Physical erosion studies of plain and lithiated graphite

Racic, Marin; Ibano, Kenzo; Raju, R.; Ruzic, D. N.

doi:10.1016/j.jnucmat.2009.01.284

Cited by 8 publications

(2 citation statements)

References 16 publications

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“…It should be noted that similar reduction of erosion yield is found for Li coatings on boron/carbon coatings in the TJ-II machine in Spain [4]. Allain et al also measured that over 95% of the sputtered plume from D and He irradiationinduced bombardment of lithiated graphite consisted of Li atoms and this result was corroborated independently by Racic et al [15,16].…”

Section: Trace Carbon Mixing With Liquid Lithiummentioning

confidence: 56%

Lithium surface-response modelling for the NSTX liquid lithium divertor

Allain¹,

Brooks²

2011

Nucl. Fusion

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We analyse lithium sputtering, evaporation and transport for the National Spherical Torus Experiment (NSTX) liquid lithium divertor (LLD) for planned high heating power plasma conditions. A temperature-dependent, data-calibrated, surface-response model is used to specify sputter yield, velocity distributions, sputtered Li ion fraction and related phenomena, for the static liquid lithium surface with D, Li and trace C impingement. Using the surface-response model, and supplied UEDGE code edge plasma parameters and LLD surface temperature profile for a typical 2 MW heating, low D-recycle shot, the REDEP/WBC code package computes Li erosion/redeposition. The results are encouraging showing negligible Li evaporation, moderate sputter erosion, and acceptable Li transport to the edge (∼7% Li/D density) and core plasma (∼1% Li/D contamination potential) and LLD adjacent surfaces. A 2% carbon plasma content does not significantly affect the LLD surface response. For fixed plasma conditions, but with hypothetically higher surface temperatures than the reference 281 °C peak, an increase to ∼350 °C appears acceptable, thus implying a significant operating temperature margin.

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Section: Trace Carbon Mixing With Liquid Lithiummentioning

confidence: 56%

Lithium surface-response modelling for the NSTX liquid lithium divertor

Allain¹,

Brooks²

2011

Nucl. Fusion

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“…From these figures, comparable lithium emission is observed in both discharges on cold LLD and on the diagnostic tile (both of which are reduced if compared to the hot LLD case in Figure 1(d)-left). While a reduction in lithium sputtering was measured on lithiated graphite in IIAX [17] and was attributed to the formation of ionic bonds between carbon and lithium, the NSTX result can be understood as due to the macroscopically thick lithium coatings, which reduce the role of the substrate in determining the surface sputtering.…”

Section: Resultsmentioning

confidence: 99%

Lithium sputtering from lithium-coated plasma facing components in the NSTX divertor

Scotti

Soukhanovskii

Ahn

et al. 2015

Journal of Nuclear Materials

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Lithium sputtering yields and gross impurity influxes from lithium-coated graphite and molybdenum plasma facing components (PFCs) have been analyzed for the first time in the National Spherical Torus Experiment (NSTX) divertor during H-mode NBI-heated discharges. Motivated by the beneficial effects of lithium conditioning on discharge performance and reproducibility, evaporative lithium coatings were the routine wall conditioning technique in NSTX. Neutral lithium sputtering yields from solid lithium coatings in NSTX were found to be consistent with values reported from test stand experiments from deuterium-saturated lithium (with sputtering yields Y Li ∼ 0.03 − 0.07). Temperature-enhanced lithium sputtering was observed on lithium-coated graphite and molybdenum as a result of PFC heating by both embedded heaters and incident plasma heat flux, leading to Y Li ∼ 0.1 − 0.2 for surface temperatures above the lithium melting point.

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