Strategic studies

WP10 - Understanding of uncertainty, risk and safety (UMAN)

Further refinement methods to make sensitivity and uncertainty analyses and the development of multi-actor network for uncertainty management

Major highlights (June 2022 - May 2023)

-     UMAN Course on Uncertainties Management, which included UMAN findings on uncertainties identification, classification and treatment along the RWM programme has been organized in February 2023.
-    Subtasks 3.6 (Second wave subtask) was started. Views of actors on the significance for safety of near field related uncertainties have been collected and analyzed. 
-    Task 4.2 (extention) identified the potential approaches for near field uncertainty management, and carried out preparatory activities for Workshop no 5 on the actors’ options for reducing, mitigation or avoiding the uncertainties impact on repository safety have been performed.
-    Several deliverables and milestones are (nearly) ready for final review.

Forward look 

-    The remaining milestones and deliverables will be completed in the coming months.


This WP is dedicated to the management of uncertainties potentially relevant to the safety of different radioactive waste management stages and programmes. It includes various activities such as exchanges on views, practices and uncertainty management options and the review of existing strategies, approaches and tools. Interactions between different types of actors including civil society are central to this WP. These interactions are aimed at meeting the shared objective of fostering a mutual understanding of uncertainty management strategies, approaches and preferences. A particular focus is put on uncertainties in direct link with RD&D WPs and with a high (and where relevant medium) priority subdomain of the SRA for which exchanges of information and experiences and strategic studies have been identified as beneficial by the JP actors themselves. The WP will consider past and present EU projects on the topics of interest and other initiatives carried out at international level such as IAEA and NEA so as to avoid duplicating existing work. The WP will allow identifying the contribution of past and on-going RD&D projects to the overall management of uncertainties as well as remaining and emerging issues associated with uncertainty management that could be addressed in subsequent waves of EURAD. 


Decisions associated with radioactive waste management programmes are made in the presence of irreducible and reducible uncertainties. Several choices made on the basis of limited information in early programme phases may also have to be confirmed before or during the construction and operation of the facility. At the end of the process, uncertainties will inevitably remain but it should be demonstrated that these uncertainties do not undermine safety arguments. Hence, the management of uncertainties is a key issue when developing and reviewing the safety case of waste management facilities and, in particular, of waste disposal facilities due to the long-time scales during which the radiotoxicity of the waste remains significant. 

As noted under the EURAD Roadmap Theme 1 - Managing implementation and oversight of a radioactive waste management programme - a clear strategy and commitment to involvement of stakeholders is essential to the decision-making process at all stages of a waste management programme. It is also explained that scientific activities associated with a waste management programme (site characterisation, process modelling, safety assessment etc.) are evolving over time leading to new view points and sometimes new uncertainties and they are less predictable in the outcome, duration or resources that may eventually be required. Accounting for such uncertainty has thus become a key part of successful programme planning, and would benefit from continued sharing of methodologies and experience. 

Therefore, uncertainty is a cross-cutting issue of the different themes and stages identified in the Roadmap. The term “uncertainty” is also explicitly mentioned in the title of several activities of common interest considered as having a medium or a high priority: Inventory uncertainty (1.1.1), Site uncertainty treatment (3.1), Geological Uncertainties (1.6.2), Uncertainty treatment (2.1.3). Furthermore, RD&D activities are aimed at improving the state-of-knowledge and thus are expected to reduce uncertainties. Understanding the contribution of these activities to the overall uncertainty management is important for the different actors involved in the decision-making process as well as for the identification of future EURAD priorities and activities.

Consequently, the raison d’être of this WP is to provide an opportunity to the organisations and different actors of the Member-States to share their experience and views on uncertainty management and to identify emerging needs associated with this topic. The WP will also contribute to understanding the added value of RD&D activities for the safety case and the decision-making process. It also contributes to the vision of EURAD by fostering mutual understanding and trust between Joint Programme participants.