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Title: Effect of Tritium-Induced Damage on Plastic Targets from High-Density DT Permeation

Direct-drive inertial fusion experiments conducted at the Laboratory for Laser Energetics implode 860-μm-diam, 8-μm-thick glow-discharge polymer (GDP) capsules that have a solid, uniform, 60- to 80-μm-thick layer of an equimolar mixture of deuterium and tritium (DT) on their interior. The DT is permeated through the capsule’s wall up to pressures of 1000 atm in small pressure steps to prevent buckling; this occurs over many hours. The capsule is then cooled, the DT is solidified, and the uniform layer is formed using thermal gradients produced by heat deposited from beta decay of the tritium. Thermal contraction of the capsule from cooling is expected to be ~1% of the diameter. Capsules permeated with DT do not exhibit this contraction and retain their room-temperature diameter after cooling. Sources of error in the imaging system were explored, and a systematic 3 μm over measurement of the diameter was revealed and corrected. However, both GDP capsules permeated with only deuterium and polystyrene capsules permeated with DT do exhibit thermal contraction. The highly cross-linked GDP shell is under compressive stress after fabrication and experiences bond breakage when exposed to high-density DT during permeation. It is speculated that some of this compressive stress is relieved during bondmore » cleavage and the capsule’s wall swells, which counteracts contraction during cooling. In addition, mass spectrometry of the DT gas in the permeation system has revealed the presence of hydrocarbons and other carbon-containing species that increase with time, confirming the radio-degradation of the polymer.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2]
  1. Univ. of Rochester, NY (United States). Lab. for Laser Energetics
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Report Number(s):
2016-253, 1388
Journal ID: ISSN 1536-1055; 2016-253, 2347, 1388
Grant/Contract Number:
NA0001944
Type:
Accepted Manuscript
Journal Name:
Fusion Science and Technology
Additional Journal Information:
Journal Volume: 73; Journal Issue: 3; Journal ID: ISSN 1536-1055
Publisher:
American Nuclear Society
Research Org:
Univ. of Rochester, NY (United States). Lab. for Laser Energetics
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Tritium-induced damage, plastic capsules, optical characterization, cryogenic targets
OSTI Identifier:
1431298

Wittman, M. D., Bonino, M. J., Edgell, D. H., Fella, C., Harding, D. R., and Sanchez, J.. Effect of Tritium-Induced Damage on Plastic Targets from High-Density DT Permeation. United States: N. p., Web. doi:10.1080/15361055.2017.1380496.
Wittman, M. D., Bonino, M. J., Edgell, D. H., Fella, C., Harding, D. R., & Sanchez, J.. Effect of Tritium-Induced Damage on Plastic Targets from High-Density DT Permeation. United States. doi:10.1080/15361055.2017.1380496.
Wittman, M. D., Bonino, M. J., Edgell, D. H., Fella, C., Harding, D. R., and Sanchez, J.. 2017. "Effect of Tritium-Induced Damage on Plastic Targets from High-Density DT Permeation". United States. doi:10.1080/15361055.2017.1380496.
@article{osti_1431298,
title = {Effect of Tritium-Induced Damage on Plastic Targets from High-Density DT Permeation},
author = {Wittman, M. D. and Bonino, M. J. and Edgell, D. H. and Fella, C. and Harding, D. R. and Sanchez, J.},
abstractNote = {Direct-drive inertial fusion experiments conducted at the Laboratory for Laser Energetics implode 860-μm-diam, 8-μm-thick glow-discharge polymer (GDP) capsules that have a solid, uniform, 60- to 80-μm-thick layer of an equimolar mixture of deuterium and tritium (DT) on their interior. The DT is permeated through the capsule’s wall up to pressures of 1000 atm in small pressure steps to prevent buckling; this occurs over many hours. The capsule is then cooled, the DT is solidified, and the uniform layer is formed using thermal gradients produced by heat deposited from beta decay of the tritium. Thermal contraction of the capsule from cooling is expected to be ~1% of the diameter. Capsules permeated with DT do not exhibit this contraction and retain their room-temperature diameter after cooling. Sources of error in the imaging system were explored, and a systematic 3 μm over measurement of the diameter was revealed and corrected. However, both GDP capsules permeated with only deuterium and polystyrene capsules permeated with DT do exhibit thermal contraction. The highly cross-linked GDP shell is under compressive stress after fabrication and experiences bond breakage when exposed to high-density DT during permeation. It is speculated that some of this compressive stress is relieved during bond cleavage and the capsule’s wall swells, which counteracts contraction during cooling. In addition, mass spectrometry of the DT gas in the permeation system has revealed the presence of hydrocarbons and other carbon-containing species that increase with time, confirming the radio-degradation of the polymer.},
doi = {10.1080/15361055.2017.1380496},
journal = {Fusion Science and Technology},
number = 3,
volume = 73,
place = {United States},
year = {2017},
month = {11}
}