Results of acoustic monitoring of ITER divertor vertical target prototype

Acoustic monitoring is a method under development to indicate the occurrence of critical heat flux (CHF) events on plasma facing components exposed to high heat fluxes (HHFs) from plasma wall interaction, in order to be able to stop plasma operation before irremediable damages appear. It is a non-intrusive promising method thanks to the property of acoustic waves to propagate in channels and to the CHF acoustic precursory indicators which have been observed in several previous HHF experimental studies. This method is on a preliminary assessment stage and HHF experiment on relevant mock-up is an opportunity to collect and analyse data for improving the method efficiency. This paper deals with the post-processing of acoustic signals recorded on a European ITER divertor qualification prototype, on which an unexpected loss of flow accident occurred and caused a cooling channel rupture. The acoustic data have been analysed in the same way as for a CHF scenario, in order to seek precursory indicators of this kind of event.