Andreas Bye

Principles for modelling function allocation

Automation is the key element in safety, reliability of industrial processes. Selecting the right type and level of automation requires careful consideration of how to allocate tasks between operators and automation. This is important in order that the joint system, human and machine as seen together, perform in the intended manner. The Halden Reactor Project is currently engaged in a project to study this topic, with an emphasis on maximizing the operators ability to maintain control and handle unexpected events. Functional models can be used to study this in a process control environment, because they explicitly describe the functions that must be provided by the process or the operator. This paper describes how functional modelling of the joint system can be used to provide a basis for how functions should be allocated.

Human–machine function allocation: a functional modelling approach

Abstract Function allocation between humans and systems is an important factor regarding safety, reliability and efficiency of industrial processes. One should allocate functions in order to maximise the operators situation understanding and ability to handle unexpected events. Functional models can be used to study function allocation in a process control environment, because they explicitly describe functions and tasks of both the plant and the operator. The Halden Reactor Project is currently engaged in such a project called function allocation methods (FAME), aimed specifically at the work in a nuclear power plant control room. This paper describes the main features of the approach, and discusses how functional modelling can be used to address the issue of how much information is necessary for the operator, and thereby give a basis for how functions should be allocated.

Bridging Human Factors and Human Reliability Analysis

Human factors (HF) and human reliability analysis (HRA) are often treated as two distinct disciplines. The former is seen under the purview of experimental psychology, while the latter is linked to an engineering approach for risk assessment. Despite this seeming separation, there exists significant overlap between these approaches, and it may be argued that the two disciplines are, in fact, more integrated than dissimilar. This paper explores the historical origins of the perceived differences between HF and HRA, discusses the seemingly disparate data end products of HF and HRA, and proposes a research framework in which the complementary nature of HF and HRA is fully realized.

Capturing control room simulator data with the HERA System

The Human Event Repository and Analysis (HERA) system has been developed as a tool for classifying and recording human performance data extracted from primary data sources. This paper reviews the process of extracting data from simulator studies for use in HERA. Simulator studies pose unique data collection challenges, both in types and quality of data measures, but such studies are ideally suited to gather operator performance data, including the full spectrum of performance shaping factors used in a HERA analysis. This paper provides suggestions for obtaining relevant human performance data for a HERA analysis from a control room simulator study and for inputting those data in a format suitable for HERA.

An empirical study of HRA methods - overall design and issues

A diversity of Human Reliability Analysis (HRA) methods are currently available to treat human performance in Probabilistic Risk Assessments (PRAs). This range of methods reflects traditional concerns with human-machine interfaces and with the basic feasibility of actions in PRA scenarios as well as the more recent attention paid to Errors of Commission and decision- making performance. Given the differences in the scope of the methods and their underlying models, there is a substantial interest in assessing HRA methods and ultimately in validating the approaches and models underlying these methods. A significant step in this direction is an international evaluation study of HRA methods, based on comparing the observed performance in simulator experiments with the outcomes predicted in HRA analyses. Its aim is to develop an empirically- based understanding of the performance, strengths, and weaknesses of the methods. This paper presents the overall methodology for this initial assessment study.

International HRA Empirical Study, Overall Methodology and HAMMLAB Results

The International HRA Empirical Study addresses the need for assessing HRA (Human Reliability Analysis) methods in light of human performance data. The study is based on a comparison of observed performance in HAMMLAB simulator trials with the outcomes predicted in HRA analyses. The project goal is to develop an empirically-based understanding of the performance, strengths, and weaknesses of a number of different HRA methods. This chapter presents the overall methodology for the initial assessment study (the pilot study), provides an overview of the HAMMLAB results and presents insights from the initial assessment.

Studies for the Future

Over the coming years, new generations of reactors are going to be introduced with new reactor designs and new control room technologies. Also, extensive upgrades and modernisations of the current fleet of reactors will take place, introducing new control room technologies. In light of that, this chapter discusses what kind of HAMMLAB research is needed in the future. A set of relevant research topics are suggested, future research methods are discussed, and technical requirements for future studies in HAMMLAB are considered.

Improving the Empirical Basis for Human Reliability Assessment by Simulator Experiments

The OECD Halden Reactor Project has incorporated Human Reliability Assessment (HRA) as a central point in its research program for 2003–2005. As part of this, several activities are undergoing in co-operation with Idaho National Engineering and Environmental Laboratory and the U.S. Nuclear Regulatory Commission to support the need for more empirical data for HRA. This paper describes how empirical data from simulator studies in HAMMLAB (HAlden huMan-Machine LABoratory) may support improvements to HRA methods.