Protective systems: Definitions and terms in the regulated risk assessment setting^éi

This paper reports on the initial results of ongoing multidisciplinary research to generate a common language for protective system risk analysis. Although established for risk analysis in the commercial nuclear power industry, these definitions can be generalized and used in other regulated profit-making enterprises. As collaborators in large-scale industry-academia-regulatory Probabilistic Risk Assessment (PRA) projects, the authors have found that misunderstanding the terms used in communication between the industry and regulator can reduce efficiency. For example, if the industry practitioner believes "deterministic analysis" is unrelated to PRA, product rework may be indicated. A review of academic literature and the Nuclear Regulatory Commission's (NRC's) website shows that some "definitions" have been assigned, through, for example, a glossary developed for general use. When agreed upon among industry and regulatory investigators, more precise definitions for several common terms such as; Risk, Risk-Informed, Probabilistic Risk Assessment, Prescriptive, Deterministic, Conservative, Risk-Based, Performance Based, and Uncertainty would be helpful in a setting of commercial nuclear power protective systems under regulation. The suggested definitions are based on the authors' information extraction and interpretations from diverse references, or based on industry expert experience. The authors will continue this research to expand the scope of these terms and to seek feedback from industry, aca-demia, and regulatory agencies, hoping to create a consensus among them. Defining these terminologies is important for efficient implementation of risk assessment information relevant to protective systems used in regulated for-profit enterprise.