Investigation of W components exposed to high thermal and high H/He fluxes

Synergistic effects of ELMs and steady state H and H/He irradiation on tungsten

“…In addition, these specimens also have pores that are one order of magnitude smaller than these holes. The results are partially similar to previous GLADIS tests on actively cooled tungsten under different loading conditions [4], where also no blister formation is observed. Although, the nano-sized pores reported in that publication are smaller sized than the pores found in this experiment.…”

“…Nevertheless, many of the exposures affect tungsten and can cause unacceptable material damage. Different experimental set-ups, such as linear plasma devices, laser-, particle-, or electron-beam facilities have been used to investigate the plasma-material interactions of different tungsten-grades to a broad range of loading conditions [1][2][3][4]. These experiments made it possible to determine material behaviour, damage mechanisms, and threshold-values, among others.…”

Tungsten erosion under combined hydrogen/helium high heat flux loading

“…Synergistic effects of simultaneous irradiation of tungsten surfaces with He particles and high heat flux were observed for instance in [1,2]. The formation of surface and near-surface features with typical dimensions in the range of nanometres to micrometres under irradiation with He or H/He mixtures has been reported for tungsten from a number of plasma or high heat flux experiments [3,4,5]. The resulting morphology after irradiation with a H/He mixture is distinctly different form the morphology after irradiation with the pure species.…”

“…In the following we investigate two of these possible causes. The most obvious is the formation of a distorted surface layer, as shown in several experiments (see references [1][2][3][4][5][6][7][8][9][10][11]), which is investigated as a function of fluence and temperature in section 3.2.1. The second is the dependence of the sputtering yield on the crystal orientation.…”

Effects of temperature on surface modification of W exposed to He particles

“…During such usage it will be exposed to both particle irradiation and high heat flux loads. Particle irradiation from the fusion plasma, especially helium (He) bombardment, is expected to lead to performance degradation of W components due to the development of significant changes in surface morphology, such as the formation of blisters, holes, fiber-form nanostructures and coral-like structures [2][3][4][5][6][7]. In addition, synergistic effects between heat loading and particle irradiation can accelerate such surface damage [2].…”