Work package OPTI – A strategic study to develop a mutual understanding about optimisation

In general, optimisation promises improvements in technical and economic aspects as well as with regard to flexibility and robustness. As such, optimisation is a process that should involve the different stakeholders and key actors, in particular research entities, regulators, technical support organisations, waste management organisations and the civil society including representing organisations. Different stakeholders will have different objectives and strategies for optimisation. The strategic study “HLW Repository optimisation including closure (OPTI)” is part of the EURAD-2 programme and includes 23 European partners from research entities, technical support organisations, waste management organisations and civil society organisations. The participants of the study are discussing what optimisation in the context of a high-level waste (HLW) repository means and how an exchange between different stakeholders could be fostered. By this the study wants to develop a mutual understanding in general and provide recommendations on methods and further activities for the design and optimisation of specific HLW repository systems, structures and components (SSCs) and processes. For mutual understanding, it is important to know about the main drivers for optimisation. Repository designs should be technically robust but also economically efficient, environmentally sustainable, and socially acceptable. These and other objectives for optimisation were identified. Other important questions are: At which points in the programme is optimisation required, recommended, not reasonable, or maybe even limited or restricted by regulatory requirements? Within each national program, changing boundary conditions (e.g. new waste types, updated regulatory frameworks, evolving societal expectations, etc.), technological developments, or the process adaptations based on operational experience will justify and require optimisation. Optimisation in preparation of the safety case and licensing is an established engineering process considering regulatory requirements and enhancing the overall safety of repository systems. Furthermore, the Strategic Study OPTI will put strong attention to optimisation after licensing or during construction and operation. This may have a different focus as safety is already demonstrated (e.g. focus on reduction of conservative assumptions, optimisation of the procurement of materials…). The work package OPTI creates a platform to share best practices for optimisation strategies and processes. The results will notably help both advanced and emerging programmes. Knowledge transfer from advanced to developing ones will be facilitated. R&D needs for specific SSCs and procedures that could be further optimised will be identified. The proposed contribution will summarise the work and achievements of the EURAD-2 Work Package OPTI.