The planned use of crushed salt as the backfill and sealing material for the final disposal of radioactive waste in rock salt is justified by the favorable crushed salt material properties. A prognostic long-term safety assessment requires sufficiently proved physical modeling that can only be met on the basis of suitable laboratory and field investigations. To reduce the currently existing uncertainties, triaxial long-term compaction tests TUC-V2 and TUC-V4 (KOMPASS II) were carried out.

For the deep geological disposal of high-level nuclear waste in rock salt formations, the safety concept includes the backfilling of open cavities with crushed salt. For the prognosis of the sealing function of the backfill for the safe containment of the nuclear waste, it is crucial to have a comprehensive process understanding of the crushed-salt compaction behavior. The KOMPASS projects were initiated to improve the scientific knowledge of using crushed salt as backfill material.

The presentation will present the results of the research work for the development, construction and commissioning of the pilot plant as well as successful mechanical-hydraulically coupled tests to demonstrate the functionality of sealing elements made of salt cut bricks.