• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physics and chemistry of the earth >Conceptual and numerical models of solute diffusion around a HLW repository in clay
【24h】

Conceptual and numerical models of solute diffusion around a HLW repository in clay

机译：粘土中HLW储存库周围溶质扩散的概念和数值模型

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Reactive transport models have been used to simulate solute diffusion, canister corrosion, interactions of the corrosion products with the bentonite and the long-term hydrochemical evolution of porewater composition around radioactive waste repositories. Such models usually rely on simplifications of the geometry and dimensionality of the problem. Detailed three-dimensional flow and transport models, on the other hand, are used which often oversimplify the geochemical reactions. There is a clear need to identify which simplifications and assumptions are admissible. Here we present conceptual and numerical models of radionuclide diffusion and sorption around a HLW repository in clay according to the French reference concept. Models of increasing dimensionality have been performed for: (1) 1D transport perpendicular to the axes of the disposal cells; (2) 1D axisymmetric transport around disposal cells for bounded and unbounded domains; (3) 2D transport through vertical planes; and (4) 1D vertical transport from the disposal cells into the overlying Oxfordian formation. Model results are compared for simulation times up to 10~6 years and for the following radionuclides and tracers: tritium, HTO, which is treated here as an ideal and conservative tracer, ~(36)Cl- which experiences anion exclusion, ~(133)Cs~+ which sorbs moderately and ~(238)U (IV) which shows a strong sorption capacity. Radionuclides are released into the disposal cell either at a fixed concentration or as an instantaneous unit pulse. Model results indicate that the 1D unbounded model is always acceptable for ~(238)U (IV) and is valid for ~(133)Cs~+ for t<10~4 years. It is valid for HTO and ~(36)Cl- only for t<10~3 years. These conclusions hold true for both release modes. Computed concentrations with the 1D parallel and the 1D axisymmetric models are significantly different. Inasmuch as solute diffusion in a radioactive waste repository is expected to show radial symmetry around the cells, the use of the axisymmetric model is strongly recommended for the long-term modeling of radionuclide migration from the repository. The 1D vertical model is valid only for conservative radionuclides released instantaneously and leads always to large errors for all radionuclides for a constant concentration.
机译：反应性运输模型已用于模拟溶质扩散，碳罐腐蚀，腐蚀产物与膨润土的相互作用以及放射性废物处置库周围孔隙水成分的长期水化学演化。此类模型通常依赖于问题的几何形状和尺寸的简化。另一方面，使用详细的三维流动和运输模型，这些模型通常会过分简化地球化学反应。显然需要确定哪些简化和假设是可以接受的。在这里，我们根据法国参考概念，介绍了粘土中HLW储存库周围放射性核素扩散和吸附的概念和数值模型。已针对以下方面执行了增加尺寸的模型：（1）垂直于处理室的轴的一维传输; （2）有界域和无界域在处置单元周围的一维轴对称运输; （3）通过垂直平面的二维运输; （4）从处理单元到上覆的牛津地层的一维垂直传输。比较了模型结果的仿真时间（最长10〜6年）以及以下放射性核素和示踪剂：tri，HTO，在这里被视为理想且保守的示踪剂〜（36）Cl-，遇到阴离子排斥，〜（133） Cs〜+适度吸附，〜（238）U（IV）吸附能力强。放射性核素以固定浓度或瞬时单位脉冲释放到处置池中。模型结果表明，一维无界模型对于〜（238）U（IV）始终是可接受的，并且对于〜（133）Cs〜+在t <10〜4年内有效。它仅对t <10〜3年有效，适用于HTO和〜（36）Cl-。这些结论对于两种发布模式均成立。一维平行模型和一维轴对称模型的计算浓度显着不同。由于预计放射性废物储存库中的溶质扩散将显示出细胞周围的径向对称性，因此强烈建议使用轴对称模型来对放射性核素从储存库中迁移进行长期建模。一维垂直模型仅对瞬时释放的保守放射性核素有效，并且对于恒定浓度的所有放射性核素始终会导致较大的误差。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号