[en] The aims of the topical session are to: - Gather information on ongoing work in national programs to address the key questions (below) - To gain an overview of operational safety issues outside RWMC and assess the potential for knowledge transfer - Starting from the key questions, to define the challenges and issues that could be of interest to, and benefit from discussion by, IGSC - To assess the need for further IGSC work on this topic and, if so, to define the activities and time frames. Key questions were identified by IGSC in the PoW: - What are the main operational safety issues that have implications for long-term performance? (To what extent are the various practices and constraints legally required? What are the minimum mining requirements and practices that apply for safe operation of a deep repository? Are there separate safety cases for operational and long-term safety? If so, how are the links made?); - How do these constraints vary according to key aspects of the disposal system concept such as waste type, host rock, planned operational lifetime, etc.? - How does the stepwise design and optimisation process balance operational and post-closure safety constraints related to conventional hazards, engineering feasibility, radiation protection? (What practical measures can be (or have been) taken to address specific hazards or issues---i.e. selection of materials, design elements? How flexible must be the design to adapt to the constraints at different stages? What methodologies are used to identify, prioritise and track the various requirements? How are these considerations balanced? Are there 'trade-off's' that must be made between short-term and long-term safety?); - What lessons can be learned from other relevant industries (e.g., especially the mining industry), and what are the limits of transferability? Eight presentations were provided on national experience related to the key questions; an additional presentation was provided by AREVA to describe the perspective and possible relevant experience on operational safety in the mining industry. The presentations were: a. Canada: Balancing operational and long-term safety in OPG's L and ILW DGR design (H. Leung and P. Gierszewski, OPG); Canada: Operational safety issues in uranium mines: application to deep geological repository (B.R. Ravishankar, CNSC); b. France: Operational safety and conventional hazards in designing a HLW repository (B. Cahen, Andra); c. France: Balancing operational and post closure safety issues (P. Bodenez and G. Dandrieux, ASN; C. Serres, IRSN); d. Germany: Implications of pre-closure activities on the backfilling and sealing measures for the ERAM LLW (R. Mauke and J. Wollrath, Federal Office for Radiation Protection, BfS); e. Germany: Experience from developing an advanced safety concept for HLW disposal in rock salt (J. Krone, DBE Technology); f. US: Balancing operational risks and worker safety with long term repository benefits in the Yucca Mountain repository design (E. Smistad, DOE-YM); g. Finland: Experience from ONKALO (M. Snellman, Saanio and Riekkola Oy); h. Industry: Operational safety and radiation protection: practical experience in uranium mining (J-M. Marino, AREVA)