A critical task performed by the operators in nuclear power plants is to monitor the technical specification. However, monitoring the technical specification is known as one of the difficult tasks due to the bulk of the document, the complexity of the contents, diversity of the interpretation, time-dependent, and high workloads. Due to these difficulties, this study proposes an operator support system to monitor technical specification. The development process consists of analysis, design, and implementation. First, this study analyses structure and surveillance requirements in the technical specification. Then, functional requirements are drawn. Second, the architecture of the system is suggested. The artificial intelligence techniques are analysed and compared for implementation of monitoring functions. Lastly, a prototype was developed by implementing the design.