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Design and commissioning of a small-scale gas/aerosol test facility for the investigation of deposition and resuspension of nuclear aerosol particles
Barth, T.; Banowski, M.; Hampel, U.;
Very High Temperate Reactors (VHTRs) are helium cooled, graphite moderated reactors for cogeneration of electricity and process heat up to 1000°C. Two basic fuel element designs exist: pebble bed and prismatic type.
During HTR standard service several amounts of irradiated graphite dust arises due to mechanical abrasion between graphite pebbles and oxidation processes resulting from helium impurities. This graphite dust deposits in the primary system. Only a limited amount of knowledge is available on the quantity of dust formed during standard service and on its spatial distribution in the primary circuit. However, the dust behaviour during a Design Basis Accident (DBA) such as a pipe break with respect to particle deposition and resuspension characteristics is rather unknown. It is of essential interest to predict how much irradiated graphite dust might exit into the containment in case of such a DBA.
A small-scale gas/aerosol test facility is designed to investigate the dynamic behaviour of the carrier phase and the complex nuclear aerosol particle motions. A brief literature review on nuclear aerosol transport and the basic design of the test facility are presented here. The turbulent flow fields captured with a Particle Image Velocimetry (PIV) system are illustrated in terms of time mean averaged velocity profiles. It is found that the wall-near region is well developed after 17 hydraulic diameters downstream of the inlet and that the core flow formation is still in progress. The formation of the aerosol particle distribution is also presented in terms of light intensity distribution of the raw PIV images. Results from this study show that the aerosol particles are evenly distributed within the fluid after 8-10 hydraulic diameters downstream of the injection point which agrees with other estimated values from various authors.
In addition, different test aerosols have been injected into the flow by means of a aerosol generator and the airborne particle number concentration, as well as the aerodynamic particle size distribution were measured by means of a Laser Aerosol Particle Size Spectrometer. Basic results on aerosol formation are presented in this work.
Keywords: Aerosol particle, deposition, High Temperature Reactor, Particle Image Velocimetry, resuspension
  • Contribution to proceedings
    European Nuclear Young Generation Forum 2011, 17.-22.05.2011, Prag, Tschechien
    Design and commissioning of a small-scale gas/aerosol test facility for the investigation of deposition and resuspension of nuclear aerosol particles

Publ.-Id: 15769 - Permalink