Development of a CFD model for the CANDU-6 moderator analysis using a coupled solver

A computational fluid dynamics (CFD) moderator analysis model by using a coupled solver has been developed for the moderator analysis of Canada deuterium uranium (CANDU) reactors. For Wolsong Units 2/3/4, a steady-state moderator circulation under operating conditions and the local moderator subcooling during a LOCA transient were evaluated using the CFD tool. When compared to a former study in the Final Safety Analysis Reports, the current analysis provided well-matched trends and reasonable results. This new CFD model based on a coupled solver shows a dramatic increase in the computing speed, when compared to that based on a segregated solver.