Dust explosion of solid/solid mixtures: application to nuclear decommissioning
Résumé
The possibility to encounter dusts composed of graphite and metals particles, during UNGG (Natural Uranium Graphite Gas) French reactors decommissioning or store in silos, has led to characterize their flammability and explosivity properties, to support the future safety analyses of dismantling operations. Even if some experimental data are available on graphite powder explosion, the potential effect of the presence of metals dusts, as magnesium or iron, on its behavior remains to be investigated. In this study, the possibility of ignition and the explosion severity of this mixtures has been assessed, observing synergitic effects, such as the doubling of the rate of pressure rise when 15%wt. of 20 µm magnesium is introduced in the graphite dust. The metal addition introduces strong modifications in the beat exchange contributions in the system, affecting also the flame propagation velocity. In the medium term, these results will support the development of a model predicting the severity of hybrid solid/solid mixtures.