Coupled Processes Associated With Nuclear Waste Repositories

Author: Chin-Fu Tsang
Publisher: Elsevier
ISBN: 0323142400
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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.

A Natural Analogue For Thermal Hydrological Chemical Coupled Processes At The Proposed Nuclear Waste Repository At Yucca Mountain Nevada

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Dike and sill complexes that intruded tuffaceous host rocks above the water table are suggested as natural analogues for thermal-hydrologic-chemical (THC) processes at the proposed nuclear waste repository at Yucca Mountain, Nevada. Scoping thermal-hydrologic calculations of temperature and saturation profiles surrounding a 30-50 m wide intrusion suggest that boiling conditions could be sustained at distances of tens of meters from the intrusion for several thousand years. This time scale for persistence of boiling is similar to that expected for the Yucca Mountain repository with moderate heat loading. By studying the hydrothermal alteration of the tuff host rocks surrounding the intrusions, insight and relevant data can be obtained that apply directly to the Yucca Mountain repository and can shed light on the extent and type of alteration that should be expected. Such data are needed to bound and constrain model parameters used in THC simulations of the effect of heat produced by the waste on the host rock and to provide a firm foundation for assessing overall repository performance. One example of a possible natural analogue for the repository is the Paiute Ridge intrusive complex located on the northeastern boundary of the Nevada Test Site, Nye County, Nevada. The complex consists of dikes and sills intruded into a partially saturated tuffaceous host rock that has stratigraphic sequences that correlate with those found at Yucca Mountain. The intrusions were emplaced at a depth of several hundred meters below the surface, similar to the depth of the proposed repository. The tuffaceous host rock surrounding the intrusions is hydrothermally altered to varying extents depending on the distance from the intrusions. The Paiute Ridge intrusive complex thus appears to be an ideal natural analogue of THC coupled processes associated with the Yucca Mountain repository. It could provide much needed physical and chemical data for understanding the influence of heat released from the repository on the tuff host rock and for THC modeling studies of the repository. Many other such intrusive complexes exist at the Nevada Test Site and in other parts of the world that could provide an extensive data set for understanding and predicting the behavior of the Yucca Mountain repository, for which the Paiute Ridge complex is just one example.

Coupled Thermo Hydro Mechanical Processes Of Fractured Media

Author: O. Stephanson
Publisher: Elsevier
ISBN: 9780080542850
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This work brings together the results, information and data that emerged from an international cooperative project, DECOVALEX, 1992-1995. This project was concerned with the mathematical and experimental studies of coupled thermo(T) -hydro(H) -mechanical(M) processes in fractured media related to radioactive waste disposal. The book presents, for the first time, the systematic formulation of mathematical models of the coupled T-H-M processes of fractured media, their validation against theoretical bench-mark tests, and experimental studies at both laboratory and field scales. It also presents, for the first time, a comprehensive analysis of continuum, and discrete approaches to the study of the problems of (as well as a complete description of), the computer codes applied to the studies. The first two chapters provide a conceptual introduction to the coupled T-H-M processes in fractured media and the DECOVALEX project. The next seven chapters give a state-of-the-art survey of the constitutive models of rock fractures and formulation of coupled T-H-M phenomena with continuum and discontinuum approaches, and associated numerical methods. A study on the three generic Bench-Mark Test problems and six Test Case problems of laboratory and field experiments are reported in chapters 10 to 18. Chapter 19 contains lessons learned during the project. The research contained in this book will be valuable for designers, practising engineers and national waste management officials who are concerned with planning, design and performance, and safety assessments of radioactive waste repositories. Researchers and postgraduate students working in this field will also find the book of particular relevance.

