Shatter Thresholds and Fragment Size Distributions of Deuterium–Neon Mixture Cryogenic Pellets for Tokamak Thermal Mitigation

Gebhart III, Trey E.; Baylor, Larry R.; Meitner, Steven J.

doi:10.1080/15361055.2020.1812991

Title: Shatter Thresholds and Fragment Size Distributions of Deuterium–Neon Mixture Cryogenic Pellets for Tokamak Thermal Mitigation

Abstract

Reliable mitigation is necessary to eliminate the detrimental effects of a disruption event in large high-current tokamaks such as ITER. To avoid serious damage to plasma-facing components during the thermal quench phase of a disruption, material is injected to radiate the plasma energy over the inner surface of the machine. The most promising method of material injection is a process known as shattered pellet injection (SPI). SPI utilizes cryogenic cooling to desublimate gas into the barrel of a pipe gun to form a solid pellet. High-pressure gas or a mechanical punch is used to dislodge the pellet and accelerate it into a bent tube to intentionally fracture it. Pellets made of a mixture of deuterium and neon are likely candidates for thermal mitigation. The survivability of these pellets throughout their flight path, before striking the shatter tube, is essential for reliable SPI operation. Experiments were conducted to determine intact speed limits for various mixtures. In this paper, we outline the details of brittle fracture theory and compare a theory-based model to experimental results from various mixtures of deuterium and neon pellets.

Authors:

^[1];

^[1]

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

Publication Date:: Fri Sep 11 00:00:00 EDT 2020

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

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

OSTI Identifier:: 1661244

Grant/Contract Number:: AC05-00OR22725

Resource Type:: Accepted Manuscript

Journal Name:: Fusion Science and Technology

Additional Journal Information:: Journal Volume: Online; Journal Issue: Online; Journal ID: ISSN 1536-1055

Publisher:: American Nuclear Society

Country of Publication:: United States

Language:: English

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Cryogenic Pellets; Mixed Gas Pellets; Disruption Mitigation; Shattered Pellet Injection; Brittle Fracture Mechanics

Citation Formats


                    Gebhart III, Trey E., Baylor, Larry R., and Meitner, Steven J. Shatter Thresholds and Fragment Size Distributions of Deuterium–Neon Mixture Cryogenic Pellets for Tokamak Thermal Mitigation.  United States: N. p., 2020. 
Web.  doi:10.1080/15361055.2020.1812991.

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                    Gebhart III, Trey E., Baylor, Larry R., & Meitner, Steven J. Shatter Thresholds and Fragment Size Distributions of Deuterium–Neon Mixture Cryogenic Pellets for Tokamak Thermal Mitigation.  United States.  https://doi.org/10.1080/15361055.2020.1812991

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                    Gebhart III, Trey E., Baylor, Larry R., and Meitner, Steven J. Fri .  
"Shatter Thresholds and Fragment Size Distributions of Deuterium–Neon Mixture Cryogenic Pellets for Tokamak Thermal Mitigation".  United States.  https://doi.org/10.1080/15361055.2020.1812991.  https://www.osti.gov/servlets/purl/1661244.

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@article{osti_1661244,

  title        = {Shatter Thresholds and Fragment Size Distributions of Deuterium–Neon Mixture Cryogenic Pellets for Tokamak Thermal Mitigation},

  author       = {Gebhart III, Trey E. and Baylor, Larry R. and Meitner, Steven J.},

  abstractNote = {Reliable mitigation is necessary to eliminate the detrimental effects of a disruption event in large high-current tokamaks such as ITER. To avoid serious damage to plasma-facing components during the thermal quench phase of a disruption, material is injected to radiate the plasma energy over the inner surface of the machine. The most promising method of material injection is a process known as shattered pellet injection (SPI). SPI utilizes cryogenic cooling to desublimate gas into the barrel of a pipe gun to form a solid pellet. High-pressure gas or a mechanical punch is used to dislodge the pellet and accelerate it into a bent tube to intentionally fracture it. Pellets made of a mixture of deuterium and neon are likely candidates for thermal mitigation. The survivability of these pellets throughout their flight path, before striking the shatter tube, is essential for reliable SPI operation. Experiments were conducted to determine intact speed limits for various mixtures. In this paper, we outline the details of brittle fracture theory and compare a theory-based model to experimental results from various mixtures of deuterium and neon pellets.},

  doi          = {10.1080/15361055.2020.1812991},

  journal      = {Fusion Science and Technology},

  number       = Online,

  volume       = Online,

  place        = {United States},

  year         = {Fri Sep 11 00:00:00 EDT 2020},

  month        = {Fri Sep 11 00:00:00 EDT 2020}

}

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Works referenced in this record:

Development of Solenoid-Driven and Pneumatic Punches for Launching High- Z Cryogenic Pellets for Tokamak Disruption Mitigation Experiments
journal, May 2019

Gebhart, T. E.; Meitner, S. J.; Baylor, L. R.
Fusion Science and Technology, Vol. 75, Issue 8
DOI: 10.1080/15361055.2019.1592997

First demonstration of rapid shutdown using neon shattered pellet injection for thermal quench mitigation on DIII-D
journal, March 2016

Commaux, N.; Shiraki, D.; Baylor, L. R.
Nuclear Fusion, Vol. 56, Issue 4
DOI: 10.1088/0029-5515/56/4/046007

Disruption Mitigation System Developments and Design for ITER
journal, September 2015

Baylor, L. R.; Barbier, C. C.; Carmichael, J. R.
Fusion Science and Technology, Vol. 68, Issue 2
DOI: 10.13182/FST14-926

Solid solutions Ne–nD2. Diagram of phase equilibrium
journal, November 2005

Belan, V. G.; Gal’tsov, N. N.; Prokhvatilov, A. I.
Low Temperature Physics, Vol. 31, Issue 11
DOI: 10.1063/1.2127875

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Title: Shatter Thresholds and Fragment Size Distributions of Deuterium–Neon Mixture Cryogenic Pellets for Tokamak Thermal Mitigation

Abstract

Citation Formats

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