Real-time wall conditioning by controlled injection of boron and boron nitride powder in full tungsten wall ASDEX Upgrade

Bortolon, A.; Rohde, V.; Maingi, R.; Wolfrum, E.; Dux, R.; Herrmann, A.; Lunsford, R.; McDermott, R. M.; Nagy, A.; Kallenbach, A.; Mansfield, D. K.; Nazikian, R.; Neu, R.

doi:10.1016/j.nme.2019.03.022

Title: Real-time wall conditioning by controlled injection of boron and boron nitride powder in full tungsten wall ASDEX Upgrade

Abstract

In ASDEX Upgrade with full-tungsten wall, boronization is an important tool to control tungsten sources and allow reliable operation at low collisionality. The duration of the beneficial effects is limited by the erosion of the boron layer, in particular on the tungsten ion-cyclotron antenna limiters. We report results from experiments exploring injection boron-rich powders in tokamak plasmas as a way to replenish boron coating and extend the lifetime of boronization effects. Pure boron and boron nitride powders were introduced gravitationally in plasma discharges at rates up to 60 mg/s for durations up to 3 s. Boron injection with cumulative amounts >100 mg appeared to improve wall conditions similarly to boronization, with indications of reduced influx of oxygen and tungsten from the antenna limiter. Moreover, cumulative injection of 340 mg of B appeared sufficient to enable successful execution of low collisionality scenarios critically relying on freshly boronized walls.

Authors:

Bortolon, A. ^[1]; Rohde, V. ^[2]; Maingi, R. ^[1]; Wolfrum, E. ^[2]; Dux, R. ^[2]; Herrmann, A. ^[2]; Lunsford, R. ^[1]; McDermott, R. M. ^[2];

^[1]; Kallenbach, A. ^[2]; Mansfield, D. K. ^[1]; Nazikian, R. ^[1];

^[2]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Max-Planck-Institut fur Plasmaphysik, Garching (Germany)

Publication Date:: Fri Mar 29 00:00:00 EDT 2019

Research Org.:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Sponsoring Org.:: USDOE

OSTI Identifier:: 1506117

Grant/Contract Number:: AC02-09CH11466

Resource Type:: Accepted Manuscript

Journal Name:: Nuclear Materials and Energy

Additional Journal Information:: Journal Volume: 19; Journal Issue: C; Journal ID: ISSN 2352-1791

Publisher:: Elsevier

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats


                    Bortolon, A., Rohde, V., Maingi, R., Wolfrum, E., Dux, R., Herrmann, A., Lunsford, R., McDermott, R. M., Nagy, A., Kallenbach, A., Mansfield, D. K., Nazikian, R., and Neu, R. Real-time wall conditioning by controlled injection of boron and boron nitride powder in full tungsten wall ASDEX Upgrade.  United States: N. p., 2019. 
Web.  doi:10.1016/j.nme.2019.03.022.

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                    Bortolon, A., Rohde, V., Maingi, R., Wolfrum, E., Dux, R., Herrmann, A., Lunsford, R., McDermott, R. M., Nagy, A., Kallenbach, A., Mansfield, D. K., Nazikian, R., & Neu, R. Real-time wall conditioning by controlled injection of boron and boron nitride powder in full tungsten wall ASDEX Upgrade.  United States.  https://doi.org/10.1016/j.nme.2019.03.022

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                    Bortolon, A., Rohde, V., Maingi, R., Wolfrum, E., Dux, R., Herrmann, A., Lunsford, R., McDermott, R. M., Nagy, A., Kallenbach, A., Mansfield, D. K., Nazikian, R., and Neu, R. Fri .  
"Real-time wall conditioning by controlled injection of boron and boron nitride powder in full tungsten wall ASDEX Upgrade".  United States.  https://doi.org/10.1016/j.nme.2019.03.022.  https://www.osti.gov/servlets/purl/1506117.

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@article{osti_1506117,

  title        = {Real-time wall conditioning by controlled injection of boron and boron nitride powder in full tungsten wall ASDEX Upgrade},

  author       = {Bortolon, A. and Rohde, V. and Maingi, R. and Wolfrum, E. and Dux, R. and Herrmann, A. and Lunsford, R. and McDermott, R. M. and Nagy, A. and Kallenbach, A. and Mansfield, D. K. and Nazikian, R. and Neu, R.},

  abstractNote = {In ASDEX Upgrade with full-tungsten wall, boronization is an important tool to control tungsten sources and allow reliable operation at low collisionality. The duration of the beneficial effects is limited by the erosion of the boron layer, in particular on the tungsten ion-cyclotron antenna limiters. We report results from experiments exploring injection boron-rich powders in tokamak plasmas as a way to replenish boron coating and extend the lifetime of boronization effects. Pure boron and boron nitride powders were introduced gravitationally in plasma discharges at rates up to 60 mg/s for durations up to 3 s. Boron injection with cumulative amounts >100 mg appeared to improve wall conditions similarly to boronization, with indications of reduced influx of oxygen and tungsten from the antenna limiter. Moreover, cumulative injection of 340 mg of B appeared sufficient to enable successful execution of low collisionality scenarios critically relying on freshly boronized walls.},

  doi          = {10.1016/j.nme.2019.03.022},

  journal      = {Nuclear Materials and Energy},

  number       = C,

  volume       = 19,

  place        = {United States},

  year         = {Fri Mar 29 00:00:00 EDT 2019},

  month        = {Fri Mar 29 00:00:00 EDT 2019}

}

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https://doi.org/10.1016/j.nme.2019.03.022

