The purpose of this study was to develop an Expert System (ES) to evaluate Nuclear Power Plant (NPP) operators. The study included a review of the Artificial Intelligence (AI) literature relevant to the NPP and human resource management, knowledge acquisition, knowledge representation, knowledge encoding, and Inference engine. An expert system development tool FuzzyCLIPS6.1 was used to develop a fuzzy rule-based expert system called NPPOEX. NPP operator records obtained from a Chinese NPP were entered into NPPOEX and the system produces a crisp value for Evaluation in the range [0,1], a certainty factor and brief explanations for the result.