Optimization will be in focus of advanced programmes as first repositories enter in construction and operation. Optimization provides benefits regarding technical, economical, long-term safety related aspects as well as flexibility and robustness. The need of optimization is justified by the long running character of repository projects and thus by expected changing boundary conditions (e.g. new waste types) or evolution of technology and/or the adaptations of processes due to operational experiences. Further, optimization is a process that shall involve all stakeholders of a RWM programme, including civil society and the regulatory bodies. Within the frame of the EURAD 2 program a work package “HLW Repository optimisation including closure – OPTI” was initiated. The objectives of the WP are to develop a mutual understanding and provide recommendations about methodologies and further activities for design and optimization of specific HLW deep geological repository systems, structures and components (SSCs) and procedures. Within the WP 23 parties from 11 European countries are involved. The participants represents waste management organizations (WMO), technical support organizations (TSO), research entities (RE) as well as representatives from the civil society. To open the discussion for additional representatives from the civil society as well as the regulatory body or other interested parties a session dealing with optimization is proposed. The session goal would be to open the discussion about optimization such as What is it? Why? When? Who is involved? etc.