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Key Topic 3: Technical Feasibility and Long-term Performance


This research area involves RD&D activities for demonstrating and optimising technology and construction[1] of a repository and disposal components.  This includes confirmation of a feasible and safe operational phase, as well as ensuring that the specified safety functions[2] will be provided over the required time frame after closure.  Included are surface-based and underground works as well as construction technologies for waste containers (including waste encapsulation or overpacking facilities), buffer, backfill, plugs and seals.  Also included is the demonstration of construction and operations of the repository and its components.  It is noted that the requirements for the definitions of these materials and their associated properties are in many cases specific to the host rock and repository design concepts.  Furthermore, this Key Topic addresses understanding of the repository components’ long-term performance and the maintenance of their safety functions.  While reference is often made to repositories, this topic also includes technical feasibility and long-term performance for other concepts that might require RD&D.

[1]  Construction includes the manufacturing of components and their emplacement.

[2]  The post-closure safety functions generally include containment of waste for a required period and limitation of groundwater and solute transport, including retention of radionuclides.


The first objective (a) for Key Topic 3 is to demonstrate, to the level typically required by national licensing approaches, that the technical design requirements based on safety of construction and operations, safety during the post-operational transient phase, and long-term safety after closure, can be met in practice by available construction technologies and related working procedures.  This includes confirmation of repository components against pre-defined design specifications to determine their state before closure and extends to optimising operations and costs over the lifetime of a repository.  As a consequence, this objective contributes strongly to the first and second pillars, “Safely Operate” and “Optimise and industrialise”, of the 2040 Vision.

The second objective (b) consists of showing that the system demonstrated, according to objective (a), will provide all the safety functions needed for the system as a whole to fulfil the long-term safety criteria.  This requires that the evolution of the engineered components and materials is sufficiently understood in the actual repository conditions over the specified timeframe.  Because of the relationship between technical design requirements and long-term performance requirements these usually must be defined iteratively.  In this context, robust design may be necessary to account for uncertainties.  The second objective contributes mainly to the second pillar, “Optimise and industrialise”, of the 2040 Vision, with some contributions also to the third pillar, “Tailor solutions”.

Each component needs to fulfil the design criteria based on the specified safety functions of the repository and meet the qualifications defined in the regulations.