Levels of Automation and User Control in Use of an Automatic Turbine System

This paper describes an empirical field study performed in a nuclear power plant simulator control room and presents how the use of an automatic turbine system (ATS) affects nuclear power plant turbine operators' ability to stay in control during different levels of automation. The paper also presents how the operators cope with the automation interface and how their problem solving ability is affected by varying levels of automation. The Contextual Control Model (COCOM) was used to analyse the turbine operators' work with the ATS. The aims were to investigate how the ATS design support the turbine operators in their work in terms of monitoring and controlling the turbine process, and to identify possible improvements in the ATS user interface design. Seven turbine operators were interviewed during the simulator training session. The results of the interviews point out that automation related problems such as out-of-the-loop performance and loss of skills exist in the control room setting. The use of COCOM as a means for analysis provided explanations to these results and implied that time for evaluation is an important factor for effective performance. Finally, improving the visibility of the underlying program logic was found to be the most important measure to enhance the ATS interface.