1. Update on Target Fabrication Tasks Presented by Dan Goodin at ARIES Meeting San Diego, California July 1-2, 2002

2. Topics Direct drive target costing study Target injection and survival -Injector system status -Protection schemes for direct drive Indirect drive target fabrication -Feasibility -Materials selections -Status on costing study  Microencapsulation scaleup studies

3. NRL radiation preheat target Chemical engineering approach to Target Fabrication Facility (TFF) Costing is done for an “nth-of-a-kind” plant Results guide process development Preliminary estimates for direct drive target production costs are encouraging Major Parameters 500,000 targets per day 2-3 weeks on “assembly line” Installed capital of $97M Annual operating cost of $19M Cost per injected target estimated at 16.6 cents TFF layout for radiation preheat target production Full Presentation - HAPL April 4/5, 2002, General Atomics (http://aries.ucsd.edu/HAPL/MEETINGS/0204-HAPL/program.html)

4. 7200 ft 2 experimental space is being refurbished for use in IFE research Target injector fabrication is underway; Bldg. 22 is being refurbished -85% of this years equipment is ordered -Preliminary tracking system optical testing took place at UCSD -First detector housing is complete, setting up for tests with translation stages -Software design spec and test plan are complete -Control system computers and Opto-22 programming and wiring has begun Opto 22 input/output hardware Tracking detector housing

5. An unprotected radiation preheat target will not survive with high chamber gas pressure The chart above was optimistic - Assumes 98% reflectivity (300 A gold is about 96% reflective, palladium is less) - Uses average convection heat flux (peak flux up to 3 times higher) - Does not include condensation - Gas may be much hotter than chamber wall (with significant plasma heating)

6. Wake shield target heating protection calculations have been carried out 1. Convective heat load is calculated as a function of target-shield separation 2. Drag is calculated as a function of target-shield separation 3. The relative motion of the target and shield is optimized 4. Average heat flux on the target is then calculated By E. Valmianski P = 50 mTorr T= 1000 K V= 400 m/s Shield radius = 5 mm

7. Membrane target protection scheme was conceived Support frame Target support membrane By R. Petzoldt and M. Shmatov Heat barrier membrane coated with frozen gas Must verify ~1000 Å film does not adversely affect target performance and gas film of appropriate variable thickness can be applied

8. 0123456 0 0.4 0.8 1.2 1.6 2 2.4 2.8 3.2 3.6 4 Distance along target (mm) Target with cone Unprotected target Target with thin shield Radius of the shield - 4mm Radius of the target - 2 mm Temperature -1773 K Density STD - 50 mtorr Speed - 400 m/s A cone used with fast ignition reduces max heat flux more than a flat shield The cone provides a 3-fold decrease in the max heat flux as compared with the unprotected target. Improvement over flat shield is due to gas reflection off lateral surfaces.

9. Topics Direct drive target costing study Target injection and survival -Injector system status -Protection schemes for direct drive Indirect drive target fabrication -Feasibility -Materials selections -Status on costing study  Microencapsulation scaleup studies HIF2002 Moscow May 26-31, 2002

10. Indirect drive target fab - main points …. A significant R&D program will be necessary to demonstrate and scaleup these processes Target fabrication is one of the key feasibility issues for inertial fusion energy Target supply requirements are challenging -~500,000/day precision, cryogenic targets with unique materials -Low cost is required for economical power production Near-term goal of program is to provide a “credible pathway” for HIF target supply We have identified potential manufacturing processes that can be developed to supply the distributed radiator HIF target

11. The distributed radiator target of Tabak and Callahan is the reference HIF design … Costs per target of about $0.30 are needed for economical electricity production (Woodworth and Meier UCRL-ID-117396, 1995) LLNL Close- Coupled Heavy Ion Driven Target  Two sided illumination by heavy ion beams  Energy deposited along hohlraum materials  Radiation distribution tailored by material density  Unique materials required Debbie Callahan Invited Talk At HIF2002

