The physics and technology basis entering European system code studies for DEMO

Wenninger, R.; Kembleton, R.; Bachmann, C.; Biel, W.; Bolzonella, T.; Ciattaglia, S.; Cismondi, F.; Coleman, M.; Donné, Ajh Tony; Eich, T.; Fable, E.; Federici, G.; Franke, Thomas; Lux, H.; Maviglia, F.; Mészáros, B.; Pütterich, T.; Saarelma, S.; Snickers, A; Villone, F.; Vincenzi, P.; Wolff, Dan; Zohm, H.

doi:10.1088/0029-5515/57/1/016011

Cited by 108 publications

(115 citation statements)

References 35 publications

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“…An allowable limit of the heat flux at the target for the DEMO reactor has been postulated to be below 5 MW m −2 , while the divertor plasma temperature should be below 5 eV to satisfy an acceptable erosion limit of the target. [8] However, P PLATE decreases below technical limits assumed for the DEMO tokamak, and the electron temperature at the outer plate is sustained above 5 eV. Profiles of the electron temperatures at the inner (left) and the outer (right) target plates are presented in Figure 3 for Γ Ne = 5.4 × 10 22 el s −1 and Γ Kr = 6.73 × 10 22 el s −1 in case of pure Ne and pure Kr seeding, respectively.…”

Section: Ne and Kr Seedingmentioning

confidence: 99%

TECXY simulations of multi‐species impurity seeding in DEMO reactor

Chmielewski

Zagórski

Ivanova‐Stanik

et al. 2018

Contributions to Plasma Physics

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Numerical studies have been performed to investigate the influence of the few impurity species on the heat load reduction and the SOL plasma parameters in the European DEMO reactor. Two‐dimensional multi‐fluid TECXY code has been used to model edge plasma transport described by the classical set of transport equations of multi‐species plasma derived by Braginskii. The TECXY code solves transport equations for few impurity species and all associated ionization stages simultaneously in a two‐dimensional poloidal geometry. This paper describes the results of numerical simulations of the edge plasma performed for the DEMO reactor with neon and krypton seeding, as well as with a mixture of neon and krypton impurities. We aimed to obtain the energy flux reduction to the target plate at the smallest possible increase of the effective charge value considering gas puffing with various mixtures of impurities. It has been found that the heat load reduction can be improved for a specific mixture of impurity species seeded simultaneously to the edge plasma.

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Section: Ne and Kr Seedingmentioning

confidence: 99%

TECXY simulations of multi‐species impurity seeding in DEMO reactor

Chmielewski

Zagórski

Ivanova‐Stanik

et al. 2018

Contributions to Plasma Physics

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“…The simulation of a whole tokamak is a complex problem because it involves different phenomena and all subsystems are not entirely independent from each other. In order to understand and design a whole fusion plant, a fast and reliable simulation code is inevitable [6,7]. The SYCOMORE code is a modular system code which aims at modelling future fusion power plants with all subsystems and to provide a global view of the whole plant [8,9].…”

Section: Introductionmentioning

confidence: 99%

Development of Extended Two-Point Model for Asymmetric Scrape-Off Layer

Wisitsorasak

Kahn²,

Pégouriè³

et al. 2019

Plasma and Fusion Research

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The SYCOMORE code is a modular system code which aims at modelling future fusion power plants with all subsystems and to provide a global view of the whole plant. The code consists in different modules handling the different subsystems of the plant, from the core plasma to the conversion of heat to electricity. Among them, the divertor is one of the most important components and must withstand high heat load. While the complex magnetic configuration in tokamaks and the peculiar transport in the scrape-off layer (SOL) give rise to an asymmetry in the high field and low field energy fluxes, this issue should be properly addressed in SYCOMORE for quick and reliable predictions. In this work, the SOLDIV code which is a scrape-off-layer and divertor module in SYCOMORE has been used to investigate this asymmetry problem based on an extended two-point model. When the outgoing fluxes of particles and heat from the plasma core enter the SOL at the stagnation point, they split into two parts: one transporting to the inner divertor, and the other transporting to the outer divertor. By introducing the imbalance factor of the energy flux between the two divertor plates, the transport equations become a set of nonlinear equations that can be numerically solved for the densities and temperatures at both divertor plates and the stagnation point. Strong temperature and density differences at the targets can be found. The analysis results are validated with the transport code SolEdge2D-EIRENE for WEST test discharges. The simulation results for ITER are also investigated.

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“…The actual model of a DEMO divertor segment with the pumping port to be positioned at the bottom of the middle cassette is shown in Fig.1. The depicted divertor configuration is based on the 2015 EU DEMO baseline design [4], which consists of 54 divertor cassettes in total and has a major radius R=9.1 m. The presented configuration has been compared with the latest 2017 DEMO divertor design and no significant geometrical discrepancies, which may influence the outcome of this study, has been observed. Due to toroidal symmetry we consider only one sector of 20°, which includes 3 divertor cassettes without the dome structure, two poloidal gaps between the cassettes (i.e inter-cassette gaps) and two toroidal gaps between the first wall and the divertor cassettes in both the low field and high field sides (LFS and HFS).…”

Section: Introductionmentioning

confidence: 99%

Effect of neutral leaks on pumping efficiency in 3D DEMO divertor configuration

Varoutis

Igitkhanov

Day

et al. 2018

Fusion Engineering and Design

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In this paper we analyze the pumping efficiency of a generic 3D DEMO divertor configuration based on the size of inter-cassette gaps. Due to symmetry conditions we consider only one segment, which is composed by 3 divertor cassettes with the pumping port located at the bottom of the middle cassette and with four inter-cassette gaps. The width of intercassette gaps or the number of pumping ports is defined by the requirement to minimize the outflow of particles from the divertor to the plasma and hence, the highest possible pumping efficiency for the particle throughput, expected in DEMO, to be achieved. The DIVGAS code is used to perform a sensitivity analysis of the pumping efficiency, defined as a ratio of pumped particle flux to the particle throughput for different inter-cassette widths. The imposed neutral boundary conditions of pressure and temperature represent a moderate divertor pressure operating point. The analysis shows that for the reference case of 20 mm a reduction on the pumped flux of the order of 10% is observed when compared with the case of a completely sealed divertor. For smaller gaps the pumped flux reduction is found to be negligible, while for large values of the gap width the pumped flux reduction may reach the value of 20%. Furthermore, almost 80% of the incoming particles are moving towards the x-point, independent of the gap width. Therefore, the gap width does not influence the outflux towards the x-point, but only strongly affects the pumping efficiency. This analysis is meant to contribute to the ongoing DEMO divertor design efforts.

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The physics and technology basis entering European system code studies for DEMO

Cited by 108 publications

References 35 publications

TECXY simulations of multi‐species impurity seeding in DEMO reactor

TECXY simulations of multi‐species impurity seeding in DEMO reactor

Development of Extended Two-Point Model for Asymmetric Scrape-Off Layer

Effect of neutral leaks on pumping efficiency in 3D DEMO divertor configuration

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