The Bentonite Laboratory
The Bentonite Laboratory is where we develop and test the bentonite clay that is required in the Spent Fuel Repository, both as a buffer and as a backfill material for the emplacement tunnels.
In the future repository one canister will be deposited each day. Around each canister a buffer of bentonite clay will be installed and at the same time six metres of the emplacement tunnel will be filled with backfill material.
Before the Spent Fuel Repository starts operating it is important for SKB to develop production and inspection methods that can be repeated under industrial conditions and with adequate quality standards. SKB’s Bentonite Laboratory is linked to the Äspö Hard Rock Laboratory. Its activities deal largely with ensuring that the installation methods for the buffer material and backfill function under all the circumstances that can be anticipated.
Experiments and trials are carried out in the Bentonite Laboratory on bentonite in various forms. It provides, for instance, equipment for mixing bentonite materials and manufacturing pellets as well as tools to lift the buffer rings. There is a specially adapted robot to stack the blocks of bentonite.
In its 450 sq. m. hall there are also full-scale and half-scale models of the emplacement tunnels in which installation equipment can be tested in controlled circumstances. There are also two holes in the floor intended to resemble the emplacement holes in the repository. This is where the emplacement process can be tested and we can find out how the bentonite reacts to differences in the flow of water. Trials are also made deep in the rock in the Äspö Laboratory to test equipment in conditions like those in the final repository.