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Generic underground research facility: Bukov URF, Czech Republic
The SURAO generic research programme is focused on the detailed testing of the
crystalline rock concept. Generic laboratories serve as training centres for staff
members, experimentation involving mock-up experiments and the development
of methodologies for the study of rock conditions in underground environments.
One of the most important aspects of generic research consists of the testing of the
validity of data collected from the earth's surface and the approximation of such
data to depths at which the construction of the repository is envisaged. SURAO
has close connections with three underground research centres in the Czech
Republic: the Josef Gallery, the Bedřichov Water Supply Tunnel and the Bukov
Underground Research Facility (Bukov URF). The Bukov underground generic
laboratory is located in the eastern part of the Czech Republic near the Kraví hora
candidate repository site and adjacent to the Rožná uranium mine at a depth of
600m below the earth's surface. From the geological point of view the facility is
located in the north eastern part of the Moldanubian Zone of the Variscan orogen
and is composed of migmatitised paragneisses with amphibolite layers. The felsic
granulites display the same deformational history as that of the nearby Kraví hora
candidate locality.
www.surao.cz
Construction Construction commenced in 2013 with the blasting of the main access tunnel.
Following an intensive drilling campaign (the total length of the boreholes
amounted to 500m) two suitable rock blocks were defined for testing purposes: a
consolidated block made up of high quality rock intended for diffusion and
demonstration experiments and slightly fractured rock for the performance of
migration, hydraulic and material tests. The laboratory itself consists of a 300m-
long connecting cross gallery with a profile of 9.2m2 leading from the access
shaft and the underground facility itself consisting of a 90m-long large-profile
chamber and a gallery niche system with a total length of 40m. The second test
chamber section consists of a 20m-long niche in the front part of the access
tunnel. Rock bolts will be used to provide support for the underground sections
supplemented with yieldable TH arches in areas exhibiting more complicated
geological conditions. The intensive drilling campaign consisted of the drilling of
a series of exploration boreholes of a total length of 500m into the walls of the
access tunnel for geophysical and hydrogeological monitoring purposes. The
conventional blasting method was used for the excavation of the access tunnel,
whereas the smooth blasting method was applied with respect to the laboratory
niches.
Prague
URF Josef
Bedřichov
URF Bukov
Introduction
The scientific programme conducted during the construction of the facility
concentrated on the characterization of the site from the geological,
geomechanical and hydrogeological points of view. TThe characterization
programme will include the following research areas:
Complex geological characterization
The application of a range of geological methods will be aimed at obtaining a
multidisciplinary description of the host rock in order to assist in determining the
optimum location for the performance of the experimental programme.
Geological characterization will comprise geological and structural mapping and
the deciphering of the temporal, spatial and thermal evolution of the ductile and
brittle pattern.
Geotechnical characterization
The geotechnical programme will be made up of three specific areas: (i) stress
monitoring, (ii) geotechnical laboratory testing and (iii) seismic monitoring.
Hydrogeological properties of the rock mass
An understanding of the behaviour of water within the repository system is
crucial in terms of safety case considerations. Hydrogeological studies therefore
include the monitoring of water influx and the evolution of the chemical and
physical properties of water collected from the surrounding rock. Borehole
hydrogeological tests, tracer tests and water pressure tests will be conducted
during the experimental phase.
Synthetic geosphere models
The application of the methods described above will result in the construction of
the following synthetic geosphere models:3D structural-geological model3D hydrogeological model3D geotechnical model
Characterization
Fig. 2 URF Bukov as part of U mine Rožná
URF Bukov
Experimental programme The underground research facility research and experimental (R&E) programme
will be conducted in very similar conditions to those expected at the location of
the future deep geological repository. The Bukov URF will serve as a test site for
assessing the behaviour of the rocks at the candidate sites at a depth matching
the expected depth of the deep geological repository until the final site is selected
and the confirmation underground laboratory is built at that site.
The experimental programme consists of 7 basic areas:
R&E Programme 1: Pilot characterization of the rocks in order to test the
methodology for setting up 3D Geo / GT / HG models of the site
R&E Programme 2: Testing of long-term monitoring methods for processes
occurring at repository depth
R&E Programme 3: Testing of groundwater flow / radionuclide transport models
of the fracture environment of the DGR
R&E Programme 4: Testing of the effect of the rock at repository depth on the
properties of the engineered barriers
R&E Programme 5: Testing of the development of excavation
disturbed/damaged zones in crystalline complex rocks at repository depth
R&E Programme 6: Investigation of the effect of the rock massif on the
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