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September 3-4, 2003/ARR1
ARIES-IFE
ARIES Project Meeting
Georgia Institute of Technology, Atlanta, Georgia
September 3-4, 2003
Summary of Issues, Results, Findings and R&D Guidance
Farrokh Najmabadi and A. René RaffrayUniversity of California, San Diego
September 3-4, 2003/ARR2
ARIES Integrated IFE Chamber Analysis and Assessment Research
Goals:
• Analyze & assess integrated and self-consistent IFE chamber concepts
• Understand trade-offs and identify design windows for promising concepts. The research was not aimed at developing a point design.
Approach:
• Six classes of target were identified. Advanced target designs from NRL (laser-driven direct drive) and LLNL (heavy-ion-driven indirect-drive) were used as references.
• To make progress, we divided the activity based on three classes of chambers:
- Dry wall chambers;
- Solid wall chambers protected with a “sacrificial zone” (e.g. liquid films);
- Thick liquid walls.
• We researched these classes of chambers in series with the entire team focusing on each concept.
• ARIES core team + contribution from a number of other players in the field.
September 3-4, 2003/ARR3
Example Results from ARIES-IFE Effort on Solid Wall Chambers
• Evolution of parametric
design window for carbon armor in a 6.5 m radius chamber for the 154 MJ direct drive target- Armor survival
(including time of flight effect)
- Laser breakdown constraint- Target survival
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–
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0
500
1000
1500
2000
2500
3000
3500
0 100 200 300
Xe Pressure (mTorr )
Armor
Sublimation
Constraint
Laser
Target
September 3-4, 2003/ARR4
Example Results from ARIES-IFE Effort on Thin Liquid Wall Chambers
• Vapor and aerosol mass histories for a 6.5 m chamber with a flibe wetted wall exposed to the photon threat spectrum of the 400 MJ indirect-drive target- Potentially major effect on
choice of mode of transport and focusing of heavy ion driver based on pre-shot chamber gas density
- Neutralized ballistic transport:
<1 mtorr - Channel transport: <1 torr. - Self-pinched transport:
< 100 mtorr.
- Need better understanding of aerosol behavior including
coagulation at wall
0
1
2
3
4
5
6
10 100 10
3
10
4
10
5
tot_mass_data
Flibe Vapor Mass
Flibe Aerosol Mass
Mass in Chamber (kg)
Time (µs)
20 mtorr
100 mtorr
500 mtorr
200 mtorr
800 mtorr
September 3-4, 2003/ARR5
ARIES-IFE Effort on Thick Liquid Wall Chambers
• Indirect-drive target
- material choice
- constraints on chamber conditions
• Heavy-ion beam
- study of transport modes
- requirements on chamber conditions
• Liquid wall ablation mechanisms
- evaporation, explosive boiling
- spalling
• Chamber dynamics
- aerosol formation and behavior
- condensation and chamber clearing
• Liquid jet reformation and droplet formation
• Shielding of driver components
- final focus magnet
• Choice of chamber structural materials
Major Processes and Areas of Study
September 3-4, 2003/ARR6
Indirect Drive Target
• Key Issues
- material choice
- constraints on chamber conditions
• Results and Findings
- single use better than recycling
- window of material choice exists
- in-chamber tracking not needed for gas densities < ~ 1g/cm3 in a 3 m chamber
• R&D Guidance
- final selection requires overall system study
• Documentation
- partly in wetted wall paper
- material choice to be included in overall thick liquid wall paper
September 3-4, 2003/ARR7
Heavy-Ion Beam Driver
• Key Issues
- mode of transport
- constraints on chamber conditions
• Results and Findings
- neutralized-ballistic transport is main approach but tight constraint on vacuum (1 mtorr)
- pinch transport are higher risk, higher payoff alternatives (channel: 100 mtorr, self-pinch: 1 torr) but need to improve transport efficiency
- not much flexibility in relaxing requirements on chamber conditions
• R&D Guidance
- need focused modeling & experimental studies of assisted-pinch and self-pinch transport for further evaluation and improvement
• Documentation
- assisted pinch transport paper already prepared?
- possible self-pinched paper to be added?
- material choice to be included in overall thick liquid wall paper
September 3-4, 2003/ARR8
Liquid Wall Ablation Mechanisms• Key Issues
- evaporation and explosive boiling
- shock-wave induced spalling
• Results and Findings
- >~100 m of ablated thickness due to explosive boiling in flibe at 0.5 m from center --> leads to large impulse and shock wave
- will shock wave be dampened as it traverses the thick liquid jet?
- for free liquid jet, fracture occurs at the back of the jet following rarefaction wave formation
- will spalled material be cleared as pocket reforms or will it reach region outside the pocket and possibly affect driver transmission?
