Evaluation of thermal-hydrodynamics for condensation pool and piping system

If the steam with high pressure and high temperature in KNGR is discharged into IRWST through the sparger submerged into it to release the pressure of coolant system by a nuclear power plant accident. The shock wave accompanying unsteady flow motion is propagated through the various piping system, it exerts high pressure load on units and may cause the structural problems and severe vibration. From the viewpoint of nuclear power plant safety, The analysis of flow behaviors in the IRWST and piping system is essential to ensure the technology for the evaluation of safety. And also the evaluation methods by the analysis of thermal hydrodynamic behaviors through the sparger is established. The results obtained show that the initial shock wave experienced reflection, diffraction and interaction with shock-induced vortex. The time-dependent maximum load exerted on the wall is largest in the T-junction, while the smallest in the branch. It is found that because there is nearly no change in pressure at condensation pool during water clearing, the system appears to be safe. However, calculations of the air clearing for 0.2 second, to analyze air that coexist with water between load reduction and sparger head were performed using VOF model. In addition, grid generation is proceeding now for the case of POSRY opening with finite time of 1.7 second consecutively