High Flux Helium Irradiation of Dispersion-Strengthened Tungsten Alloys and Effects of Heavy Metal Impurity Layer Deposition

Tungsten has been chosen as the plasma-facing material (PFM) for divertor region in ITER and also a candidate PFM future plasma-burning nuclear fusion reactors. During device operation, PFMs will be exposed to low-energy He irradiation at high temperatures, resulting sub-surface bubbles surface morphology changes such pores fuzz. Carbide dispersion-strengthened W materials may enhance ductility of W, but their behavior under flux remains unclear. In this work, response tungsten flux, low energy temperature is examined. alloyed with 1, 5, or 10 wt. % tantalum carbide titanium these conditions result pores, coral-like feature growth helium bubbles. Reactor-relevant (5x1026 m-2 fluence) combined powered laser pulses simulate off-normal reactor events does not significantly alter morphology, nanostructures appear stable cracks are only observed on localized one sample. However, specimens show development an impurity layer surface, likely deposition from sample holder during irradiation, mixed surface. Helium exist layer, obscure conclusions about interactions dispersoids. Nonetheless, it clear that dispersoid microstructure limits bubble formation subsequent nanostructuring, attributed composition.