Сравнение вариантов литиевого дивертора для токамака ДЕМО-ТИН

For the DEMO-FNS tokamak being developed in Russia, the choice of the divertor concept with evaporating liquid lithium is discussed, which meets the requirements for removing the heat load from the peripheral plasma and provides an acceptable level of change in the ionic composition of the core plasma. The paper presents the results of numerical modeling and optimization of divertor parameters with several chambers partitioned by slotted nozzles. The parameters of lithium fluxes flowing into the peripheral layer are estimated for the temperature range of the divertor chambers from 500 to 1000 K under gas-kinetic and molecular flow regimes of lithium vapor from the divertor. The fulfilled analysis of processes that reduce the outflow of lithium from the chambers and its penetration into the core plasma volume inside the separatrix showed that sectioning effectively reduces the Li fluxes to acceptable levels of ~ 1020 atoms per second.

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SOLPS-ITER simulations of a CPS-based liquid metal divertor for the EU DEMO: Li vs. Sn

Nuclear Fusion ◽

10.1088/1741-4326/ac4867 ◽

2022 ◽

Author(s):

Giuseppe Francesco Nallo ◽

Giuseppe Mazzitelli ◽

Matteo Moscheni ◽

Fabio Subba ◽

Roberto Zanino

Keyword(s):

Heat Flux ◽

Liquid Metal ◽

Heat Load ◽

Erosion Rate ◽

Neutral Model ◽

The Core ◽

Operational Window ◽

Self Consistent ◽

Core Plasma ◽

The Eu

Abstract In this work, we study the effect of installing a liquid metal divertor (LMD) using a capillary-porous structure in the EU DEMO tokamak within the same envelope of the baseline solid divertor. We used the SOLPS-ITER code to model the Scrape-Off Layer (SOL) plasma and neutrals, coupled to a target thermal model to enable the self-consistent calculation of the LM target erosion rate, and adopting a fluid neutral model for the sake of simplicity. First calculations considering only D and Li (or Sn) showed a significant reduction of the steady state target heat load with respect to simulations considering only D, thanks to vapor shielding. Nevertheless, the computed peak target heat flux (~31 MW/m2 and ~44 MW/m2 for Li and Sn, respectively) was still larger than/borderline to the power handling limit of the LMD concepts considered. Moreover, the impurity concentration in the pedestal - a proxy for the core plasma dilution/contamination - was computed to be above/close to tolerability limits suggested by previous COREDIV calculations. These results indicate that the operational window of an LMD for the EU DEMO, without any additional impurity seeding, might be too narrow, if it exists, and that Sn looks more promising than Li. A second set of calculations was then performed simulating Ar seeding in the SOL, to further reduce the target heat load, and consequently the metal erosion rate. It was found that the mitigation of the plasma heat load due to Ar radiation in the SOL effectively replaces the radiation associated to vapor shielding in front of the target, thus allowing to operate the LMD in a regime of low target erosion. The resulting operational window was found to be significantly wider, both in terms of tolerable peak target heat flux and of acceptable core plasma contamination.

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Observations on the W-transport in the core plasma of JET and ASDEX Upgrade

Plasma Physics and Controlled Fusion ◽

10.1088/0741-3335/55/12/124036 ◽

2013 ◽

Vol 55 (12) ◽

pp. 124036 ◽

Cited By ~ 58

Author(s):

T Pütterich ◽

R Dux ◽

R Neu ◽

M Bernert ◽

M N A Beurskens ◽

...

Keyword(s):

The Core ◽

Core Plasma

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Physics analyses on the core plasma properties in the helical fusion DEMO reactor FFHR-d1

Nuclear Fusion ◽

10.1088/0029-5515/54/4/043010 ◽

2014 ◽

Vol 54 (4) ◽

pp. 043010 ◽

Cited By ~ 9

Author(s):

J. Miyazawa ◽

Y. Suzuki ◽

S. Satake ◽

R. Seki ◽

Y. Masaoka ◽

...

Keyword(s):

Plasma Properties ◽

The Core ◽

Core Plasma

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Confinement improvement during detached phase with RMP application in deuterium plasmas of LHD

Nuclear Fusion ◽

10.1088/1741-4326/ac42f3 ◽

2021 ◽

Author(s):

Masahiro Kobayashi ◽

Ryosuke Seki ◽

Yuki Hayashi ◽

Tetsutarou Oishi ◽

Kanji Tanaka ◽

...

Keyword(s):

Heat Load ◽

Field Application ◽

Edge Plasma ◽

Magnetic Fluctuations ◽

Transport Barrier ◽

Radiation Level ◽

Hydrogen Plasmas ◽

Core Plasma ◽

Load Increase ◽

Stochastic Layer

Abstract In order to explore compatibility of good core plasma performance with divertor heat load mitigation, interaction between cold edge plasma and core plasma transport including edge transport barrier (ETB) has been analysed in the divertor detachment discharges of deuterium plasmas in LHD with RMP (resonant magnetic perturbation) field application. The RMP application introduces widened edge stochastic layer and sharp boundary in the magnetic field structure between the confinement region and the edge stochastic layer. The widened edge stochastic layer enhances impurity radiation and provides stable detachment operation as compared with the case without RMP. It is found that ETB is formed at the confinement boundary at the onset of detachment transition. However, as the detachment deepens resistive pressure gradient driven MHD mode is excited, which degrade the ETB. At the same time, however, the core transport decreases to keep global plasma stored energy (Wp) unchanged, showing clearly core-edge coupling. After gradual increase of density fluctuation during the MHD activity, spontaneous increase of Wp and recovery of ETB are observed while the detachment is maintained. Then the coherent MHD mode ceases and ELM like bursts appear. In the improved mode, the impurity decontamination occurs, and the divertor heat load increase slightly. Key controlling physics in the interplay between core and cold edge plasma is discussed. Comparison between deuterium and hydrogen plasmas show that the hydrogen plasmas exhibit similar features as the deuterium ones in terms of density and magnetic fluctuations, impurity decontamination toward higher confinement etc. But most of the features are modest in the hydrogen plasmas and thus no clear confinement mode transition with clear ETB formation is defined. Better global confinement is obtained in the deuterium plasmas than the hydrogen ones at higher radiation level.

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