Real-time measurements and modeling of sodium combustion aerosol dynamics in test chamber to improve the evaluation of SFR containment aerosol behaviour

Abstract

The initial size distribution and morphological parameters of sodium aerosols are critical in evaluating the accidental suspended aerosol behaviour in Sodium-cooled Fast Reactor (SFR) containment. Mass-based measurements were more familiar in characterizing the sodium aerosols. Real-time number size distribution measurements are carried out in this study. The sensitivity analysis of sodium aerosol effective density (ρe) in deriving the actual number size distributions from the measured Aerodynamic Particle Size Distributions (APSD) and predicting suspended aerosol dynamics is presented. Tests are conducted in a 1 m3 chamber at 47 ± 3% RH for different initial mass concentrations (M0) of 0.1, 1, and 2.9 g/m3. The initial APSDs measured just after the generation completions are observed to be polydisperse with the count median aerodynamic diameter (CMAD) < 1 μm. The literature reported ρe values of sodium aerosols, 2.27, 1.362, and 0.61 g/cm3 are used to derive mobility equivalent PSDs from APSD in each test. The real-time number concentration decay and size growth for four different PSDs are measured and compared with the estimate using nodal method-based code to ascertain the actual parameters. The validated parameters CMD = 0.66 μm, σg = 1.96, ρe = 1 g/cm3 and χ = 1 are used for improved estimation of sodium aerosol dynamics in Indian SFR containment with M0 = 4 g/m3 for severe accident scenarios.

Keywords

• Sodium aerosol
• Effective density
• Aerodynamic size distribution
• Mobility equivalent size distribution
• Concentration decay
• Size growth