Deep geological repositories (DGR) are designed to ensure the safe disposal of radioactive waste over very long timescales. Ensuring and demonstrating the criticality safety of a DGR is a safety requirement in all national programmes that must dispose of high-level radioactive waste such as spent nuclear fuel. Assessing criticality safety in the repository post-closure phase presents unique challenges due to the exceptionally long timescales involved. The EURAD-2 Work Package 17 "Criticality Safety for Disposal" (CSFD) is undertaking innovative research and development to address these challenges and strengthen the technical basis for demonstrating post-closure criticality safety. This presentation will provide an overview of the current state of the art as documented in the WP-17 initial SoTA report, introduce the key objectives and activities of the work package, and present the current status of the ongoing R&D programme.