200 PROCEEDINGS of the HUMAN FACTORS AND ERGONOMICS SOCIETY 38th ANNUAL MEETING-1994 OPERATOR PERFORMANCE IN COGNITIVELY COMPLEX SIMULATED EMERGENCIES: IMPLICATIONS FOR COMPUTER-BASED SUPPORT SYSTEMS

An empirical study was conducted examining operator performance in cognitively demanding simulated nuclear power plant emergencies. During emergencies operators follow highly prescriptive written procedures. The objectives of the study were to understand and document what role higher-level cognitive activities such as diagnosis, or more generally 'situation assessment, ' play in guiding operator performance, given that operators utilize procedures in responding to the events. The study examined crew performance in two simulated emergencies. Up to 11 crews from each of two plants participated in two simulated emergencies for a total of 38 cases analyzed. Crew performance was videotaped and partial transcripts were produced and analyzed. The results revealed a number of instances where higher-level cognitive activities such as situation assessment and response planning enabled operators to handle aspects of the situation that were not fully addressed by the procedures. This paper describes these cases and discusses their implications for the design of computer-based support systems