Speaker
Description
The integrity of plasma-facing components (PFCs), particularly tungsten (W), against synergistic irradiation damage, specifically from high-energy particles, high-flux plasmas, and high heat loads, remains a critical challenge for future magnetic confinement fusion reactors. This research investigated the combined effects of high-flux, low-energy plasma, and high-energy particle beams on advanced W materials. We established a novel synergistic irradiation experimental platform that coupled a MeV radio frequency quadrupole (RFQ) accelerator with a low-energy, high-density linear plasma device. This unique setup allows for the simultaneous exposure of PFC materials to fusion-relevant conditions.
This study employs three distinct W materials chosen for their varying microstructures: single-crystal W (SCW), commercial polycrystalline W (PCW), and oxide dispersion strengthened W (ODS-W). The samples were synergistically irradiated using a mixed deuterium (D) and helium (He) plasma and high-energy hydrogen (H) ions. The experimental parameters included D/He plasma fluences ranging from 6 × 1024 m-2 to 2 × 1026 m-2, sample temperatures from 773 K to 1373 K, and incident ion energies from 40 eV to 90 eV. The energy of the high-energy hydrogen ions was 0.75 MeV, with associated irradiation dose ranging from 0.01 dpa to 0.1 dpa. The microstructures of the original materials and irradiated samples were thoroughly characterized using Electron Backscatter Diffraction (EBSD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM).
Initial results revealed that the D permeability of unirradiated ODS-W was higher than that of pure W. After He plasma irradiation, the formation of surface fuzz structures significantly increased D permeability, an effect that correlated positively with fuzz thickness and the permeation temperature. Regarding high-energy H ion effects, D retention in annealed W after 0.01 dpa proton irradiation was comparable to unirradiated samples, but increased by approximately one order of magnitude after 0.1 dpa irradiation, with the TDS spectra exhibiting multiple distinct desorption peaks.
We conducted further synergistic irradiation experiments, and well report results on the influence of irradiation damage under these various experimental parameters on deuterium permeation and retention behavior.