12. The distributed radiator target of Callahan and Tabak is the reference HIF design A: AuGd0.1 g/cc B: AuGd13.5 g/cc C: Fe0.016 g/cc D: (CH) 0.97 Au 0.03 0.011 g/cc E: AuGd0.11 g/cc F: Al0.07 g/cc G: AuGd 0.26 g/cc H: CD 2 0.001 g/cc I: Al0.055 g/cc J: AuGd “sandwich” 0.1/1.0/0.5 K: DT0.0003 g/cc L: DT0.25 g/cc M: Be 0.995 Br 0.005 1.845 g/cc N: (CD 2 ) 0.97 Au 0.03 0.032 g/cc The heavy-ion driven target has a number of unique and challenging materials Nuclear Fusion 39, 1547 … Simplification and material substitutions are needed to reduce complexity of the target

13. PartMaterialAlternate Materials AAuGd [high-Z only]Various - Au, Pb/Ta, Pb/Ta/Cs, Hf/Hg/Xe/Kr BAuGd [high-Z only]Various - Au, Pb/Ta, Pb/Ta/Cs, Hf/Hg/Xe/Kr CFeAu-doped CH foam D(CH) 0.97 Au 0.03 -- E AuGd [high-Z only]Various - Au, Pb/Ta, Pb/Ta/Cs, Hf/Hg/Xe/Kr FAlSilica aerogel GAuGd [high-Z only]Various - Au, Pb/Ta, Pb/Ta/Cs, Hf/Hg/Xe/Kr H CD 2 He gas I AlCH or doped CH J AuGd sandwich (high-Z only) Various - Au, Pb/Ta, Pb/Ta/Cs, Hf/Hg/Xe/Kr K DT-- L DT-- M Be 0.995 Br 0.005 Polystyrene (CH) N (CD 2 ) 0.97 Au 0.03-- Physics of Plasmas, May 2000, pp. 2083-2091 Material substitutions are defined in conjunction with target designers to reduce target cost Pathways to simplify the target are being defined Recent Material Choices (Loss compared to Au/Gd D. Callahan) Au or Pb~10-15% gain loss Pb/Hf~2% gain loss Pb/Hf/Xe~0% gain loss

14. Process steps for target fabrication are challenging.... Process development programs for target fabrication and target injection are underway 1) Fabricating the spherical capsule 2) Fabricating the hohlraum case 3) Fabricating the radiators 4) Filling the capsule with fuel 5) Cooling the capsule to cryo 6) Layering the DT into shell 7) Assembling the cryo components 8) Accelerating for injection 9) Tracking the target’s position 10) Providing steering/timing info Some Possible Indirect Drive Specifications Capsule MaterialCH Capsule Diameter~4.6 mm Capsule Wall Thickness250  m Out of Round<0.1% of radius Non-Concentricity<1% of wall thickness Shell Surface Finish10-200 nm RMS Ice Surface Finish1-10  m RMS Temperatureat shot~18.5K Positioning in chamberless than ± 1-5 mm Alignment with beams<200  m Every step except the first one is done with radioactive materials (tritium and recycled materials), so remote handling is required

15. There are many decisions to be made when selecting a target supply pathway StepMethodsComments/Issues Capsule FabricationMicroencapsulationSimple, suitable for hi-volume Issues: sphericity, non-concentricity GDP coating onto mandrelsCould solve NC problem; demo’d in small coaters; Issues: multi-step adds cost Solution spray dryingProduce stronger, higher density PI; Issues: surface smoothness, cost FillingPermeationDemonstrated; Issues: T inventory Liquid fillingDevelopmental, capsule damage LayeringFluidized bedDemo’d in principle, req’s fast assembly In-hohlraumExtreme precision/uniformity Hohlraum Comp. FabCastingFor Flibe sleeve, remote handling LCVDFor hi-Z matl’s, developmental, cost Metal foamsPore sizes, density Wire arraysUniformity, structural integrity Doping of CH foamsFor radiator matl’s, mass-prod methods, handling, precision Target Injection/TrackingGas-gun, electromagneticBuilding demo system.... Many of the steps above have issues associated with remote handling, dose rate, CTE mismatches on assembly

16. Fluidized beds for mass-production of capsules is being investigated …. These coating methods are all two-step processes Coating Mandrel PAMS Mandrels in Fluidized Bed ~ 3 micron thick GDP coating on PAMS Aerosol microspray of polyamic acid solution; 4-8 micron droplet size ~ 7 micron thick PAA coating on PAMS PAMS mandrel PAA coating 7.3  m Experimental system Polyamic acid  polyimide coating

17. Direct capsule fabrication by microencapsulation Microencapsulation may be most cost-effective pathway... Laboratory scale rotary contactor Schematic of microencapsulationPower spectrum of 4.6mm CH capsule, 45  m wall, OOR <1% of radius, NC <3% of wall, rate 36/minute (M. Takagi) NIF Spec (green) ~16 cm Approaching IFE Requirements!

