Glossary of Risk-Related Terms in Support of Risk-Informed Decisionmaking (NUREG-2122)

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Publication Information

Manuscript Completed: May 2013
Date Published: November 2013

Prepared by:
M. Drouin1, M. Gonzalez1,
S. Herrick1, J. S. Hyslop1, D. Stroup1
J. Lehner2, T. Pratt2
M. Dennis3, J. LaChance3, T. Wheeler3

1U.S. Nuclear Regulatory Commission
Washington, DC 20555

2Brookhaven National Laboratory
Upton, NY 11973

3Sandia National Laboratories
Albuquerque, NM 87185

M. Drouin, NRC Project Manager

Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

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The policy statement on the “Use of Probabilistic Risk Assessment (PRA) Methods in Nuclear Regulatory Activities” (Ref. 31) expressed the Commission’s belief that the use of PRA technology in U.S. Nuclear Regulatory Commission (NRC) regulatory activities should be increased. Consequently, the NRC carried out numerous risk-informed activities in all areas of NRC regulation. With increased risk-informed activities came the recognition that the agency could enhance regulatory stability and efficiency if it implemented the many potential applications of risk information in a consistent and predictable manner. An essential part of consistent and predictable implementation is the use of consistent terminology to ensure accurate communication and transfer of information. Further, the NRC recognizes that some risk-related terms have been used in ambiguous ways by practitioners. The increased development of guidance documents, regulations, and procedures related to risk-informed activities makes the fundamental understanding of these risk-related terms more imperative. Consistent terminology is essential to the appropriate implementation of risk-informed activities and the communication between the NRC and its stakeholders. It allows practitioners to eliminate communication issues and avoid unnecessary discussions that may have been erroneously perceived as technical issues. Therefore, a glossary with agreed-upon definitions of risk-informed related terms is an essential tool for future risk-informed activities. This glossary addresses risk-related terms used in the context of risk associated with a reactor of a nuclear power plant.

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