SAVER - Development of a salt breeze-based backfilling concept with the option of retrievability
Project duration and partners
2021 to 2025 - BMWi
Project description
The project (funding code: 02E12173), which is funded by the Federal Ministry for Economic Affairs and Climate Protection and the Karlsruhe Project Management Agency, is concerned with the use of a new type of matrix-stabilised salt breeze material for backfilling high-level radioactive waste repositories. In the project, the material is being tested for potential use in a future repository by means of laboratory tests and large-scale underground tests. Matrix-stabilised salt breeze can provide an alternative to conventional moistened salt breeze due to its rapid load-bearing capacity.
The results of the predecessor project GESAV I can be accessed here .
In 2017, the Federal Republic of Germany used the Site Selection Act to designate rock salt as one of three host rock options for a deep geological repository for high-level radioactive waste (HLW). For such a repository, underground cavities for access, waste transport, infrastructure and the storage itself are created by mining. Once emplacement is complete, the cavities created must be backfilled to restore the geological barrier function of the containment effective rock zone, among other things. Various requirements are placed on the backfill material and the backfill body in order to achieve the resulting backfill targets. The Institute of Mining and Specialised Civil Engineering at TU Bergakademie Freiberg has long been conducting research into construction and backfill materials for mining and repository mining, as well as the necessary technologies. The aspect of backfilling potential HAW repositories in salinar has been investigated since 2012 as part of the R&D project "Structure-stabilised salt breeze backfill - Phase 1" (GESAV I) and since 2017 in the subsequent R&D project "Structure-stabilised salt breeze backfill - Phase 2" (GESAV II). As part of the GESAV I R&D project, a backfill material (GESAV material) suitable for use in HAW repositories in salinar was developed, analysed in the laboratory and patented. This salt breeze-based material is characterised by its ease of processing, species-specificity and strength development.
After completion of the development and laboratory phase in 2017, the applicability of GESAV material in-situ in a rock salt formation in the "Glückauf" Sondershausen salt mine (GSES) was investigated as part of the GESAV II R&D project. Based on the backfilling method successfully developed in GESAV II, the current SAVER project (development of a salt breeze-based backfilling concept with the option of retrievability) is now investigating its application to various salt breeze mixtures. In addition, a POLLUX container dummy is being used. This will be filled with cut salt and then covered with a roadway closure made of GESAV or KOMPASS material over the entire cross-section of the roadway. Over the next few years, important parameters (e.g. settlement, temperature) will be measured and analysed using high-tech measuring equipment. These large-scale tests are particularly characterised by the fact that they are set up and carried out in-situ in the GSES GmbH mine in Sondershausen. The research into various materials, both in-situ and in the laboratory, the continuous exchange with national and international project partners and, last but not least, the realistic research represent an important contribution to the topic of safe final disposal.
Louis Schaarschmidt
TU Bergakademie Freiberg
Institute of Mining Engineering and Special Civil Engineering
Chair for Underground Mining Methods
Research and Training Mine "Reiche Zeche"
Fuchsmühlenweg 9
09599 Freiberg
+49 3731 39-3831
Louis [dot] Schaarschmidt [at] mabb [dot] tu-freiberg [dot] de (Louis[dot]Schaarschmidt[at]mabb[dot]tu-freiberg[dot]de)