Studies of lithiumization and boronization of ATJ graphite PFCs in NSTX-U

• Published in: Nuclear materials and energy Vol. 12; pp. 334 - 340
• Main Authors: Domínguez-Gutiérrez, F.J., Bedoya, F., Krstic, P.S., Allain, J.P., Neff, A.L., Luitjohan, K.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2017; Elsevier
• Subjects: Boronization; Carbon; Deuterium retention; Lithiumization; NSTX; Plasma-surface interactions; Boronization; Lithiumization; NSTX; Carbon; Plasma-surface interactions; Deuterium retention
• ISSN: 2352-1791; 2352-1791
• DOI: 10.1016/j.nme.2016.12.028

•Boronized and lithiumized carbon material is studied under exposure of deuterium irradiation.•Retention of deuterium and sputtering processes were studied by atomistic simulations.•Chemistry inside a mixed material was measured by XPS plasma and beam experiments and compared with atomistic simulations.•Boronized and lithiumized surfaces show comparable deuterium retention, boron is slightly more efficient.•While oxygen plays crucial role in processes with lithiated surfaces, boronized surfaces are not as sensitive to oxygen. This work examines the effect of boron and lithium conditioned ATJ graphite surface bombarded by low-energy deuterium atoms on the deuterium retention and chemical sputtering. We use atomistic simulations and compare them with experimental in situ studies with x-ray photoelectron spectroscopy (XPS), to understand the effects of deuterium irradiation on the chemistry in lithiated, boronized and oxidized amorphous carbon surfaces. Our results are validated qualitatively by comparison with experiments and with quantum classical molecular dynamic simulations. We explain the important role of oxygen in D retention for lithiated surfaces and the suppression of oxygen role by boron in boronized surfaces. The calculated increase of the oxygen role in deuterium uptake after D accumulation in BCO surface configuration is discussed. The sputtering yield per low energy D impact is significantly smaller in boronized than in lithiated surfaces.