Imaging of dust re-suspension in case of LOVA

Abstract

Dust re-suspension and mobilization is one of the more challenging safety issues in industries and fusion reactors (Tokamaks). In Tokamaks, plasma-material interactions generate dust by several different mechanisms called Plasma-Material Interactions. In these reactors, Loss of Vacuum Accidents (LOVA) may occur and imply dust re-suspension and mobilization. These events must be avoided since dust could involve reactor function problematics, toxic and radiological releases and dust explosions. The Quantum Electronics and Plasma Physics (QEP) research group is studying the dust mobilization through an experimental device, Small Tank for Aerosol Removal and DUST Upgrade (STARDUST-Upgrade), able to reproduce LOVAs. An optical experimental apparatus has been implemented on STARDUST-U in order to measure dust mobilization and re-suspension. In this work, the authors show the results of dust re-suspension measurements in case of LOVA reproduced in mid-height of the vessel (valve E). The experimental results are argued referring to numerical data from a monophase Computational Fluid Dynamics (CFD) and they show the meaning of dust initial position and dust properties in these kinds of events. The authors discuss the impossibility to adopt simple numerical models, such as 1-way coupling model, to describe, accurately, the phenomenon.