MERICA’S dependence onimported oil currently accounts

for a trade deficit of $60 billion peryear. As time passes, the worlddemand for energy will continue togrow, in part for demographicreasons, such as the rapidlyincreasing energy use per capita indeveloping Asian and LatinAmerican countries together withthe expected doubling of the world’spopulation over the next 50 years.Our deficit and world energydemand will also grow forenvironmental reasons, particularlyin the United States, which will needa substantial new source of energyto power zero-emissiontransportation and reduce urban airpollution, to charge batteries inelectric cars, or to produce clean-

only dependable in the limited desertregions of the world, some fusionfuels can be extracted from seawater,making them available to allcountries of the world. Fusion powerplants, if they can be developedeconomically, will also have manyadvantages over fission. Theradiation hazard presented by fusionpower plants can potentially bethousands of times smaller than thatof fission power plants, with properchoice of materials.

Two Approaches to Fusion

Fusion combines nuclei of lightelements into helium to release energyand is the same process that powers thesun. As noted, the fuel for fusion(deuterium and lithium, which can

burning hydrogen fuel by waterelectrolysis. Clearly, an alternativeenergy source is needed.

At present, there are only threeknown inexhaustible primary energysources for the future: the fissionbreeder reactor, solar energy, andfusion. All are superior to coal or oil-based power plants because theyare environmentally cleaner andecologically safer. They will releaselittle or no radioactivity per unit of power, as do coal mining andburning in the form of radon,uranium, and thorium,1 and they willemit none of the gases (carbondioxide and nitrogen dioxide) thatcontribute to greenhouse effects.Fusion, however, offers certainadvantages over fission and solarenergy. Unlike solar energy, which is

The Role of NIF in DevelopingInertial Fusion Energy

The National Ignition Facility will demonstrate fusionignition, which is central to proving the feasibility of

inertial fusion energy. It will also help us determine thefull potential of this alternate energy source.

33

A

capture a neutron to regenerate tritium)can be extracted from seawater. Themost likely fuel for any approach tofusion energy is DT (either liquid, gas,or a combination as in inertial fusionenergy targets), which is a mixture ofdeuterium and tritium isotopes ofhydrogen. This DT must be heateduntil it is hotter than the interior of the sun, but it fuses at the lowesttemperature of any fusion fuel.

To explore the feasibility ofeconomical fusion power plants, theDepartment of Energy is currentlydeveloping two primary approachesto fusion energy—magnetic fusionenergy and inertial fusion energy(IFE). Both approaches use DT fueland offer the potential advantagesdescribed above, but they must be developed more fully beforeeconomical fusion energy can beassured. Because the two approachesuse different physics and presentdifferent technological challenges, the National Energy Policy Act of19922 calls for both to be developedto the demonstration (DEMO) stage.

Magnetic fusion ignition is thegoal of the proposed InternationalThermonuclear Experimental Reactor,which uses strong superconductingmagnets to confine a low-density DT

plasma inside a large, high-vacuum,toroidally-shaped vacuum chamber.3The IFE approach to fusion, incontrast, is one of the goals of theNational Ignition Facility (NIF), thesubject of this article. This approachuses powerful lasers or ion beams(drivers) to demonstrate fusionignition and energy gain in thelaboratory by imploding and ignitingsmall, spherical DT fuel capsules(targets) to release fusion energy in aseries of pulses (see box on p. 38). Inits quest to accomplish this goal, theNIF supports a primary nationalsecurity mission for science-basedstockpile stewardship (see precedingarticle) and secondary missionssupporting energy and basic science.

The IFE Power Plant

Figure 1 is a conceptual view of ageneric IFE power plant, showing itsfour major parts—the driver, targetfactory, fusion chamber, and steam-turbine generator (balance of plant).This figure demonstrates some of theprincipal advantages of IFE as anenergy source:• The driver and target factory areseparated from the fusion chamber toavoid radiation and shock damage to

the most complex plant equipment.The separation between the driver andfusion chamber also allows a singledriver to drive multiple fusionchambers, thus permitting flexibility inthe required chamber pulse rate andlifetime and allowing for the stageddeployment of several fusion chambersto achieve low-cost electricity.4• Progress in inertial fusionexperiments on the Nova laser facilityat LLNL allows the most importanttarget physics affecting target gain tobe modeled successfully by computercodes such as LASNEX. When thesecomputer models are better confirmedby target-ignition tests in the NIF,they can be used to design targets forfuture IFE power plants.• IFE fusion chambers do not requirea hard vacuum; therefore, a widerrange of materials can be used toachieve very low activation andradioactive waste. IFE chamberdesigns that protect the structuralwalls with thick, renewable fluidflows are also possible, which willeliminate the need to replace thechamber’s internal structuralcomponents periodically.5,6

• The cost of developing IFE can bediluted by sharing NIF for defenseand energy missions.

