This paper describes development of GRAPE, a plant simulator for introductory education of nuclear engineering and nuclear safety. GRAPE is not a full-featured real-time simulator but a kind of scenario-based analysis and visualization platform using a best-estimate code such as RELAP/SCDAPSIM. The PWR and BWR plant models which can be adopted to the scenarios under severe accident conditions are also developed and maintained.
GRAPE is designed and implemented by taking advantage of recent technologies of the Web such as HTML5, CSS and JavaScript in combination with the modern software architecture. Intuitive graphical user interface was established to meet user needs while maintaining flexibility, extensibility and maintainability. It is also effective for study and research projects as visualization and/or sensitivity platforms since GRAPE can import existing RELAP-based calculation results using a converting utility program to visualize the calculation results. A macro language is available to automate the workflow in sensitivity analysis and make the process more efficient.