Analytical W-H, H-H and H-He interatomic potentials for a W-H-He system

XC Li and YW Li and HX Huang and YH Li and HB Zhou and GH Lu and HQ Deng and HS Zhou and GN Luo, JOURNAL OF NUCLEAR MATERIALS, 607, 155666 (2025).

DOI: 10.1016/j.jnucmat.2025.155666

Tungsten (W) is regarded as a primary candidate for plasma-facing materials in nuclear fusion devices. Within fusion reactors, high-energy neutron irradiation leads to the accumulation of numerous defects within materials, including vacancies, interstitial atoms, dislocations, and dislocation loops. The deuterium-tritium fusion reaction and neutron transmutation generate a substantial amount of helium (He) atoms in W, subsequently influencing the permeation and retention behavior of hydrogen (H) isotopes in W. The synergistic effects between these damages and H/He directly dictate the performance of W in fusion reactors. A profound understanding of the interaction mechanisms between irradiation-induced defects and H/He in fusion reactor materials constitutes a fundamental basis for their application. To systematically investigate the behavior of H/He in W, we constructed a new ternary potential for the W-H-He system, building upon a rigorous selection of existing W-He potentials. Utilizing structural and energetic data of defect clusters interacting with H/He in W, derived from first- principles calculations, and considering properties such as H/He diffusion, a lattice relaxation fitting method was applied to successfully establish a ternary W-H-He potential. Based on the current potential, a comprehensive evaluation was conducted, revealing good agreement between the interaction binding energies of various irradiation defects with H/He and the results obtained from first- principles calculations. We further explored the dynamics behavior of nanoscale H-He-void. It was clearly observed that H and He perfectly formed a typical core-shell structure within nanovoids, with He located internally and H externally, which aligns with experimental observations. Consequently, the new W-H-He potential provides a powerful tool for exploring the synergistic effects of irradiation defects and H/He in W.

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