Executive summary -- 1. Introduction -- 2. Workshop objectives and structure -- 3. Process issues EBS examples -- 4. Working group findings: Working group A. Pre-closure processes -- Working group B. Thermal management and analysis -- Working group C. Alteration of non-metallic barriers and evolution of solution chemistry -- Working group D. Radionuclide release and transport -- 5. Workshop Conclusions -- 6. References -- Appendix A. Workshop agenda -- Appendix B. Papers presented to the workshop: Overview of projects and activities related to the EBS processes, carried out as part of the 5th and 6th Euratom framework programmes (1998-2006) / C. Davies -- An approach to analysing potential effects of pre-closure processes on the long-term safety of a geological repository / H. Umeki, H. Ueda, M. Naito, H.Takese, and K. Yamada -- The Swedish safety report SR-CAN: near-field processes and concepts during repository operation / I. Puigdomenech and P. Sellin -- Thermal management and analysis for a potential Yucca Mountain repository / A. Van Luik -- Development of thermal criteria for a SF/HLW repository in Opalinus Clay / L. Johnson, P. Blumling, A. Gautschi, and P. Wersin -- Alteration of non-metallic barriers and evolution of solution chemistry in salt formations in Germany / H-J. Herbert, D. Becker, S. Hagemann, Th. Meyer, U. Noseck, A. Rubel, R. Mauke and J. Wollrath -- Characterising the evolution of the in-drift environment in a proposed Yucca Mountain repository / A. Van Luik -- Transport of radionuclides in spanish performance assessments / J. Alonso -- Appendix C. Membership of working groups -- Appendix D. List of participants -- List of figures -- List of tables.

The Integration Group for the Safety Case (IGSC) of the Nuclear Energy Agency (NEA) is co-sponsoring a project with the European Commission to develop a greater understanding of how to achieve the necessary integration for successful design, construction, testing, modelling and performance assessment of engineered barrier systems (EBS). These proceedings include the main findings and presented papers from the second workshop of the EC-NEA EBS project, which covered inter alia research and development work on pre- and post-closure processes; thermal management; thermal, hydraulic, mechanical and chemical process models; and repository design. The workshop was hosted by the US Department of Energy in Las Vegas, USA, on 14-17 September 2004.