Work package 3: Engineered barrier and seals

For more information, please contact Patrik Sellin, (WP3) leader.

Gas generation from either the waste form or the engineered barriers is an unavoidable but generally undesired effect in most European repository concepts for radioactive waste. Gas generation and migration can potentially alter the hydraulic and mechanical properties of the repository (possibly the thermal and chemical properties as well). The purpose of this work package is to investigate gas migration processes and the consequences of gas migration in the EBS of the repositories. The WP will deliver results that can be used for:

• Direct qualitative and quantitative confirmation of the consequences of gas migration to be used in long-term safety assessments
• Scientific knowledge about the gas migration processes to be used in the development of conceptual models
• Quantitative data to be used in the development and testing of numerical models for the simulation and prediction of gas migration and its consequences

The work in this work package will be divided into four areas:

• Bentonite URL Experiments: Field-scale experiments with bentonite buffers and seals that can be used directly as a confirmation in safety assessment and also give important information on the effects of up-scaling and realistic boundary conditions.
• Bentonite Laboratory Experiment: The test will complement the URL in the sense that it is possible to investigate the importance of different parameters and processes (materials, boundary conditions, etc) and provide detailed and high quality data to both conceptual and numerical models.
• Interface Laboratory Experiment: Test that will be specifically designed to study the importance of interfaces between different materials or construction parts for the gas migration processes. These tests will supply data to modelling, but also aid in the interpretation of other laboratory and field scale tests.
• Concrete Laboratory Experiments: Tests that will be used to study the gas migration process in concrete structures and barriers in the repository. The aim is to study the effects of degree of saturation, gas pressures and alteration of the cement as well as effects of gases on the cementitious materials themselves and provide detailed and high quality data to both conceptual and numerical models.