Coupled Thermal-Hydraulic/Neutronics/Crud Framework in Prediction of Crud-Induced Power Shift Phenomenon

A thermal-hydraulics (TH)/neutronics/crud multiphysics coupling framework to simulate the crud deposits' impact on crud-induced power shift (CIPS) phenomenon is proposed in this paper. The coupling among three essential physics (i.e., TH, crud, and neutronics) was implemented by coupling the computational fluid dynamics software STAR-CCM+, a newly developed crud module, and the neutronics code DeCART. A typical 3 × 3 pressurized water reactor fuel pin problem was analyzed with this framework and simulation results are presented. Time-dependent results are provided for a 12-month simulation. Simulation results provide the history of crud deposits inventory and their distributions on fuel rods, boron hideout amount inside crud deposits, and power shape changing over time. The obtained results clearly showed the power shape suppression in regions where crud deposits exist, a clear indication of CIPS phenomenon.