Evaluation of Human Reliability on the Basis of Operational Experience
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Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH [Society for Systems and Reactor Safety Inc] Evaluation of Human Reliability on the Basis of Operational Experience Dissertation GRS-170 Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH [Society for Systems and Reactor Safety Inc] Evaluation of Human Reliability on the Basis of Operational Experience Dissertation of Oliver Sträter August 2000 GRS-170 ISBN 3-931995-37-2 Note: The printout is tested on various printers showing problems that cannot be covered in advance. In case the printout has some layout failures please · try to adjust the printer-font settings into either “loading true-type fonts as bitmap” or “loading true-type fonts as graphics” in case the text has some misprints (like incorrect hyphenation) · try to adjust the graphic settings in case the pictures and/or tables are incorrect or improper (graphics grid, graphics color settings in the printer driver) · consider that the document was formatted for European standard pages sized A4 (21 cm * 29,7 cm). To assure the original size of the document, please disable the check-box “Fit to page”. To adjust the page to other formats, please enable the check-box “Fit to page” in the Print Dialog Box of Acrobat Reader. · see for further Information "www.lfe.mw.tum.de/forschung/mms/cahr". This book is a complete Translation of the Report GRS-138 "Beurteilung der menschlichen Zuverlässigkeit auf Basis von Betriebserfahrung" published January 1997 by GRS, Co- logne/Germany (ISBN 3-923875-95-9). All rights reserved. No part of this book may be used or reproduced in any manner whatsoever without written permission, except in the case of referred quotations. Key Words: Operational Experience, Human Reliability Assessment, Human Reliability Analysis, HRA, Data Bank, Evaluation, System of Experts, Error, Human, Model, Probabilistic Safety Analyses, Reliability Chair of Ergonomics of the Munich Technical University Evaluation of Human Reliability on the Basis of Operational Experience Oliver Sträter Translation of the Complete copy of the dissertation towards the academic degree of Doctor of Philosophy approved by the Faculty of Economics and Social Sciences of the Munich Technical University. Chairman: Univ.-Prof. Dr. rer. pol. Dr. h.c. R. Reichwald Dissertation Examiners: 1. Univ.-Prof. Dr. rer. nat. H. Bubb 2. Univ.-Prof. Dr. rer. nat. B. Zimolong, Ruhr University Bochum The dissertation was submitted to the Munich Technical University on 21 May 1996 and was accepted by the Faculty of Economics and Social Sciences on 15 January 1997. Summary This dissertation was conducted at the Society for Systems and Reactor Safety, Inc. [GRS - Gesellschaft für Anlagen und Reaktorsicherheit], on the basis of project RS 872 of the Federal Ministry of Research and Technology [BMBF], entitled „Development of Methodological Foundations and Computation Programs for Probabilistic Safety Analyses.“ A central problem in the evaluation of human reliability is represented by the fact that the data needed for the evaluation procedure have thus far been incomplete and have been inadequately validated. Practical experience in the form of error events does constitute a source that thus far has not been used in a systematic manner and is suitable for solving this data problem. The object of this dissertation was to develop a method for the evalua- tion of events with a view to the human factor and to make the practical experience con- tained in events useful in terms of qualitative and quantitative evaluations of human reliability. To develop the method, available models were used for the purpose of qualita- tive evaluation of human error behavior (for instance, Swain, Hacker, Rasmussen) and various approaches providing a quantitative evaluation of human error actions were investigated (for example, Technique for Human Error Rate Prediction [THERP], Accident Sequence Evaluation Programs [ASEP], Human Action Reliability [HCR], Success Likeli- hood Index Method [SLIM], in an effort to prepare a profile of requirements. On that basis, a method was developed for the acquisition and evaluation of erroneous actions. The method is broken down into the two sectors of event analysis and event evaluation: first of all, events are analyzed regarding all information that is significant for errors in human actions. In addition to data on the course of a particular event, consideration was also given to possible conditions leading to the failure of a particular action. An evaluation of human reliability calls for manifold evaluation possibilities; therefore, to evaluate the collected events, a connectionism method was developed on the basis of a discussion of various approaches from artificial intelligence; this connectionism method facilitates both qualitative and quantitative statements in a uniform approach. To test the efficiency of the method, a set of 165 events featuring human error behavior were investigated from the „Special Events“ databank of the Society for Systems and Reactor Safety. The analysis of these cases offered new findings regarding the error I mechanisms and the validation of data of existing assessment methods. Among other things, it was also possible to trace errors of confusion back to an interference effect of cognitive skills. Furthermore, 30 factors that influence human reliability were identified from this operational experience. In order to investigate quantitative statements regarding human reliability in addition to qualitative data, the data from practical operational experi- ence were compared to 79 items of the THERP method. Overall, there was good agree- ment between the predictions derived from practical operational experience with the ones of THERP. Some deviations - that are important to probabilistic analyses - were also found. Wide use of the analysis method presented here would facilitate a better estimate of these deviations. The successful validation also lead to the conclusion that the method presented here might be used as an approach towards a further developed process for the analysis 1 and evaluation of human reliability. 1 Many other work has been performed in the area of enhancing the Human Reliability Assessment methods in the years during and after the study presented here. Therefore this study represents only one brick in the wall of progress in this area. Besides this study, the author would like to mention especially the ATHEANA-method, the MERMOS-method, the work conducted in the OECD-PWG5 Task 97-2 on "Errors of Commission", the common project of PSI/Switzerland and GRS/Germany and the CREAM-method. See for these developments the Literature below. The developments couldn't be included in this work since this study was finished end of 1995. All these activities are now concentrated in the MOSAIC-group where the various methods in relation to "Errors of Commission" are discussed and elaborated. For having a look at these, see the section: "Related Bibliography after first Publication of this Book" (p. 276). II Acknowledgments At this point, I would like to express my thanks to all those who contributed to the produc- tion of this study. I want to express my special gratitude here to Professor Heiner Bubb (Chair of Ergonomics of the Munich Technical University) who always helped me in solving problems and who provided valuable suggestions for this work. I want to thank Professor Bernhard Zimolong for his great interest in my work and for taking on the job of second reporter. I also thank Wolfgang Preischl (GRS), Dr. Bernhard Reer (former Juelich Research Center, now Paul Scherrer Institute), Juergen Bonfert (former ISTec, now Siemens), the „Human Reliability and Safety“ study group of the Association of German Engineers, as well as the EARTH study group (see Mosneron-Dupin et al., 1997) for the numerous technical discus- sions on the topics of human reliability, data processing, and artificial intelligence. This work would have been inconceivable also without the moral support of my family and Christina, as well as many staff members of the GRS, among whom I would like to express my special thanks to Dr. David Beraha, Dr. Werner Bastl and Thomas Voggenberger. · Acknowledgments for the Translation of this Book This translation would not exist without the initiative of Mrs. Ann Ramey-Smith from the US Nuclear Regulatory Commission (NRC), former technical coordinator of the ATHEANA method. I would like to convey my gratitude and special thanks to her. The translation was performed by the NRC (NRC-3447) with the intention to supplement the information about the CAHR method provided in the report of the OECD-PWG5 Task 97-2 on "Errors of Commission" (OECD-NEA, 2000) and to facilitate the exchange of information about innovations in methods for human reliability analysis. III Table of Contents Summary.............................................................................................................................I Acknowledgments ............................................................................................................III Table of Contents ............................................................................................................ IV List of Tables ................................................................................................................. VIII List of Figures ................................................................................................................... X List of Abbreviations ......................................................................................................XIV