Retention analysis of aerosol inside narrow channels of the containment

•A one-dimensional analysis method of aerosol retention in narrow channels is developed.•The laminar flow and turbulence flow of carrier gas are discussed in narrow channels.•The aerosol deposition mechanisms of inlet loss, turbulent deposition and steam condensation are analyzed.•The aerosol retention effects in steel containment narrow channels are calculated. Aerosol retention inside narrow channels is the optimization direction of the leakage source term assessment for nuclear power plant containment. Based on the flow characteristics of carrier gas and the deposition characteristics of transported aerosol, a one-dimensional analysis method of aerosol retention in narrow channels is developed through considering different deposition mechanisms of inlet loss, gravity settlement, Brownian diffusion, turbulent deposition and steam condensation. The flow models of carrier gas and the retention models of aerosol are analyzed and verified, respectively. The flow of carrier gas deviates from laminar flow earlier through using the drag model of narrow channels. The prediction accuracy of aerosol penetration factor calculated by current analysis method in narrow channels is improved under laminar flow and turbulent flow through comparing with the previous calculation methods. Aerosol retention analysis is conducted on the narrow channels of steel containment under the typical severe accident. The turbulent deposition introduced by larger leakage channels increases the aerosols retention effect in narrow channels.