Summary of a Sandia National Laboratories Workshop on Extended Probabilistic Risk Assessment (ePRA)

Fifty years ago, it was realized that the complexity of operating large-scale nuclear power plants (NPP) necessitated new mechanisms for identifying, measuring and assessing the risk of undesired events—resulting in the development of probabilistic risk assessment (PRA) as a generally agreed to framework for addressing the safety risks of nuclear power. Safety-focused risk analysis and assessment approaches, however, struggle to adequately address malicious acts against nuclear material, infrastructure, and facilities and non-proliferation issues. Yet, responding by treating safety, security, and safeguards concerns independently is inefficient. At best, this assumption may not take explicit advantage of measures that provide benefits against multiple risk domains, and, at worst, it may lead to implementations that increase overall risk due to incompatibilities.What is needed is an integrated safety, security and safeguards risk (or “3SR”) framework for describing and assessing nuclear power risks that can enable direct trade-offs and interactions in order to inform risk management processes — a potential paradigm shift in risk analysis and management. In an ideal future, regulators, nuclear power plant operators, and designers will utilize a unified analysis framework to inform decision making processes and to understand overall risks across the domains of safety, security, and safeguards—perhaps in terms of an “extended probabilistic risk analysis” framework, or ePRA.This conference paper summarizes the proceedings of a Sandia National Laboratories-hosted Workshop on Extended Probabilistic Risk Assessment (ePRA) in August 2017 as an attempt to begin the discussions to move towards a 3S Risk approach. Further, this paper reviews the historical approaches, current challenges and modern approaches to nuclear power risk assessment presented at the workshop. It will then discuss key challenges and takeaways identified by the participants. Ultimately, this paper provides a notional research agenda to improve risk assessment for the nuclear energy discipline. SAND2018-0951 A.