Expert systems are a new and fast-changing field of artificial intelligence that is currently being adapted for use in all areas of the nuclear industry. This monograph provides both a compilation and a critical review of the ways expert systems can be applied to the design, management, and operation of research, test, and commercial power reactors. The applications are identified and assessed relative to the capability of the technology. Specific systems are also examined in detail. Almost 300 expert systems are described, grouped under more than 60 different applications.