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首页> 外文学位 >Evaluation and computer modeling of long-term durability of concrete engineered barriers in the tumulus technology for the disposal of solid low-level radioactive waste.
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Evaluation and computer modeling of long-term durability of concrete engineered barriers in the tumulus technology for the disposal of solid low-level radioactive waste.

机译：地下技术中用于处理固体低放射性废物的混凝土工程屏障的长期耐用性评估和计算机建模。

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摘要

The above-grade tumulus disposal technology can provide a major means for the disposal of low-level radioactive waste provided that the concrete pad and disposal vaults (which are structural components as well as engineered barriers against migration of radionuclides) are designed and fabricated for long-term durability.;The objective of this study was to examine the longevity of the concrete used for the engineered barriers. Alkali-aggregate reactivity, permeability (measured as rapid chloride permeability), freeze-thaw resistance, and strength were identified as key properties of hardened concrete that are important to ensure the long-term durability of tumulus concrete, and the testing and evaluation of the properties were conducted on laboratory concrete samples prepared with the concrete component materials and/or fly ash and silica fume field concrete samples. The second part of the research program was to develop computer model that can predict the long-term performance of the concrete engineered barriers utilized in the tumulus disposal technology; the overall strategy consisted of three parts: hydration modeling of portland cement paste, pore solution modeling of portland cement paste, and mass transport modeling in the concrete engineered barrier.;Although there were minor variations in properties, the mix design of both the fly ash concrete and silica fume concrete appeared to be adequate for the intended applications, assuming the concretes were produced properly. Based on the information generated for the both concretes, the merits of the silica fume concrete over the fly ash concrete in the light of long-term durability, particularly in the application for the tumulus disposal technology, are not conclusive yet.;It was predicted that, during the entire expected service life of 300 years, the pore solution of the tumulus pad concrete will maintain highly alkaline conditions remaining at pH 12.5 or above depending on whether or not the equilibrium release of the adsorbed alkali back into the pore solution is taken into account. In addition to the function as a physical barrier offered by the tumulus concrete pad, the highly alkaline environments being maintained inside the concrete pad during the entire expected service life will also function adequately as a chemical barrier against migration of radionuclides and other hazardous species in the case of an accidental breach of the steel waste containers and concrete waste vaults.
机译：只要设计和制造长久的混凝土垫块和处置库（其是结构组件以及防止放射性核素迁移的工程屏障），以上等级的古塔姆处置技术就可以提供用于处置低放射性废物的主要手段。耐久性。这项研究的目的是检查用于工程屏障的混凝土的寿命。碱集料的反应性，渗透性（以快速的氯化物渗透性衡量），抗冻融性和强度被确定为硬化混凝土的关键性能，这些对确保翻新混凝土的长期耐久性至关重要，并且对混凝土的测试和评估也很重要。性能是对用混凝土成分材料和/或粉煤灰和硅粉田间混凝土样品制备的实验室混凝土样品进行的。研究计划的第二部分是开发计算机模型，该模型可以预测在古墓处置技术中使用的混凝土工程屏障的长期性能。总体策略由三部分组成：硅酸盐水泥浆的水化模型，硅酸盐水泥浆的孔溶液模型以及混凝土工程屏障中的传质模型。尽管性能差异很小，但两种粉煤灰的混合设计假定混凝土生产正确，混凝土和硅粉混凝土似乎足以满足预期的应用。根据生成的两种混凝土的信息，从长期耐久性的角度来看，硅粉混凝土在粉煤灰混凝土上的优点尚无定论，尤其是在颗粒处理技术的应用方面。在整个300年的预期使用寿命中，垫层混凝土的孔隙溶液将保持在pH 12.5或更高的高碱性条件，这取决于是否吸收了吸附的碱平衡释放到孔隙溶液中考虑在内。除了担架混凝土垫层提供的物理屏障功能外，在整个预期使用寿命期间在混凝土垫层内部保持的高碱性环境也将充分发挥化学屏障的作用，以防止放射性核素和其他有害物质迁移到地下。意外破坏钢制废物容器和混凝土废物库的情况。

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  • 作者

    Lee, Joon H.;

  • 作者单位

    The Pennsylvania State University.;

  • 授予单位 The Pennsylvania State University.;
  • 学科 Engineering Nuclear.;Environmental Sciences.;Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 1993
  • 页码 425 p.
  • 总页数 425
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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