Development of coupled analysis method for a fast reactor plant thermal-hydraulics evaluation in natural circulation conditions

Hamase, Erina ; Fujisaki, Tatsuya*; Kawamura, Takumi*; Miyake, Yasuhiro*; Doda, Norihiro  ; Ono, Ayako ; Tanaka, Masaaki  

To accurately evaluate the plant behavior during natural circulation decay heat removal using a dipped-type direct heat exchanger, we have developed a coupled analysis method using a plant dynamics analysis code and a CFD code. As a result of coupled analysis for a transient test using PRACS in the PLANDTL-1, the results demonstrated that the thermal-hydraulic behavior in the primary loop can be evaluated by considering local phenomena within a reactor vessel (RV), and the phenomena in the RV can be simulated by incorporating feedback from thermal-hydraulics in the primary loop. We confirmed the coupled analysis method was applicable to evaluate the plant transient behavior.