Surface morphology and deuterium retention in tungsten exposed to low-energy, high flux pure and helium-seeded deuterium plasmas

Abstract

Blistering and deuterium retention in re-crystallized tungsten exposed to low-energy, high flux pure and helium-seeded D plasmas to a fluence of 10 27 D/m 2 have been examined with scanning electron microscopy, thermal desorption spectroscopy, and the D(

Microstructural modifications in tungsten induced by high flux plasma exposure: TEM examination

“…The present observation of dense dislocation networks proves that the nature of high dome blisters is related to extensive sub-surface plastic deformation. One can also note that the reduction of the dislocation density to the level of the reference value beyond a depth of 10 μm correlates well with the strong gradient of the D concentration retained after the high flux plasma exposure, as measured by NRA [3][4][5][6]. We would like to stress that the above observations are grounded by considerable statistics.…”

“…Typical measurements done by nuclear reaction analysis (NRA) show that concentration of retained D sharply decreases within first several μm (see e.g. [3][4][5][6]). However, the resolution of NRA does not allow probing deeper than 10 μm.…”

Sub-surface structures of ITER-grade W (Japan) and re-crystallized W after ITER-similar low-energy and high-flux D plasma loadings

“…The D retention of these specimens was determined by TDS and NRA using the reaction D( 3 He,p) 4 He by scanning the 3 He energy from 690 keV up to 4 MeV. The results are presented in [12,13,16]. The surface topography and the 3D morphology of the plasma-exposed tungsten were analysed by SEM.…”

“…The data on D retention in re-crystallised W and ITER-grade W measured by NRA and TDS [12,13,16] are shown in Fig. 1.…”

Deuterium retention in single-crystal tungsten irradiated with 10–500 eV/D+

“…However, only limited retention data exist for low energy D + (10 eV [6] and 38 eV [7]) characteristic of Franck-Condon energies in the ITER divertor. Previous low-energy D retention studies used plasma devices [8][9][10][11]. Here,…”