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 Special Publication highlights the importance of clays and clayey material, and their multiple roles, in many national geological disposal facilities for higher activity radioactive wastes. Clays can be both the disposal facility host rock and part of its intrinsic engineered barriers, and may be present in the surrounding geological environment. Clays possess various characteristics that make them high-quality barriers to the migration of radionuclides and chemical contaminants, e.g. very little water movement, diffusive transport, retention capacity, self-sealing capacity, stability over millions of years, homogeneity and lateral continuity.

Focused attention by world leaders is needed to address the substantial challenges posed by disposal of spent nuclear fuel from reactors and high-level radioactive waste from processing such fuel. The biggest challenges in achieving safe and secure storage and permanent waste disposal are societal, although technical challenges remain. Disposition of radioactive wastes in a deep geological repository is a sound approach as long as it progresses through a stepwise decision-making process that takes advantage of technical advances, public participation, and international cooperation. Written for concerned citizens as well as policymakers, this book was sponsored by the U.S. Department of Energy, U.S. Nuclear Regulatory Commission, and waste management organizations in eight other countries.

It is internationally accepted that the safest and most sustainable option for managing radioactive waste is geological disposal, utilizing both engineering and geology to isolate the waste and contain the radioactivity. This Special Publication contains 25 scientific studies presented at the 6th conference on ‘Clays in natural and engineered barriers for radioactive waste confinement’ held in Brussels, Belgium in 2015. The conference and this resulting volume cover many of 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. The papers in this volume consider research into argillaceous media under the following topic areas: large-scale geological characterization; general strategy for clay-based disposal systems; geomechanics; mass transfer; bentonite evolution and gas transfer. The collection of different topics presented in this Special Publication demonstrates the diversity of geological repository research.

Over the past decade significant progress has been achieved in the development of waste characterization and control procedures and equipment as a direct response to ever-increasing requirements for quality and reliability of information on waste characteristics. Failure in control procedures at any step can have important, adverse consequences and may result in producing waste packages which are not compliant with the waste acceptance criteria for disposal, thereby adversely impacting the repository. The information and guidance included in this publication corresponds to recent achievements and reflects the optimum approaches, thereby reducing the potential for error and enhancing the quality of the end product. -- Publisher's description.

Provides detailed information on the handling, processing and storage techniques most widely used and recommended for waste from non-fuel-cycle activities. The report was designed to meet the needs of developing countries by focusing on the most simple, affordable and reliable techniques and discussing their advantages and limitations.

Drawing on the authors' extensive experience in the processing and disposal of waste, An Introduction to Nuclear Waste Immobilisation, Second Edition examines the gamut of nuclear waste issues from the natural level of radionuclides in the environment to geological disposal of waste-forms and their long-term behavior. It covers all-important aspects of processing and immobilization, including nuclear decay, regulations, new technologies and methods. Significant focus is given to the analysis of the various matrices used, especially cement and glass, with further discussion of other matrices such as bitumen. The final chapter concentrates on the performance assessment of immobilizing materials and safety of disposal, providing a full range of the resources needed to understand and correctly immobilize nuclear waste.