Mechanistic assessment of aerosol transport in a SFR cover gas space under operating condition

The cover gas space is an inert isolation layer provided for sodium systems in sodium-cooled fast reactors. During normal reactor operation, sodium aerosols are generated continuously in the cover gas space. Understanding the complex dynamics of the evolution and transport of the aerosol is essential from the perspective of the reactor operation. Such assessments provides vital insights into deposition patterns of aerosols to the components mounted on the roof slab. In the present manuscript, the evolution and transport of aerosol in the cover gas space as well as in roof-slab annular gaps are studied in detail with the help of computational fluid dynamics tool. The present model is validated against the experimental data from the literature. There is good agreement between temperature variation, aerosol number and mass concentration across the cover gas height. Post validation, the study of thermal and aerosol transport in the full-scale reactor cover gas for a medium-sized reference reactor is carried out. It is observed that aerosol sizes greater than ∼31 μm are mostly concentrated near either the sodium pool surface, component wall or near the vessel boundary. It is found that the average mass concentration in the cover gas space is uniform (∼ 29 g/m3). However, the annular regions are found to have a non-uniform distribution of aerosols with heavier particles confined to the lower annular regions in wavy like patterns having the same Count Mean Diameter (CMD) as in the bulk cover gas space. The CMD in the top annular regions is ∼ 2 μm. A coupled analysis of aerosol transport in cover gas space and roof-slab annular gaps using modified aerosolEulerFoam is carried out.Validation of the numerical model is performed with data from two experiments (Furukawa et al., 1984; Kumar et al., 2015). Where, average aerosol mass concentration and size distributions were compared.Detailed aerosol transport studies for the full scale primary cover gas of the reference reactor is carried out.Aerosol size greater than ∼31 μm are mostly concentrated near either sodium pool surface, component wall or near the vessel boundary. A coupled analysis of aerosol transport in cover gas space and roof-slab annular gaps using modified aerosolEulerFoam is carried out. Validation of the numerical model is performed with data from two experiments (Furukawa et al., 1984; Kumar et al., 2015). Where, average aerosol mass concentration and size distributions were compared. Detailed aerosol transport studies for the full scale primary cover gas of the reference reactor is carried out. Aerosol size greater than ∼31 μm are mostly concentrated near either sodium pool surface, component wall or near the vessel boundary.