This report presents the outcomes of a joint NEA-EC workshop, organised in Oxford on 25-27 September 2002 and hosted by United Kingdom Nirex Limited. The main objectives of the workshop were to provide a status report on engineered barrier systems in various national radioactive waste management programmes considering deep geological disposal; to establish the value to member countries of a project on EBS; and to define such a project’s scope, timetable and modus operandi.

Executive Summary
1. Introduction
2. Workshop Objectives and Agenda
3. EBS Function, Design, Characterisation, and Assessment
4. Working Group Sessions
-A. Design Criteria and Construction
-B. Thermo-Hydro-Mechanical Processes
-C. Geochemical Processes
-D. Radionuclide Release and Migration
5. Workshop Conclusions
6. References
Appendix A. Workshop Agenda
Appendix B. Papers Presented
-Managing Design Requirements for a Repository in Crystalline Rock by Timo Aikas
-Managing Design Requirements of the French HLLW Programme in Clay Media byJean-Michel Hoorelbeke, Stefan Mayer, and Frederic Plas
-Closure Concept for the Morsleben LLW Repository for Radioactive Waste Design of Drift Seals in a Former Salt Mine by Ralf Mauke, Jurgen Wollrath and Nina Muller-Hoeppe
-CROP - A Project for Comparative Description of National Concepts for Disposal of Radioactive Waste by Roland Pusch and Christer Svemar
-The Role of the EBS in Demonstrating Post-Closure Safety of the Proposed Yucca Mountain Repository by Robert J. MacKinnon
-Engineered Barriers System Modelling and Performance Assessment in SAFIR 2 by Xavier Sillen,Jan Marivoet, Jean-Paul Boyazis, Philippe Lalieux, Peter De Peter and Johan Bel
-EBS Modelling and Performance Assessment from H12: Results from Conclusions and Future Priorities by Hiroyuki Umeki, Horoyoshi Ueda, Morimasa Naito, and Masao Shiotsuki
-On-Going Activities of the EC Project BENIPA - Current Status, Key Issues, and Achievements by Jesus Alonso
Appendix C. Remit and Composition of Working Groups
Appendix D. List of Participants