Numerical Studies to Assess the Effect of Simulated Recombiner on Helium Distribution and Mixing in a Scale Down Containment Facility, CSF

Hydrogen may get released into the containment building during postulated severe accident conditions in nuclear power plants (NPPs). Effective management of this hydrogen is a major safety goal for the designers. One of the most important safety features integrated into NPPs is Passive Catalytic Recombiner Devices (PCRD). It is important to find the optimum number and the location of PCRDs to manage the accident scenario effectively with maximum efficiency. In this regard, CFD-based hydrogen distribution studies in the presence of PCRDs is indispensable for all kind of containment structure. Before using the CFD codes in actual reactor calculations, validation exercise is required to be performed to have confidence in the prediction. In this study, CFD-based numerical studies are performed as a part of blind calculations before performing experiments to characterize the helium gas distribution and mixing in a multi-compartment scaled-down containment facility, CSF. In this study, helium gas has been used as a surrogate to hydrogen gas as handling large quantities of hydrogen is hazardous and poses safety concern. PCRD plates are replaced with heater plates to simulate the thermally induced flow. The details of CSF geometry, modelling approaches and the results are discussed in this paper.