Size Evolution of Sodium Combustion Aerosol with Various RH%

Abstract

Studies on sodium aerosol characteristics are very important for fast reactor safety. Physical and chemical changes that occur at various times at various atmospheric conditions to sodium aerosols would results particles in various diameters. In this context, a study has been conducted in Aerosol Test Facility, Radiological Safety Division, in which sodium combustion aerosols were generated in a controlled manner and made to hover in a confined volume. The particle diameter (Mass Median Diameter -MMD) is measured on-line with progress of time by using Mastersizer. The experiments are conducted by generating aerosols in two different mass concentrations viz. 3.0 g m -3 and 0.5 g m -3 and in three different relative humidity conditions viz. 20%, 50% and 90% to show the influence of relative humidity on the particle diameter. A theoretical simulation of particle growth due to coagulation is drawn and compared with the experimental value. It is observed that sodium combustion aerosols size grow due to absorption of moisture (hygroscopic growth) in the initial period of times say in first 20 minutes followed by Brownian coagulation. An empirical relation is determined based on the difference between coagulation growth and experimental observation and applied to match experimental observation of particle diameter. A detailed experimental procedure, theoretical simulation and comparison of results of particle growth between experimental observation and theoretical simulation are presented in this paper.

Aerosol Optical Properties of Extreme Global Wildfires and Estimated Radiative Forcing With GCOM‐C SGLI

“…The results show that the smoke particle size increases (i.e., AE decrease) with time in almost all locations. This might be caused by the process of aerosol coagulation and concentration including hygroscopic growth (Konovalov et al., 2021; Kumar et al., 2015). However, the characteristics of California are partially different from other regions, as the particle size decreases beyond ∼4° rom the hotspot area.…”

State of Knowledge on Aerosols and Bubble Transport for Mechanistic Source Term Analysis of Molten Salt Reactors

“…In SFRs, the formation of sodium vapors and aerosols is a potential concern because large amounts of sodium have been documented in the cover gas region above liquid sodium volumes, especially at high temperatures [9][10][11][12][13][14][15][16][17]. The evaporated sodium can condense on cold structures and penetrations above, which can interfere with proper operation.…”

“…During this sequence, aerosols form from the failed fuel pins and transport inside ejected gases up to the cover gas space. Also, when the suspended sodium mists leak or confront air during air ingress events, an energetic reaction occurs that produces sodium oxide aerosols [15,18,[21][22][23][24][25][26][27][28][29]. Therefore, understanding the characteristics of aerosols in the cover gas region is important to fully tracking aerosol behavior in SFRs.…”

Modeling of the chemical behavior of sodium fire aerosols during atmospheric dispersion

“…In the case where the pores are filled with air (Case 2), the reaction interface being at the particle's internal surface, the diameter of the aerosol does not vary during carbonation as the sodium carbonate is formed within the porous layer towards the core of the particle, which implies a progressive decrease of the absorption interface. Based on the experimental study by Kumar et al (2014) during the carbonation of sodium fire aerosols, the mass median diameter increases by a factor of 1.15 to 1.6 depending on the RH. This suggests that Case 1 is more representative of the phenomenology according to experimental data.…”