Experiments
Thoroughly examining all aspects of the safety and technical feasibility of geological disposal in a deep clay layer requires a great many experiments, many of which are carried out in the HADES underground research laboratory.
The diagram below gives an overview of past and present experiments conducted by EIG EURIDICE, both above and below ground, and of all the other experiments that have been set up in HADES.
Some experiments started more than 25 years ago. This means that the models developed to describe how a disposal system evolves over time can be compared against actual changes and fine-tuned if necessary. Since HADES is a licensed nuclear facility, a wide range of radioactive tracers and sources may be used there, making it a unique underground research tool.
From small and simple to large and complex
A number of relatively simple experiments are designed to examine one specific aspect or process of the disposal system. This gives researchers an opportunity to study and understand the different properties and processes that are important for assessing the safety and technical feasibility of a waste repository. For the ATLAS experiment, for instance, a heat source and measuring instruments have been introduced into the clay in order to determine the thermal conductivity of the Boom Clay host rock. It is important to have this information because some of the waste will still produce a certain amount of heat after being placed in the disposal galleries. Researchers can then calculate how high the temperature in the clay will rise.
In the case of integrated experiments, several of these aspects are combined in a single experiment with the aim of approximating the complex actual conditions of a waste repository as closely as possible. This enables scientists to study the interaction between specific phenomena, like those expected to occur in a repository. CORALUS is an example of an experiment investigating the combined effect of heat and radiation on the stability of the glass matrix for vitrified waste.
Lastly, large-scale demonstration tests make it possible to ascertain the safety and feasibility of a waste repository on a scale that approximates the actual conditions encountered in a real repository. They can also be used to confirm the results of small-scale experiments and to fine-tune the predictive models developed on the basis of these findings. This means that a reliable assessment of the long-term safety of a repository can be made. In the PRACLAY experiment, for example, the expected heat output in a disposal gallery is being simulated by heating a 30-metre section of the PRACLAY gallery for 10 years and studying the thermal impact on the surrounding clay and the gallery lining.
European context
The European Commission has played a crucial part in the development and implementation of a great many experiments and tests. The experiments and projects that have benefited from EU support, within the R&D Framework Programmes, are marked with a European flag in the list shown below. In some cases, the project phase has ended but the measurement data are still being monitored or the experimental set-ups are being re-used as part of the Belgian research programme on geological disposal.
Experiments
| ARCHIMEDE |  |
1991-1995 |
Study of pore water chemistry of Boom Clay |
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| ATLAS I, II, III, IV | 1992-present |
Study of hydro-mechanical properties of clay when subjected to heat |
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| BACCHUS I, II | |
1988-1995 |
Study of clay as a backfill material |
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| CACTUS I, II | |
1990-1994 |
Study of hydro-mechanical properties of clay when subjected to heat |
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| CERBERUS | 1985-1999 |
Effect of radiation, heat and mechanical disturbance on hydro-chemical properties of clay |
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| CLIPEX | 1997-2003 |
Monitoring of hydro-mechanical response to excavation of the Connecting gallery |
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| CORALUS I, II, III, IV | 1997-present |
Research on the stability of the glass matrix under realistic disposal conditions, in the presence of a heat source and radiation |
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| CONNECTING GALLERY | 2001-2002 |
Construction of a gallery on an industrial scale, using a tunnelling machine |
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| CORROSION | 1985-1997 |
Experiments to test the deterioration (corrosion) of different waste packaging materials in contact with clay |
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| ESDRED | |
2004-2009 |
Repository design studies |
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| FORGE | |
2011-present |
Research on gas migration in the excavation-damaged zone |
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| MEGAS | |
1992-1996 |
Study of gas formation and migration of gas in clay |
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| MIGRATION | 1988-present |
Experiments to study the dispersion (migration) of radioactive substances in clay |
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| MINE-BY-TEST | 1984-2002 |
Construction of a shaft and gallery in unfrozen clay |
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| MODERN | |
2009-2013 |
Development of a monitoring strategy and testing of monitoring sensors |
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| MORPHEUS | 2001-present |
Research on any variability in pore water chemistry of Boom Clay |
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| NF-PRO | |
2004-2007 |
- Study of the effect of oxidation on Boom Clay |
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| OPHELIE | 1992-2002 |
Surface testing of emplacement of radioactive waste in a disposal gallery |
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| ORPHEUS | 2000 |
Study of the geochemistry (Eh and pH) of Boom Clay pore water |
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| PEGASUS | 2004 |
Study of the evolution of the partial pressure of dissolved gas |
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| PHEBUS | |
1991-1995 |
Study of the desiccation of clay induced by the ventilation in HADES |
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| PRACLAY | 2007-present |
- Gallery & Crossing tests: construction of a gallery perpendicular to the main gallery |
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| PRETEL | 1994-2004 | Design and testing of a system for installing the gallery lining in micro-tunnels in poorly indurated clay | |||
| RADWASTOM3 | |
1986-1989 |
In-situ characterisation of Boom Clay behaviour |
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| RESEAL I, II | |
1997-2007 |
Sealing of a borehole and shaft in poorly indurated clay |
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| SELFRAC | |
2001-2004 |
Research on the self-sealing capacity of Boom Clay |
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| TIMODAZ | |
2006-2010 |
Effect of increased temperature on the excavation-damaged zone around the galleries |
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| TRANCOM | |
1996-2004 |
Study of the migration behaviour of organic material in clay |
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