|dc.description.abstract||At the heart of traditional risk assessment and risk management lies the notion that analytic tools are able to predict the future. There are, however, activities where risk is considered over long time frames, theoretically eternal, for which the future is truly unpredictable. This thesis reviews the methodologies and regulations of three activities where a safe strategy is needed for handling hazardous materials, with extreme consequences that could occur in a far future. These activities are i) permanent nuclear waste disposal, ii) plugging and abandonment of wells in the oil and gas industry, and iii) carbon dioxide sequestration in deep geological formations.
The thesis is based on an understanding of risk as a combination of the consequences of an activity, with associated uncertainty, which goes beyond traditional probabilistic thinking about risk, and also includes the knowledge and surprise dimensions of risk. Current risk assessment and risk management of the three above-mentioned activities are reviewed with this new risk concept in mind, resulting in concerns about the effectiveness of currently used methods. In particular, concerns are raised related to the effectiveness of the current methodologies to see, study, plan, and act in the occurrence of unforeseen events. Suggestions for improvements are given, aiming to provide more adaptive risk assessment and risk management strategies, and building resilience towards unexpected events.