Download or read book Generic study of coupled t h m processes of nuclear waste repositories as near field initial boundary value problems bmt2 written by T. Chan and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coupled Thermo Hydro Mechanical Processes of Fractured Media written by O. Stephanson and published by Elsevier. This book was released on 1997-02-10 with total page 597 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Coupled Processes Associated with Nuclear Waste Repositories written by Chin-Fu Tsang and published by Elsevier. This book was released on 2012-12-02 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Numerical Study of the Thm Effects on the Near field Safety of a Hypothetical Nuclear Waste Repository Bmt1 of the Decovalex Iii Project Part 1 written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Geological disposal of the spent nuclear fuel uses often the concept of multiple barrier systems. In order to predict the performance of these barriers, mathematical models have been developed, verified and validated against analytical solutions, laboratory tests and field experiments within the international DECOVALEX III project. These models in general consider the full coupling of thermal (T), hydraulic (H) and mechanical (M) processes that would prevail in the geological media around the repository. For Bench Mark Test no. 1 (BMT1) of the DECOVALEX III project, seven multinational research teams studied the implications of coupled THM processes on the safety of a hypothetical nuclear waste repository at the near-field and are presented in three accompany papers in this issue. This paper is the first of the three companion papers, which provides the conceptualization and characterization of the BMT1 as well as some general conclusions based on the findings of the numerical studies. It also shows the process of building confidence in the mathematical models by calibration with a reference T-H-M experiment with realistic rock mass conditions and bentonite properties and measured outputs of thermal, hydraulic and mechanical variables.
Download or read book Erinnerungen an Goethe und seine Umwelt written by and published by . This book was released on 1949 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparative Simulation Study of Coupled THM Processes Nearback filled and Open drift Nuclear Waste Repositories in Task D of TheInternational DECOVALEX Project written by Y. Oda and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As part of the ongoing international DECOVALEX project, fourresearch teams used five different models to simulate coupled thermal, hydrological, and mechanical (THM) processes near underground wasteemplacement drifts. The simulations were conducted for two genericrepository types, one with open and the other with back-filled repositorydrifts, under higher and lower post-closure temperature, respectively. Inthe completed first model inception phase of the project, a goodagreement was achieved between the research teams in calculating THMresponses for both repository types, although some disagreement inhydrological responses are currently being resolved. Good agreement inthe basic thermal-mechanical responses was also achieved for bothrepository types, even though some teams used relatively simplifiedthermal-elastic heat-conduction models that neglect complex near-fieldthermal-hydrological processes. The good agreement between the complexand simplified process models indicates that the basic thermal-mechanicalresponses can be predicted with a relatively high confidencelevel.
Download or read book Numerical Study of the THM Effects on the Near field Safety of Ahypothetical Nuclear Waste Repository BMT1 of the DECOVALEX IIIproject Part 3 written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: BENCHPAR project, the impact of thermal-hydrological-mechanical (THM) couplings on the performance of a bentonite-back-filled nuclear waste repository in near-field crystalline rocks is evaluated in a Bench-Mark Test problem (BMT1) and the results are presented in a series of three companion papers in this issue. This is the third paper with focus on the effects of THM processes at a repository located in a sparsely fractured rock. Several independent coupled THM analyses presented in this paper show that THM couplings have the most significant impact on the mechanical stress evolution, which is important for repository design, construction and post-closure monitoring considerations. The results show that the stress evolution in the bentonite-back-filled excavations and the surrounding rock depends on the post-closure evolution of both fields of temperature and fluid pressure. It is further shown that the time required to full resaturation may play an important role for the mechanical integrity of the repository drifts. In this sense, the presence of hydraulically conducting fractures in the near-field rock might actually improve the mechanical performance of the repository. Hydraulically conducting fractures in the near-field rocks enhances the water supply to the buffers/back-fills, which promotes a more timely process of resaturation and development of swelling pressures in the back-fill, thus provides timely confining stress and support to the rock walls. In one particular case simulated in this study, it was shown that failure in the drift walls could be prevented if the compressive stresses in back-fill were fully developed within 50 years, which is when thermally induced rock strain begins to create high differential (failure-prone) stresses in the near-field rocks.