Coupled Thermo Hydro Mechanical Chemical Processes In Geo Systems

Author: Ove Stephansson
Publisher: Elsevier
ISBN: 9780080530062
Size: 31.61 MB
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Among the most important and exciting current steps forward in geo-engineering is the development of coupled numerical models. They represent the basic physics of geo-engineering processes which can include the effects of heat, water, mechanics and chemistry. Such models provide an integrating focus for the wide range of geo-engineering disciplines. The articles within this volume were originally presented at the inaugural GeoProc conference held in Stockholm and contain a collection of unusually high quality information not available elsewhere in an edited and coherent form. This collection not only benefits from the latest theoretical developments but also applies them to a number of practical and wide ranging applications. Examples include the environmental issues around radioactive waste disposal deep in rock, and the search for new reserves of oil and gas.

Groundwater Contamination Use Of Models In Decision Making

Author: G. Jousma
Publisher: Springer Science & Business Media
ISBN: 9400923015
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The protection of groundwater resources has emerged in recent years as a high priority topic on the agenda of many countries. In responding to the growing concern over deteriorating groundwater quality, many countries are developing a comprehensive regulatory framework for the management of subsurface water resources with management referring to both quantity and quality aspects. Within this framework, groundwater models are rapidly coming to playa central role in the development of protection and rehabilitation strategies. These models provide forecasts of the future state of the groundwater aquifer systems and/or the unsaturated zone in response to proposed management initiatives. For example, models will predict the effects of implementing a proposed management scheme on water levels and on the transport and fate of pollutants. The models are now used in the formulation of policies and regulations, the issuing of permits, design of monitoring and data collection systems, and the development of enforcement actions. The growth in the use of these sophisticated tools has led to many unforeseen problems in groundwater management. Lingering issues include reliability of codes, quality assurance in model development and applications, efficient utiliza tion of human and material resources, technology transfer and training. Some issues have legal ramifications, as in cases where the applications of models have been contested in courts.

Multiple Code Benchmaek Simulation Stidy Of Coupled Thmc Processes In The Excavation Disturbed Zone Associated With Geological Nuclear Waste Repositories

Author: H. Lee
Publisher:
ISBN:
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An international, multiple-code benchmark test (BMT) study is being conducted within the international DECOVALEX project to analyze coupled thermal, hydrological, mechanical and chemical (THMC) processes in the excavation disturbed zone (EDZ) around emplacement drifts of a nuclear waste repository. This BMT focuses on mechanical responses and long-term chemo-mechanical effects that may lead to changes in mechanical and hydrological properties in the EDZ. This includes time-dependent processes such as creep, and subcritical crack, or healing of fractures that might cause ''weakening'' or ''hardening'' of the rock over the long term. Five research teams are studying this BMT using a wide range of model approaches, including boundary element, finite element, and finite difference, particle mechanics, and elasto-plastic cellular automata methods. This paper describes the definition of the problem and preliminary simulation results for the initial model inception part, in which time dependent effects are not yet included.

Impact Of Thermo Hydro Mechanical Chemical Thmc Processes On The Safety Of Underground Radioactive Waste Repositories

Author: European Commission. Directorate-General for Research and Innovation
Publisher:
ISBN: 9789279260575
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"The international conference and workshop on the impact of thermo-hydro-mechanical-chemical (THMC) processes on the safety of underground radioactive waste repositories was successfully held in Luxembourg in September/October 2009 with an attendance of more than 100 participants from 15 countries. The event was organized jointly by the European Commission (EC), Euridice, Belgium and the Royal Institute of Technology, Sweden in the framework of the two EC projects of the 6th Euratom Framework Programme for research and training TIMODAZ(Thermal Impact on the Damaged Zone around a Radioactive Waste Disposal in Clay Host Rocks) and THERESA (Coupled Thermal-Hydrological-Mechanical-Chemical Processes for Application in Repository Safety Assessment). The present report includes a review of the key issues related to coupled THMC processes in the near-field of radioactive waste repositories in salt, clays and bentonite-crystalline rock systems to date, the three working group reports of the workshop, as well as the conference and workshop proceedings (with papers of 4 keynote lectures, 9 oral and 55 poster presentations)."--Editor.