116-99 jy

QTYUIOP

IFE TARGET FABRICATION AND INJECTION

IFE Direct Drive Targets

IFE Indirect Drive Targets

IFE Target Injector Concept

K.R. SchultzDirector of Inertial Fusion Technology

General Atomics

SEAB Task Force on Fusion EnergyLawrence Livemore National Laboratory

May 26, 1999

Fast GasValve

GasReservoir

Transport fromTarget Factory

VacuumPumping

Recovery ofSabots

TargetLoader

Gun Barrel

RotatingShield

SabotCatcher Vacuum

Chamber

1 cm Tracking Stations

Blanket

Vapor

Fuel DTCH (DT)641951 µm

0.8 µm of CH + 5% Au

1690 µm1500 µm

116-99/rs

QTYUIOP

TARGET FABRICATION AND INJECTION ARE PART OFTHE IFE COMMUNITY’S PHASED DEVELOPMENT STRATEGEY

● Next Step: Decide at end of Phase l if and how to proceed to an IFE Integrated Research Experiment (IRE)

● During Phase I, before the IRE decision, we must show that a credible pathway exists for low cost IFE target fabrication and accurate target injection and tracking

DecisionYearInvestment

~ 2012

~ 2025

~ 2040

Inertial Fusion Energy (IFE) Development StratagyA Look Backward from the “End Game”

Economic (or no-go!)

Total project cost $3B.

Phase III$80M -120M/yr

Phase IIITotal project cost <$2B.

Attractive, Commercial IFE

Power Plant

IFE Demo

Integrated Research Experiment(s)

- IRE - (Lasers and/or ions)

National Ignition Facility - NIF - and ignition

program

(Separately DOE/DP funded)

Supportingpower

technologies forthe Demo

Advanced driver and target R&D.

Supporting technology R&D

?

?

?

~ 2003

Phase I~$50M/yr

Heavy Ion Beams

Diode-Pumped Solid State Lasers

Krypton Fluoride Lasers

Target design and Technology

R&D

?

Engineering Test Facility

- ETF -

QTYUIOP116–99

CREDIBLE TARGET FABRICATION AND INJECTIONARE NEEDED FOR IFE

● Design studies show plausiblemanufacturing and injectionprocesses and reasonable costs

● We must demonstrate:— Technical feasibility of approaches— Accuracy can meet requirements— Survival of targets during injection— Reliability of providing ~5 targets/

second, 24 hours a day, >300 days/year— Low cost of production — including labor,

capital, materials and disposal

● We have now begun to addressthese issues— Need to show a credible pathway to IFE

exists during Phase I, before investingin the IRE

Design Studies: Target factory costs $50–90M Unit cost 20–30¢/target

Typical Specifications

Capsule out-of-round ≤0.1%Ablator thickness ≤1%Outer surface smoothness ≤200 ÅInner surface smoothness ≤1 µmCapsule centered in hohlraum ≤25 µmAllowed ∆T after layering ≤0.5 K

Location at shot time (indirect) (direct)

±200 µm±20 µm

Reliability ≥99%

116-99 jyQTYUIOP

CURRENT ICF TARGETS MEET STRINGENT REQUIREMENTSFOR FABRICATION, DT LAYERING AND ALIGNMENT

● ICF capsules must meet strict sphericity,concentricity and surface finish standards:

● Natural “beta layering” provides DT ice layering; requires a very uniform thermalenvironment (±0.1 K control, ±25 µK uniformity)

● These requirements have been met for Nova and Omega, and success is expectedfor ignition on NIF in 2006–2008

105CH+5%O+0.25%Br(1.05 g/cc)

DT (0.25 g/cc)

NIF Indirect Drive:Out of Round: <1 µm∆W <2 µmSurface Roughness: <0.2 µm rms (l > 2)DT Ice surface roughness <1 µm rmsLocation to ±5 cmAlignment to ±6 µm

DT (0.3mg/cc)

1110 µm950 µm

870 µm

NIF CH Capsule

104

103

102

101nm2

100

10–1

10–2

10–31 10

Mode NumberPrototype NIF Capsule Power Spectrum

100 1000

NIF standard

QTYUIOP116–99

IFE WILL HAVE SIMILAR SPECS — AND WILL NEEDLOW-COST MASS PRODUCTION

● Larger target size makes accuracy more difficult butwe have achieved specs to date— Nova: 0.5 mm, Omega: 1.0 mm, NIF: 2–3 mm, IFE: 4–5 mm— Larger size may allow relaxed specification