Download or read book DECOVALEX written by L. Jing and published by . This book was released on 1994 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book DECOVALEX written by and published by . This book was released on 1995 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book DECOVALEX written by and published by . This book was released on 1996 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Disposal of All Forms of Radioactive Waste and Residues written by Michael Lersow and published by Springer Nature. This book was released on 2019-11-16 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes repository solutions for all types of radioactive waste and residues in different geotechnical repository structures. The focus is initially on existing or planned final disposal sites in Germany and the process of finding sites. However, international comparisons are drawn, especially to locations in the US. This affects both the repository structures and the legal requirements. The radioactive substances considered include residues from uranium ore processing, as well as low and intermediate level radioactive waste up to heat generating, high level radioactive wastes, such as spent fuel and vitrified waste from reprocessing. In order to evaluate the repository structures and their inventories, a dimensionless radiotoxicity index Ai / Fi [activity of radionuclide quantity (Ai) related to the exemption limit of radionuclide (Fi)] has been introduced. This gives the reader a well-founded overview of the degree of inconsistency in the handling of safety requirements for the respective geotechnical environmental structures. This creates the necessary transparency on this issue, which has not been previously available and is required by stakeholders today. The long-term security, the duration of the observation period and the certainty of the safety prognosis are also discussed in the book as well as the participation of subsequent generations in current and possible future repositories. This is vital as nuclear energy will continue to be used worldwide in the long term. The international repository projects presented have all been subjected to the same evaluation criteria. This applies both to existing operational project as well as those about to be commissioned and the processes for seeking locations. Special attention has been paid to monitoring, both operational and long-term monitoring. This broad range of topics makes this book a very valuable read for both the interested public and the professional world.
Download or read book A Case Study on the Influence of THM Coupling on the Near Field Safety of a Spent Fuel Repository in Sparsely Fractured Granite written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to demonstrate the feasibility of geological disposal of spent CANDU fuel in Canada, a safety assessment was performed for a hypothetical repository in the Canadian Shield. The assessment shows that such repository would meet international criteria for dose rate; however, uncertainties in the assumed evolution of the repository were identified. Such uncertainties could be resolved by the consideration of coupled Thermal-Hydro-Mechanical-Chemical (THMC) processes. In Task A of the DECOVALEX-THMC project, THM models were developed within the framework of the theory of poroelasticity. Such model development was performed in an iterative manner, using experimental data from laboratory and field tests. The models were used to perform near-field simulations of the evolution of the repository in order to address the above uncertainties. This paper presents the definition and rationale of task A and the results of the simulations. From a repository safety point of view, the simulations predict that the maximum temperature would be well below the design target of 100 C, however the load on the container can marginally exceed the design value of 15 MPa. However, the most important finding from the simulations is that a rock damage zone could form around the emplacement borehole. Such damage zone can extend a few metres from the walls of the emplacement holes, with permeability values that are orders of magnitude higher than the initial values. The damage zone has the potential to increase the radionuclide transport flux from the geosphere; the effect of such an increase should be taken into account in the safety assessment and mitigated if necessary by the provision of sealing systems.
Download or read book A Progress Report for the Large Block Test of the Coupled Thermal mechanical hydrological chemical Processes written by and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Science Based Approach to Understanding Waste Form Durability in Open and Closed Nuclear Fuel Cycles written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: There are two compelling reasons for understanding source term and near-field processes in a radioactive waste geologic repository. First, almost all of the radioactivity is initially in the waste form, mainly in the spent nuclear fuel (SNF) or nuclear waste glass. Second, over long periods, after the engineered barriers are degraded, the waste form is a primary control on the release of radioactivity. Thus, it is essential to know the physical and chemical state of the waste form after hundreds of thousands of years. The United States Department of Energy's Yucca Mountain Repository Program has initiated a long-term program to develop a basic understanding of the fundamental mechanisms of radionuclide release and a quantification of the release as repository conditions evolve over time. Specifically, the research program addresses four critical areas: (a) SNF dissolution mechanisms and rates; (b) formation and properties of U{sup 6+}-secondary phases; (c) waste form-waste package interactions in the near-field; and (d) integration of in-package chemical and physical processes. The ultimate goal is to integrate the scientific results into a larger scale model of source term and near-field processes. This integrated model will be used to provide a basis for understanding the behavior of the source term over long time periods (greater than 105 years). Such a fundamental and integrated experimental and modeling approach to source term processes can also be readily applied to development of advanced waste forms as part of a closed nuclear fuel cycle. Specifically, a fundamental understanding of candidate waste form materials stability in high temperature/high radiation environments and near-field geochemical/hydrologic processes could enable development of advanced waste forms ''tailored'' to specific geologic settings.
Download or read book Multiple Code BenchMaek Simulation Stidy of Coupled THMC Processes IN the EXCAVATION DISTURBED ZONE Associated with Geological Nuclear Waste Repositories written by H. Lee and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Technical Basis and Programmatic Requirements for Large Block Testing of Coupled Thermal mechanical hydrological chemical Processes written by Wunan Lin and published by . This book was released on 1993 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Coupled Thermo hydro mechanical Processes of Fractured Media written by Ove Stephansson and published by Elsevier Science Publishing Company. This book was released on 1996 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt: Full text e-book available as part of the Elsevier ScienceDirect Earth and Planetary Sciences subject collection.
