2020/09/01 by Martin Wortman, Wortman, Martin, Ernest Kee +3
Decision Sciences · Engineering · #Diverse Scientific and Engineering Research #FOS: Computer and information sciences #FOS: Electrical engineering #Methodology (stat.ME) #Probabilistic and Robust Engineering Design #Risk and Safety Analysis #Systems and Control (eess.SY) #electronic engineering #information engineering
paper · pdf · doi:10.48550/arxiv.2009.00208
openalex publication_date 2020/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Certain modeling assumptions underlying Probabilistic Risk Assessment (PRA) allow a simple computation of core damage frequency (CDF). These assumptions also guarantee that the time remaining until a core damage event follows an exponential distribution having parameter value equal to that computed for the CDF. While it is commonly understood that these modeling assumptions lead to an approximate characterization of uncertainty, we offer a simple argument that explains why the resulting exponential time until core damage distribution under-estimates risk. Our explanation will first review operational physics properties of hazard functions, and then offer a non-measure-theoretic argument to reveal the the consequences of these properties for PRA. The conclusions offered, here, hold for any possible operating history that respects the underlying assumptions of PRA. Hence, the measure-theoretic constructs on filtered probability spaces is unnecessary for our developments. We will then conclude with a brief discussion that connects intuition with our analytical development.