CFD-simulation of coolant transient benchmark v1000ct –1, exercise 3 using results of Dyn3d/Athlet coupled code calculation

Transient CFD calculations have been performed for the thermal-hydraulic benchmark V1000CT-1, exercise 3
The numerical grid model was generated with the grid generator IC4C (ICEM-CFD) and the preprocessor CFX-5 and contains 4.7 Mio. tetrahedral elements. The output of the Best Practice Guidelines for optimizing the numerical studies in different reactor types was used in the numerical simulation. Data from a coupled code calculation with DYN3D/ATHLET were used as inlet boundary conditions. 4 different Mixing Scalars were utilized to obtain information about the contribution of each loop during the transient. The results show a clear sector formation of the affected loops at the downcomer and core inlet. At the beginning of the start-up of loop 3 the sectors of loop 1,2,4 cover a bigger area.