Materials Studies on Z (x-rays) and RHEPP (ions)

C.L. Olson, T.J.Tanaka, T.J. Renk, G.A.Rochau, M.A. Ulrickson

Sandia National Laboratories, Albuquerque, NM

M.Thompson, Cornell University, Ithaca, NY

F. Davies, KTech, Albuquerque, NM

P. Peterson, University of California, Berkeley, CA

R.R. Peterson*, I. Golovkin, D. Haynes, G. Kulcinski,

University of Wisconsin

*Los Alamos National Laboratory, Los Alamos, NM

M.S. Tillack, R.A. Raffray, F. Najmabadi,

University of California, San Diego, CA

T.R. Knowles, Energy Sciences Laboratories, Inc., San Diego, CA

HAPL Meeting at NRLHAPL Meeting at NRL

December 5-6, 2002December 5-6, 2002Supported by NRL by the HAPL program by DOE NNSA DPSupported 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.

Regimes of IFE Materials Response Studies for x-rays and ions

AblationDepth (m)

F(J/cm2)

Net AblationNo net ablation, but surface roughening

Threshold for ablation

Goals (for each material): examine net ablation to validate codes find threshold for ablation understand roughening find threshold for roughening

Threshold for roughening

X-rays and ions deposit energy with different spatial profiles

X-rays (keV)

Ions (MeV)

I

-E/x

photoelectric absorption of photons

photons removed from flux

I decreases exponentially

absorption length R = ()-1

penetrates beyond R

ion collisions with electrons

ions slow down continuously

|-E/x| increases to Bragg peak

range is R

essentially no penetration beyond R

R

R

Need to reproduce:

(1) specific energy deposition S = E/V F(J/cm2)/R(g/cm2)

(2) temporal profile S(t) [S/t, pulse width,…)

rate of rise competes with thermal conductivity

(3) spatial profile S(x) [deposition profile,…]

deposition scale length compared to

grain size, impurity scale size,…

temperature gradients in deposition region

Materials response testing should accurately reproduce specific energy deposition in candidate materials

Z and RHEPP can replicate the conditions in IFE chamber walls• Though there are some differences between IFE target spectra and Z and RHEPP, the experiments study the most important issues• The surface temperature histories and temperature profiles are similar

Chamber Materials Response Program (Z and RHEPP)

FY02

SNL $162k Overall coordination Olson Z experiments and x-ray spectra Tanaka, Rochau RHEPP experiments RenkCornell $0k Temperature diagnostic on RHEPP ThompsonU. Wisconsin $90k Bucky simulations of Z and RHEPP Peterson*, Golovkin (*LANL) Haynes, KulcinskiESLI $23k Carbon velvets KnowlesUCSD $65k Temperature diagnostic for RHEPP Tillack, Rafray, and materials suggestions NajmabadiUCB $42k Flibe samples, calculations PetersonK-Tech $23k Data-base of materials on Z Davies _____ $405k

Predicted threat to wallMaterial

Buckypredictedablationthreshold

Analyticpredictedablationthreshold

Experimentmeasuredablationthreshold

Experimentmeasuredrougheningthreshold

154 MJ target

400 MJ target

Poco graphite 4.25 J/cm2 3.3 J/cm2 8 J/cm2 grain removal 8 J/cm2

tungsten 4 J/cm2 2.4 J/cm2 2.3-19 J/cm2 2.3 J/cm2

tungsten/Re 19 J/cm2 2.3 J/cm2

X-rays__ on Z

(10 ns exposure)

tungsten/La 19 J/cm2 2.3 J/cm2

0.4 J/cm2 1.2 J/cm2

Poco graphite 3.2 J/cm2 1.8 J/cm2 2.5-3.0 J/cm2 1 J/cm2

pyrolitic graphite 1.6 J/cm2 2.5 J/cm2 ll

1.2 J/cm2 3.0 J/cm2 ll

3.5-4.0 J/cm2 2.5 J/cm2

tungsten 6 J/cm2 5.1 J/cm2 6 J/cm2 1.25 J/cm2

Ions___on RHEPP

(100 ns exposure)

tungsten/Re 6 J/cm2 3.5 J/cm2

8.5 J/cm2

(1.8 J/cm2 ift1/2 applies)

21.1 J/cm2

(4.5 J/cm2 ift1/2 applies)

Summary of exposures of IFE candidate first wall materials

X-ray threat does not appear to be a problem Ion threat does appear to be a problem

