Three decades of underground research laboratories: what have we learned?

Delay, J.; Bossart, Paul; Li, Ling; Blechschmidt, Ingo; Ohlsson, Mats; Vinsot, Agnès; Nussbaum, Christophe; Maes, N.

doi:10.1144/sp400.1

Cited by 33 publications

(15 citation statements)

References 34 publications

(33 reference statements)

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“…A final objective is the evaluation of transferability of individual parameters, investigation techniques, data evaluation methods, process understanding, and conceptual models to reach high-level conclusions (e.g. engineering feasibility, safety aspects) relevant to a safety case 1 for a future repository program (Mazurek et al 2008;Blechschmidt and Vomvoris 2010;Delay et al 2014;Alexander et al 2015).…”

Section: Objectives Of Underground Rock Laboratoriesmentioning

confidence: 99%

Mont Terri rock laboratory, 20 years of research: introduction, site characteristics and overview of experiments

Bossart¹,

et al. 2017

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Geologic repositories for radioactive waste are designed as multi-barrier disposal systems that perform a number of functions including the long-term isolation and containment of waste from the human environment, and the attenuation of radionuclides released to the subsurface. The rock laboratory at Mont Terri (canton Jura, Switzerland) in the Opalinus Clay plays an important role in the development of such repositories. The experimental results gained in the last 20 years are used to study the possible evolution of a repository and investigate processes closely related to the safety functions of a repository hosted in a clay rock. At the same time, these experiments have increased our general knowledge of the complex behaviour of argillaceous formations in response to coupled hydrological, mechanical, thermal, chemical, and biological processes. After presenting the geological setting in and around the Mont Terri rock laboratory and an overview of the mineralogy and key properties of the Opalinus Clay, we give a brief overview of the key experiments that are described in more detail in the following research papers to this Special Issue of the Swiss Journal of Geosciences. These experiments aim to characterise the Opalinus Clay and estimate safetyrelevant parameters, test procedures, and technologies for repository construction and waste emplacement. Other aspects covered are: bentonite buffer emplacement, highpH concrete-clay interaction experiments, anaerobic steel corrosion with hydrogen formation, depletion of hydrogen by microbial activity, and finally, release of radionuclides Geosci (2017) 110:3-22 DOI 10.1007 into the bentonite buffer and the Opalinus Clay barrier. In the case of a spent fuel/high-level waste repository, the time considered in performance assessment for repository evolution is generally 1 million years, starting with a transient phase over the first 10,000 years and followed by an equilibrium phase. Experiments dealing with initial conditions, construction, and waste emplacement do not require the extrapolation of their results over such long timescales. However, experiments like radionuclide transport in the clay barrier have to rely on understanding longterm mechanistic processes together with estimating safety-relevant parameters. The research at Mont Terri carried out in the last 20 years provides valuable information on repository evolution and strong arguments for a sound safety case for a repository in argillaceous formations.

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Section: Objectives Of Underground Rock Laboratoriesmentioning

confidence: 99%

Mont Terri rock laboratory, 20 years of research: introduction, site characteristics and overview of experiments

Bossart¹,

et al. 2017

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“…This know-how has been successfully transferred to other underground laboratories (e.g. Delay et al 2014;Naves et al 2010).…”

Section: Discussionmentioning

confidence: 99%

Exploring diffusion and sorption processes at the Mont Terri rock laboratory (Switzerland): lessons learned from 20 years of field research

Leupin

Loon

Gimmi

et al. 2017

Mont Terri Rock Laboratory, 20 Years

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Transport and retardation parameters of radionuclides, which are needed to perform a safety analysis for a deep geological repository for radioactive waste in a compacted claystone such as Opalinus Clay, must be based on a detailed understanding of the mobility of nuclides at different spatial scales (laboratory, field, geological unit). Thanks to steadily improving experimental designs, similar tracer compositions in different experiments and complementary small laboratory-scale diffusion tests, a unique and large database could be compiled. This paper presents the main findings of 20 years of diffusion and retention experiments at the Mont Terri rock laboratory and their impact on safety analysis.

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“…1), in north-western Switzerland at a depth of about 300 m below ground level . It is a ''methodological laboratory'' (Delay et al 2014) in the Opalinus Clay, which is a well consolidated Jurassic age claystone with a hydraulic conductivity below 3 9 10 -12 m/s (Thury and Bossart 1999).…”

Section: Geological Context and Rock Characteristicsmentioning

confidence: 99%

Natural gas extraction and artificial gas injection experiments in Opalinus Clay, Mont Terri rock laboratory (Switzerland)

Vinsot

Appelo²,

Lundy

et al. 2017

Swiss J Geosci

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Two experiments have been installed at Mont Terri in 2004 and 2009 that allowed gas circulation within a borehole at a pressure between 1 and 2 bar. These experiments made it possible to observe the natural gases that were initially dissolved in pore-water degassing into the borehole and to monitor their content evolution in the borehole over several years. They also allowed for inert (He, Ne) and reactive (H 2 ) gases to be injected into the borehole with the aim either to determine their diffusion properties into the rock pore-water or to evaluate their removal reaction kinetics. The natural gases identified were CO 2 , light alkanes, He, and more importantly N 2 . The natural concentration of four gases in Opalinus Clay porewater was evaluated at the experiment location: N 2 2.2 mmol/L ± 25%, CH 4 0.30 mmol/L ± 25%, C 2 H 6 0.023 mmol/L ± 25%, C 3 H 8 0.012 mmol/L ± 25%.Retention properties of methane, ethane, and propane were estimated. Ne injection tests helped to characterize rock diffusion properties regarding the dissolved inert gases. These experimental results are highly relevant towards evaluating how the fluid composition could possibly evolve in the drifts of a radioactive waste disposal facility.

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Three decades of underground research laboratories: what have we learned?

Cited by 33 publications

References 34 publications

Mont Terri rock laboratory, 20 years of research: introduction, site characteristics and overview of experiments

Mont Terri rock laboratory, 20 years of research: introduction, site characteristics and overview of experiments

Exploring diffusion and sorption processes at the Mont Terri rock laboratory (Switzerland): lessons learned from 20 years of field research

Natural gas extraction and artificial gas injection experiments in Opalinus Clay, Mont Terri rock laboratory (Switzerland)

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