Multi purpose test facility
Before building a final repository, further studies of buffer and backfill under different installation conditions are required. SKB has therefore built a multi purpose test facility at Äspö designed for studies of buffer and backfill materials. The facility has been in operation since spring 2007, and was previously called “the bentonite laboratory”. As the facility was useful for more than just bentonite studies, it was renamed the multi purpose test facility during 2018.
The multi purpose test facility enables full-scale experiment under controlled conditions and makes it possible to vary the experiment conditions in a manner which is not possible in the Äspö HRL tunnel.
Construction and equipment
The multi purpose test facility was constructed in 2006 and opened in 2007. It includes two stations where the emplacement of buffer material at full scale can be tested under different conditions. The facility has also been used for continued testing of different types of backfill material and the further development of techniques for the backfilling of deposition tunnels. A wood frame mock-up of a deposition tunnel in full scale in the facility has been used in such testing.
Other equipment in the facility includes an Eirich bentonite mixer with a load capacity of 1000 kg to allow mixing of bentonite with desired water ratio, and a KAHL model pellet press combined with a Baron CXL 4500 transporter and a CZ Multiscreen. The press produces extruded pellets with a diameter of 6 mm and a length of 20 mm. The production capacity is approx. 700 kg/h. A self cleaning filter system ensures a good working environment with low dust emissions. The entire press equipment has received a CE marking.
Studies performed in the multi purpose test facility includes testing on the impact of water inflow in backfilled deposition tunnels, tests of the properties of the pellet bed and tests of various bentonite related equipment. During recent years the facility has been used to test and fine tune robot equipment for backfilling, tests and simulations of THM processes relevant for buffer installation and tests of the buffer protection system.