Experimental research on gas flow and aerosol scrubbing characteristics under low Weber number pool scrubbing conditions

Radioactive aerosol may be released from the molten core during a severe accident in a nuclear power plant. Pool scrubbing, a representative aerosol scrubbing process incorporated in several severe accident scenarios, has been modeled in MELCOR. Under gas injection conditions with a low Weber number, gas flow regimes above the nozzle are globule and swarm. Based on visual scrubbing experiments, we investigated the gas flow and aerosol scrubbing characteristics under low-Weber-number injection conditions. We systematically analyzed the relationship between scrubbing efficiency and gas flow behavior through experiments and the applicability of the aerosol scrubbing model in MELCOR to different pool scrubbing conditions. Also, the variation of the globule and swarm shapes with the inlet pressure was obtained to evaluate the applicability of the gas flow model in MELCOR. Additionally, the bubble size distribution and Sauter average diameter were used to characterize the swarm flow characteristics based on the image processing results. Finally, we used a modified scrubbing model to compare the experimental results and evaluate the most suitable swarm characterization parameters.