United States Nuclear Regulatory Commission - Protecting People and the Environment

An Integrated Human Event Analysis System (IDHEAS) for Nuclear Power Plant Internal Events At-Power Application (NUREG-2199, Volume 1)

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Publication Information

Date Published: May 2016

Prepared by:

Jing Xing1, Gareth Parry2, Mary Presley3,
John Forester4, Stacey Hendrickson5, Vinh Dang6
1 U.S. Nuclear Regulatory Commission
2 Jensen Hughes, Inc.
3 Electric Power Research Institute
4 Idaho National Laboratory
5 Sandia National Laboratories
6 Paul Scherrer Institute, Switzerland

U.S. Nuclear Regulatory Commission
Office of Nuclear Regulatory Research (RES)
Washington, D.C. 20555-0001

U.S. NRC-RES Project Managers
Erasmia Lois and Jing Xing

Electric Power Research Institute (EPRI)
3420 Hillview Avenue
Palo Alto, CA 94304-1338

EPRI Project Managers
Stuart Lewis and Mary Presley

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

Availability Notice


This report is Volume 1 of the NUREG-2199 series that describes a new human reliability analysis (HRA) method, an Integrated Human Event Analysis System (IDHEAS) for Nuclear Power Plant Internal Events At-Power Application. This report is a technical basis document of the method. IDHEAS for Nuclear Power Plant Internal Events At-Power Application was developed based on the cognitive basis for human reliability analysis (NUREG-2114) and IDHEAS General Methodology (NUREG-2198). It incorporates the strengths of existing methods and addresses their weaknesses. The goals were to reduce analyst-to-analyst variability in HRA, add realisms to HRA, improve transparency and traceability of the HRA process, and base the method on state-of-art understanding of human cognition and behaviors. IDHEAS improves upon existing HRA methods by providing a structured approach to task analysis through crew response diagrams, a model addressing time uncertainties, a quantification model based upon insights from cognitive psychology and human behavior literature, and a set of human error probabilities in the quantification model estimated by a structured panel of informed experts. The method addresses post-initiating, internal at-power events. It assumes that the crews being modeled are the nuclear power plant control-room crews that have been trained to work together within pre-defined team structures and work processes. Therefore, it models the errors made by trained crews performing required responses to plant disturbances. It is applicable to development of probabilistic risk analysis models for internal at-power events and can be used to support risk-informed decision-making including the Significance Determination Process and the Accident Sequence Precursor programs.

This report focuses on the technical basis aspects of the method, while other reports in the NUREG-2199 series will describe the process of estimating human error probabilities through expert judgment (Volume 2), the process and results of testing the method (Volume 3), and the users manual of the method (Volume 4).

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