Operator cognitive processes under abnormal plant conditions with conventional and advanced control room designs

Using a real-time simulator, an experimental study was conducted to analyze operator cognitive processes under abnormal plant conditions. A two-factor design was used, in which two levels of scenarios and three levels of mode generated by the combination of the addition of secondary malfunction(s) and two levels of man-machine interface design created six modes of operations. As the primary source of information with which the cognitive processes would be analyzed, verbal protocols were collected by the think-aloud method. The analysis of protocol patterns suggested that the use of protocols can be useful only as a supplemental information source, since it was found to be difficult to extract information from them that would enable straightforward analysis of cognitive information processes such as diagnosis and operational decision-making. In order to obtain a better method, it is considered necessary to establish a means which enables accurate tracing of parameters monitored by operators to introduce models with which monitored parameter sequences are analyzed in terms of information processing strategies.<>