ELBRock – Development of High-Level Radioactive Waste Container Concepts for Final Disposal in Crystalline Host Rock

A consortium of GNS Gesellschaft für Nuklear-Service mbH and BGE TECHNOLOGY GmbH started the joint project ELBRock in 2022 on behalf of BGE mbH. It will be completed at the end of 2025. Its main objective has been the development of initial container concepts for the deep geological disposal of high-level waste, which was pursued in a systematic, 4‑phase development process. Based on a thorough analysis of state of the art in science and technology, the legal requirements in Germany, the applicable technical regulations, and project-specific specifications (phase 1), fundamental requirements for HLW containers for crystalline host rock were derived and summarized in a requirements catalogue (phase 2).

The requirements for such containers are manifold and complex. Depending on the safety concept, the high-level waste containers, as technical barriers, and the surrounding backfill (bentonite in ELBRock), as geotechnical barriers, must safely retain radionuclides for up to 1,000,000 years. Consequently, long-term safety aspects such as criticality safety, corrosion protection, compatibility (thermic, radiological, and chemical) with the other barriers and the host rock or the preservation of mechanical integrity during final disposal are fundamental. Based on these and additional operational safety requirements, for example, suitable material pairings were compiled, evaluated, and ranked (phase 3). The three most promising combinations – outer walls made of copper, stainless steel, or nickel-based alloys, paired with baskets made of either cast iron or unalloyed steel – are currently further elaborated as "initial concepts" in the final project phase 4.

This contribution focuses on the main results for derived ELBRock concepts, indicates ELBRock scope limits, and addresses fundamental research needs.