Numerical simulation method using a Cartesian grid for oxidation of core materials under steam-starved conditions
カーテシアン格子系を用いた水蒸気枯渇条件下での炉心構造物の酸化計算手法
山下 晋 ; 佐藤 拓未 ; 永江 勇二 ; 倉田 正輝 ; 吉田 啓之
Yamashita, Susumu; Sato, Takumi; Nagae, Yuji; Kurata, Masaki; Yoshida, Hiroyuki
We newly developed a detailed simulation method for the oxide layer growth/recession under steam-starved conditions using computational fluid dynamics (CFD) methodologies to elaborate the understanding of failure conditions of fuel assemblies during severe accidents. The new method uses the concept of the distance function in a Cartesian grid and is implemented in the original multiphase/multicomponent CFD code named JUPITER (JAEA Utility Program for Interdisciplinary Thermal-hydraulics Engineering and Research). A distance calculation of the normal direction from the interface is generally difficult in a Cartesian grid. However, the distance function can give a distance normal to the surface of materials by referring to the value of the function. Thus, the growth/recession calculations, which require the distance normal to the interface, become very easy. We checked the availability of JUPITER, considering these models against the verification and validation problems. As a result, we confirmed that JUPITER gives good results, which may contribute to understanding the progress of core degradation under steam-starved conditions.