● Current ICF Target cost ~$2500 each due to:— Few-of-a-kind designs — constantly changing— High development cost — est. 10% actual production— Small scale production — batches of ~5–25 targets— Labor-intensive fabrication process for ~103/year— Extensive characterization — each individual target

has a “pedigree”

● IFE Targets must cost ≤25¢ each— Few designs, few changes— Continuous production processes— Fully automated fabrication— Characterization only for statistical process control

● ~5 targets/second are needed — 108/year— “Learning curve” progress ratio of 0.66 to meet goal is reasonable

NIF — 2 mm

Omega — 1 mm

Nova — 0.5 mm

116-99 jy

QTYUIOP

IFE CAN BUILD UPON ICFTARGET FABRICATION TECHNIQUES

2 mm

Foam Shells

High-Z coating

DT Ice Layer Metal on Foam

Overcoated Foam

WettedDT foam

DTice

DTgas

Radiative PreheatDirect Drive IFE Target Design

QTYUIOP116–99

SOME CURRENT ICF PROCESSES EXTRAPOLATETO IFE; OTHERS REQUIRE ALTERNATIVES

Extrapolate to IFE ?

Fabrication Step ICF Process Specs ? Cost ? Alternatives

CAPSULES— Indirect Drive

— Direct Drive

PAMS-GDP

PAMS-GDP

Probably

Probably

Probably not

Probably

Microencapsulation,Fluid bed coater

FOAMS Microencapsulation Probably Yes

HOHLRAUMS Machine-plate-leach Yes No Stamp, mold

ASSEMBLY Micro-manipulation Yes Yes (Automate)

CHARACTERIZATION Extensive “pedigree” Yes Yes (Statistical sampling)

FILLING Permeation Yes Yes Injection fill

LAYERING Beta layering, IR andµW enhanced

Yes Probably Fluidized bed

104 REDUCTION IN HTGR FUEL PRODUCTION COSTIS ENCOURAGING FOR IFE

116–99QTYUIOP

● High-temperature gas-cooled reactor (HTGR)fuel has similarity to IFE capsules— Multiple layers of high and low density coatings— Stringent quality requirements

● Over 1011 fuel particles have been produced ina small commercial production facility forFort St. Vrain reactor

● Quality control was carried out by statistical means— Production yield was ~90%

● Cost reduction was ~104 due toscale up— Bench scale 20¢ per particle

— FSV was less than 0.2¢ per particle— Projected commercial 0.002¢ per particle

500-1000 µm

HTGR fuel particle with 4 different coating layers

. . . Indicates that low cost IFE targets are not out of reach, but greater precision will be required

PilotScale70’s

HTGR Fuel Particles

Initial cost~20 cents/particle

Current cost~$2,000/target

IFE Targets($)

FSV80’s

ProjectedHTGR00’s

Scale-up and Learning (Time)

10’s 20’s 30’s 40’sBenchScale60’s

10–3

10–2

10–1

Cost

(Cen

ts/P

artic

le)

Projected IFE-Target Cost(Dollars/Target)

100

101

100

10–1

101

102

103

116-99 jy

QTYUIOP

NEXT-STEP DEVELOPMENT PLANS FOR IFE TARGET FABRICATION

● Work with target designers and power plant studies to selectpromising designs, optimizing gain, robustness and cost

● Develop materials for IFE requirements, such as

● Develop mass production fabrication processes

● Develop statistical on-line quality control characterization

● Bench-scale experiments for production processes● Evaluate processes for accuracy, reliability and cost● Provide prototype targets to the IRE

— Robust foams, doped ablators, distributed converter hohlraums for HIF

— Identify suitable industrial technologies

— Demonstrate they can achieve the accuracy needed— Project they can meet cost goals

Phase l:

★ Microencapsulation, fluid bed coaters, die casting/injection molding for hohlrams

Phase ll:

QTYUIOP116–99

TARGET INJECTION SYSTEMS ARE NOW BEING ADDRESSED● Cryogenic target development for Omega and NIF

leads the way— Targets must be layered (~150 µm thick solid DT)

3333 Requires accuracy of ~0.1 K and uniformity of ~25 µK

— Targets must be kept cold (DT at ~18 K at target chambercenter)3333 Heat up of only ~0.5 K allowed to ensure ice integrity

— Targets are relatively fragile yet must withstand handling

Nike 60 cm Mirror Actuators● Injection studies are promising

— Long injection distance (up to ~7.5 m exposed to up to 1500°C) requires velocities thathave been demonstrated (100–1000 m/s)

— DT pellet injectors for MFE exceed IFE speeds and injection rate (~5 Hz)3333 MFE accuracy specs are low

— Indirect/direct drive require accurate placement (±5 mm/5 mm) and tracking (±200 µm/20 µm) oftargets based on:3333 Beam steering capability3333 Hohlraum/capsule irradiation uniformity requirements

— Design studies indicate these specifications can be met with systems using currently availabletechnology

116-99/rs

QTYUIOP

THERMAL PROTECTION MUST BE CONSIDERED FOR IFE TARGET, CHAMBER AND INJECTOR DESIGN

0.001

0.01

0.1

1

10

100

0 200 400 600 800 1000 1200

NRL Radiation Heated Ablator Target18 K Injection Temperature99% Capsule Surface Reflectivity

Ablator Outer Surface1800 K, 0.5 Torr Xe

“Allowable” Temperature Change

OSIRIS770 K, Vac.

