Faire avancer la sûreté nucléaire

La Recherchev2


Etude expérimentale de la pénétration des aérosols à travers des fissures sur béton.



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Mot de passe :

F. Gensdarmes, T. Gelain, J. Vendel, N. Orbovic, M. Bouchon, European Aerosol Coference (EAC 2003), 31/08-05/09/2003, Madrid (Espagne).



Within the framework of the safety assessment of the nuclear fuel facilities, we study the leakage of a reinforced concrete wall subjected to shear stresses characteristic of a seism. For that, we measure the gas flowrate and the retention of the aerosol particles in the concrete cracks for upstream and downstream pressure differences ranging from 10 hPa to 200 hPa, which are representatives of the wind effect or the fire risk onto a building. The main objective of this work is to provide data in order to validate a model for the retention of the aerosols by cracks in concrete walls. This subject is complex because many factors contribute to the retention of aerosols in the cracks. One can quote the deposit inside the crack, the deposit at the entry of the crack and the evolution of the flowrate due to the possible clogging of the crack. These phenomena were studied with ideal geometries such as capillaries or slots (Morewitz 1982, Clement 1995, Carrié and Modera 2002), but very few data are available with concrete crack (Van de Vate 1984, Farrar and Girrens 1992).

Our approach consists to determine the aeraulic characteristics of a network of cracks (equivalent single crack width, flow Reynolds number) obtained by shearing a reinforced concrete wall, then to measure the retention of the particles by the cracks for various aerosols diameter and gas flowrates.

Finally, experimental measurements on the retention of the aerosols are analysed in terms of the characteristics of the cracks and the various models of aerosol deposition existing in the literature.