DEVELOPMENT OF INTEGRATED NUMERICAL ANALYSIS MODEL FOR UNSTEADY PHENOMENA IN UPPER PLENUM AND HOT-LEG PIPING SYSTEM OF JAPAN SODIUM-COOLED FAST REACTOR

Flow-induced vibration of hot-leg pipings is one of concerns for the design of Japan Sodium-cooled Fast Reactor (JSFR) which is now being developed. The flow field in the hot-leg pipings is supposed to be affected by flow disturbances at the entrance, so it is important to evaluate flow fields including the upper plenum. In this study, a simulation model of the upper plenum and the hot-leg piping system of JSFR was developed. Unsteady fluid flow analyses were then conducted by unsteady Reynolds averaged Navier-Stokes simulation (URANS) with Reynolds stress model. The appropriateness of the calculated results was discussed by comparing available scale model test results. Furthermore, a prototype model for vibration analysis of the hot-leg piping was developed. In the model, the transient pressure data predicted by the URANS were used as input data for the vibration analysis. The number of element was significantly reduced from that of CFD model by considering the correlation length of stress fluctuation. In addition, a stress mapping tool from a CFD model to a model for vibration analysis was created.