Overview of the clay-mineralogy studies presented at the ‘Clays in natural and engineered barriers for radioactive waste confinement’ meeting, Brussels, March 2015

M Van Geet,R Dohrmann

doi:10.1180/claymin.2016.051.2.01

Abstract

This special issue of Clay Minerals contains 13 full papers presented at the 6th conference on ‘Clays in natural and engineered barriers for radioactive waste confinement’ held in Brussels during 2015. The conference was organized by the Belgian Agency for Radioactive Waste and Enriched Fissile Materials (ONDRAF/NIRAS) together with partner organizations ANDRA (France), COVRA (The Netherlands), NAGRA (Switzerland), NWMO (Canada), POSIVA (Finland) and SKB (Sweden) and a broad international scientific committee. Since 2002, this conference has developed into the most important event for scientists from the world over, dealing with the disposal of highly and long-lived radioactive waste. After each of these conferences, a special issue of a journal was published which focused on clay radioactive waste (radwaste), research which has contributed in a significant way to the outstanding scientific level of the research in this field ( e.g . Landais & Aranyossy, 2011; Landais et al ., 2013; Norris et al ., 2014). Therefore, Clay Minerals - Journal of Fine Particle Science , is happy to be able to provide the present compilation of recent HLW-disposal research in clay mineralogy in an open access issue. Most of the 13 papers published in this special 2016 issue were taken from the session on alteration processes. Papers from this conference which focus on large-scale geological characterization, general strategies for clay-based disposal systems, geomechanics, or mass and gas transfer will be published in a ‘Special Publication’ of the Geological Society of London. Many countries have chosen to dispose of all or some of their radioactive waste in facilities constructed in stable geological formations. Geological disposal as a safe solution for the long-term management of radioactive waste is in line with international recommendations and practices. The development of a geological disposal facility at a specific site requires a systematic and integrated approach taking …

Highlights

Safety assessment is concerned with the postclosure performance and safety of a disposal system and is the means by which various lines of evidence, arguments and analyses for passive long-term safety, radiological and non-radiological, are identified and assessed critically
A safety assessment typically considers several different evolution scenarios, and different assessment cases for each scenario, where an assessment case is a specific realization of how the disposal system might evolve and perform over time within the corresponding evolution scenario
In the different national programs on geological disposal, research continues on the phenomenological description of the disposal system and its evolution in order to provide a description of the initial state of the disposal system at the time of emplacement of the first waste package and a description of the expected evolution of the system

Summary

Introduction

The CEC decreased towards the heater and ion exchange occurred while solutes were transported along the columns confirming the results of large-scale field tests of bentonites in crystalline rocks. From the perspective of long-term safety, the question of illitization of bentonite in a geological disposal environment must be raised because Cs sorption in such a barrier system might be important.

Results

Conclusion