Abstract
As to operations in dynamic environments, especially in coping with anomalies, it has been considered as a crucial issue to ensure the operabilities and adaptibities of interfaces suitable to human cognitive performance. Factors contributing to improvements of the human interface may have diverse varieties, however, one of the most desirable and crucial factors is reducing operators' workload in coping with anomalies, because relatively high performance should be required in emergency situations. This paper presents the methodology for evaluating dynamic workload of four different cognitive functions separately such as perception, thought, memory, and behavior by simulating operator's cognitive and behavioral activities. Simulations were executed in coping with anomalies occurring at a simplified boiling water reactor (BWR). Simulation results involve plant transients, communications between operators, and both operations and actions including cognitive behavior of each operator. These results were compared with those obtained in the experiments including typical four kinds of malfunctions, and so it was shown that both were in good agreements. In the simulations, the activating frequencies of each cognitive function were accumulated during a periodic interval. It was suggested that obtained frequencies would be considered to indicate a relative strength of each workload component. It means that this methodology could be applicable to making relative comparisons between several types of human interfaces without manufacturing mockups, in the respect of operators' workload.