18. Preliminary “Target Fabrication Facility” (TFF) layout 100’ PS shell generation Ethanol/Water Exchange & Vacuum Drying DT Filling (Permeation Cells) Layering (Fluidized Bed) To Chamber QA/QC Lab 80’ Injector Hohlraums Hohlraum Production Area Full-scale rotary contactor: 50x50 cm, 50% liquid, 8% shells by volume, 8h target supply ~1.4m Preliminary cost estimates indicate ~$0.11 per capsule for capsule fabrication, filling, and layering (not including hohlraum materials and assembly) Hohlraum Cryo- Assembly

19. Filling of the capsules with DT can be done by permeation through the capsule wall Issue = Minimum T inventory “at-risk” Targets typically contain ~3-4 mg of tritium 1.5 to 2 kg of tritium/day injected into reactor NEEDLE JET PIERCE “Advanced” methods of filling have also been evaluated Methodology by A. Schwendt, A. Nobile (LANL), Fusion Science and Technology (to be published) Six shots per second Void fraction - 5% Fill Temperature - 27C Cool time - 0.5 h Evacuation time - 1 h  -Layering time - 8 h IR-Layering time - 2 h Fill overpressure - 75% of buckle Pressure cell with trays Hohlraum cryo-assembly

20. Layering in-hohlraum or not? “Cold Assembly” DT Diffusion Fill Capsule Cool to Cryo Temps Evacuate DT Layer DT Ice Cold Assemble Hohlraum Hohlraum Cryogenic Assembly Layer DT Ice Inject Manufacture Materials 1.In-hohlraum layering “Warm Assembly” DT Diffusion Fill Assemble Hohlraum Cool to Cryo Temps Evacuate DT 2.Fluidized bed layering of capsules 3.Warm Assembled Hohlraum Layer DT Ice Three routes for indirect drive target processing are possible: …Tritium inventory will likely require cryogenic assembly

21. Neopentyl alcohol as surrogate for hydrogen - proof of principle demo COLD HELIUM FLUIDIZED BED WITH GOLD PLATED (IR REFLECTING) INNER WALL INJECT IR Two potential HIF layering methods identified ASSEMBLED HOHLRAUMS ARE STAGED IN VERTICAL TUBES WITH PRECISE TEMPERATURE CONTROL ~1 m In-hohlraum “tube” layering Cryogenic fluidized bed layering …Fluidized bed layering is can be used for either direct or indirect drive targets Before After

22. Manufacture of the hohlraum components and assembly …Remote processing will be required for assembly Begin with casting a Flibe sleeve to provide a structural support Add 15  m high-Z layer by CVD or “exploding wire” (B) B Add high-Z (A) by LCVD New die set & assemble precast foams (E,D,C) Continue stacking (G,F,N,J,I) Kapton film to hold capsule Completed assembly with films to seal in gas (“H”) 2% W-doped 30 mg/cc CH foam Laser-assisted Chemical Vapor Deposition is being evaluated at LANL (J. Maxwell, IAEA-TM June 17-19, 2002)

23. Flowsheet for HIF targets Preliminary hohlraum plant layout over next few months….

24. Main points and summary Target fabrication is one of the key feasibility issues for inertial fusion energy Target supply requirements are challenging -~500,000/day precision, cryogenic targets with unique materials -Low cost is required for economical power production Near-term goal of program is to provide a “credible pathway” for HIF target supply We have identified potential manufacturing processes that can be developed to supply the distributed radiator HIF target

25. Topics Direct drive target costing study Target injection and survival -Injector system status -Protection schemes for direct drive Indirect drive target fabrication -Feasibility -Materials selections -Status on costing study  Microencapsulation scaleup studies

26. Next Step: build modular components to demonstrate scaleup - microencapsulation Lab-scale rotary contactor ~16 cm  Equipment dedicated to IFE development and scaleup (GA-funded; put in Bldg 22)  Provide shells for fluidized bed studies  Determine viability and effects of scaleup of rotary contactor (evaluate alternates) Full-scale rotary contactor: 50x50 cm, 50% liquid, 8% shells by volume, 8h target supply ~1.4m First shells! Motion during curing is critical