Exposures of Candidate First Wall Materials

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Exposures of Candidate First Wall Materials

• C.L. Olson, T.J. Tanaka, T.J. Renk, G.A. Rochau
• Sandia National Laboratories, Albuquerque, NM
• R.R. Peterson
• Los Alamos National Laboratory, Los Alamos, NM
• University of Wisconsin, Madison, Wisconsin
• HAPL Program Workshop
• University of Wisconsin
• Madison, Wisconsin
• September 24-25, 2003
• Supported by NRL by the HAPL program by DOE NNSA
  DP

Sandia is a multiprogram laboratory operated by
Sandia Corporation, a Lockheed Martin
Company,for the United States Department of
Energy under contract DE-AC04-94AL85000.
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Regimes of FW Materials Response Studies for
x-rays and ions
Ablation Depth (mm)
Net Ablation
No net ablation, but surface roughening
F(J/cm2)
Threshold for ablation
Threshold for roughening
Goal is to find and understand roughening
threshold
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Strategy for use of RHEPP and Z to test FW
materials
Ion fluence for HAPL dry wall is an issue -
present emphasis is to use ion beams on RHEPP
(many shots) for extensive testing, and modeling
with Bucky

• test roughening phenomena in heated samples on
  RHEPP (many shots)
• examine potential mechanisms for roughening
• surface stress/yield at below melt
  temperatures,
• strain-rate and grain size effects,
  etc.
• establish threshold for roughening

X-ray fluence for HAPL dry wall does not appear
to be an issue - but needs to be verified on Z

• use RHEPP/Bucky results to narrow list of
  candidate materials
• test best candidate materials on Z to verify
  threshold for roughening
• heater for 1000 C, new filtered Z spectra,
  schedule for HAPL shots
• on Z is all ready (next vu-graphs)

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Layout for HAPL experiments on Z
Sample Field of View
Peak Diode Emission Temps
17.8 cm
Pinch Aperture 3mm tall x 8mm wide
Shielding Box
Z-Pinch
Heater
Sample_at_ 1000 C
51.2 cm
63.3 cm
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Z-machine sample heater

• Heater with sample holder clips and thermocouple
• Temperatures up to 1200C
• 1 cm test diameter
• 4 samples/shot
• Fluence levels ?1 J/cm2 and up

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Calculated Z Spectrum for Nov. HAPL Experiments
Time-integrated spectrum on sample with 8 mm Be
1 mm CH filter
ltEgt 1100 eV F 1 J/cm2
X-ray fluence at sample location is very uniform
and ? 1 keV
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Z Shot Schedule
HAPL add-on shots
HAPL add-on shots
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Next Talks

• RHEPP experiments of candidate materials - Tim
  Renk
• extensive list of materials tested (heated, many
  shots)
• (various forms of W W25Re Re Cu CFC
  Graphite
• foams C-C-W velvet etc.)
• extensive list of results (effects of grain
  structure ion species
• dependent roughening deep-lying cracking some
  samples
• unexpectedly survive amazingly well)
• BUCKY simulations of tungsten RHEPP experiments -
  Bob Peterson
• effects of initial sample temperature
• effects of ion species
• stress/yield effects for surface temperatures
  below melting