Dust generation in tokamaks: Overview of beryllium and tungsten dust characterisation in JET with the ITER-like wall

Rubel, M.; Widdowson, A.; Grzonka, J.; Fortuna-Zaleśna, E.; Moon, S.; Petersson, P.; Ashikawa, N.; Asakura, N.; Hamaguchi, Dai; Hatano, Yuji; Isobe, K.; Masuzaki, S.; Kurotaki, H.; Oya, Yasuhisa; Oyaidzu, M.; Tokitani, M.

doi:10.1016/j.fusengdes.2018.03.027

Cited by 55 publications

(50 citation statements)

References 30 publications

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“…Considering also the beryllium walls currently used in JET and planned for ITER, the case of beryllium particles (with density 1850 kg/m3) is also studied here. We consider for simplification that particles made of beryllium are spherical with the same range of diameters, d = 1,2, 5,10, 20 ^m [12,13]. Particles are considered in the non oxydized form (density of pure tungsten and beryllium are used in the later calculations).…”

Section: Types and Sizes Of Partialesmentioning

confidence: 99%

“…The Derjaguin-Müller-Toporov (DMT) theory [18] provides the adhesion force for a sphere (of diameter d) and a smooth wall of the same material: FDMT = nEA,W d (13) where EA,W denotes here the adhesion energy of tungsten. We give in Tab.…”

Section: Adhesion Forcesmentioning

confidence: 99%

“…Particles used in that experiment were non-spherical but did not exhibit any elongated shape. The ratio of the experimental adhesion force Fa of tungsten particles on a rough tungsten surface, equation (14), to the theoretical adhesion force Fdmt according to the DMT theory, equation (13), is represented in figure 7 for the particles of Tab. 1.…”

Section: Adhesion Forcesmentioning

confidence: 99%

“…(17)) versus pressure, for the calculations starting at a pressure of 500 Pa and 1000 Pa. Dashed lines: using the DMT adhesion force(13). Solid lines: using the experimental adhesion force on a rough surface(14).…”

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confidence: 99%

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Particle behavior close to the lower wall of a tokamak type geometry during a loss of vacuum accident

Feuillebois

Gensdarmes

Gélain

2020

Fusion Engineering and Design

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The behavior of tungsten and beryllium particles close to the wall of a tokamak type geometry (i.e. a toroidal vacuum vessel) during a loss of vacuum accident (LOVA) is explored in this paper.Values of the flow field and temperature of the air surging into the torus were calculated by Computational Fluid Dynamics (CFD) simulations from an initial low pressure of 1000 Pa by Gelain et al, Fusion Engineering and Design, 100:87-99, 2015. A new CFD calculation is performed here for an initial low pressure of 500 Pa. The aerodynamic forces on particles in rarefied flow are derived from the calculated friction velocity and temperature in the lowest wall region. The focus is on spherical particles, but these values of forces are complemented for comparison with an estimate of the force on an elongated particle following Sentman (1961). Typical particles with diameters of 1, 2, 5, 10, 20 ^m are considered. The possibility for particles which are detached from the lower wall to be entrained away the wall is explored. A particle may be detached by the flow field provided it escapes the adhesion force with the wall, which occurs only for a rough wall and large particles. It is then entrained away from the lower part of the wall provided its weight is smaller than the aerodynamic force, which occurs even at low pressure for all sizes of studied beryllium particles and only for specific sizes and a pressure above 1500 Pa for tungsten particles. This key influence of particle weight on the particle dynamics in rarefied gas flow is the focus of the paper. As a result, only particles of intermediate diameters may be resuspended and transfered away from the wall during the whole pressurisation sequence of the vessel. Using the data for the initial low pressure of 500 Pa, these particle diameters are 5, 10 ^m for tungsten and 5, 10, 20 ^m for beryllium.

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Section: Types and Sizes Of Partialesmentioning

confidence: 99%

Section: Adhesion Forcesmentioning

confidence: 99%

Section: Adhesion Forcesmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Particle behavior close to the lower wall of a tokamak type geometry during a loss of vacuum accident

Feuillebois

Gensdarmes

Gélain

2020

Fusion Engineering and Design

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“…2016; Rubel et al. 2018), contaminants in industrial processing plasmas (Watanabe 1997; Kersten et al. 2003; Shumova et al.…”

Section: Introductionmentioning

confidence: 99%

Controlled photo-discharge of dust in a complex plasma

McKinlay

Thomas

2021

J. Plasma Phys.

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One of the limitations in studying dusty plasmas is that many of the important properties of the dust (like the charge) are directly coupled to the surrounding plasma conditions rather than being determined independently. The application of high-intensity ultraviolet (UV) sources to generate discharging photoelectric currents may provide an avenue for developing methods of controlling dust charge. Careful selection of the parameters of the UV source and dust material may even allow for this to be accomplished with minimal perturbation of the background plasma. The Auburn Magnetized Plasma Research Laboratory (MPRL) has developed a ‘proof-of-concept’ experiment for this controlled photo-discharging of dust; a high-intensity, near-UV source was used to produce large changes in the equilibrium positions of lanthanum hexaboride ( $\textrm {LaB}_6$ ) particles suspended in an argon DC glow discharge with negligible changes in the potential, density and temperature profiles of the background plasma. The shifts in equilibrium position of the dust are consistent with a reduction in dust charge. Video analysis is used to quantify the changes in position, velocity and acceleration of a test particle under the influence of the UV and Langmuir probes are used to measure the effects on the plasma.

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First Monte‐Carlo modelling of global beryllium migration in ITER using ERO2.0

Romazanov

Brezinsek

Kirschner

et al. 2019

Contributions to Plasma Physics

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ERO2.0 is a recently developed Monte‐Carlo code for modelling global erosion and redeposition in fusion devices. We report here on the code's application to ITER for studying the erosion of the beryllium (Be) first wall armour under burning plasma steady state diverted conditions. An important goal of the study is to provide synthetic signals for the design of two key diagnostics: the main chamber visible spectroscopy and the laser in‐vessel viewing systems. The simulations are performed using toroidally symmetric plasma backgrounds obtained by combining SOLPS simulations extended to the wall using the OSM‐EIRENE‐DIVIMP edge code package. These are then further combined with a shadowing model using magnetic field line tracing to provide a three‐dimensional correction for the flux patterns. The resulting plasma wetted area, which amounts to ∼10% of the total first wall area, is in excellent agreement with shadowing calculations obtained with the SMITER field line tracing code. The simulations reveal that the main Be erosion zones are located in regions intersected by the secondary separatrix, in particular the upper Be panels, which are close to the secondary X‐point. For the particular high‐density Q = 10 background plasma case studied here, ∼80% of the eroded Be is found to re‐deposit on main chamber surfaces. The rest migrates in almost equal parts to the inner and outer divertor and is deposited close to the strike lines.

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Dust generation in tokamaks: Overview of beryllium and tungsten dust characterisation in JET with the ITER-like wall

Cited by 55 publications

References 30 publications

Particle behavior close to the lower wall of a tokamak type geometry during a loss of vacuum accident

Particle behavior close to the lower wall of a tokamak type geometry during a loss of vacuum accident

Controlled photo-discharge of dust in a complex plasma

First Monte‐Carlo modelling of global beryllium migration in ITER using ERO2.0

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