1. A system for receiving monitoring parameter input signals from a plurality of monitors monitoring operation of a nuclear reactor said system comprising: a data base containing predetermined setpoints; means for identifying abnormal behavior of said nuclear reactor by utilizing said setpoints and said input signals from said monitors; means for determining a cause of said identified abnormal behavior including predetermined artificial intelligence rules associated with each primary one of said monitoring parameters and based on performance of preselected related secondary ones of said monitoring parameters; and means for determining a control parameter to mitigate said abnormal behavior.