Development of RELAP5-3D Model for an Integrated Test Facility for Advanced Reactor Systems

This paper presents the development and application of a RELAP5-3D model to assist in the design optimization of a 5-MW(thermal) integrated electrically heated test facility, making it capable of simulating the transient behaviors of advanced reactor systems based on high-temperature gas-cooled reactors and sodium-cooled fast reactors with various production modes, such as power generation, hydrogen cogeneration, and heat storage. Built upon the existing capability of the RELAP5-3D code, the model incorporates the advanced component models and specific fluid properties required to compute the thermal and fluid behaviors of advanced reactors and their balance of plants. Through several iterations of design aided by insights gained through the RELAP5-3D simulation, the final facility design successfully captured the realistic transient behaviors of full-scale reactor system designs rated at hundreds of megawatts in thermal power.This paper presents the development of the RELAP5-3D model for the facility, including the modeling of the unique components and fluids present in the facility, and discusses how the model was successfully applied to analyze and close the performance gaps of the small-scale test facility from the key known transient behaviors of the full-scale plants, which the facility design aimed to simulate. This paper concludes by outlining the plan for further expansion of the mode l and for verification of the model through the construction and testing of the facility.