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Title: Infrared imaging systems for wall protection in the W7-X stellarator (invited)

Abstract

Here, Wendelstein 7-X aims at quasi-steady state operation with up to 10 MW of heating power for 30 min. Power exhaust will be handled predominantly via 10 actively water cooled CFC (carbon-fiber-reinforced carbon) based divertor units designed to withstand power loads of 10 MW/m 2 locally in steady state. If local loads exceed this value, a risk of local delamination of the CFC and failure of entire divertor modules arises. Infrared endoscopes to monitor all main plasma facing components are being prepared, and near real time software tools are under development to identify areas of excessive temperature rise, to distinguish them from non-critical events, and to trigger alarms. Tests with different cameras were made in the recent campaign. Long pulse operation enforces additional diagnostic design constraints: for example, the optics need to be thermally decoupled from the endoscope housing. In the upcoming experimental campaign, a graphite scraper element, in front of the island divertor throat, will be tested as a possible means to protect the divertor pumping gap edges during the transient discharge evolution.

Authors:
ORCiD logo [1]; ORCiD logo [2];  [2];  [2]; ORCiD logo [3];  [2];  [2];  [4];  [2];  [2];  [2];  [5];  [2];  [2];  [2];  [6];  [2];  [7]; ORCiD logo [4];  [2]
  1. Max-Planck-Institut fur Plasmaphysik, Greifswald (Germany); Univ. of Szczecin, Szczecin (Poland)
  2. Max-Planck-Institut fur Plasmaphysik, Greifswald (Germany)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Univ. of Cagliari, Cagliari (Italy)
  5. Forschungszentrum Julich GmbH, Julich (Germany)
  6. Thermadiag, Meyreul (France)
  7. CEA Cadarache, Cadarache (France)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
Contributing Org.:
W7-XTeam
OSTI Identifier:
1481978
Report Number(s):
LA-UR-18-20296
Journal ID: ISSN 0034-6748
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Accepted Manuscript
Journal Name:
Review of Scientific Instruments
Additional Journal Information:
Journal Volume: 89; Journal Issue: 10; Conference: High Temperature Plasma Diagnostics Conference, San Diego, CA (United States), 16 Apr 2018; Journal ID: ISSN 0034-6748
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; Magnetic Fusion Energy

Citation Formats

Jakubowski, Marcin, Drewelow, Peter, Fellinger, Joris, Sitjes, Aleix Puig, Wurden, Glen Anthony, Ali, Adnan, Biedermann, Christoph, Cannas, Barbara, Chauvin, Didier, Gamradt, Marc, Greve, Henry, Gao, Yu, Hathiramani, Dag, König, Ralf, Lorenz, Axel, Moncada, Victor, Niemann, Holger, Ngo, Tran Thanh, Pisano, Fabio, and Pedersen, Thomas Sunn. Infrared imaging systems for wall protection in the W7-X stellarator (invited). United States: N. p., 2018. Web. doi:10.1063/1.5038634.
Jakubowski, Marcin, Drewelow, Peter, Fellinger, Joris, Sitjes, Aleix Puig, Wurden, Glen Anthony, Ali, Adnan, Biedermann, Christoph, Cannas, Barbara, Chauvin, Didier, Gamradt, Marc, Greve, Henry, Gao, Yu, Hathiramani, Dag, König, Ralf, Lorenz, Axel, Moncada, Victor, Niemann, Holger, Ngo, Tran Thanh, Pisano, Fabio, & Pedersen, Thomas Sunn. Infrared imaging systems for wall protection in the W7-X stellarator (invited). United States. doi:10.1063/1.5038634.
Jakubowski, Marcin, Drewelow, Peter, Fellinger, Joris, Sitjes, Aleix Puig, Wurden, Glen Anthony, Ali, Adnan, Biedermann, Christoph, Cannas, Barbara, Chauvin, Didier, Gamradt, Marc, Greve, Henry, Gao, Yu, Hathiramani, Dag, König, Ralf, Lorenz, Axel, Moncada, Victor, Niemann, Holger, Ngo, Tran Thanh, Pisano, Fabio, and Pedersen, Thomas Sunn. Tue . "Infrared imaging systems for wall protection in the W7-X stellarator (invited)". United States. doi:10.1063/1.5038634. https://www.osti.gov/servlets/purl/1481978.
@article{osti_1481978,
title = {Infrared imaging systems for wall protection in the W7-X stellarator (invited)},
author = {Jakubowski, Marcin and Drewelow, Peter and Fellinger, Joris and Sitjes, Aleix Puig and Wurden, Glen Anthony and Ali, Adnan and Biedermann, Christoph and Cannas, Barbara and Chauvin, Didier and Gamradt, Marc and Greve, Henry and Gao, Yu and Hathiramani, Dag and König, Ralf and Lorenz, Axel and Moncada, Victor and Niemann, Holger and Ngo, Tran Thanh and Pisano, Fabio and Pedersen, Thomas Sunn},
abstractNote = {Here, Wendelstein 7-X aims at quasi-steady state operation with up to 10 MW of heating power for 30 min. Power exhaust will be handled predominantly via 10 actively water cooled CFC (carbon-fiber-reinforced carbon) based divertor units designed to withstand power loads of 10 MW/m2 locally in steady state. If local loads exceed this value, a risk of local delamination of the CFC and failure of entire divertor modules arises. Infrared endoscopes to monitor all main plasma facing components are being prepared, and near real time software tools are under development to identify areas of excessive temperature rise, to distinguish them from non-critical events, and to trigger alarms. Tests with different cameras were made in the recent campaign. Long pulse operation enforces additional diagnostic design constraints: for example, the optics need to be thermally decoupled from the endoscope housing. In the upcoming experimental campaign, a graphite scraper element, in front of the island divertor throat, will be tested as a possible means to protect the divertor pumping gap edges during the transient discharge evolution.},
doi = {10.1063/1.5038634},
journal = {Review of Scientific Instruments},
number = 10,
volume = 89,
place = {United States},
year = {2018},
month = {10}
}

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Cited by: 14 works
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Figures / Tables:

FIG. 1 FIG. 1: One out of 10 W7-X divertors. Each one consists of horizontal target modules(TM1-4h, TM5-6h and TM7-9h), vertical target modules (TM1-3v) and divertor baffles. Depending on the magnetic configuration different parts of the divertor are receiving power loads from plasma edge. Target modules TM1-4h, TM1-3v form a so-called standardmore » divertor region and TM7-9h a so-called high iota divertor. Both names refer to magnetic configurations, which put loads on those parts of the W7-X divertor. In the present campaign (OP1.2) the divertor is inertially cooled. From 2020 (OP2)it will be water-cooled. The observation with IR cameras is performed mostly through ca. 2 m long port tubes (labeled AEF and AEA)« less

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