THE IDA COGNITIVE MODEL FOR THE ANALYSIS OF NUCLEAR-POWER-PLANT OPERATOR RESPONSE UNDER ACCIDENT CONDITIONS .1. PROBLEM-SOLVING AND DECISION-MAKING MODEL

This paper is the first of a series of papers describing IDA which is a cognitive model for analysing the behaviour of nuclear power plant o perators under accident conditions. The domain of applicability of the model is a relatively constrained environment where behaviour is sign ificantly influenced by high levels of training and explicit requireme nt to follow written procedures. IDA consists of a model for individua l operator behaviour and a model for control room operating crew expan ded from the individual model. The model and its derivatives such as a n error taxonomy and data collection approach has been designed with u ltimate objective of becoming a quantitative method for human reliabil ity analysis (HRA) in probabilistic risk assessment (PRA). The present paper gives a description of the main components of IDA such as memor y structure, goals, and problem solving and decision making strategies . It also identifies factors that are at the origin of transitions bet ween goals or between strategies. These factors cover the effects of e xternal conditions and psychological state of the operator. The descri ption is generic at first and then made specific to the nuclear power plant environment and more precisely to abnormal conditions. (C) 1997 Elsevier Science Limited. All rights reserved.