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Title: Comparison of an Electrothermal Plasma Source to a Light Gas Gun for Launching Large Cryogenic Pellets for Tokamak Disruption Mitigation

Abstract

Future large tokamaks, such as ITER, will require a reliable technique for rapid energy dissipation to mitigate harmful effects from disruptions. Two main methods developed for disruption mitigation are massive gas injection and shattered pellet injection (SPI). Argon and neon are favorable materials for both injection methods. When launching pellets with SPI, it has proven difficult to launch intact pellets of pure argon and/or neon owing to their high material strength at cryogenic temperatures. In this work, we compare two methods of launching relatively high-Z pellets. An electrothermal plasma source is an experimental alternative to the fast opening, high-pressure, gas valve. The electrothermal source was used to launch Lexan™ pellets with approximately the same size and mass of comparable mixed gas (D 2 and Ne) cryogenic pellets launched by gas guns. As a result, we describe comparisons of achieved pellet velocities, energy efficiencies of each system, and the implications of implementing each respective method on an operating tokamak.

Authors:
 [1];  [1]; ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1410950
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Fusion Science and Technology
Additional Journal Information:
Journal Volume: 73; Journal Issue: 1; Journal ID: ISSN 1536-1055
Publisher:
American Nuclear Society
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Tokamak disruption mitigation; pellet injection; electrothermal plasma source

Citation Formats

Gebhart, T. E., Combs, S. K., and Baylor, Larry R. Comparison of an Electrothermal Plasma Source to a Light Gas Gun for Launching Large Cryogenic Pellets for Tokamak Disruption Mitigation. United States: N. p., 2017. Web. doi:10.1080/15361055.2017.1372683.
Gebhart, T. E., Combs, S. K., & Baylor, Larry R. Comparison of an Electrothermal Plasma Source to a Light Gas Gun for Launching Large Cryogenic Pellets for Tokamak Disruption Mitigation. United States. https://doi.org/10.1080/15361055.2017.1372683
Gebhart, T. E., Combs, S. K., and Baylor, Larry R. Thu . "Comparison of an Electrothermal Plasma Source to a Light Gas Gun for Launching Large Cryogenic Pellets for Tokamak Disruption Mitigation". United States. https://doi.org/10.1080/15361055.2017.1372683.
@article{osti_1410950,
title = {Comparison of an Electrothermal Plasma Source to a Light Gas Gun for Launching Large Cryogenic Pellets for Tokamak Disruption Mitigation},
author = {Gebhart, T. E. and Combs, S. K. and Baylor, Larry R.},
abstractNote = {Future large tokamaks, such as ITER, will require a reliable technique for rapid energy dissipation to mitigate harmful effects from disruptions. Two main methods developed for disruption mitigation are massive gas injection and shattered pellet injection (SPI). Argon and neon are favorable materials for both injection methods. When launching pellets with SPI, it has proven difficult to launch intact pellets of pure argon and/or neon owing to their high material strength at cryogenic temperatures. In this work, we compare two methods of launching relatively high-Z pellets. An electrothermal plasma source is an experimental alternative to the fast opening, high-pressure, gas valve. The electrothermal source was used to launch Lexan™ pellets with approximately the same size and mass of comparable mixed gas (D2 and Ne) cryogenic pellets launched by gas guns. As a result, we describe comparisons of achieved pellet velocities, energy efficiencies of each system, and the implications of implementing each respective method on an operating tokamak.},
doi = {10.1080/15361055.2017.1372683},
url = {https://www.osti.gov/biblio/1410950}, journal = {Fusion Science and Technology},
issn = {1536-1055},
number = 1,
volume = 73,
place = {United States},
year = {2017},
month = {10}
}

Works referenced in this record:

Recent advances in electrothermal-chemical gun propulsion at United Defense, L.P
journal, January 1997


The use of an electrothermal plasma gun to simulate the extremely high heat flux conditions of a tokamak disruption
journal, September 1993


Optimization of Fusion Pellet Launch Velocity in an Electrothermal Mass Accelerator
journal, October 2013


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


Disruption mitigation by massive gas injection in JET
journal, November 2011


Pellet fuelling and control of burning plasmas in ITER
journal, May 2007


Solidification and Acceleration of Large Cryogenic Pellets Relevant for Plasma Disruption Mitigation
journal, September 2016