Self-healing liquid Metal Divertors (LMDs) are currently being considered among the alternative strategies to address the power exhaust problem in future fusion reactors such as the EU DEMO tokamak. To characterize the power exhaust scenario for a tokamak equipped with an LMD, a self-consistent approach is required, accounting for the mutual interactions between the Scrape-Off Layer (SOL) plasma, the divertor targets and the evaporated metal. To this aim, the SOLPS-ITER code, a 2D multi-fluid solver for the plasma and neutral species, was coupled to a purposely developed LM target erosion/evaporation model and then applied to simulate the EU DEMO plasma in the presence of a liquid Sn divertor. Calculations considering only D and Sn as plasma (and neutral) species indicates that vapor shielding arising from the interactions of the eroded/evaporated metal with the near-surface plasma effectively mitigates the target heat flux, reducing the computed peak value from ∼ 60 MW/m2 (computed for a pure D case, mimicking a solid divertor) to ∼ 44 MW/m2. However, this value is still larger than the power handling limit of ∼ 40 MW/m2 for the considered LMD design. Moreover, the computed Sn concentration in the core plasma was close to the estimated compatibility limit of ∼ 0.05%. These results motivated further simulations considering the injection of Ar in the SOL plasma to radiate part of the plasma power before it reaches the target, also leading to a reduced erosion/evaporation rate. The results indicated a significant widening of the operational window for the EU DEMO equipped with an LMD using Sn, both in terms of tolerable target heat fluxes and in terms of core plasma contamination.

Scrape-Off Layer Plasma Modelling for the EU DEMO Fusion Reactor with a Liquid Metal Divertor / Nallo, GIUSEPPE FRANCESCO; Subba, Fabio; Zanino, Roberto. - ELETTRONICO. - (2021). (Intervento presentato al convegno NENE 2021 tenutosi a Bled, Slovenia nel 6-9 September 2021).

Scrape-Off Layer Plasma Modelling for the EU DEMO Fusion Reactor with a Liquid Metal Divertor

Giuseppe Francesco Nallo;Fabio Subba;Roberto Zanino
2021

Abstract

Self-healing liquid Metal Divertors (LMDs) are currently being considered among the alternative strategies to address the power exhaust problem in future fusion reactors such as the EU DEMO tokamak. To characterize the power exhaust scenario for a tokamak equipped with an LMD, a self-consistent approach is required, accounting for the mutual interactions between the Scrape-Off Layer (SOL) plasma, the divertor targets and the evaporated metal. To this aim, the SOLPS-ITER code, a 2D multi-fluid solver for the plasma and neutral species, was coupled to a purposely developed LM target erosion/evaporation model and then applied to simulate the EU DEMO plasma in the presence of a liquid Sn divertor. Calculations considering only D and Sn as plasma (and neutral) species indicates that vapor shielding arising from the interactions of the eroded/evaporated metal with the near-surface plasma effectively mitigates the target heat flux, reducing the computed peak value from ∼ 60 MW/m2 (computed for a pure D case, mimicking a solid divertor) to ∼ 44 MW/m2. However, this value is still larger than the power handling limit of ∼ 40 MW/m2 for the considered LMD design. Moreover, the computed Sn concentration in the core plasma was close to the estimated compatibility limit of ∼ 0.05%. These results motivated further simulations considering the injection of Ar in the SOL plasma to radiate part of the plasma power before it reaches the target, also leading to a reduced erosion/evaporation rate. The results indicated a significant widening of the operational window for the EU DEMO equipped with an LMD using Sn, both in terms of tolerable target heat fluxes and in terms of core plasma contamination.
2021
978-961-6207-51-5
File in questo prodotto:
File Dimensione Formato  
Nallo_NENE2021_1307.pdf

accesso aperto

Tipologia: 2a Post-print versione editoriale / Version of Record
Licenza: PUBBLICO - Tutti i diritti riservati
Dimensione 5.1 MB
Formato Adobe PDF
5.1 MB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11583/2956032