Development of evaluation method for thermal behavior in and around fuel debris based on two-fluid model

Yoshida, Hiroyuki  ; Horiguchi, Naoki   

To reduce contaminated water at the Fukushima Daiichi Nuclear Power Plant and consider the fuel debris retrieval method, a numerical simulation method is required to evaluate the effects of water injection. Then, we are developing a multiphase CFD simulation method based on the three-dimensional two-fluid model to evaluate thermal-hydraulic behavior in the primary containment vessel. The numerical simulation method was developed by introducing the required functions into the ACE-3D. This paper presents an overview of the porous model introduced to the ACE-3D to evaluate thermal-hydraulic behavior in fuel debris. In addition, we performed the numerical simulation for the Fukushima Daiichi Nuclear Power Plant unit 2 under the condition in which water injection stopped. And we compared the analysis results by the modified ACE-3D with more detailed three-dimensional CFD results by JUPITER.