Mechanisms of retention and blistering in near-surface region of tungsten exposed to high flux deuterium plasmas of tens of eV

Shu, W.M.; Luo, G.-N.; Yamanishi, Toshihiko

doi:10.1016/j.jnucmat.2007.04.005

Cited by 71 publications

(29 citation statements)

References 16 publications

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“…The tungsten plate with purity of 99.99 wt% and with 99.7% of theoretical density was prepared (A.L.M.T. Corp., Japan) by powder metallurgy and hot-rolled reduction [5,6]. The plate was cut into specimens of 10102 mm 3 , double-sided mechanically and electrochemically polished to a high optical quality, and recrystallized at 2073 K for 1 h. The typical grain size was in the range 20-100 m (see below).…”

Section: Methodsmentioning

confidence: 99%

Effect of sputtering on self-damaged recrystallized W mirror specimens

Voitsenya

Balden

Belyaeva

et al. 2013

Journal of Nuclear Materials

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The effect of heavy sputtering and of neutron irradiation simulated by displacement damaging with of 20 MeV W 6+ ions on the optical properties of tungsten mirrors was studied. Ar + ions with 600 eV of energy were used as imitation of charge exchange atoms ejected from fusion plasma. The ion fluence dependence of the surface topography and the optical properties of polycrystalline, recrystallized tungsten (grain size 20 -100 µm) were studied by optical microscopy, interferometry, reflectrometry and ellipsometry. Furthermore, after sputtering in total a layer of 3.9 μm in thickness, the orientation and the thickness of the eroded layer of many individual grains was determined by electron backscattering diffraction and confocal laser scanning microscopy. Concluding from the obtained data the neutron irradiation, at least at the damage level would be achieved in ITER, has not to make an additional contribution in the processes developing under impact of charge exchange atoms only.

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Section: Methodsmentioning

confidence: 99%

Effect of sputtering on self-damaged recrystallized W mirror specimens

Voitsenya

Balden

Belyaeva

et al. 2013

Journal of Nuclear Materials

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“…For a tungsten PFC, physical and chemical sputtering produce relatively modest erosion. Instead, helium and hydrogen ion fluxes, coupled with a high wall temperature, cause blistering [7], the formation of pits, holes, and bubbles [8,9], and micron-in-length nano-fuzz [10], which are sources for erosion in the form of dust particles.…”

Section: Introductionmentioning

confidence: 99%

Survivability of dust in tokamaks: Dust transport in the divertor sheath

Delzanno

Tang

2014

Physics of Plasmas

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The survivability of dust being transported in the magnetized sheath near the divertor plate of a tokamak and its impact on the desired balance of erosion and redeposition for a steady-state reactor are investigated. Two different divertor scenarios are considered. The first is characterized by an energy flux perpendicular to the plate q 0 1 MW/m 2 typical of current short-pulse tokamaks.The second has q 0 10 MW/m 2 and is relevant to long-pulse machines like ITER or DEMO.It is shown that micrometer dust particles can survive rather easily near the plates of a divertor plasma with q 0 1 MW/m 2 because thermal radiation provides adequate cooling for the dust particle. On the other hand, the survivability of micrometer dust particles near the divertor plates is drastically reduced when q 0 10 MW/m 2 . Micrometer dust particles redeposit their material non-locally, leading to a net poloidal mass migration across the divertor. Smaller particles (with radius ∼ 0.1 µm) cannot survive near the divertor and redeposit their material locally. Bigger particle (with radius ∼ 10 µm) can instead survive partially and move outside the divertor strike points, thus causing a net loss of divertor material to dust accumulation inside the chamber and some non-local redeposition. The implications of these results for ITER are discussed.

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“…Deep inward diffusion and trapping of D far beyond the ion range is reported. Quite often the D retention is accompanied by formation of blister-like surface structures ( [4] and references therein, [5,6,7,8,9,10,11]), which is assumed to be responsible for a minimum in the deuterium depth profiles [12].…”

Section: Introductionmentioning

confidence: 99%

“…Most publications describe SEM investigations of surface features and only a few investigations deal with their subsurface morphology [7,8,11,17,18,19]. The observed shape, size, and number of the blister-like structures depend strongly on the exact exposure conditions, like ion species (e.g.…”

Section: Introductionmentioning

confidence: 99%