ABSTRACT
High risk environments such as control rooms are extremely stressful for front line operators because they are solely responsible for ultimate decision making under high task load situations during accidents involving a large complex system. Individuals working as a team constantly interact with each other and therefore introduce team related issues such as coordination, supervision and conflict resolution which are influenced by nontechnical, cognitive and social skills of team members. The aggregate impact of multiple human errors inside communication loops in a team context can give rise to complicated failure modes; thus the reliability of human to human interactions in a safety critical environment is extremely important. This research develops a systematic method to explicitly model the operating crew as a social interactive unit and investigate their dynamic behavior under upset situations through the application of simulation methods. The ultimate goal is to capture and study the effects of team factors and team dynamics on system risk with main focus being on team errors, associated causes and error management processes and their impact on team performance. Meanwhile, team activities such as information collection and sharing, structure of shared mental models, team decision making and combined action execution are modeled and examined. An object based modeling methodology is applied to represent system elements and different roles and behaviors within the operating team. The basic ingredients of the individual operator model are from IDAC (Information, Decision, and Action in Crew context) cognitive model, and scenario generation follows typical DPRA (Dynamic Probabilistic Risk Assessment) methodologies. The approach is applied to simulate the operating crew behavior in response to malfunctions of a four train feed water system as a representation of a larger size plant in order to demonstrate the proposed modeling and simulation capabilities. Different configurations of team characteristics and influencing team factors have been simulated and compared to each other by observing parameters of interest. In addition, this research has developed CREWSIM, a customized library in MATLAB Simulink environment which facilitates the modeling process for similar applications of the methodology.
