The overall objective of the project is to develop and test the tools necessary for the assessment of the hydro-mechanical evolution of an installed bentonite barrier and its resulting performance. This will be achieved by cooperation between design and engineering, science and performance assessment. The evolution from an installed engineered system to a fully functioning barrier will be assessed. One of the challenges is to take into account initial heterogeneities introduced in the system by conception with a combination of block and pellets or due to the size of the bentonite component (several 100 m3). It will require a more detailed understanding of material properties, of the fundamental processes that lead to homogenisation, of the role of scale effects and improved capabilities for numerical modelling. The goal is to verify the performance of current designs for buffers, backfills, seals and plugs. The overall driver for the project is the assessment cases that will be defined at the onset of the project (WP1). The quantitative models currently available are not fully able to represent all the complexities of the evolution of an installed bentonite. A substantial effort is needed to improve both the conceptual approaches and the numerical solutions in the current models (WP3). The updated/newly developed models need to be tested and verified using available data (WP5). There are some areas where fundamental data and the understanding of materials are incomplete. An efficient experimental programme will support model development and testing (WP4). There is already a large database from experiments performed within EC projects and national programmes, both laboratory and Underground Research Laboratory (URL) experiments. Many of the tests have been performed with other purposes in mind, but the results can be used in the Beacon project. The objective of WP2 is to collect the relevant information and process it to a level where it can be used in this project