Speaker
Rodrigo Mateus
(Instituto de Plasmas e Fusão Nuclear)
Description
Migration of impurities during ITER plasma discharges will result in the formation of co-deposited mixed materials on the surface of plasma facing components (PFC) with properties distinct from those of the original PFC. These issues have motivated the fusion community to investigate Be-W coatings, in particular their fuel retention behaviour, since in ITER the deposits will present a beryllium (Be) and tungsten (W) matrix. Also recent investigations have shown that the erosion and deposition rates of plasma impurities in the exposed surfaces highly depend on their morphologies [1]. On the other hand the chemical effect can hinder the individual role of superficial roughness in the fuel retention mechanisms and must be investigated in dedicated irradiation experiments involving specific Be-W stoichiometries.
It is assumed that fuel retention is lower in pure W layers than in Be. Nevertheless, previous irradiation experiments carried out in a wide range of compositions evidenced already lower deuterium retention rates in Be:W (50:50) coatings presenting a smooth topography.
The goal of the present investigation is to correlate the retention rate of deuterium implanted in different sets of Be-W coatings presenting specific compositions and distinct roughness morphologies imposed by the thermionic vacuum arc method procedure [2,3]. Energetic 22H++ ions will be implanted up to fluences of 5e17 ions/cm22 in selected samples. Before and after implantation, the topography and chemical composition of the samples will be studied by atomic force and electron microscopies and by ion beam technics.
[1] H. Bergsåker et al., J Nucl. Mater. 463 (2015) 956.
[2] A. Anghel, I. Mustata, C. Porosnicu, C.P. Lungu, J. Nucl. Mater. 385 (2009) 242.
[3] A. Anghel et al., Nucl. Instr. Meth. Phys. Res. B 267 (2009) 426.
Topic of the abstract in the SOFT 2016 conference: F - Plasma Facing Components
Co-authors
Anti Hakola
(VTT Technical Research Centre of Finland, 02044 VTT, Finland)
Corneliu Porosnicu
(National Institute for Lasers, Plasma and Radiation Physics, Bucharest 077125, Romania)
Cristian P. Lungu
(National Institute for Lasers, Plasma and Radiation Physics, Bucharest 077125, Romania)
Eduardo Alves
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
Rodrigo Mateus
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal)
