Regensburg 2025 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 35: Transport in Materials: Diffusion, Charge or Heat Conduction
MM 35.3: Talk
Friday, March 21, 2025, 10:45–11:00, H22
Diffusion and activation energies of hydrogen and its isotopes in boron structure — •Bianca Solomonea1, 2, Calin Pantis-Simut2, 3, Mihaela Cosinschi2, 3, Paul Dinca1, Corneliu Porosnicu1, and George Nemnes2, 3 — 1National Institute for Laser, Plasma and Radiation Physics (INFLPR), Atomiştilor Street 409, 077125 Măgurele, Ilfov, Romania — 2Faculty of Physics, Univer- sity of Bucharest, Atomistilor 405, Magurele-Ilfov 077125, Romania — 3Horia Hulubei National Institute for Physics and Nuclear Engineer- ing, Reactorului 30, Magurele-Ilfov 077125, Romania
The retention and release of hydrogen isotopes in plasma-facing materials (PFM) is a critical concern for the ITER project. The decision to construct the Tokamak reactor as a fully tungsten-based machine presents challenges regarding plasma ignition and stability, particularly due to impurities in the working gases. Boronization is applied to retain impurities by forming covalent bonds with oxygen and nitrogen. This study uses ab initio calculations via Density Functional Theory (DFT), molecular dynamics (MD), and the nudged elastic band (NEB) method in the SIESTA code to examine boron structures in crystalline and amorphous forms. Activation energies for trapping, detrapping, and diffusion processes are determined. Given the difficulty of defining hydrogen-isotope diffusion in boron structures, and its importance for retention and desorption in redeposited or co-deposited layers of the PFM, we focus on identifying the potential diffusion trajectories of hydrogen within the boron structure. This includes mapping a potential landscape and locating local minima and saddle points.
Keywords: boron; hydrogen; diffusion; activation energies