Analyses of the influence of the recycling coefficient on He confinement in DEMO reactor

Ivanova‐Stanik, I.; Poradziński, M.; Zagórski, R.; Siccinio, M.

doi:10.1016/j.fusengdes.2019.03.091

Cited by 9 publications

(8 citation statements)

References 17 publications

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“…This means that there is a small margin in respect to ρ * . Note that in [39] similar results were obtained for EU-DEMO1 parameters. There, the ratio ρ * varies in the range of 2.6 ÷ 7.8.…”

Section: Numerical Solutions For the Selected Tokamak-reactors Parame...supporting

confidence: 83%

Effect of impurity radiation and helium particle confinement on tokamak–reactor plasma performance

Mavrin

2020

Plasma Phys. Control. Fusion

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In this paper two important matters for assessments the D–T plasma performance of future tokamak–reactors such as ITER and EU–DEMO projects are discussed. The first issue is the heat removal via the radiation of intrinsic and seeded impurities. The second is the helium particle confinement and ash removal. To study these issues, a simple numerical 0.5D-model is proposed. The impurity radiation in the tokamak high–temperature plasma is described by the coronal model. Coronal radiative cooling used rates are based on the tabulated data published in the recent works. Helium particle confinement and ash exhaust efficiency are determined by the variable parameter ρ* characterizing the ratio between the global helium particle confinement time τ H e ∗ and the energy confinement time τ E . Such approach allows simultaneously obtaining solutions of the particle and energy balance equations in steady–state conditions, taking account of the effect of impurity radiation loss and ash poisoning. Using known energy confinement scaling τ E and design parameters of the ITER and EU–DEMO projects the particle and energy balance equations have been solved. For fixed values of impurities concentration and ratios ρ*, iso–curves of constant fusion power were obtained. These curves are similar to the well–known Plasma OPeration CONtours (POPCON). The POPCON curves are often used to study the operating points of tokamak–reactors. It is shown that for the ITER parameters there is a noticeable margin in the ratio ρ*. For the design parameters of the EU–DEMO project, the margin for ratio ρ* is very small, which casts doubt on the feasibility of the project in its current form (at least with regard to the EU–DEMO steady–state project). Further research in this area is required. The methods and results obtained in this paper can be used for further conceptual analysis of tokamak–reactors operating space.

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Section: Numerical Solutions For the Selected Tokamak-reactors Parame...supporting

confidence: 83%

Effect of impurity radiation and helium particle confinement on tokamak–reactor plasma performance

Mavrin

2020

Plasma Phys. Control. Fusion

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“…The dependence of plasma current (Ip) and line averaged plasma density (<ne,line>) on R and BT are presented in Table I. In the simulations, 71.6% of the alpha power (Pα) heats the electrons and the remaining 28.4% the ions, as suggested in other papers [13,14], while the very important parameter ζ=D/χe, ratio between the particle and heat cross-field diffusion coefficients in the core is set to 0.35, as for the past COREDIV simulations [3,4,13]. Its magnitude determines the amount of the He ashes accumulation, and then that of the produced fusion power.…”

Section: Investigation With the Self-consistent Code Coredivmentioning

confidence: 72%

Analysis of the performances of a fusion reactor in a reduced H-mode confinement

et al. 2020

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The feasibility of a tokamak fusion reactor working in a reduced H-mode confinement, typical of the type III (or grassy) ELMs regime is here analyzed with two codes. The first is COREDIV that provides an integrated and self-consistent description of both the core and SOL plasma. The analysis is complemented by the 2D code TECXY which models the SOL more accurately and can then provide better estimates of the power deposited on the divertor targets. As for the present version of the EU DEMO, the auxiliary power is fixed at 50 MW and q95=3.5, while the energy confinement time is downgraded to 0.6 times the standard H-mode. The major radius R is increased by 1 m step from 9 up to 12 m and the toroidal magnetic field BT by 1 T step from 6 up to 8 T, with density kept at its Greenwald limit. An interesting working window around R=11 m and BT=7 is identified with the fusion gain Q≈30. The impurity seeding by either Xe or Kr, which can reduce the power input into the SOL and hence the load on the plates, can however affect the sustainment of the H mode, even if degraded. Argon is then considered for enhancing the radiated power inside the SOL. The TECXY analysis of this issue shows that the loads on to the target can be maintained at a very acceptable level, still preserving the core performance. Using liquid tin as divertor target material can be very advantageous for exhausting the power entering the divertor chamber provided argon is used in conjunction. In conclusion the option of a reactor working in a safer and simpler low confinement mode should not be put aside prematurely.

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“…The simulations are prepared for the EU DEMO1 2018 configuration with the following main parameters: toroidal radius RT= 9.0 m, plasma radius a = 2.9 m, plasma current Ip = 17.75 MA, toroidal magnetic field BT =5.85 T, elongation -1.65, electron density <ne>VOL = 7.26×10 19 m -3 , separatrix density was kept at the 40% level of the volume average (ne sep = 0.4 <ne>VOL) and for standard case is ne sep = 2.9×10 19 m -3 , the confinement factor H-factor (IPB98(y,2) [16]) was equal to H98 = 1.1 whereas the auxiliary heating power was set to Paux =50 MW. In our simulation, we have assumed that 28.4% of alpha power (Pα) is transfer to ions and remaining 71.6% to the electrons [18].…”

Section: Numerical Resultsmentioning

confidence: 99%

“…In Ref. [16], we shown that the helium recycling coefficient has strong influence on the He confinement time. The He confinement increases linearly from 7.25 s to 26.9 s for RHe values going from lowest to highest recycling coefficient.The burn-up fraction in our model is defined as: fbr = 2Γα/Γful, where Γα is α-particle source and Γful is the fueling source.…”

Section: Modelmentioning

confidence: 98%

Analysis of the influence of the different impurity seeding on the burn-up fraction and plasma confinement in the EU DEMO reactor

Ivanova‐Stanik

Siccinio

Poradziński

et al. 2020

Fusion Engineering and Design

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Analyses of the influence of the recycling coefficient on He confinement in DEMO reactor

Cited by 9 publications

References 17 publications

Effect of impurity radiation and helium particle confinement on tokamak–reactor plasma performance

Effect of impurity radiation and helium particle confinement on tokamak–reactor plasma performance

Analysis of the performances of a fusion reactor in a reduced H-mode confinement

Analysis of the influence of the different impurity seeding on the burn-up fraction and plasma confinement in the EU DEMO reactor

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