非構造格子版ナトリウム－水反応現象解析コード SERAPHIM の開発

（非構造格子化の効果及びベンチマーク解析）

抄録

In case pressurized water or vapor leaks from an enlarged crack of a heat transfer tube in a steam generator of sodium-cooled fast reactors, a high-velocity, high-temperature, and corrosive jet with sodium-water chemical reaction may cause wastage on adjacent tubes. The mechanistic computational fluid dynamics code called SERAPHIM for compressible multicomponent multiphase flows with sodium-water chemical reaction has been developed to evaluate the effect of the reacting jet. For application to a complex-shaped domain including tube bundle, an unstructured mesh-based analysis method has been integrated into this code which was originally developed by difference method. In this study, structured- and unstructured-mesh simulations of sodium-water reaction under an actual condition of steam generators was performed. In the case of the coarse structured mesh, non-physical flow behavior appeared after impinging at adjacent tubes. This behavior was improved by the unstructured mesh. The unstructured-mesh simulation could represent measured temperature with an acceptable error range.