Extending the Dynamic Flowgraph Methodology (DFM) to Model Human Performance and Team Effects (NUREG/CR-6710)

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Publication Information

Manuscript Completed: January 2001
Date Published: March 2001

Prepared by:
A. Milici, R. Mulvihill, S. Guarro

ASCA, Inc.
704 Silver Spur Road
Rolling Hills, CA 90274

J. J. Persensky, NRC Project Manager

Prepared for:
Division of Systems Analysis and Regulatory Effectiveness
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

NRC Job Code W6251

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This report addresses the development of a structure for the modeling and analysis of control room teams to represent team related human errors of commission and omission in nuclear power plant accident scenarios. The structure includes the identification of unsafe actions (UAs) and error forcing contexts (EFCs) during abnormal or accident situations that can lead to a human failure event. This report also describes guidelines for the screening of sequences for which a dynamic flowgraph methodology (DFM) analysis could be effectively applied. The screening, DFM modeling and DFM analysis processes are demonstrated, via case studies, within the general human reliability analysis approach provided by the ATHEANA framework. In addition, this report describes extensions to the DFM methodology devised specifically to facilitate its application to teams effects modeling and analysis; in particular, it describes a library of pre-built DFM model modules that represent typical team-related cognitive, assessment and interaction processes.

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