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Communication Dans Un Congrès Année : 2023

Reducing plasma-material interactions in the DIII-D low-Z and high-Z divertors with impurity powders

Losada U.
  • Fonction : Auteur

Résumé

In the DIII-D tokamak, boron (B) and boron nitride (BN) powder injections have demonstrated effectiveness in mitigating heat fluxes and suppressing tungsten erosion and divertor leakage in closed divertor configurations without compromising core plasma performance. Upon integrating the small-angle slot (SAS) divertor with a W-coated outer ring (SAS-VW), the dynamics of impurity interactions became evident, showcasing the capability of low-Z impurity injections to counteract high-Z erosion. 25-50 mg/s BN powder increased the divertor neutral pressure up to 10-fold and reduced the peak parallel heat flux from 30 to 3 MW/m2 in the divertor. BN powders emerged as superior dissipators, especially in closed divertors, compared to pure B powder. An experiment with a collector probe provided evidence that tungsten leakage from the SAS-VW reduced by 50% when measured at the outer midplane during boron powder injections. Both increases in boron and reduction in W were measured in the far scrape-off layer, suggesting that real-time boronization with powders can even be successful in those remote areas. The assessment of boron powder injection is supported by computational simulations using EMC3-EIRENE and the dust-injection simulator (DIS), which suggest that B deposition area increases for larger particle sizes. The modeling reveals these distinct effects in the deposition in the closed divertor under the assumption that re-erosion and redeposition are neglected. These findings underscore the promise of powder injection for managing plasma-material interactions in future fusion reactors, with potential enhancements via multiple toroidal injection points.
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hal-04253635 , version 1 (23-10-2023)

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  • HAL Id : hal-04253635 , version 1

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Florian Effenberg, Bortolon A., Abe S., Maingi R., Nagy A., et al.. Reducing plasma-material interactions in the DIII-D low-Z and high-Z divertors with impurity powders. 29th IAEA Fusion Energy Conference (FEC 2023), International Atomic Energy Agency (IAEA), Oct 2023, London, United Kingdom. ⟨hal-04253635⟩
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