The U.S. HRA Empirical Study – Assessment of HRA Method Predictions against Operating Crew Performance on a U.S. Nuclear Power Plant Simulator (NUREG-2156)

On this page:

Download complete document

Publication Information

Manuscript Completed: September 2015
Date Published:
June 2016

Prepared by:
John Forester1,7, Huafei Liao1, Vinh N. Dang2, Andreas Bye3, Erasmia
Lois4, Mary Presley5, Julie Marble4, Rod Nowell6, Helena Broberg3,
Michael Hildenbrandt3, Bruce Hallbert7, and Tommy Morgan7

1Sandia National Laboratories, Albuquerque, NM, USA
2Paul Scherrer Institute, Villigen PSI, Switzerland
3OECD Halden Reactor Project, Institute for Energy Technology, IFE, Haden, Norway
4U.S. Nuclear Regulatory Commission, Washington, DC, USA
5Electric Power Research Institute, Palo Alto, CA, USA
6South Texas Project, TX, USA
7Idaho National Laboratory, Idaho Falls, ID, USA

Erasmia Lois and Y. James Chang, NRC Project Managers

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

Availability Notice


This report documents the U.S. Human Reliability Analysis (HRA) Empirical Study (referred to as the U.S. Study in the report), which is a large systematic data collection effort supported by the U.S. Nuclear Regulatory Commission with participation of organizations from five countries representing industry, regulators, and the research community. The objective of the U.S. Study was to improve the insights developed from the International HRA Empirical Study [1–4] (referred to as the International Study) and address the limitations of that study.

Similar to the International Study, the U.S. Study evaluated the performance of different HRA methods by comparing method predictions to actual crew performance in simulated accident scenarios conducted in a U.S. nuclear power plant (NPP) simulator. There was significant agreement in the findings and conclusions between the International and U.S. studies in terms of the strengths and weaknesses of the HRA methods evaluated in both studies and in the overall findings about HRA and the identified needed improvements. In addition to identification of some new HRA- and method-related issues, the design of the U.S. Study allowed insights to be obtained on some issues that were not resolved in the International Study. In particular, because multiple HRA teams applied each method in the U.S. Study, comparing their analyses and predictions allowed separation of analyst effects from method effects and allowed conclusions to be drawn on aspects of methods that are susceptible to different application or usage by different analysts that may lead to differences in results. The findings serve as a strong basis for improving the consistency and robustness of HRA, which in turn facilitates identification of mechanisms for improving operating crew performance in NPPs.

Page Last Reviewed/Updated Tuesday, March 09, 2021