Gas Migration in Deep Radioactive Waste Repositories; a Review of Processes, Data and Models PDF Download

Author: R. M. Jeffries
Publisher:
ISBN:
Category : Radioactive wastes
Languages : en
Pages :

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Book Description

Author: R. M. Jeffries
Publisher:
ISBN:
Category : Radioactive wastes
Languages : en
Pages :

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Book Description

Author: R. M. Jeffries
Publisher:
ISBN:
Category :
Languages : en
Pages : 144

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Book Description

Author: R.P. Shaw
Publisher: Geological Society of London
ISBN: 1862397228
Category : Science
Languages : en
Pages : 260

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Book Description
Understanding the behaviour of gases in the context of radioactive waste disposal is a fundamental requirement in developing a safety case for the disposal of radioactive waste. Of particular importance are the long-term performance of bentonite buffers and cement-based backfill materials that may be used to encapsulate and surround the waste in a repository, and the behaviour of plastic clays, indurated mudrocks and crystalline formations that may be the host rocks for a repository. The EC Euratom programme funded project, FORGE, has provided new insights into the processes and mechanisms governing gas generation and migration with the aim of reducing uncertainty. This volume brings together papers on aspects of this topic arising from both the FORGE project and work undertaken elsewhere. This has been achieved by the acquisition of new experimental data coupled with modelling, through a series of laboratory and field-scale experiments performed at a number of underground research laboratories throughout Europe.

Author: M. A. Jones
Publisher:
ISBN:
Category : Radioactive wastes
Languages : en
Pages :

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Book Description

Author: W. R. Rodwell
Publisher:
ISBN:
Category : Fluid mechanics
Languages : en
Pages : 86

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Book Description

Author: Nuclear Energy Agency
Publisher: Nuclear Energy Agency, Organisation for Economic Co-operation and Development
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 200

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Book Description
These conference proceedings examine gas generation, accumulation and migration in underground repository systems for radioactive waste: safety-relevant issues.

Author: Elias Ernest Dagher
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
This work provides a comprehensive assessment into the processes governing two-phase flow in a swelling geomaterial under critical gas pressures whereby the material strength of the soil may be exceeded and for which dilation and dilation-controlled gas flow is expected to occur. The author first provides background on the importance of understanding such processes in the safe geological disposal of radioactive waste. This is followed by a review of experimental studies to describe mechanisms of gas migration processes through natural (host rock formations) and engineered barrier materials, and an evaluation of existing studies that have attempted to numerically model multi-phase flow in expansive soils. Finally, the author provides a literary synthesis of the hydraulic and mechanical behaviour of bentonite clays observed in laboratory experiments under saturated and unsaturated conditions. The novel contribution of this work is then presented through a series of articles. The author first develops a fully-coupled hydro-mechanical (HM) mathematical model for advective-diffusive visco-capillary controlled two-phase flow through a geomaterial and applies it to simulate a 1-dimensional (1D) flow problem using the Finite Element Method (FEM) commercial code COMSOL Multiphysics®. The model results are compared to experimental data and although several key-features of the experimental results were realized, additional flow mechanisms would be necessary to achieve complete gas breakthrough of the sample. In the second article, a verification study is performed, whereby analytical solutions for a 1D steady-state and 1D transient gas flow problem under constant volume boundary conditions were derived. Successful verification of the numerical model was completed by comparing the pore-gas pressure evolution and stress evolution to that of the results of the analytical solution, which showed near-perfect agreement. Building upon the authors original mathematical model, an investigation of enhanced processes and characteristics which may be contributing to dilation-controlled gas flow were conducted. These processes included the introduction of material heterogeneity, consideration of the Klinkenberg "slip flow" effect, and the presence of a swelling strain, and were applied to simulate the same 1D flow problem. The results showed significant improvement over the previous work, including observing complete breakthrough and matching experimental stress evolution. However, the results showed a high degree of gas saturation within the sample and a plug outflow behavior, which were not characteristic of dilation-controlled gas flow. To further improve the mathematical model, the author conducted a detailed investigation of the highly coupled relationship between mechanical deformation and flow. This included assessing the effect of plasticity, damage, and non-localization to dilation-controlled gas flow, while incorporating the knowledge gained from previous studies. These advanced mathematical models were applied to numerically simulate 1D flow and a 3D spherical flow under constant boundary conditions. Some results demonstrated very good agreement with experimental data and provide further understanding of the processes involved. The collection of this research provides much needed insight into the possible mechanisms controlling two-phase flow and the capability of continuum models to do so. The intent of this research is to expand the literature further and provide a few steps closer in the development of a robust numerical model that can be used to support long-term safety assessments for radioactive waste disposal, by correctly capturing major features of two-phase flow.

Author: S. M. Sharland
Publisher:
ISBN: 9780705806190
Category : Radioisotopes
Languages : en
Pages : 38

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Book Description

Author: Chin-Fu Tsang
Publisher: Elsevier
ISBN: 0323142400
Category : Technology & Engineering
Languages : en
Pages : 816

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Book Description
Coupled Processes Associated with Nuclear Waste Repositories covers the proceedings of the 1985 International Symposium on Coupled Processes Associated with Nuclear Waste Repositories. The study of the behavior of geologic waste repositories is based on the coupled thermal, hydrologic, chemical, and mechanical processes that may occur in these systems. The symposium is sponsored by the U.S. Nuclear Regulatory Commission and the U.S. Department of Energy, in collaboration with the Nuclear Energy Authority in Paris and the Commission of the European Communities in Brussels. This book is organized into five parts encompassing 58 chapters. The introductory parts survey the concerns and interests from American and European agencies that have responsibilities in nuclear waste isolation research. These parts also provide overviews of coupled processes, with a particular emphasis on hydrology, geomechanics, and geochemistry. These topics are followed by summaries of major field projects on nuclear waste repositories in the U.S.A., France, Sweden, Canada, Belgium, and Switzerland. The fourth part covers considerable research results from topical studies of particular coupled processes. The concluding part provides the comments and discussion of various international researchers on the subject. This work will be of value to geology, hydrology, chemistry, thermodynamics, and rock mechanics students and researchers.