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Works referenced in this record:

Wall conditioning in fusion devices and its influence on plasma performance
journal, September 1996

Winter, J.
Plasma Physics and Controlled Fusion, Vol. 38, Issue 9
DOI: 10.1088/0741-3335/38/9/001

Review of in Situ Boronization in Contemporary Tokamaks
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Buzhinskij, Oleg I.; Semenets, Yuri M.
Fusion Technology, Vol. 32, Issue 1
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Jackson, G. L.; Winter, J.; Taylor, T. S.
Physical Review Letters, Vol. 67, Issue 22
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Influence of boronization on operation with high-Z plasma facing components in Alcator C-Mod
journal, June 2007

Lipschultz, B.; Lin, Y.; Marmar, E. S.
Journal of Nuclear Materials, Vol. 363-365
DOI: 10.1016/j.jnucmat.2007.01.227

Wall conditioning in ASDEX Upgrade
journal, June 2007

Rohde, V.; Dux, R.; Kallenbach, A.
Journal of Nuclear Materials, Vol. 363-365
DOI: 10.1016/j.jnucmat.2007.01.200

Effect of boronization on ohmic plasmas in NSTX
journal, March 2002

Skinner, C. H.; Kugel, H. W.; Maingi, R.
Nuclear Fusion, Vol. 42, Issue 3
DOI: 10.1088/0029-5515/42/3/313

A multi-species powder dropper for magnetic fusion applications
journal, October 2018

Nagy, A.; Bortolon, A.; Mauzey, D. M.
Review of Scientific Instruments, Vol. 89, Issue 10
DOI: 10.1063/1.5039345

Transport-driven scrape-off layer flows and the x-point dependence of the L-H power threshold in Alcator C-Mod
journal, May 2005

LaBombard, B.; Rice, J. E.; Hubbard, A. E.
Physics of Plasmas, Vol. 12, Issue 5
DOI: 10.1063/1.1876294

Works referencing / citing this record:

Wall conditioning in fusion devices with superconducting coils
journal, January 2020

Wauters, T.; Borodin, D.; Brakel, R.
Plasma Physics and Controlled Fusion, Vol. 62, Issue 3
DOI: 10.1088/1361-6587/ab5ad0

Active conditioning of ASDEX Upgrade tungsten plasma-facing components and discharge enhancement through boron and boron nitride particulate injection
journal, October 2019

Lunsford, R.; Rohde, V.; Bortolon, A.
Nuclear Fusion, Vol. 59, Issue 12
DOI: 10.1088/1741-4326/ab4095

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Title: Real-time wall conditioning by controlled injection of boron and boron nitride powder in full tungsten wall ASDEX Upgrade

Abstract

Citation Formats

Wall conditioning in fusion devices and its influence on plasma performance journal, September 1996

Review of in Situ Boronization in Contemporary Tokamaks journal, August 1997

Regime of very high confinement in the boronized DIII-D tokamak journal, November 1991

Influence of boronization on operation with high-Z plasma facing components in Alcator C-Mod journal, June 2007

Wall conditioning in ASDEX Upgrade journal, June 2007

Effect of boronization on ohmic plasmas in NSTX journal, March 2002

A multi-species powder dropper for magnetic fusion applications journal, October 2018

Transport-driven scrape-off layer flows and the x-point dependence of the L-H power threshold in Alcator C-Mod journal, May 2005

Wall conditioning in fusion devices with superconducting coils journal, January 2020

Active conditioning of ASDEX Upgrade tungsten plasma-facing components and discharge enhancement through boron and boron nitride particulate injection journal, October 2019

Wall conditioning in fusion devices and its influence on plasma performance
journal, September 1996

Review of in Situ Boronization in Contemporary Tokamaks
journal, August 1997

Regime of very high confinement in the boronized DIII-D tokamak
journal, November 1991

Influence of boronization on operation with high-Z plasma facing components in Alcator C-Mod
journal, June 2007

Wall conditioning in ASDEX Upgrade
journal, June 2007

Effect of boronization on ohmic plasmas in NSTX
journal, March 2002

A multi-species powder dropper for magnetic fusion applications
journal, October 2018

Transport-driven scrape-off layer flows and the x-point dependence of the L-H power threshold in Alcator C-Mod
journal, May 2005

Wall conditioning in fusion devices with superconducting coils
journal, January 2020

Active conditioning of ASDEX Upgrade tungsten plasma-facing components and discharge enhancement through boron and boron nitride particulate injection
journal, October 2019