性地球化学分析

• 批准号: 05402065
• 负责人: SUZUKI Atsuyuki
• 金额: $ 8.06万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05402065/
• 关键词: Engineering Barrier; Migration; Uncertainty Analysis; Actinide; Colloid; Illite; Americium; Neptunium; 吸着性能; スメクタイト; 物質移行; 透水係数; ベントナイト空隙水; 吸着

Waste management of high revel waste disposal is the hopeful method to prevent isolate radioactive waste disposal from human beings. The scenario, however, is concluded on the assumptions that the properties of engineering barrier is unique for a long time. In fact, it is known that smectites change into illites by ion-exchange with cation in the ground water.As a result of this research, The effect that smectites change into illites, on migration in the bentonite can be evaluated. Results are summarized as follows.(1) Chemical conditions, i.e.pH,oxidation-reduction potential and concentration of carbonate acid of the water in the bentonite porosity, were experimentally measured before worsening and it can be edited that those values agree with the simulation results. It is made clear that americium change into pseudo-colloids by attaching to microsperes from bentonite. By supposing pseudo-colloids, that experimentally measured effect on adsorb of americium can be explained theoretically.(2) By exprimentally measuring sorption distribution coefficient of smectites, illites, and mixture and using these measured data and Altarner model, a model, by which the change of properties can be quantitatively explained, was made. Furthermore, By measuring sorption distribution coefficient for smectites, illites, and mixture with another mixing ratio, the properties of these elements were found out.(3) According to results of (1) and (2), a model of radionuclide migration was made, considering change of bentonite as time passed. The results of simulation show that the change of bentonite property dependant on time quantitatively makes effects on the migration in bentonite.

高放射性废物处置的废物管理是防止放射性废物处置与人类隔离的最有希望的方法。然而，该方案是在假设工程屏障的性质在很长一段时间内是独特的基础上得出的。事实上，众所周知，蒙皂石通过与地下水中的阳离子进行离子交换而变成伊利石。通过这项研究，可以评估蒙皂石变成伊利石对膨润土中迁移的影响。结果总结如下。(1)实验测定了膨润土孔隙中水的pH值、氧化还原电位和碳酸盐浓度等化学条件，并对这些化学条件进行了编辑，使其与模拟结果一致。明确了镅是通过吸附在膨润土的微孔上而形成假胶体的。通过假定假胶体，可以从理论上解释实验测量到的对镅吸附的影响。(2)通过实验测定蒙脱石、伊利石和混合物的吸附分配系数，并将测定数据与Altarner模型相结合，建立了一个能定量解释性质变化的模型。通过对蒙脱石、伊利石以及不同配比的混合物的吸附分配系数的测定，了解了这些元素的性质。(3)根据（1）和（2）的结果，建立了考虑膨润土随时间变化的核素迁移模型。模拟结果表明，膨润土性质随时间的变化定量地影响着迁移。