- vapor cloud from photon energy deposition will absorb most of the debris ion energy reducing the total amount of evaporated liquid
• R&D Guidance
- need combination of experimental and modeling studies to better understand and evaluate mechanisms under IFE like conditions
- experiments in facilities reproducing IFE photon energy deposition and time scale such as in a laser facility
• Documentation
- full journal paper being prepared
- also briefly summarized in town meeting paper
September 3-4, 2003/ARR9
Chamber Dynamics
• Key Issues
- aerosol formation and behavior
- condensation and chamber clearing
• Results and Findings
- need to prevent debris accumulation in beam access region
- need condensation surfaces for droplets ablated from inner surface of the pocket and venting through jet array
• R&D Guidance
- aerosol behavior in out-of-pocket region needs to be better understood
- comprehensive model required including ablation source term, gas dynamics, condensation and aerosol formation and dynamics
- condensation dynamics for prototypical material and conditions needs to be studied experimentally
• Documentation
- as part of town meeting paper
September 3-4, 2003/ARR10
Liquid Jet Dynamics
• Key Issues
- liquid jet reformation
- droplets formation
• Results and Findings
- possible droplets formation from criss-crossing series of jet could lead to unacceptable aerosol densities affecting driver transmission
• R&D Guidance
- Combination of scaled experimental and modeling studies to better understand droplet formation and behavior in a chamber-like jet geometry
• Documentation
- partly in overall thick liquid wall paper
- fully described in separate paper?
September 3-4, 2003/ARR11
Shielding of Driver Components
• Key Issues
- final magnet shielding
• Results and Findings
- should liquid shield be replaced by solid shielding block?
• R&D Guidance
-
• Documentation
- as part of overall thick liquid wall paper
September 3-4, 2003/ARR12
Structural Material Assessment
• Key Issue
- Choice of structural material for thick liquid wall chamber of HYLIFE IFE power plant
• Results and Findings
- Initial choice of 304SS to alleviate need for advanced structural material development. However, this raises possible swelling, activation and He embrittlement concerns
- Swelling and activation issues could perhaps be alleviated by compliant design and drastically reducing Nb and Mo impurities
- He embrittlement issue and thermal creep limits would seriously impact the operating temperature window (<~550C) when utilized in conjunction with a flibe blanket
- Recommendation that other structural materials (in particular ODS FS) be considered for power plant application
• R&D Guidance
- R&D info on advanced structural material, including ODS FS
• Documentation
- already documented as a UCSD technical report
- part of overall thick liquid wall paper
September 3-4, 2003/ARR13
Suggested List of Papers for ARIES-IFE Study on Thick Liquid Wall
1. Overall thick liquid wall paper: “Title to be confirmed”
2. Chamber dynamics paper based on town meeting presentations and discussion: “Thick Liquid Wall Chamber Dynamics: Key Issues, Existing Models and Experiments, and Future R&D”
3. Paper on ablation mechanisms: “IFE Liquid Wall Response to the Prompt X-ray Energy Deposition:Investigation of Physical Processes and Assessment of Ablated Material”
4. Paper on liquid jet dynamics including droplet formation: (separate or as part of overall paper?)
5. Other paper(s)?
September 3-4, 2003/ARR14
“Thick Liquid Wall Chamber Dynamics: Key Issues, Existing Models and Experiments, and Future R&D”
R. Raffray, W. Meier, S. Abdel-Khalik, R. Bonazza, P. Calderoni, C. Debonnel, Z. Dragojlovic, L. El-Guebaly, D. Haynes, J. Latkowski, C. Olson, P. Peterson, S. Reyes, P. Sharpe, M. Tillack and M. Zaghloul
Outline (some sections already written)
• Introduction (~1 page)
2. TLW Chamber Concept and Operation (~2 pages)- General description of TLW concept - Example HYLIFE-II design with HI driver and ID target - Driver and target constraints
3. Chamber/Liquid Wall Dynamics (~5-7 pages)Describe mechanisms with illustrative analytical results (as needed)- Liquid wall response to threats and early chamber dynamics (to ~1 ms)- Chamber clearing mechanisms (to ~100 ms)
4. Existing Models (~5-7 pages)(capabilities to simulate mechanisms described above, example results and planned improvement) (~0.5-1 page per model)
5. Existing Experimental Facilities (~5-7 pages)(capabilities to simulate and measure mechanisms described above,
6. R&D Needs
7. Conclusions
September 3-4, 2003/ARR15
“IFE Liquid Wall Response to the Prompt X-ray Energy Deposition:Investigation of Physical Processes and Assessment of Ablated Material”
M. Zaghloul, R. Raffray, and the ARIES Team
Outline (paper being written)
1. Introduction2. X-ray Energy Deposition
- X-ray Spectra- Photon Energy Deposition in The Cavity and Wall- Cold Opacities of Candidate Materials- Profiles of the Percentage of Energy Deposition in the Cavity and Wall
3. Wall Response (Physical Processes and Material Removal Mechanisms)- Thermal Response and Phase Transitions
- Normal (Surface) Vaporization- Normal Boiling (Vaporization into HeterogeneousNuclei)- Phase Explosion (Explosive Boiling) and HomogeneousNucleation
- Mechanical Response and Ruptures- Fractures and Spall
4. Material Properties- Relevant Material Properties of Candidate Materials- Theoretical Spall Strength and EOS
5. Modelling Approaches- Volumetric vs. Kinetic- Justification for the Volumetric Approach
6. Scoping Results - Results for different ablated amounts
- Pb, flibe- Comparison with ABLATOR
7. Discussion and Conclusions