UCSD contributions to materials testing

W materials and test plan• W-1%La2O3 supplied• Plansee W-Re alloys explored, not

purchased due to cost• Working with PPI now to obtain samples

Search for innovative materials• Exploration of nanoporous materials,

collaboration with PPI• Support of ESLI C-fiber development effort

Ultra-fast in-situ optical thermometer• Prototype constructed, testing underway• “Fieldable” version, suitable for delivery

to SNLA, now under development

100 nmPlasma-spray alumina from nano-size particles (PPI)

Vacuum plasma sprayed W from 3m particle size (PPI)

20 m

UC Berkeley Materials Response Research• X-ray ablation of molten salts

– Samples of LiF have been exposed at 41 J/cm2

• Predicted 2.8 m ablation matches 3 - 4 m measured with LiF

– Samples of Flibe have been prepared for x-ray experiments• Now awaiting availability of Z shots

– Flibe EOS work is underway• Experiments are now measuring BeF2 vapor pressure,

will soon measure Flibe vapor pressure and composition• Improved models for vapor/liquid equilibrium are being

developed• Improved EOS for ABLATOR is being incorporated into

the TSUNAMI code– High fluence (>1000 J/cm2) data for lithium will soon be

available• KTech report is in preparation• UCB will validate ABLATOR and TSUNAMI with this new

data• Scaling studies for dry-wall response in the ETF

– UC Berkeley will be initiating new research to study the scaling of dry-wall chamber response phenomena with target yield, chamber dimensions, and chamber repetition rate

– Will result in a range of scaling options for the laser ETF chamber that will permit accelerated, reduced cost component testing

Example of castand diced Flibe sample

5 mm

LiF at 41 J/cm2

with ablation step

Chambers Phase I Goals

1. Develop a viable first wall concept for a fusion power plant.2. Produce a viable “point design” for a fusion power plant

UCSDWisconsinSNLORNLLLNLUCSD

Long term material issues are being resolved.

Example- Ion exposures on RHEPP

0 2 4 6 8 10time (sec)

Surface temperature

3000

2500

2000

1500

1000

5000 2 4 6 8 10

time (sec)

Surface1 micron5 microns10 microns100 microns

3000

2600

2200

1800

1600

1200

600

200Ch

amb

er W

all T

emp

erat

ure

(d

eg C

)

400 MJ TargetGraphite wall @ 8.25 m radius25 mTorr Xe in chamber

154 MJ TargetTungsten wall @ 6.5 m radiusNo gas in chamber

0 2 4 6 8 10time (sec)

Surface temperature

3000

2500

2000

1500

1000

5000 2 4 6 8 10

time (sec)

Surface1 micron5 microns10 microns100 microns

Surface1 micron5 microns10 microns100 microns

3000

2600

2200

1800

1600

1200

600

200Ch

amb

er W

all T

emp

erat

ure

(d

eg C

)

400 MJ TargetGraphite wall @ 8.25 m radius25 mTorr Xe in chamber

154 MJ TargetTungsten wall @ 6.5 m radiusNo gas in chamber

Objectives for Materials Development over the next three years

FY03

•Establish the capability for heated samples on Z

•Establish the use of a shutter on Z to eliminate the debris issue

•Enhance scheduling of add-on shots on Z

•Establish options for x-ray spectra for Z and Saturn

•Continue testing of materials on Z (and start on Saturn as appropriate)

•Establish the capability for heated samples on RHEPP

•Establish enhanced diagnostics on RHEPP [T(t), etc. ]

•Continue testing of materials on RHEPP

•Explore engineered materials (e.g., coated carbon velvets)

Objectives for Materials Development over the next three years

FY04, FY05

•Establish a data base of materials tested on Z to show that thresholds for x-ray roughening and ablation are below the expected target threat spectra

•Establish a data base of materials tested on RHEPP to determine the gap between the thresholds for ion roughening and ablation and the expected target threat spectra

•Explore new materials to minimize or eliminate the gap

•Examine wetted-wall and thick-liquid wall materials such as Flibe, Flinabe, Li, PbLi, and surrogates such as LiF.

Next Talks

Z Experiments Tina Tanaka (SNL) 15 min

RHEPP Experiments Tim Renk (SNL) 20 min.

Bucky Simulations of Z and RHEPP

Robert Peterson (LANL and U. Wisc.)

15 min.