This is how the Morsleben repository is to be decommissioned
On the basis of comprehensive investigation programmes a decommissioning concept has been developed that takes into account the complicated geological, geo-technical, mining and long-term safety requirements. It has been designed in such a way that the protection goals will be kept over long periods of time (at least 1 million years).
The safe sealing of the radioactive waste from the biosphere for the long term is to be achieved with the concept of the wide backfilling of the mine and of the sealing structures around the emplacement areas in the western-southern field and the eastern field. For this purpose circa 75 per cent of the cavities are to be backfilled, 22 sealing structures constructed and the shafts Bartensleben and Marie are to be sealed and backfilled.
Wide backfilling of the mine
As a result of the wide backfilling the mine will be mechanically stabilised and the cavities will be reduced, so that it will be impossible for cracks to form in the surrounding rock and in the overburden. At the same time flow paths in the mine are to be minimised. In the long term, already existing cracks or that can form in the meantime will close in the plastic salt. With less than 0.15 millimetres per year the subsidence at the Earth’s surface is low and has a downward trend.
The remaining cavities serve to provide volume for the gas formation expected in order to reduce gas pressure. Furthermore there are cavities whose further backfilling is not required for stabilising the mine.
Inflow of saline solutions delayed by sealings
The inflow of saline solutions into the emplacement areas and the pressing of radioactive solution is delayed by the sealing constructions for such a long period that in particular the radionuclides with short decay times will then have decayed to a wide extent.
The direct connections to the surface, the shafts Bartensleben and Marie, will be sealed with particularly high-quality sealing structures.
Duration of the planned decommissioning
Once the planned closure has been licensed the works until final decommissioning are currently expected to take 15 to 20 years.
State of 2016.02.02