HAPL MWG Workshop: Ion Transport and Surface-Thermomechanics in W and SiC Armor


15-16 May 2006
UCLA


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Monday, May 15, 2006

INTRODUCTION  
8:00 - 8:30
(30) 		Coffee and Bagels  
8:30-8:45
(15)		 Welcome-Defining Goals of Workshop (ppt) Ghoniem (UCLA)
ION TRANSPORT: Helium EXPERIMENTS (Chair: L. Snead)
(20 min presentation + 10 min discussion)		  
8:45 - 9:00
(15) 		Introduction: Defining Goals of Helium Session L. Snead (ORNL)
9:00 - 9:20
(30) 		Summary of Experiments L. Snead (ORNL)
9:30 - 9:50
(30) 		Knowledge gaps for extrapolation of experimental data to modeling (ppt) N. Ghoniem (UCLA)
10:00 - 10:20
(30)		 UNC He Implantation and Desoprtion Results (ppt) N. Parikh (UNC)
10:30 - 10:50
(30)		 IEC He Implantation (ppt) R. Radell
J. Kulcinski (UW-M)
 10:50 - 11:20
(30)		 Experimental Tools (Positron, NRA, Thermal...) (ppt) B. Wirth (UCB)
11:20 - 12:30
(70)		 DISCUSSION (all): What can be tested for model verification All
LUNCH BREAK  
12:00 - 1:15
(75)		 Lunch (next door cafeteria; large selection)  
ION TRANSPORT: Review of MODELS (Chair: N. Ghoniem)
(20 min presentation + 10 min discussion)		  
1:15 - 1:30
(15)		 Introduction: Defining Goals of Models Session N. Ghoniem (UCLA)
1:30 - 1:50
(30)		 Helium: Grouping Method (ppt) S. Gulobov (ORNL)
2:00 - 2:20
(30)		 Spatial Kinetic Rate Theory: HEROS (ppt), Cb (avi), Rr (avi) Q. Hu (UCLA)
2:30 - 2:50
(30)		 Carbon Diffusion Model (ppt) S. Sharafat (UCLA)
3:00 - 4:00
(60)		 DISCUSSION (all): Identify gaps in knowledge required for extrapolation of available experimental data to HAPL All
4:00 - 5:00
(60)		 MWG Members Discussions B. Wirth, L. Snead, N. Ghoniem, J. Blanchard, S. Zinkle

Tuesday, May 16, 2006

SURFACE THERMO-MECHANICS* (Chair B. Wirth)  
8:00 - 8:15
(15)		 Coffee and Bagels  
8:15 - 8:30
(15)		 Introduction: Defining Goals of Thermo. Session Session Chair: B. Wirth (UCB)
8:30 - 8:50
(20)		 Overview of the Mechanics of the Chamber Wall (ppt) J. Blanchard (UW-M)
8:50 - 9:10
(20)		 Modeling Surface Roughening (ppt) M. Anderson (UCLA)
9:10 - 9:35
(15)		 IR-Lamp (heating) L. Snead (ORNL)
9:35 - 9:50
(15)		 RHEPP (Ions) (ppt) T. Renk (SNL)
9:50 - 10:05
(15)		 XAPPER (x-rays) (ppt) J. Latkowski (LLNL)
10:05 - 10:20
(15)		 Dragon Fire (Laser) (ppt) F. Najmabadi (UCSD)
10:20 - 10:30
(10)		 ORNL's New EBEAM Facility (ppt) L. Snead (ORNL)
10:30 - 10:40
(10)		 HiCAT - A Novel Diagnostic for Mass Loss and Species Composition Analysis (ppt) L. Schmitz (UCLA)
10:40 - 11:40
(60) 		Discussions (all): Requirement for reproducible and well characterized experimental operating parameters Is there any hope to fully understand the degradation mechanisms required for models. All
11:30 - 1:00
(90) 		MWG Member Discussions B. Wirth
L. Snead
N. Ghoniem
J. Blanchard
S. Zinkle
1:00 adjourn  

*Note: The 15 minute long facilities talks (RHEPP, XAPPER, Dragon Fire, IR-Lamp) should include:

5 minutes - current capabilities
5 minutes - results since ORNL HAPL meeting
5 minutes - planned improvements

John Sethian's Comments (04/20/06):

  1. Need to have a plan to expose VPS tungsten on REHPP and Dragonfire evaluate/model the results. I want to see this sooner, rather than later.
  2. Look at Scott O'Dell's presentation on high porosity tungsten, with structure on the order of 500 nm. How can this help us from either thermo-mechanical or helium issues?
  3. Make sure your discussion on helium retention and exfoliation and the attendant modeling takes the proper time dependencies into account. In a real IFE system, the helium is implanted in 2 usec into tungsten, which other than a 2 usec peak, is sitting at 750 °C.
  4. In light of the above, you need to review and discuss Wisconsin's results for helium exfoliation.

    5. The Wisconsin experiment is arguably closer in parameters to an actual IFE system than the UNC experiments, and the results are alarming: Ross sees 1 um of wall loss for every 1019 He+/cm2. (that's about two days)

    IFE:
    Helium Flux; 5 x 1018 He/cm2/day
    Implantation pulse width: 2 usec
    Spectrum 50 keV to 500 keV (bulk between 100 and 300 keV)
    Rep rate: 5 Hz
    Wall temperature: Initial temp 600 °C, with 2 usec spike up to 2400 °C

    Wisconsin:
    Helium Flux: 1019 He/cm2 total (I.E. two days worth)
    Spectrum 100 keV
    Implantation pulse width: 1 msec
    Rep rate: 25 Hz
    Sample temp: 1150 °C continuous
    Result: 1 um lost in 1019 cm2

    UNC:
    Helium flux: up to 1022 He/m2 = 1018 He/cm2 total (I.E. three minutes)
    Spectrum: Very accurate with new degrader foils
    Implantation pulses width: dunno
    Rep-Rate: 1 per 90 seconds (1000 cycles in 24 hours)
    Sample temperature: 850 °C, annealed to 2000 °C for 5 sec up, 2 sec flat, 5 sec down.
    Result: Minimal retained He in single crystal W

  5. Glad you are leaving lots of time for discussions.

References

Scott O'Dell small diameter tungsten

Wisconsin:
http://aries.ucsd.edu/HAPL/MEETINGS/0603-HAPL/Oral/31%20Radel--Helium%20Bombardment%20on%20W.ppt

UNC:
Also see S.B. Gilliam et al, Nuclear Instruments and Methods in Physics Research B 241 (2005) 491495

 

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