Human-machine Interaction in Nuclear Power Plants

Recently, the use of computers has rapidly expanded in every field of human endeavor. From the viewpoint of research on human-machine systems, we see that computers do many tasks automatically at the human-machine interface. Because computers themselves are machines, modern machine systems have a double structure of machines within machines; that is, the original machines built-in computers. The complexity of human-machine systems derives from the double-structured machine system. In these systems, computers replace the traditional human works of manual control by automatically controlling systems step by step. In addition, the problem of the human factor is emerging due to frequent human errors (or cognitive errors) in human-machine interaction. The safety problem of cognitive errors at the humanmachine interface is universal, as evidenced by two severe accidents at nuclear power plants, namely the Three Mile Island accident in 1979 and the Chernobyl accident in 1986. Since then, numerous studies have been conducted on the human factor in many nuclear power plants developing countries around the world with a view to understanding the nature and characteristics of humanmachine interaction and to overcome problems with the human-machine interface. Nuclear power plants are generally large complex plants with highly automated systems. Whenever a rare plant emergency occurs, the plant operators must cope with the emergency under severe mental stress without committing any fatal errors. In addition, the operators must train to improve and maintain their ability to cope with every conceivable situation, though it is almost impossible to be fully prepared for an infinite variety of situations In view of the limited capability of operators in emergency situations, there has been a new approach to preventing the human error caused by improper humanmachine interaction. Based on the concept of humancentered human-machine systems, the new approach has been triggered by the introduction of advanced information systems that help operators recognize and counteract plant emergencies. We now discuss the adverse effect of automation in human-machine systems, followed by human-machine systems for ideal human-machine interaction. Lastly, new proposals will be presented on how to organize technologies that effectively enable various states to be Advanced nuclear power plants are generally large complex systems automated by computers. Whenever a rare plant emergency occurs the plant operators must cope with the emergency under severe mental stress without committing any fatal errors. Furthermore, The operators must train to improve and maintain their ability to cope with every conceivable situation, though it is almost impossible to be fully prepared for an infinite variety of situations. In view of the limited capability of operators in emergency situations, there has been a new approach to preventing the human error caused by improper human-machine interaction. The new approach has been triggered by the introduction of advanced information systems that help operators recognize and counteract plant emergencies. In this paper, the adverse effect of automation in human-machine systems is explained. The discussion then focuses on how to configure a joint human-machine system for ideal human-machine interaction. Finally, there is a new proposal on how to organize technologies that recognize the different states of such a joint human-machine system.