HLW repository optimisation including closure (OPTI)

Objectives

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.

Description of the WP

Context

• Optimization will be in focus of advanced programmes as first repositories enter in construction / operation periods
• 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), evolution of technology and/or the adaptations of processes due to operational experiences
• Optimization is a process that shall involve all stakeholders of a RWM programme, civil society included
• Optimization provides necessary benefits regarding technical, economical, long-term safety related aspects as well as flexibility and robustness

Impact

• A mutual understanding about the views of the different actors on optimisation will be developed (e.g. what are the main drivers for optimization, At that points in the program is optimization needed, recommended or forbidden? What main key challenges are seen for optimization?)
• If appropriate, formulation of a common understanding about optimization,  considering the  views of the different colleges/stakeholders
• Networking about best practices for Optimisation strategies for SSCs (e.g. EBS) and DGR processes
• Outcomes will help less advanced programmes in their earlier phases of repository development
• Transfer of knowledge from advanced to less developed programmes will be facilitated
• R&D needs about specific SSCs and procedures that could be optimized further will be identified

Outcomes

A major outcome will be the joint proposals for future activities related to the optimisation of repositories, considering views from all actors (including the Civil Society). Other important outcomes will be in particular:

• Overview of approaches to and related optimisation strategies for specific EBS components and DGR processes (buffer, backfill, seals, support structures; emplacement, …). SRA: 5.2.2, 5.1, 3–3 - drivers: innovation for optimisation, implementation safety
• Possible optimisation of options/plans related to closure processes (possible closure criteria/acceptability criteria...). SRA: 5.1.1 - drivers: Societal Engagement, implementation safety
• Mutual understanding about robustness of mechanical structures such as lining in different environment and their potential optimisation. SRA: 5.1.1 – driver: Innovation for Optimisation