Impact of water ingress on deuterium release, oxidation, and dust generation in beryllium plasma-facing components

Beryllium samples from the JET ITER-like wall limiter tiles with either co-deposits or surface cracks caused by melt damage, were immersed into boiling water for 4 h 15 min to simulate and assess the impact of coolant water ingress into a tokamak on the state of Be components. Microscopy of the water-treated surfaces and the lack of residue in the water revealed that no thermomechanical damage (cracking or exfoliation) occurred to the samples during the exposure. Ion beam analysis showed no measurable release of deuterium from the samples. Combined ion beam analysis and Raman spectroscopy indicated only some degree of surface oxidation, but no thick oxide films were formed.

Automated summary

In this study, beryllium samples with co-deposits or surface cracks caused by melt damage were immersed into boiling water to simulate the impact of coolant water ingress into a tokamak. The results showed that there was no thermomechanical damage to the samples during exposure, and no measurable release of deuterium occurred. Only some degree of surface oxidation was observed, but no thick oxide films were formed.