Applicability investigation of reactor vessel thermal-hydraulics analysis method for transient toward natural circulation condition

Hamase, Erina ; Doda, Norihiro  ; Ono, Ayako ; Tanaka, Masaaki  ; Miyake, Yasuhiro*; Imai, Yasutomo*

We have developed the reactor vessel thermal-hydraulic analysis model (RV-CFD) with the subchannel CFD (SC) model for assembly with a low computational cost to evaluate the core-plenum interactions occurred in the natural circulation decay heat removal during the dipped-type direct heat exchanger operation in sodium-cooled fast reactor. In this study, the non-equilibrium thermal model which can consider the heat capacity and thermal load of fuel pins was developed in the SC model. Through the transient analysis simulating the power reduction due to reactor scram using the RV-CFD, the applicability of RV-CFD to the transient analysis was confirmed.