%0 Journal Article
%A Gago, Mauricio
%A Kreter, Arkadi
%A Unterberg, Bernhard
%A Wirtz, Marius
%T Bubble Formation in ITER-Grade Tungsten after Exposure to Stationary D/He Plasma and ELM-like Thermal Shocks
%J Journal of nuclear engineering
%V 4
%N 1
%@ 2673-4362
%C Basel
%I MDPI
%M FZJ-2023-01430
%P 204 - 212
%D 2023
%X Plasma-facing materials (PFMs) in the ITER divertor will be exposed to severe conditions, including exposure to transient heat loads from edge-localized modes (ELMs) and to plasma particles and neutrons. Tungsten is the material chosen as PFM for the ITER divertor. In previous tests, bubble formation in ITER-grade tungsten was detected when exposed to fusion relevant conditions. For this study, ITER-grade tungsten was exposed to simultaneous ELM-like transient heat loads and D/He (6%) plasma in the linear plasma device PSI-2. Bubble formation was then investigated via SEM micrographs and FIB cuts. It was found that for exposure to 100.000 laser pulses of 0.6 GWm−2 absorbed power density (Pabs), only small bubbles in the nanometer range were formed close to the surface. After increasing Pabs to 0.8 and 1.0 GWm−2, the size of the bubbles went up to about 1 µm in size and were deeper below the surface. Increasing the plasma fluence had an even larger effect, more than doubling bubble density and increasing bubble size to up to 2 µm in diameter. When using deuterium-only plasma, the samples showed no bubble formation and reduced cracking, showing such bubble formation is caused by exposure to helium plasma.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:001188658700001
%R 10.3390/jne4010016
%U https://juser.fz-juelich.de/record/1005321