EBS Materials / Innovative Engineered Barrier System materials for improved sustainability, passive safety and robustness (EBS)

Objective

To develop innovative sustainable materials and solutions that enhance the robustness and passive safety of radioactive waste disposal systems using alternative structural materials, innovative backfill materials and closure materials.

Description of the WP

The purpose of this Work Package (WP) is to support national programmes in making informed decisions regarding EBS solutions that address both current and future challenges. The WP is structured around a set of complementary EBS solutions aligned with national interests, enabling the exploration and assessment of multiple sustainable alternatives that can improve safety and address ageing of excavated materials. Regarding the disposal concept, the most of materials target geological disposal although some, for example backfill for expansive waste, are more applicable to surface disposal. The final decision on the material choice, however, depends on the end-user. The combined outcomes of the individual subtasks will provide a broad range of potential solutions and knowledge that can be applied by end-users. To ensure comparability and comparability across different approaches, the sustainability task (Task 3) will establish a common set of indicators for their evaluation.
After a three-year period, stakeholders (end-users and partners) will have the evidence and results needed to determine which solutions from the spectrum of EBS components could be used or advanced into next stages of research. To support this process, each subtask will be organised around logical milestones designed to deliver meaningful results throughout the project in indication of possible future upscaling possibilities. 
Impact
•    National programme benefits: Solutions for expanding conditioned waste matrices, sustainable alternatives for EBS materials, increased use of local raw materials, efficient and cost-effective use of space in repositories through material reuse, options for alternative materials that can be used in the future, facilitation in decision making process related to EBS.
•    Enhanced robustness and long-term passive safety: By developing of radiation/heat-resistant concretes the disposal system achieves better durability under extreme conditions (ionizing radiation, elevated temperatures). Improved backfill material prevent mechanical damage from expansive reactions and gas formation, ensuring the integrity of engineered barrier systems (EBS). Compatibility of excavated aged materials for backfilling will be assessed.
•    Sustainability and ecology: Development of materials with stronger emphasis on sustainability dimensions through reuse/repurposing strategies for waste minimisation, the use of local raw material, reduction of environmental footprint and durability that can contribute to long-term safety. The effect of rocks aging processes (the acidification of the percolating water and/or the leaching of trace elements) to the environment will be examined.

Innovation
•    Novel materials: Introduction of sustainable cementitious composites, repurposing of clay materials and more durable and temperature/irradiation-resistant concretes offer a potentially more sustainable replacement of conventional EBS materials.
•    Backfill material design: Innovative approaches allow for controlled expansion and water ingress minimization in near surface systems—addressing challenges not solved by current solutions and, gas accommodation in geological disposals.
•    Sustainable use of materials: Reuse and repurposing of closure/backfill and excavated materials introduce a new paradigm of resource efficiency in disposal system design and local availability of EBS materials.
•    Behaviour and effects of ageing of excavated materials.

Added-Value
•    For EURAD-2 partners: Focused development of advanced EBS materials promotes the evolution of cost-effective and sustainable solutions across national programmes and knowledge transfer. 
•    For disposal system safety: Increased passive safety and robustness, lowering costs.
•    For society: finding sustainable alternative EBS solutions with comparable safety, impact of excavated materials on the environment 
•    For the end-users: Extended choice between sustainable alternatives of EBS materials that can improve safety and address ageing of excavated materials  
Our approach to sustainability will incorporate specific attributes for radioactive waste disposal, namely long-time scales, one-time project and dominant safety aspects. Identification, implementation and follow up of sustainability indicators in all sustainability dimensions (social, environmental and economic) will be implemented during the project execution to support the decision making of the end-users.  

Outcomes

•    Adapted and/or redefined criteria for sustainability assessment in the framework of radioactive waste disposal that involve specific waste disposal characteristics such as long time scales, one time project and dominant safety aspects. 
•    Design of backfilling material to accommodate for stresses caused by expanding waste and/or gas generation in waste
•    Development of more durable and radiation-resistant concretes 
•    Providing options for the use of local materials by reuse and repurposing of excavated or waste materials
•    Analysis of the effect of ageing of excavated materials
•    Approaches and concepts regarding sustainability in the context of nuclear waste management.