Irradiation effects of hydrogen and helium plasma on different grade tungsten materials

• Main Authors: X. Liu, Y.Y. Lian, H. Greuner, B. Boeswirth, Y.Z. Jin, F. Feng, J.B. Wang, L. Chen, J.P. Song, Y. Yu, T. Zhang, C.S. Liu, J. Tan, D.P. Liu, X.R. Duan
• Format: Article
• Language: English
• Published: Elsevier 2017-08-01
• Series: Nuclear Materials and Energy
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352179116301582

Fine-grain tungsten alloys could be one of the solutions for the plasma facing materials of future DEMO reactors. In order to evaluate the service performances of the newly developed W alloys under edge plasma irradiation and the synergetic effect of fusion plasma together with high heat flux, both low energy He ions and high energy H, H/He mixed neutral beam irradiation on W-ZrC, W-K, W-Y2O3, W-La2O3 and CVD-W coating were performed respectively at a liner plasma facility (Dalian Nationality University, China) and the neutral beam facility GLADIS (IPP, Germany). Surface damages were characterized, and the crack formation and extension behaviors under ELM-like transient loading after H and H/He mixed beam irradiation were also investigated in the 60kW EMS-60 facility (Electron beam Materials testing Scenario) at SWIP (Southwestern Institute of Physics, China). The experimental results indicated that surface damages induced by low or high energy H/He ion/neutral beam didn't closely correlate with the type of tungsten materials. However, H/He (6at% He concentration) neutral beam induced more significant surface damages of the tested W materials than only H neutral beam irradiation under the similar irradiation conditions. Similarly, the mixed H/He pre-exposure remarkably reduced the critical power of crack initiation compared with the un-irradiated samples under 100 repetitive loads of 1ms pulse, while no significant degeneration for the case of only H beam irradiation was observed. Keywords: CVD-W coating, Dispersion strengthened W alloys, Divertor, H/He irradiation, Surface damages, Crack initiation