DEVELOPMENT AND NEW RESEARCH PROGRAMS IN THE MEUSE HAUTE-MARNE
UNDERGROUND RESEARCH LABORATORY (FRANCE)
Gilles Armand, Sarah Dewonck, Jean-Michel Bosgiraud, Laurence Richard-Panot
ANDRA, Meuse Haute Marne Underground Research Laboratory, Bure, France
ABSTRACT
The Meuse/Haute-Marne Underground Research Laboratory (URL) is located on the eastern boundary of the Paris Basin. The URL started to be built in 2000 (shaft sinking operations) in the framework of
ANDRA’s (French national radioactive waste management agency) research program aimed at determining the feasibility of a reversible deep geological disposal of high-level and intermediate-level long-lived radioactive waste (HLW, IL-LLW). Its underground drifts are used to study the Callovo-
Oxfordian claystone layer between 420 m and 550 m in depth.
The main objective of the first research phase (2000-2005) was to characterize the confining properties of the clay through in situ hydrogeological tests, chemical measurements and diffusion experiments and to demonstrate that the construction and operation of a geological repository (aka Cigéo) would not introduce pathways for radionuclides migration (Delay et al , 2007) to support evidence required for the repository safety assessment.
The ongoing research program (started in 2006) following the “Technology Readiness Level” Scale is more dedicated to technologies improvement and demonstration issue of the different disposal systems, even if characterization studies are still ongoing.
For example in geochemistry, after studying the confining properties of the Callovo-Oxfordian claystone, the focus is more on interactions between different materials constitutive of the disposal (concrete, steel, glass) and the claystone by the way of:

Tests in boreholes in which materials are tested under various conditions (in straight contact with clay, or in contact of pore water, at high temperature, …)
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Opportunistic measurements (measurement of chemical composition of gas inside or outside the steel casing of HLW horizontal cells, …)
In rock mechanic, at the main level of the URL (located at 490 m), construction and evolution of disposal cells of different size are studied for HLW and IL-LLW packages:
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A step by step approach, started in 2006, is carried out based on comparison of HM behavior of parallel drifts excavated/supported by different construction methods (Fig 1). Hydraulic hammer technique was first used for excavation. Bolts, sliding arches and 10 cm-thick layer of shotcrete were set in place immediately after a two-meter maximum progression. Other excavation and construction techniques have been and will be used, like road header (drift GET, GCS, GCR), stiff and flexible support. A tunnel boring machine has also been operated (GRD drift) to test segments
(concrete wedges) emplacement technique with different gap filling materials. All new experimental drifts are instrumented in order to measure the short and long term hydro mechanical behavior. These various configurations give insight of the influence of construction method on the
EDZ extent and evolution and on the progressive loading of the support, which are key issues to design the Cigéo disposal drifts.
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The concept of disposal cells studied for HLW consists in horizontal micro-tunnels 80 m long and
70 cm in diameter.
Several campaigns of tests have been carried out (Fig 2) since 2009 in order to demonstrate the feasibility of excavation of such micro-tunnels and study their behavior under different conditions (with and without back filling the annular gap between the rock and the casing, watertight or not casing). A full scale demonstrator representative of the benchmark concept has also been excavated, to study its behaviour under thermal loading with heat produced by electrical heaters.

Figure 1 – Meuse / Haute-Marne URL drifts network
Figure 2 – Disposal cells of HLW: (a) in operation configuration, (b) In situ experiment (25 m long) with surrounding boreholes to study THM behavior of the cell.
KEYWORDS
Underground research laboratory, Claystone, excavation methods, nuclear waste disposal
REFERENCES
Delay J, Vinsot A, Krieguer J M, Making of the underground scientific experimental program at the
Meuse/Haute-Marne underground research laboratory, northeastern France. Physics and Chemistry of the
Earth, 2007, 32 (1/7): 2–18.