United States Nuclear Regulatory Commission - Protecting People and the Environment

International HRA Empirical Study – Phase 1 Report (NUREG/IA-0216, Volume 1)

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Publication Information

Date Published: November 2009

Prepared by:
E. Lois 1, V.N.Dang2, J. Forester3, H. Broberg5,
S. Massaiu5, M. Hildebrandt5,P. Ø. Braarud5,
G. Parry1, J. Julius4, R. Boring3, I. Männistö5,
A. Bye5

1 U.S. Nuclear Regulatory Commission, USA
2 Paul Scherrer Institute, Switzerland
3 Sandia National Laboratories, USA
4 Scientech, USA
5 OECD Halden Reactor Project, Norway

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

Availability Notice


Volume 1 of NUREG/IA-0216 documents the Pilot Phase of the International Human Reliability Analysis (HRA) Empirical Study. This three-phase study is a multinational, multiteam effort supported by the Organization for Economic Cooperation and Development (OECD) Halden Reactor Project, the Swiss Federal Nuclear Safety Inspectorate, the U.S. Electric Power Research Institute, and the U.S. Nuclear Regulatory Commission (NRC). The Pilot has also been documented as a Halden publication: HWR-844, October 2009.

The objective of this study is to develop an empirically based understanding of the performance, strengths, and weaknesses of different HRA methods used to model human response to accident sequences in probabilistic risk assessments (PRAs). The empirical basis was developed through experiments performed at the Halden Reactor Project HAMMLAB (HAlden huMan-Machine LABoratory) research simulator, with real crews responding to accident situations similar to those modeled in PRAs. The scope of the study is limited to HRA methods thought appropriate for use in PRAs evaluating internal events during full power operations of current light water reactors. The study consists of performing HRAs for predefined human actions, with different HRA teams using different methods. Nuclear power plant crews perform these human actions at the Halden simulator, Halden experimentalists collect and interpret the data to fit HRA data needs, and an independent group of experts compare the results of each HRA method/team to the Halden crew performance data.

The Pilot Phase consisted of developing, testing, and revising the study's methodology and design. Phase 2, which will be documented in Volume 2, consists of the comparison of HRA predictions for all nine steam generator tube rupture human actions. Phase 3, which will be documented in Volume 3, consists of the comparison of four loss-of-feedwater human actions, as well as documentation of the overall study results. The results of the Empirical Study will provide a technical basis for improving individual methods, improving existing guidance documents for performing and reviewing HRAs (e.g., NUREG-1792, HRA Good Practices), and developing additional guidance and training materials for implementing individual methods.

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