From Fukushima to Advanced Reactors: Enabling Robust External Hazard Probabilistic Risk Assessments

Abstract

The Fukushima Dai-ichi nuclear accident and other events affecting conventional light-water reactors have highlighted the importance of understanding and mitigating the risks posed by external hazards to nuclear power plants. In addition, while advanced reactors have enhanced safety features, external hazards can still impose concurrent loading on active and passive structures, systems, and components (SSC), introducing complex dependencies in SSC performance. Probabilistic risk assessment (PRA) provides a well-established and effective framework for assessing risks at nuclear power plants. However, current PRA tools and methods are limited in their ability to fully capture dependencies in SSC performance and to support a comprehensive assessment across all hazard classes, particularly those with substantial spatial and temporal complexity. This presentation will highlight recent research efforts to identify and address several key technical and practical challenges associated with external-hazard PRA for multiple classes of natural hazards that can occur individually or in combination. Topics will include strategies to improve hazard characterization, approaches for modeling correlated SSC performance, and the use of novel computational tools (e.g., Bayesian networks and machine-learning surrogate models). The ultimate goal of this research is to enable improved risk-informed decision-making for both conventional and advanced reactor technologies.

Biography

Assistant Professor in CEE at the University of Maryland Michelle (Shelby) Bensi's research focuses on the application of probabilistic risk assessment concepts and tools as well as statistical/machine learning techniques to problems involving engineered systems exposed to natural hazards. Dr. Bensi focuses primarily on topics related to the probabilistic assessment of natural hazards (e.g., seismic, coastal, inland flooding, precipitation), risk-informed applications, and disaster resilience.  

Bensi serves as a member of the American Nuclear Society and American Society of Mechanical Engineers (ANS/ASME) Joint Committee on Nuclear Risk Management and chairs the working group responsible for the ANS/ASME Standard for external flooding probabilistic risk assessment at nuclear power plants.