Abstract
Research issues in the development of methodology and analysis techniques to study how nuclear power plant operators cope with multi-fault incidents are discussed. Simulation was selected as the best means of observing operator behaviour. Factors which influence the retention of realism in the simulation scenario are described. A post-simulation commentary technique was used to obtain data to support the analysis of cognitive processes. The influence of such questions concerning the unit of behaviour, the classification, organization, and assessment of operator behaviour and the associated terminology on die development of the analysis techniques is discussed.