This article describes the development of some computerized operator support systems in the FRG with the main emphasis on safety aspects. The tasks of the systems are to: Log and record disturbances and accidents. Reduce the information load and present only essential alarms and messages. Improve signal supervision and verification. Enable a fast survey of the plant status (especially in case of accidents) and of the character and location of a disturbance. Carry out automatic diagnosis of disturbances. Compute process parameters that cannot be measured directly. Support operators as they follow procedures in the operating manual