The Bundesgesellschaft für Endlagerung (BGE) reports on the current status of the retrieval planning at today’s Asse-2 support group meeting. The focus is on the current plans for the retrieval mine as well as the technical procedure for retrieval from the emplacement chambers. “With the planning status presented today, for the first time, we are describing in concrete terms what the retrieval mine will look like and how the Asse 5 shaft will be built”, says Dr Thomas Lautsch, Managing Director of the BGE.
The current plans for the retrieval mine assume that the Asse 5 shaft will be constructed to the east of the Remlingen 15 exploratory borehole, which was drilled in the summer of 2013. It is expected to be drilled to a depth of 850 metres. A total of three drifts will connect the retrieval mine with the existing Asse II mine. Dr Thomas Lautsch says: “We assume that an area of at least 20,000 square metres must be created for the underground infrastructure rooms. To build the cavities, we will have to move about one million tonnes of rock”. The excavated material will be stored on pithead stocks near the mine.
The BGE has already reported on the technical plans for the retrieval of radioactive waste from emplacement chamber 8a at the 511-metre level and emplacement chamber 7 at the 725-metre level. In emplacement chamber 8a/511, the waste is recovered with the help of a technique located on the ground. Because of high gamma radiation, the technique must be carried out remotely. In emplacement chamber 7 at the 725-metre level, a ridge-guided tripod excavator is used for recovery. In order to minimise the radiation dose to employees, remote-handling technology will predominantly be used here as well.
With the plans now presented, the BGE provides information on the techniques to be used for retrieval from the emplacement chambers at the 750-metre level. Here, the retrieval is to take place in the form of partial area mining. “We are looking at whether retrieval can be done in several levels or over the entire height of the emplacement chamber. The latter would enable us to make faster progress overall”, says Dr Thomas Lautsch. Further planning will show exactly which technology will be used. The BGE expects all concept plans for the 750 m level to be finalised by 2021.