Experimental Study on the Behavior of Suspended Aerosols of Sodium and Nonradioactive Fission Products (SrO<sub>2</sub>and CeO<sub>2</sub>) in a Closed Vessel

Subramanian, V.; Baskaran, R.; Misra, J.; Indira, R.

doi:10.13182/nt11-a12544

Cited by 12 publications

(3 citation statements)

References 8 publications

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“…6. The first slope lasts upto 2000 s and indicates particle number loss rate due to coagulation c , while the second slope is very steep and indicates particle number loss rate due to settling beyond 2000 s d (Harrision, 1996;Subramanian et al, 2011). The experimental net coagulation coefficient is found to be 6 × 10 -9 cm 3 /s (Hinds, 1982.…”

Section: Sro 2 Aerosolsmentioning

confidence: 99%

Investigation of Aerosol Mass and Number Deposition Velocity in a Closed Chamber

Misra

Subramanian

Kumar

et al. 2013

Aerosol Air Qual. Res.

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In the event of a core disruptive accident in a sodium cooled fast reactor, the Reactor Containment Building (RCB) is bottled-up with coolant (sodium), fuel and fission product aerosols. The aerosols suspended in the closed environment undergo coagulation and gravitational settling. Sodium aerosols are generated by combustion, while fission product aerosols are generated by vaporization and condensation, with the resulting particles having two flow regimes. It is expected that the mass concentration of sodium aerosols is relatively high, on the order of a few g/m 3 , while that of the fuel and fission products is only a few mg/m 3 . Taking into account the concentration criteria, experiments are carried out by generating sodium aerosols (mono dispersed) with the concentration of 3.0 g/m 3 , and the deposition velocity over time is determined by mass measurements (concentration and flux). Similarly, non-radioactive species of SrO 2 aerosols are generated (mono dispersed) with a number concentration of 10 6 /cm 3 , and their deposition velocity over time is determined by number measurements (concentration and flux). The mass deposition velocity of sodium aerosols was found to be more than two orders of magnitude greater than the number deposition velocity of SrO 2 aerosols. As the SrO 2 aerosols are generated in the free molecular regime, the depletion pattern of the number concentration of suspended aerosols follows a process of simultaneous coagulation and settling. A theoretical formulation for the rate of depletion of the number concentration is developed, and the rate coefficients of coagulation and deposition velocity are determined from the theoretically fitted equation. The experimental and theoretical results are compared and found to be nearly same. The deposition velocity of sodium aerosols is used to predict the deposition time for the suspended aerosol mass concentration inside the RCB. The mass and number deposition velocities are determined by using a state of art Turn Table Instrument fabricated in our lab.

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Section: Sro 2 Aerosolsmentioning

confidence: 99%

Investigation of Aerosol Mass and Number Deposition Velocity in a Closed Chamber

Misra

Subramanian

Kumar

et al. 2013

Aerosol Air Qual. Res.

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“…The carbonation of sodium aerosols is studied and a phenomenological modeling is carried out based on shrinking core model by considering of diffusion of CO 2 into a particle of hydroxide formed at various RH conditions i.e., shrinking of hydroxide core with progress of time as carbonation progress from the surface (Gilardi et al, 2013). In addition to all these studies, the particle size is important to be considered for the settling phenomena, as the aerosols are formed inside a confined environment undergo coagulation followed by gravitational settling (Misra et al, 2010;Subramanian et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Size Evolution of Sodium Combustion Aerosol with Various RH%

Kumar

Subramanian

Baskaran

et al. 2015

Aerosol Air Qual. Res.

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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.

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“…wall of the chamber. More details on ATF can be found elsewhere(Baskaran et al, 2004;KUMAR, 2010;Subramanian et al, 2017). The experimental setup consists of PTAGS, material feeder, aerosol chamber, Data Acquisition System (DAS), and aerosol diagnostic instruments.…”

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confidence: 99%

Study on characterization of SrO Aerosols Generated by Optimized Thermal Plasma Torch Aerosol Generator

Kumar,

Usha

2024

Preprint

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Plasma Torch Aerosol Generation System (PTAGS) has been employed to generate nano aerosols with desirable characteristics. The operational parameters of PTAGS installed in the aerosol test facility have been optimized, and aerosols are generated using non-radioactive SrO2 powder. The current-voltage characteristics, electro-thermal efficiency and torch power are studied as a function of the flow rate of the plasma-generating gas (mixture of argon and nitrogen) and the arc current of the plasma torch. The arc characteristics relation is determined using the Nottingham formulation. Based on this, torch parameters are evolved and optimized as 20 kW power, 70% electro-thermal efficiency, 25 L min− 1 flow rate of plasma forming gas, 5 mg min− 1 powder feed rate and for 4–5 min torch operation towards the generation of SrO nano aerosols to achieve 1012 m− 3 and ~ 25 mg m− 3 for the count and mass concentration of aerosol respectively. The initial size distribution of the aerosols is in the few tens of nanometre range (10–40 nm) with a mean diameter of 26 nm (σg = 1.45). SEM and EDAX analysis reveal that the morphology of nano aerosols was nearly spherical and the formation of SrO nanoparticles. A set of operational parameters of PTAGS has been standardized to perform further experiments related to reactor safety analysis. PTAGS shall be tuned for aerosol generation in a large facility to achieve the characteristics equivalent to reactor accidental conditions.

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Experimental Study on the Behavior of Suspended Aerosols of Sodium and Nonradioactive Fission Products (SrO₂and CeO₂) in a Closed Vessel

Cited by 12 publications

References 8 publications

Investigation of Aerosol Mass and Number Deposition Velocity in a Closed Chamber

Investigation of Aerosol Mass and Number Deposition Velocity in a Closed Chamber

Size Evolution of Sodium Combustion Aerosol with Various RH%

Study on characterization of SrO Aerosols Generated by Optimized Thermal Plasma Torch Aerosol Generator

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Experimental Study on the Behavior of Suspended Aerosols of Sodium and Nonradioactive Fission Products (SrO2and CeO2) in a Closed Vessel

Cited by 12 publications

References 8 publications

Investigation of Aerosol Mass and Number Deposition Velocity in a Closed Chamber

Investigation of Aerosol Mass and Number Deposition Velocity in a Closed Chamber

Size Evolution of Sodium Combustion Aerosol with Various RH%

Study on characterization of SrO Aerosols Generated by Optimized Thermal Plasma Torch Aerosol Generator

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Experimental Study on the Behavior of Suspended Aerosols of Sodium and Nonradioactive Fission Products (SrO₂and CeO₂) in a Closed Vessel