Fuel Outer Surface1800 K, 0.5 Torr Xe

Fuel Inner Surface1800 K, 0.5 Torr Xe

Velocity (m/s)

∆T (K

)

● IFE targets will need DT ice at precise temperature (18–19 K, ±0.5 K)

● Ice surface smoothness and layer integrity appear to be sensitive to temperature change; ∆T ≤ 0.5 K needed after layering

● The target chamber offers a hostile environment for cryogenic targets;T ~ 500˚–1500˚C, possible gas for wall protection

● Hohlraums provide protection for indirect drive targets

● Direct drive targets require trade-off of target albedo, chamber temperature and pressure, and injection velocity.Reflective metal coatings will help

QTYUIOP116–99

STATUS OF IFE TARGET INJECTION AND TRACKING● Requirements set by thermal and mechanical robustness of targets

— Indirect Drive: injection at 100 m/s to ±5 mm, tracking to ±200 µm— Direct Drive: without thermal protection, injection at 100 to 1000 m/s

may be needed, to ±5 mm, tracking to ±20 µm

● Gas gun experiments at LBNL have demonstrated the indirect drive requirementscan be reliably and repeatable achieved at room temperature and low rep rate

● Preliminary experiments with surogate direct drive targets in vacuum at roomtemperature and V≈100 m/s also met indirect drive accuracy specs

● For low albedo targets, direct drive may require development of thermalprotection schemes and/or high speed injection and tracking technologies

IFE Target Injection Experiment at LBNL

QTYUIOP116–99

NEXT-STEP DEVELOPMENT NEEDED FORIFE TARGET INJECTION AND TRACKING

● Phase I:— Work with target designers and power plant studies to select promising

target and chamber designs and to define their injection requirements— Select, design and develop target protection and injection system best

suited for direct drive targets— Demonstrate injection and tracking of simulated targets at

room temperature— Measure the thermal response of cryogenic targets and

demonstrate methods for thermal protection

● Phase II: (IRE)— Add cryogenic target capability and high temperature surrogate

chamber to Phase l injection-tracking system for experiments— Provide target injection-tracking system to the IRE

QTYUIOP116–99

IFE TARGET FABRICATION, INJECTION ANDTRACKING IS A TEAM EFFORT

● Being developed as part of the IFE Chamber and Target Technology element of the OFESVirtual Laboratory for Technology by LANL and GA

● Plans for Phase l will demonstrate that a credible pathway exists for low cost IFE targetfabrication, filling, layering, injection and tracking to support the decision at the end of Phase lof whether and how to proceed with the IFE IRE

● Budget requirements is ~$3M/yr for Phase l

FY00 FY01 FY02

LANL GA LANL GA LANL GA

3.0 Target Technology R&D 3.1 Target Fabrication

3.1.1 Assess Target Designs X X X 3.1.2 Investigate Target Matls & Man Tech X X X 3.1.3 Dev Manuf Process for Fab/Fill/Layer X X X X X X 3.2 Target Injection R&D

3.2.1 Target Thermal Response X X X 3.2.2 Target Injection Accuracy & Tracking X X X 3.2.3 Target Acceleration Response X X X 3.2.4 Target Property Measurements X X

QTYUIOP116–99

WE PROPOSE TO DEMONSTRATE A CREDIBLE PATHWAYFOR IFE TARGET FABRICATION AND INJECTION

● To meet IFE target fabrication and injection specifications we will buildon ICF experience and on development planned for NIF capsules and DTice layers

● Fabrication techniques that extrapolate to low cost mass production havebeen proposed. Favorable HTGR fuel particle experience is encouraging

● Target injection and tracking component requirements appear consistentwith present technology. Early target injection experiments at roomtemperature appear favorable. Extrapolation to cryogenic targets is needed

● IFE target fabrication and injection development is planned within theproposed IFE Technology program

● During Phase l of the IFE Plan, we propose to demonstrate that acredible pathway exists for IFE target fabrication and injection