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The WEST experiment is currently operating with tungsten plasmafacing components and testing ITER-like divertor monoblocks. In order to support WEST experiments interpretation, numerical analyses were carried out. Starting from WEST experimental data, realistic background plasma conditions were reproduced through SolEdge-EIRENE and used as input for ERO2.0 simulations to investigate tungsten migration. Tungsten contamination due to the different plasmafacing components was modelled under different plasma conditions, highlighting a non-negligible contribution of tungsten coming from the tokamak main chamber. Tungsten penetration factor was computed and used as an indication for tungsten screening by the background plasma at the different tokamak plasma-facing components. Simulations showed the main chamber components to be very weakly screened. Light impurities charge was showed to influence not only tungsten sputtering, but also its probability to enter the confined plasma. Simulations results indicated that even when the tungsten source is not heavily influenced by self-sputtering, contamination of the confined plasma can be strongly impacted by it in low density 1 background plasma conditions. Finally, a one-to-one comparison between tungsten visible spectroscopy at the lower divertor from experimental data and from synthetic diagnostics was performed, showing that it is possible to reproduce a realistic lower divertor signal following experimental evidence on light impurities asymmetry between the targets.
The influence of the input power, pu ng rate and neutral pressure on the fuel (hydrogen isotopes) inventory of the WEST and ITER divertors is investigated. For the chosen range of parameters (relatively low temperature at the strike points), the inventory of the WEST divertor evolves as the power 0.2 of the pu ng rate and as the power 0.3 of the input power. The inventory at the strike points is highly dominated by ions whereas it is dominated by neutrals in the private zone. Increasing the fuelling rate increases the retention in the private zone and decreases slightly the retention at the strike points. Increasing the input power increases the inventory at the strike points and does not a↵ect much the inventory at the private flux region. The inventory of the ITER divertor is not strongly dependent on the divertor neutral pressure. The inventory increases from 0 Pa to 7 Pa and then decreases slightly from 7 Pa to 10 Pa. After 10 7 s of continuous exposure, the maximum inventory in the ITER divertor was found to be 14 g. The inventory is not maximum at the strike points due to the high surface temperature of the monoblocks in this region. The maximum accumulation of H in the ITER divertor is below 5 mg per 400 s discharge and below 2 mg per 400 s discharge after 200 discharges.
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