On the nature of aerosols produced during a severe accident of a water-cooled nuclear reactor
Résumé
Particle behaviour depends strongly on classic characteristics, e.g., size, and less macroscopic ones involving structure and composition these being especially important in situations of strong differential forces on a particle, i.e., surface impact or intensely-shearing flows. The former situation may lead to particle deposition or break-up and re-entrainment (with potential accident-management implications). This paper reviews information on aerosols from prototypical experiments identifying common features and typical variations. It emerges that a particle comprising one-third metal, one-third metal oxide and one-third a mixture of fission-product species would not be out of place in any potential reactor-accident sequence. Particle shapes appear relatively compact without branching chain-like structures. On size and structure, aerosols in the upstream part of the primary circuit would comprise a near-lognormal population with AMMD no more than 2 μm and geometric standard deviation around 2, particles comprising agglomerates of highly-coordinated clusters as small as 0.1 μm. In the containment, aerosols can typically be represented by primary-circuit particles and their agglomerates though particular circumstances (core-concrete interaction, hot-leg accident sequence) can alter this simple picture. © 2008 Elsevier B.V. All rights reserved.
Mots clés
Accidents
Aerosols
Agglomeration
Air pollution
Atmospheric aerosols
Atomizers
Chlorine compounds
Ketones
Metallic compounds
Metals
Nuclear propulsion
Nuclear reactors
Standards
Break-up
Chain-like structures
Common features
Geometric standard deviation
Lognormal
Management implications
Metal oxides
Particle depositions
Particle shapes
Primary circuits
Re-entrainment
Severe accident
Hazardous materials