NUREG/CR-4862, Vol. 3, "Cognitive Environment Simulation: an Artificial Intelligence System for Human Performance Assessment, Cognitive Reliability Analysis Technique."

This report documents the results of Phase II of a three phase research program to develop and validate improved methods to model the cognitive behavior of nuclear power plant (NPP) personnel. In Phase II a dynamic simulation capability for modeling how people form intentions to act in NPP emergency situations was developed based on techniques from artificial intelligence. This modeling tool, Cognitive Environment Simulation or CES, simulates the cognitive processes that determine situation assessment and intention formation. It can be used to investigate analytically what situations and factors lead to intention failures, what actions follow from intention failures (e.g., errors of omission, errors of commission, common mode errors), the ability to recover from errors or additional machine failures, and the effects of changes in the NPP person-machine system. The Cognitive Reliability Assessment Technique (or CREATE) was also developed in Phase II to specify how CES can be used to enhance the measurement of the human contribution to risk in probabilistic risk assessment (PRA) studies. The results are reported in three self-contained volumes that describe the research from different perspectives. Volume 1 provides an overview of both CES and CREATE. Volume 2 gives a detailed description of the structure and content of the CES modeling environment and is intended for those who want to know how CES models successful and erroneous intention formation. Volume 3 describes the CREATE methodology for using CES to provide enhanced human reliability estimates. Volume 3 is intended for those who are interested in how the modeling capabilities of CES can be utilized in human reliability assessment and PRA.