Aerosol behavior model development and validation of SPRUCE code source term module

• SPRUCE aerosol model integrates deposition, coagulation, hygroscopic growth and resuspension for source term analysis. • Model validated against LACE LA4, KAEVER (K123, K148, K186, K188) and STORM SR11 international experiments. • Predicts aerosol behavior for soluble, insoluble, and mixed types under varied thermal-hydraulic conditions. • Demonstrates reliable simulation of aerosol concentration evolution and deposition/resuspension processes. • Establishes foundation for SPRUCE application in severe accident analysis and future module validation. The aerosol behavior plays an important role in the assessment of the source term during severe accidents in nuclear power plants. This paper presents the development and validation of the aerosol behavior model within the source term module of the SPRUCE code, an integral severe accident analysis code independently developed by the China Nuclear Power Technology Research Institute (CNPRI). The model comprehensively incorporates the key physical processes governing aerosol behavior, including deposition (gravitational settling, thermophoresis, diffusiophoresis, and Brownian diffusion), coagulation (Brownian, gravitational, and turbulent), hygroscopic growth, and resuspension. To validate the reliability of model, simulations were compared against the internationally recognized experimental data, including the LACE LA4, KAEVER (K123, K148, K186, K188), and STORM SR11. The results demonstrate that the SPRUCE code successfully predicts the temporal evolution of aerosol concentration and deposition/resuspension behavior in various thermal–hydraulic conditions and aerosol types (soluble, insoluble, and mixed). The favorable agreement with experimental data confirms the capability and credibility of the SPRUCE code and its implemented aerosol models for simulating aerosol behavior under severe accident conditions. This work establishes a solid foundation for the application of SPRUCE in severe accident source term analysis, paving the way for future validation of other critical source term phenomena and other modules of SPRUCE.