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Impact of plasma-wall interaction and exhaust on the EU-DEMO design

Authors :
C. Vorpahl
J. Gerardin
Irena Ivanova-Stanik
Wolfgang Biel
M. Cavedon
Stylianos Varoutis
Mattia Siccinio
M. Firdaouss
C. Bachmann
Volker Hauer
Francesco Maviglia
Fulvio Militello
R. Kembleton
E. Fable
Fabio Subba
G. Federici
F. Janky
Maviglia, F
Siccinio, M
Bachmann, C
Biel, W
Cavedon, M
Fable, E
Federici, G
Firdaouss, M
Gerardin, J
Hauer, V
Ivanova-Stanik, I
Janky, F
Kembleton, R
Militello, F
Subba, F
Varoutis, S
Vorpahl, C
Source :
Nuclear materials and energy 26, 100897-(2021). doi:10.1016/j.nme.2020.100897, Nuclear Materials and Energy, Nuclear materials and energy, 26, Art.-Nr. 100897, Nuclear Materials and Energy, Vol 26, Iss, Pp 100897-(2021)
Publication Year :
2021
Publisher :
Elsevier, 2021.

Abstract

In the present work, the role of plasma facing components protection in driving the EU-DEMO design will be reviewed, focusing on steady-state and, especially, on transients. This work encompasses both the first wall (FW) as well as the divertor. In fact, while the ITER divertor heat removal technology has been adopted, the ITER FW concept has been shown in the past years to be inadequate for EU-DEMO. This is due to the higher foreseen irradiation damage level, which requires structural materials (like Eurofer) able to withstand more than 5 dpa of neutron damage. This solution, however, limits the tolerable steady-state heat flux to ~1 MW/m2, i.e. a factor 3–4 below the ITER specifications. For this reason, poloidally and toroidally discontinuous protection limiters are implemented in EU-DEMO. Their role consists in reducing the heat load on the FW due to charged particles, during steady state and, more importantly, during planned and off-normal plasma transients. Concerning the divertor configuration, EU-DEMO currently assumes an ITER-like, lower single null (LSN) divertor, with seeded impurities for the dissipation of the power. However, this concept has been shown by numerous simulations in the past years to be marginal during steady-state (where a detached divertor is necessary to maintain the heat flux below the technological limit and to avoid excessive erosion) and unable to withstand some relevant transients, such as large ELMs and accidental loss of detachment. Various concepts, deviating from the ITER design, are currently under investigation to mitigate such risks, for example in-vessel coils for strike point sweeping in case of reattachment, as well as alternative divertor configurations. Finally, a broader discussion on the impact of divertor protection on the overall machine design is presented.

Details

Language :
English
ISSN :
23521791
Database :
OpenAIRE
Journal :
Nuclear materials and energy 26, 100897-(2021). doi:10.1016/j.nme.2020.100897, Nuclear Materials and Energy, Nuclear materials and energy, 26, Art.-Nr. 100897, Nuclear Materials and Energy, Vol 26, Iss, Pp 100897-(2021)
Accession number :
edsair.doi.dedup.....b5a1335285d6e3724cca50d2b823e4fb
Full Text :
https://doi.org/10.1016/j.nme.2020.100897