Advances In Understanding Engineered Clay Barriers

The use of clay barriers for waste-isolating purposes has gained increasing attention in the geotechnical engineering community. Practical interest is linked to fundamental research, which includes examination of the behaviour of compacted materials and expansive clays. The interaction between the barrier, waste and the surrounding ground may involve several thermo-hydro-mechanical and chemical-coupled processes that have been analyzed by means of 'in situ' tests, laboratory experiments and numerical modelling. Large-scale field tests have been developed in recent years by European Agencies dealing with the management of radioactive waste. These experiments have provided an opportunity to calibrate and to validate research models and offer benefits in terms of experience of instrumentation and installation techniques. The book includes about sixty papers presented in a symposium held in Spain in 2003. The four main topics of the book are: field emplacement and instrumentation techniques; fundamental research, material behaviour (i.e. bentonite), and laboratory testing; barrier behaviour and THM modelling; and chemical effects, HC and THMC modelling.

Clays are used as barriers for the isolation of landfills and contaminated sites. They are envisioned as long-term storage media for hazardous materials and radioactive wastes, and as seals in the case of geological CO2 sequestration or energy storage. Clay properties greatly influence the integrity, efficiency, and safety of these applications. Natural and Engineered Clay Barriers provides a clear view of the fundamental properties of clay materials and how these properties affect their engineering applications. This volume focuses on how the mass transfer properties (hydraulic permeability, gas fluxes, molecular diffusion, semi-permeable membrane properties), geochemical reactivity (adsorption, dissolution) and mechanical properties of clay barriers at the macroscale are influenced by phenomena that occur at clay mineral - water interfaces. Examines clay properties from the molecular to the macroscopic scale Addresses experimental and modeling issues Authored by experts in the properties of clay barriers

This Special Publication contains 43 scientific studies presented at the 5th conference on ‘Clays in natural and engineered barriers for radioactive waste confinement’ held in Montpellier, France in 2012. The conference and this resulting volume cover all the aspects of clay characterization and behaviour considered at various temporal and spatial scales relevant to the confinement of radionuclides in clay, from basic phenomenological process descriptions to the global understanding of performance and safety at repository and geological scales. Special emphasis has been given to the modelling of processes occurring at the mineralogical level within the clay barriers. The papers in this Special Publication consider research into argillaceous media under the following topic areas: large-scale geological characterization; clay-based concept/large-scale experiments; hydrodynamical modelling; geochemistry; geomechanics; mass transfer/gas transfer; mass transfer mechanisms. The collection of different topics presented in this Special Publication demonstrates the diversity of geological repository research.

This volume details recent global advances in laboratory and field testing of unsaturated soils. Coverage includes mechanical, hydraulic, and geo-environmental testing and applications of unsaturated soil monitoring to engineering behavior of geo-structures.

High Level Radioactive Waste (HLW) Disposal, A Global Challenge presents the most recent information on proposed methods of disposal for the most dangerous radioactive waste and for assessing their function from short- and long-term perspectives. It discusses new aspects of the disposal of such waste, especially HLW. The book is unique in the literature in making it clear that, due to tectonics and long-term changes in rock structure, rock can serve only as a ""mechanical support to the chemical apparatus"" and that effective containment of hazardous elements can only be managed by properly designed and manufactured containers (""canisters""). This contradicts the common belief that the rock itself is an effective barrier to the transport of contaminants like radionuclides. The importance of the longevity of the containers becomes clear and requires a consideration of all degrading physical/chemical processes, which occupies a considerable part of the book. The book is thus an important contribution to the literature because it proposes design principles that can make repositories for HLW radioactive waste much safer.

Geological Repository Systems for Safe Disposal of Spent Nuclear Fuels and Radioactive Waste, Second Edition, critically reviews state-of-the-art technologies and scientific methods relating to the implementation of the most effective approaches to the long-term, safe disposition of nuclear waste, also discussing regulatory developments and social engagement approaches as major themes. Chapters in Part One introduce the topic of geological disposal, providing an overview of near-surface, intermediate depth, and deep borehole disposal, spanning low-, medium- and high-level wastes. Part Two addresses the different types of repository systems – crystalline, clay, and salt, also discussing methods of site surveying and construction. The critical safety issue of engineered barrier systems is the focus of Part Three, with coverage ranging from nuclear waste canisters, to buffer and backfill materials. Lastly, Parts Four and Five focus on safety, security, and acceptability, concentrating on repository performance assessment, then radiation protection, environmental monitoring, and social engagement. Comprehensively revised, updated, and expanded with 25% new material on topics of current importance, this is the standard reference for all nuclear waste management and geological repository professionals and researchers. Contains 25% more material on topics of current importance in this new, comprehensive edition Fully updated coverage of both near-surface/intermediate depth, and deep borehole disposal in one convenient volume Goes beyond the scientific and technical aspects of disposal to include the political, regulatory, and societal issues involved, all from an international perspective

Ground water reactive transport models are useful to assess and quantify contaminant precipitation, absorption and migration in subsurface media. Many ground water reactive transport models available today are characterized by varying complexities, strengths, and weaknesses. Selecting accurate, efficient models can be a challenging task. This ebook addresses the needs, issues and challenges relevant to selecting a ground water reactive transport model to evaluate natural attenuation and alternative remediation schemes. It should serve as a handy guide for water resource managers seeking to ach.

A summary of the current state-of-the-art in volcanic and tectonic hazard assessment of nuclear facilities for researchers, geologists and engineers.