EMPLACEMNET AND RETRIEVAL CONCEPTS FOR GERMAN SF/HLW REPOSITORIES IN CLAYSTONE

摘要

Within the framework of the R&D project ANSICHT (Safety Assessment Methodology for a German High-level Waste Repository in Clay Formations), DBE TECHNOLOGY GmbH, BGR, and GRS developed an integrated methodological approach on how to demonstrate the safety of a HLW repository in claystone in Germany. One challenging aspect of this approach was the design of a repository concept for the two known potential host rock formations; huge Jurassic claystone layers in the northern part of Germany and thinner but well-known claystone layers in the South, also known as Opalinus Clay. For the northern reference geology, the disposal of unshielded canisters in vertical boreholes was designed as preferred emplacement concept. For the Opalinus Clay, drift disposal of shielded POLLUX~® casks was identified as the most suitable emplacement concept. In addition, the ERNESTA study (Development of Technical Concepts for the Retrieval of Waste Containers with Heat-generating Waste and Spent Fuel from Repositories in Salt and Clay Formations) was initiated to investigate in parallel how to fulfil the requirement for retrievability in both concepts. In Germany, retrievability is a design criterion and requirement for licensing stipulated by the "Safety Requirements Governing the Final Disposal of Heat-Generating Radioactive Waste ", established in 2010.