This project will involve the preparation of a synthesis report on Engineered Barrier Systems (EBS) and the safety of deep geological repositories for high-level radioactive waste. The objective of the report will be to bring together the main conclusions from a series of key thematic international workshops organised by the OECD/NEA on the Engineered Barrier Systems (EBS). Using the proceedings of the workshops as a starting point, a report will be drawn up developing common views on the role that EBS play in the disposal system through reinforcing the performance of the natural barrier and on how integration is necessary to achieve successful design, construction, testing, modelling and performance assessment. The work will be conducted in collaboration with the EC and the OECD/NEA and members of the EBS Programme Committee convened by the OECD/NEA. The report will describe progress regarding EBS studies that occurred during the course of the OECD/NEA EBS project, will identify key messages from the four OECD/NEA EBS workshops, will discuss specific examples from national disposal programmes, and will identify open issues where further challenges may exist.