Description of the site

The Äspo Hard Rock Laboratory (HRL) is an underground scientific facility below the Äspo Island located at approximately 300 km south of Stockholm, in the Simpevarp peninsula surrounded by the Baltic Sea. This Research and Development (R&D) site was built in 1986 (Cosma et al., 2001; Milnes, 2002) by the Swedish Nuclear Waste Management Company (SKB) to develop new methodologies and technologies to develop the know-how to build a nuclear waste storage hardrock. The HRL will never become a disposal site itself and will remain an experimental site. The laboratory consists of a 3.6 km long main tunnel, and several adjacent tunnels from the surface to a depth of 450 m. The laboratory is mainly built in fractured granite rocks that are more than 1.7 billion years old (Cosma et al., 2001).  

For more than 30 years, a multitude of research and monitoring activities have been carried out within this laboratory to contribute to the design of the final waste disposal site nuclear power that is planned at Forsmark (SKB, 2019). The purpose of these investigations is to characterize the crystalline rock in an environment similar to that of the future storage site and which has not been disturbed at depth by former mining activities (Milnes, 2002).  

As a first phase, a plan for the construction and positioning of the underground facility was developed, firstly using surface field experiments that study the natural characteristics of the bedrock (geological, hydrogeological and geotechnical studies) and secondly, using different tunneling techniques tested to evaluate the mechanical response of the rock and their hydrogeological impact. In a second step, the characteristics of the crystalline rock were analyzed by different methods to study the capacity of the bedrock to act as a natural barrier. For example, geophysical studies using different imaging techniques such as seismic, GPR, electrical resistivity, induced polarization (Cosma et al., 2001; Molron et al., 2020; Walton et al., 2015) have been carried out to characterize fractured environments and the physical properties of the rock; fracture mapping (Hardenby et al., 2008; Petersson et al., 2017) was designed for the development of fracture models (Le Goc et al., 2017); hydrogeological studies (Gustafson & Krásný, 1994; Nordqvist et al., 2015) were developed to characterize groundwater flow processes in fractures at depth; hydraulic fracturing studies (Zang et al., 2016) were conducted to study the influence of the constraints on fractures. Lastly, studies have been carried out on the behavior of protective and filling buffer materials and on copper canisters tested under different environmental conditions (SKB, 2019). For more information, you can visit the SKB website.  

References

1. C. Cosma, O. Olsson, J. Keskinen, and P. Heikkinen. Seismic characterization of fracturing at the Äspö Hard Rock Laboratory, Sweden, from the kilometer scale to the meter scale. International Journal of Rock Mechanics and Mining Sciences, 38(6):859 — 865, 2001. [ DOI ]
2. G. Gustafson and J. Krásný. Crystalline rock aquifers: Their occurrence, use and importance. Applied Hydrogeology, 2(2):64–75, 1994. [ DOI ]
3. C. Hardenby, O. Sigurdsson, L. Hernqvist, and N. Bockgård. The TASS-tunnel project “Sealing of tunnel at great depth”, Geology and hydrogeology–Results from the pre-investigations based on the boreholes KI0010B01, KI0014B01 and KI0016B01. Technical Report IPR-08-18, Retrieved from Stockholm, Sweden, 2008.
4. R. Le Goc, C. Darcel, and P. Davy. Advanced DFN models from multi-support data for underground facilities. Procedia Engineering, 191:1015 — 1022, 2017. [ DOI ]
5. A. G. Milnes. Swedish deep repository siting programme. guide to the documentation of 25 years of geoscientific research (1976-2000). Technical Report TR-02-18, Retrieved from Stockholm, Sweden, 2002. [ .pdf ]
6. J. Molron, N. Linde, L. Baron, J.-O. Selroos, C. Darcel, and P. Davy. Which fractures are imaged with Ground Penetrating Radar? results from an experiment in the Äspö Hardrock Laboratory, Sweden. Engineering Geology, 273:105674, 2020. [ DOI ]
7. R. Nordqvist, A. Lindquist, P. Thur, J. Byegård, and E. Gustafsson. A single-well injection-withdrawal (SWIW) experiment with synthetic groundwater. Technical Report R-12-08, Retrieved from Stockholm, Sweden, 2015. [ .pdf ]
8. J. Petersson, C. H. Wahlgren, P. Curtis, P. Hultgren, H. Mattsson, and S. Carlsten. Äspö site descriptive model. Simplified geological single-hole interpretation of drill cores from the period 1988-2002. Technical Report P-14-12, Retrieved from Stockholm, Sweden, 2017. [ .pdf ]
9. SKB. Äspö hard rock laboratory – annual report 2015. Technical Report TR-16-10, Retrieved from Stockholm, Sweden, 2016. [ .pdf ]
10. SKB. Äspö hard rock laboratory – annual report 2017. Technical Report TR-18-10, Retrieved from Stockholm, Sweden, 2019. [ .pdf ]
11. G. Walton, M. Lato, H. Anschütz, M.A. Perras, and M.S. Diederichs. Non-invasive detection of fractures, fracture zones, and rock damage in a hard rock excavation – Experience from the Äspö Hard Rock Laboratory in Sweden. Engineering Geology, 196:210 — 221, 2015. [ DOI ]
12. A. Zang, O. Stephansson, L. Stenberg, K. Plenkers, S. Specht, C. Milkereit, E. Schill, G. Kwiatek, G. Dresen, G. Zimmermann, T. Dahm, and M. Weber. Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array. Geophysical Journal International, 208(2):790–813, 2016. [ DOI ]

Data availability

Predefined requests

To help finding general datasets, predefined database requests have been created and are regularly executed. Results can be downloaded from the links available here:

KMZ viewer

The viewer below represents Google Earth module and provides a site visualization and information on available. This interface also provides an information on types of measurements, locations, dates, etc. Data can be directly downloaded from the links available on this interface.