Events and processes due to climatic developments are relevant for assessing the safety of a repository for nuclear waste including operational safety of e.g. surface installations and long-term safety of a deep geological repository (DGR). Short-term events, such as floods or storms, may impact transport infrastructure and surface installations. Long-term processes, such as glacial erosion, subglacial valley formation or permafrost thawing/freezing as results of certain climate states modify the setting of the overburden and can potentially even impact the geological barrier of a DGR. The investigation of the impact of such events and processes on the safe containment of the radioactive waste when describing the safety case is paramount and ongoing in the international context but still challenging due to uncertainties regarding the future climate evolution. Nevertheless, such future climate scenarios are required as part of the FEP analysis (Features, Events and Processes) for estimating the performance of a repository. Research is also being undertaken to better understand the influence of recent (anthropogenic) climate change on the long-term evolution of expected climate patterns as a basis for estimating future climate scenarios and their impact on repository safety.
This session shall combine a broad array of presentations on the effects of climate events and processes of relevance to the safety of radioactive waste management on all relevant timescales – from operational safety to long-term safety, for all waste types, and for all disposal concepts. Theoretical and experimental or field based works are equally welcome in this session.

Storing the radioactive waste in a deep geological repository (DGR) is considered a robust solution to minimize the risks to human health and the environment, even in the far future. However, how do we know it is truly safe? How can we manage uncertainties in an analysis extending up to 1 million years into the future? This session will focus on the methods used to assess post-closure safety of a DGR. We invite contributions related to all aspects of post-closure safety, from evaluating how the technical barriers contribute to the long-term safety of a DGR to calculating radiation doses to humans as well as non-human biota. Suggested topics may include (but are not limited to):
• Quantifying uncertainties related to long-term evolution of a DGR and its environment
• Defining scenarios for post-closure safety analyses, including different climate evolutions
• Evaluating how natural and technical barriers contribute to post-closure safety
• Determining representative persons and life habits over long timescales
• Evaluating radionuclide transport and dose to humans and non-human biota
• Assessing landscape development and identifying potential release areas
• Strategies for using generic versus site-specific data in post-closure safety analyses
• Methods for choosing and evaluating Features, Events and Processes (FEPs) of importance for post-closure safety
• Engineering and modelling perspectives on post closure safety
• Are there alternative waste-management solutions to DGRs?

Description

As a socio-technical endeavour, deep geological disposal of radioactive waste links to different aspects of sustainability – particularly concerning time. Due to its very long timeframe (several decades for implementation, operation and closure to hundred thousands of years for long-term safety) and scope, it is unique compared to other infrastructure projects: it is a clear transgenerational project, which automatically raises questions of sustainability. Not only waste management organisations (WMOs) - tasked with the implementation of radioactive waste disposal - but also other actors like regulators face sustainability challenges with regard to time-related aspects. This includes for example safety, intra- and intergenerational justice, endurance of institutions, participation of civil society, or knowledge management. However, is sustainability just a fashionable label in the discourse on geological disposal of radioactive waste? Is the discussion on sustainability even necessary? What are possible positive inputs of this discussion? In order to approach these questions, this session focusses on sustainability questions specifically related to the temporal aspects of final disposal of radioactive waste.

Objectives and scope

This session discusses various topics connecting time and sustainability in the implementation of geological disposal of radioactive waste. It focusses on the institutions involved, public participation and empowerment of society as well as preserving expertise and knowledge. In this context, it addresses the following general questions: What does sustainability mean regarding implementing final disposal of radioactive waste – especially for the WMOs? How can WMOs respect sustainability aspects and meet the respective challenges? Time is a safety factor: no compromise to the best possible safety shall be made but WMOs have to implement the geological disposal efficiently with reaching milestones and goals within a certain time. The relationship between safety and sustainability should be discussed, i.e. aspects of reciprocity, dependency or mutual exclusion. Moreover, aspects of justice, responsibility and fairness towards current and future generations as well as in the corresponding processes are relevant. Difficulties in predicting long-term future social, political, economic and environmental developments lead to the question of sustainability of the involved institutions. In view of the time scales, institutions are required that are able to act over long periods and to develop in line with changing boundary conditions. From the perspective of time and sustainability, questions of securing institutions as well as institutional embedding of the task are relevant. This includes additional aspects: transparent knowledge transfer and participation of the civil society and further stakeholder raise the question of whether and how corresponding formats are received and perceived. The task of transferring knowledge to future generations with changing social conditions and structures is challenging which requires a successful interaction between civil society and WMOs. In the field of knowledge management, it is and will be relevant to enable sustainable preservation of expertise - both now and in the future. In this context, retrospective considerations and evaluations of sustainability aspects in earlier approaches and programs can also be helpful (e.g. the relation of time planning and progress in reality as a permanent dilemma). Even before the forthcoming and popularization of the term ‘sustainability’, there was a discussion how to realize geological disposal of radioactive waste in a safe but economically efficient manner.

Contributions

Contributions with a socio-technical focus from all disciplines on national and international perspective are welcome and can address but are not limited to the following topics in context of time and sustainability:
• Safety and sustainability: aspects of reciprocity, dependency, exclusion
• Intra- / intergenerational and procedural aspects: responsibility, justice
• Endurance of institutions: resilient systems, long-term governance, organisational learning, aspects of error and safety culture, development of political landscape (e.g. relationship between the executive and legislative power, changing political majorities or public opinion)
• Participation of civil society: evaluation and results of formats of stakeholder involvement, models for evaluating participation formats
• Knowledge management: processes of preservation of knowledge and expertise, digital systems
• History: lessons learned from former approaches, programs and projects