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Title: Overview of design and analysis activities for the W7-X scraper element

The Wendelstein 7-X stellarator is in final stages of commissioning, and will begin operation in late 2015. In the first phase, the machine will operate with a limiter, and will be restricted to low power and short pulse. But in 2019, plans are for an actively cooled divertor to be installed, and the machine will operate in steady state at full power. Recently, plasma simulations have indicated that, in this final operational phase, a bootstrap current will evolve in certain scenarios. This will cause the sensitive ends of the divertor target to be overloaded beyond their qualified limit. A high heat flux scraper element (HHF-SE) has been proposed in order to take up some of the convective flux and reduce the load on the divertor. In order to examine whether the HHF-SE will be able to effectively reduce the plasma flux in the divertor region of concern, and to determine how the pumping effectiveness will be affected by such a component, it is planned to include a test divertor unit scraper element (TDU-SE) in 2017 during an earlier operational phase. Several U.S. fusion energy science laboratories have been involved in the design, analysis (structural and thermal finite element, as wellmore » as computational fluid dynamics), plasma simulation, planning, prototyping, and diagnostic development around the scraper element program (both TDU-SE and HHF-SE). As a result, this paper presents an overview of all of these activities and their current status.« less
Authors:
ORCiD logo [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [3] ;  [4] ;  [4] ; ORCiD logo [5] ;  [5] ;  [6]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Max Planck Institute for Plasma Physics, Garching bei Munchen (Germany)
  3. Univ. of Tennessee, Knoxville, TN (United States)
  4. Max Planck Institute for Plasma Physics, Greifswald (Germany)
  5. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  6. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
IEEE Transactions on Plasma Science
Additional Journal Information:
Journal Volume: 44; Journal Issue: 9; Conference: 26th Symposium on Fusion Engineering (SOFE) colocated with the 20th Pulsed Power Conference , Austin, TX (United States), 31 May - 4 Jun 2015; Journal ID: ISSN 0093-3813
Publisher:
IEEE
Research Org:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 42 ENGINEERING; divertor; high heat flux; modeling and simulation; Wendelstein 7X (W7-X)
OSTI Identifier:
1332514

Lumsdaine, A., Bjorholm, T., Harris, J., McGinnis, D., Lore, J. D., Boscary, J., Tretter, J., Clark, E., Ekici, K., Fellinger, J., Holbe, H., Neilson, H., Titus, P., and Wurden, G. A.. Overview of design and analysis activities for the W7-X scraper element. United States: N. p., Web. doi:10.1109/tps.2016.2598486.
Lumsdaine, A., Bjorholm, T., Harris, J., McGinnis, D., Lore, J. D., Boscary, J., Tretter, J., Clark, E., Ekici, K., Fellinger, J., Holbe, H., Neilson, H., Titus, P., & Wurden, G. A.. Overview of design and analysis activities for the W7-X scraper element. United States. doi:10.1109/tps.2016.2598486.
Lumsdaine, A., Bjorholm, T., Harris, J., McGinnis, D., Lore, J. D., Boscary, J., Tretter, J., Clark, E., Ekici, K., Fellinger, J., Holbe, H., Neilson, H., Titus, P., and Wurden, G. A.. 2016. "Overview of design and analysis activities for the W7-X scraper element". United States. doi:10.1109/tps.2016.2598486. https://www.osti.gov/servlets/purl/1332514.
@article{osti_1332514,
title = {Overview of design and analysis activities for the W7-X scraper element},
author = {Lumsdaine, A. and Bjorholm, T. and Harris, J. and McGinnis, D. and Lore, J. D. and Boscary, J. and Tretter, J. and Clark, E. and Ekici, K. and Fellinger, J. and Holbe, H. and Neilson, H. and Titus, P. and Wurden, G. A.},
abstractNote = {The Wendelstein 7-X stellarator is in final stages of commissioning, and will begin operation in late 2015. In the first phase, the machine will operate with a limiter, and will be restricted to low power and short pulse. But in 2019, plans are for an actively cooled divertor to be installed, and the machine will operate in steady state at full power. Recently, plasma simulations have indicated that, in this final operational phase, a bootstrap current will evolve in certain scenarios. This will cause the sensitive ends of the divertor target to be overloaded beyond their qualified limit. A high heat flux scraper element (HHF-SE) has been proposed in order to take up some of the convective flux and reduce the load on the divertor. In order to examine whether the HHF-SE will be able to effectively reduce the plasma flux in the divertor region of concern, and to determine how the pumping effectiveness will be affected by such a component, it is planned to include a test divertor unit scraper element (TDU-SE) in 2017 during an earlier operational phase. Several U.S. fusion energy science laboratories have been involved in the design, analysis (structural and thermal finite element, as well as computational fluid dynamics), plasma simulation, planning, prototyping, and diagnostic development around the scraper element program (both TDU-SE and HHF-SE). As a result, this paper presents an overview of all of these activities and their current status.},
doi = {10.1109/tps.2016.2598486},
journal = {IEEE Transactions on Plasma Science},
number = 9,
volume = 44,
place = {United States},
year = {2016},
month = {8}
}