Micro-particles in ITER: A comprehensive review

Grisolia, C.; Rosanvallon, S.; Sharpe, Peter J. H.; Winter, J.

doi:10.1016/j.jnucmat.2008.12.192

Cited by 10 publications

(9 citation statements)

References 10 publications

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“…These stratified co-deposits split into 20-30 nm thin strata that easily disintegrate into very fine matter. As already discussed in previous papers [22], accumulation of water vapor in porous dust pieces and deposits causes splitting and flaking of the layers. The effect is enhanced when the layer is again subjected to vacuum conditions either in the SEM chamber or in a tokamak after a shut down period.…”

Section: Discussionmentioning

confidence: 59%

“…installation of tiles. More exact numbers cannot be given because the ultra-fine dust could not be weighed: (a) it sticks to the filtering paper; (b) some fine matter could not be removed from PFC because of strong adhesion to the substrate, probably due to Van der Waals forces as suggested in [22]. After subtracting the mass of above-mentioned larger debris and ceramics the amount of carbon matter is 0.1-0.2 g. The other side of the equation for the conversion factor includes the amount of material eroded and re-deposited on PFC.…”

Section: Discussionmentioning

confidence: 99%

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Survey of dust formed in the TEXTOR tokamak: structure and fuel retention

et al. 2009

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A detailed survey of erosion and deposition on plasma-facing components was performed in the TEXTOR tokamak. Co-deposits and dust particles were collected from graphite limiters and from several locations on the Inconel liner. The total amount of dust (loose material), originating mainly from carbon-rich co-deposits detached from the limiters and the liner, was around 2 g, with sizes from 0.1 µm to 1 mm. The morphology and fuel retention was determined using microscopy methods, ion beam analysis and thermal desorption spectrometry. The study revealed differences in structure and fuel content between deposits from the toroidal and main poloidal limiters. There were also splashes, up to 1 mm in diameter, of molten metal (mainly nickel) on the toroidal limiters. Issues of the dust conversion factor (erosion-to-dust) are addressed and a comparison with results of previous dust surveys at TEXTOR is also briefly presented.

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Section: Discussionmentioning

confidence: 59%

Section: Discussionmentioning

confidence: 99%

Survey of dust formed in the TEXTOR tokamak: structure and fuel retention

et al. 2009

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“…It is well known, however, that PMI can also create mobilizable solid particulates or dust (from current carbon-based tokamaks, the dust production rate relative to gross erosion is estimated around 10-15% [5]), whose role in affecting the required local balance between erosion and redeposition is particularly important for a solid tungsten PFC. This is a far greater challenge, as impurity neutrals can be ionized near the wall and hence promptly sent back to the wall, but solid dust particles can traverse long distances in the plasma chamber [6].…”

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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“…Also, due to high internal stresses, the redeposited layers can break, forming small and large size dusts. Dust occurrence represents a continuing concern in the scientific community for the thermonuclear facilities, because it raises the risk of contamination, both for the fusion facility and for the operators [2][3][4][5]. These contaminations come from the capacity of the dust material to incorporate tritium, due to their large specific surface area (SSA).…”

Section: Introductionmentioning

confidence: 99%

Material Erosion and Dust Formation during Tungsten Exposure to Hollow-Cathode and Microjet Discharges

et al. 2020

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Tungsten erosion and dust occurrence are phenomena of great interest for fusion technology. Herein, we report results concerning the material damage and dust formation in the presence of high temperature and large area or concentrated discharges in helium and argon. In order to generate adequate plasmas, we used tungsten electrodes in two experimental discharge systems, namely a hollow discharge and a microjet discharge. In both exposure cases, we noticed surface modification, which was assigned to sputtering, melting, and vaporization processes, and a significant dust presence. We report the formation on electrode surfaces of tungsten fuzz, nano-cones, nanofibers, and cauliflower- and faced-like particles, depending on the discharge and gas type. Dust with various morphologies and sizes was collected and analyzed with respect to the morphology, size distribution, and chemical composition. We noticed, with respect to erosion and particle formation, common behaviors of W in both laboratory and fusion facilities experiments.

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Micro-particles in ITER: A comprehensive review

Cited by 10 publications

References 10 publications

Survey of dust formed in the TEXTOR tokamak: structure and fuel retention

Survey of dust formed in the TEXTOR tokamak: structure and fuel retention

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

Material Erosion and Dust Formation during Tungsten Exposure to Hollow-Cathode and Microjet Discharges

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