(GRS 352) Geoelectric Monitoring of Bentonite Barrier Resaturation in the Äspö Prototype Repository

In 1994, SKB started constructing the “Prototype Repository”, a full-scale replica of a part of a future KBS-3 repository in crystalline rock, at the Äspö Hard Rock Laboratory. Six emplacement boreholes were planned and constructed in two tunnel sections until end of 1999.
The international EC co-funded Prototype Repository project was started in 2000 (contract FIKW-CT-2000-00055). The project partners were SKB (Sweden), POSIVA (Finland), ENRESA (Spain), GRS (Germany), BGR (Germany), UWC (UK), and JNC (Japan). Between 2000 and 2003 the complete Prototype Repository was equipped and instrumented, and monitoring was started. In February 2004 the EC funding expired. The Prototype Repository project was continued with national funding of the project partners. In 2011, dismantling of Section II was started in a three-year project. Backfill, buffer and canisters as well as part of the instrumentation were retrieved, and numerous laboratory investigations on buffer and backfill samples were performed.
GRS’ part in the Prototype Repository was the monitoring of backfill and buffer resaturation using geoelectric tomography. The measurements were completed in 2013.