Numerical simulation on two-phase flow in the 44 fuel bundle with the spacer by the mechanistically based method

Ono, Ayako ; Yamashita, Susumu   ; Suzuki, Takayuki*; Yoshida, Hiroyuki  

JAEA is implementing the 3D detailed nuclear-thermal-coupled analysis code in order to analyze the transition state of the core and to reduce the likelihood of the design. In the development plan, the computational fluid dynamics code based on the VOF method, JUPITER, is applied for TH part of the 3D detailed nuclear-thermal-coupled analysis code. In this study, the JUPITER code is examined to apply for the two-phase flow simulation of 44 fuel assembly with the spacer grid. The simulation results and previous study relating to observation of the two-phase flow in the fuel bundle are compared to validate the simulation results and considered reproducibility of the effect of the spacer grid.