Abstract
In this study, a three-dimensional PWR pressure vessel model has been developed using the CFD and TRACE codes to simulate the flow behaviors and thermal-hydraulic phenomena in the downcomer and lower-plenum of Maanshan PWR nuclear power plant. Detailed geometriss of vessel components such as neutron shield panels, core support, lower core plate, butt-type columns were considered in this model for flow calculations. Important settings of the present CFD model were first validated with the test data from ROCOM facility. Following those settings and considering the geometries and operating conditions of Maanshan NPP, the CFD model of Maanshan PWR pressure vessel was first built for steady-state simulations and prepared for transient accident analyses. In order to provide sufficient transient boundary conditions for transiem: CFD simulations, the TRACE Maanshan model was coupled with the present CFD pressure vessel model. In this study, main steam line break accident (MSLB) was chosen as a transient event for simulations and analyses. It was found that unexpected temperature and pressure variations can be found in vessel within a short period. In addition, the locations of loop inlets and the neutron shielding plate in downcomer may affect the core flow distributions and enhance core cooling rate in some parts of pressure vessel. This study demonstrated that a methodology of TRACE/CFD model for Maanshan PWR pressure vessel has been successfully developed, and the present simulation results and analyses can be used for reactor safety analyses and further transient applications.