Porewater Extraction from Argillaceous Rocks for Geochemical Characterisation [electronic resource]: Methods and Interpretations /
Organisation for Economic Co-operation and Development.
Nuclear Energy Agency.
Paris : OECD Publishing,
2000.
The definition of the chemical and isotopic composition of the groundwater present in argillaceous formations, which are considered as potential host rocks for radioactive waste disposal, is crucial for establishing their barrier properties. Therefore, a critical review of the relevant literature on the current methods applied to extract water and solutes and on the various approaches to the interpretation of their results was commissioned to the Laboratoire d’hydrologie et de géochimie isotopique (Université de Paris-Sud, France). The present document provides a synthesis of available extraction methods, assesses their respective advantages and limitations, identifies key processes that may influence the composition of the extracted water, describes modelling approaches that are used to determine in situ porewater composition, and highlights, wherever possible, some of the unresolved issues and recommendations on ways to address them.
Description based upon print version of record.
FOREWORD; ACKNOWLEDGEMENTS; CONTENTS; TABLE OF CONTENTS; EXECUTIVE SUMMARY; PREFACE - SCOPE, OBJECTIVES AND LIMITS OF THE STUDY; PART I - INTRODUCTION TO THE CLAY-WATER SYSTEM; 1. Clay minerals; 1.1 Definition and structure; 1.2 Chemical properties; 2. Interactions between water, solutes and clay; 2.1 Water molecule structure and cation hydration; 2.2 Clay-water interaction; 2.3 Clay-solute interaction; 3. Porosity, salinity and hydration; 3.1 High water content systems; 3.2 Low water content systems; 3.3 Chemical porosity; 4. Organic matter
4.1 Definition, origins and composition of the organic matter4.2 Properties of the organic matter; 5. Clay environments of interest for the present study; PART II - EXPERIMENTAL METHODS; 1. Field techniques for fluid extraction and characterization; 1.1 Piezometer and borehole drilling; 1.2 Piezometers and boreholes equipment; 1.3 Field techniques for fluid extraction; 1.4 In-situ physico-chemical measurements; 1.5 Field techniques for indirect fluid characterization; 2. Rock sampling, storage and preservation; 2.1 Evidence for artefacts; 2.2 In-situ freezing and coring
2.3 Noble gases sampling procedure3. On sample laboratory techniques; 3.1 Centrifugation; 3.2 Pressure filtering or squeezing; 3.3 Leaching; 3.4 Distillation technique for stable isotope analysis; 3.5 Direct analysis of water isotope contents; 3.6 Other techniques; 3.7 Organic matter extraction; PART III - PROCESSES AND CURRENT INTERPRETATIONS; 1. Extraction techniques; 1.1 Performances of the extraction techniques; 1.2 Processes related to water and solute extraction; 1.3 Current understanding; 2. Geochemical modelling; 2.1 Dissolution-precipitation; 2.2 Sorption
2.3 Requirements for geochemical modelling2.4 Computer codes; 3. Indirect approach to porewater composition using geochemical modelling; 4. Conclusions, recommendations and topics for further investigation; 4.1 Chemical studies; 4.2 Isotopic studies; 4.3 Guidelines for benchmark experiments; GLOSSARY AND FREQUENTLY USED ABREVIATIONS; REFERENCES
Includes bibliographical references (pages 163-185).
The definition of the chemical and isotopic composition of the groundwater present in argillaceous formations, which are considered as potential host rocks for radioactive waste disposal, is crucial for establishing their barrier properties. Therefore, a critical review of the relevant literature on the current methods applied to extract water and solutes and on the various approaches to the interpretation of their results was commissioned to the Laboratoire d’hydrologie et de géochimie isotopique (Université de Paris-Sud, France). The present document provides a synthesis of available extraction methods, assesses their respective advantages and limitations, identifies key processes that may influence the composition of the extracted water, describes modelling approaches that are used to determine in situ porewater composition, and highlights, wherever possible, some of the unresolved issues and recommendations on ways to address them.
Analytical geochemistry.
Rocks
Radioactive waste disposal in the ground.
Radioactive waste management