Thermal analysis of Test Divertor Unit Scraper Element for Wendelstein 7-X

Lumsdaine, Arnold; Lore, Jeremy D.; McGinnis, Dean William; Fellinger, Joris; Loesser, Douglas

doi:10.1016/j.fusengdes.2018.04.048

Title: Thermal analysis of Test Divertor Unit Scraper Element for Wendelstein 7-X

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Abstract

The Wendelstein-7X stellarator will go through three operational phases, with successively more energy as more complex divertors are installed. The first operational phase operated without a divertor, instead using five limiters (one in each of the five field periods), the second phase uses ten uncooled test divertor units (TDU), and the third will include an actively cooled divertor. Simulations of plasma operation have shown that the evolution of a toroidal current can lead to significant heat fluxes sweeping across sensitive regions in the divertor, possibly exceeding their qualified limit. A “Scraper Element” (SE) has been proposed to protect these sensitive divertor regions. To examine the effectiveness of this high heat-flux SE, a TDU Scraper Element (TDU-SE) is scheduled to operate with the TDU. A thermal analysis has been performed to correlate to measurements to be obtained during operation to evaluate the location and intensity of the convective plasma flux. The analysis will give an understanding of what is occurring at the plasma edge. As a result, it will also allow for a quick evaluation of the safety margin during initial, low power pulses so that the experiment can nimbly move to higher power operation.

Authors:

^[1];

^[1]; Fellinger, Joris ^[2]; Loesser, Douglas ^[3]

Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Max Planck Institute for Plasma Physics, Greifswald (Germany)
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Publication Date:: Tue May 01 00:00:00 EDT 2018

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE Office of Science (SC)

OSTI Identifier:: 1480632

Grant/Contract Number:: AC05-00OR22725

Resource Type:: Accepted Manuscript

Journal Name:: Fusion Engineering and Design

Additional Journal Information:: Journal Volume: 136; Journal Issue: PB; Journal ID: ISSN 0920-3796

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Wendelstein 7-X; Divertor; High heat-flux; Plasma facing component; Modeling and simulation

Citation Formats


                    Lumsdaine, Arnold, Lore, Jeremy D., McGinnis, Dean William, Fellinger, Joris, and Loesser, Douglas. Thermal analysis of Test Divertor Unit Scraper Element for Wendelstein 7-X.  United States: N. p., 2018. 
Web.  doi:10.1016/j.fusengdes.2018.04.048.

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                    Lumsdaine, Arnold, Lore, Jeremy D., McGinnis, Dean William, Fellinger, Joris, & Loesser, Douglas. Thermal analysis of Test Divertor Unit Scraper Element for Wendelstein 7-X.  United States.  https://doi.org/10.1016/j.fusengdes.2018.04.048

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                    Lumsdaine, Arnold, Lore, Jeremy D., McGinnis, Dean William, Fellinger, Joris, and Loesser, Douglas. Tue .  
"Thermal analysis of Test Divertor Unit Scraper Element for Wendelstein 7-X".  United States.  https://doi.org/10.1016/j.fusengdes.2018.04.048.  https://www.osti.gov/servlets/purl/1480632.

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@article{osti_1480632,

  title        = {Thermal analysis of Test Divertor Unit Scraper Element for Wendelstein 7-X},

  author       = {Lumsdaine, Arnold and Lore, Jeremy D. and McGinnis, Dean William and Fellinger, Joris and Loesser, Douglas},

  abstractNote = {The Wendelstein-7X stellarator will go through three operational phases, with successively more energy as more complex divertors are installed. The first operational phase operated without a divertor, instead using five limiters (one in each of the five field periods), the second phase uses ten uncooled test divertor units (TDU), and the third will include an actively cooled divertor. Simulations of plasma operation have shown that the evolution of a toroidal current can lead to significant heat fluxes sweeping across sensitive regions in the divertor, possibly exceeding their qualified limit. A “Scraper Element” (SE) has been proposed to protect these sensitive divertor regions. To examine the effectiveness of this high heat-flux SE, a TDU Scraper Element (TDU-SE) is scheduled to operate with the TDU. A thermal analysis has been performed to correlate to measurements to be obtained during operation to evaluate the location and intensity of the convective plasma flux. The analysis will give an understanding of what is occurring at the plasma edge. As a result, it will also allow for a quick evaluation of the safety margin during initial, low power pulses so that the experiment can nimbly move to higher power operation.},

  doi          = {10.1016/j.fusengdes.2018.04.048},

  journal      = {Fusion Engineering and Design},

  number       = PB,

  volume       = 136,

  place        = {United States},

  year         = {Tue May 01 00:00:00 EDT 2018},

  month        = {Tue May 01 00:00:00 EDT 2018}

}

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