How the NIF Can Help DevelopIFE

In 1990, the Fusion PolicyAdvisory Committee7 recommendedthat inertial fusion ignition bedemonstrated in the NIF as a keyprerequisite to IFE. In addition toignition, IFE needs development inthree major areas of technology:• High-gain, injectable, mass-produced, low-cost targets.• An efficient high-pulse-rate driver.• A suitable, long-lasting fusionchamber.A major facility following the NIF, tobe called an Engineering Test Facility

Inertial Fusion Energy E&TR December 1994

34

Beams

HeatHeat

Recycled target material

TargetsDriver

Turbinegenerator

Targetfactory

Fusionchamber

Figure 1. Conceptual view of a four-part IFE power plant, showing the driver (either laseror ion particle beams), the target factory, the fusion chamber, and the turbine generator thatproduces electricity.

(ETF), is planned to test the feasibilityof these three areas of technologyintegrated together. The ETF willexplore and develop the high pulserate (several pulses per second) andoverall system efficiency needed foreconomical IFE power production.

Filling Technological NeedsTargets. The targets for IFE must

be capable of high energy gain.Energy gain is achieved when thefusion energy released from a reactionexceeds the energy that was put intothe target by a laser or ion-beamdriver. For high gain, the energyreleased from the target should bemore than 50 to 100 times greaterthan the driver energy. Tests ofinertial fusion target physics andignition in the NIF will allow us topredict confidently the performance ofseveral candidate IFE target designs.

For IFE targets to produceelectricity at competitive rates (lessthan 5 cents per kilowatt-hour), theymust be mass-producible at a cost ofless than 30 cents each. This meansnew target-fabrication techniques must be researched and developed. Inaddition, we will have to develop andtest methods of target injection andtracking for driver–target engagementsat pulse rates of 5 to10 Hz. The NIFcan test the performance of candidatemass-produced IFE targets and, atleast for a limited number of pulses ina short burst, the associated target-injection methods.

The option of using direct-drive inaddition to indirect-drive targets (seethe box on pp. 38-39) is underconsideration for the NIF. If direct-drive implosion experiments on theOmega Upgrade (an upgrade of theOmega glass laser to 60 beams) at theUniversity of Rochester’s Laboratoryof Laser Energetics are successful,this option will be exercised, and bothdirect- and indirect-drive targets willbe examined on the NIF. Figure 2

E&TR December 1994 Inertial Fusion Energy

35

Indirect-drive laser target

Laser-driven model of heavy-ion target

(a)

Direct-drive laser target

(b)

Figure 2. The NIF target area and beam-transport system (a) for indirect-drive experimentsrelevant to either laser or heavy-ion targets and (b) for direct-drive laser targets only. Note that the target area and beam-transport system in the baseline system (a) could bereconfigured to design (b) by the repositioning of 24 four-beam clusters, making direct-driveexperiments possible.

shows the laser-beam configurationsaround the NIF fusion chamber thatwill be used to conduct indirect-drive (Figure 2a) and direct-driveexperiments (Figure 2b). Figure 2also shows examples of indirect- anddirect-drive targets that can be testedin each configuration.

Figure 3 shows a heavy-ion-driventarget for IFE (Figure 3a) comparedwith a modified laser-driven target(Figure 3b) that is designed to modelmore closely the IFE heavy-iontarget. The latter (Figure 3b)illustrates how the NIF could use alaser to test the soft-x-ray transportand plasma dynamics inside a higher-fidelity hohlraum geometry similar tothat in Figure 3a. Note that thecapsule performance and implosionsymmetry requirements for indirect-drive targets are independent ofwhether the x rays are generated witha laser or an ion-beam driver. We canalso use the NIF for special laser-target experiments that simulate manyaspects of heavy-ion targets.

Drivers. Although the key target-physics issues that NIF will resolveare largely independent of the type of driver used, it is essential inevaluating the potential of IFE todetermine the minimum driver energy

needed for ignition. Regardless ofdriver type, all IFE drivers for powerplants need a similar combination ofcharacteristics: high pulse-repetitionrates (5 to 10 Hz) and high efficiency(i.e., driver output beamenergy/electrical energy input to thedriver greater than 10 to 20%,depending on target gain). Inaddition, they should be highlyreliable and affordable whencompared with nuclear generatorplants.

The Energy Research branch ofDOE is developing heavy-ionaccelerators to meet the aboverequirements.8 Heavy-ion drivers canbe either straight linear accelerators(linacs) or circular (recirculating)beam accelerators like that shown in the box on p. 39. The DefensePrograms branch of DOE, in contrast,is pursuing advanced solid-statelasers, krypton–fluoride lasers, andlight-ion pulsed-power acceleratorsfor defense applications that may,with improvements, lead to alternateIFE drivers. Diode-pumped solid-state lasers will be able to build onthe laser technology being developedfor the NIF.9

While other DOE researchexamines the direct-drive option

and develops more efficient, high-repetition-rate IFE drivers(principally heavy-ion beamaccelerators) for power plants, theNIF can be built and achieve itsmission with current solid-state lasertechnology. Diode-pumped solid-state lasers (DPSSLs), which alsobuild on NIF laser technology, mayprove to be a backup to the heavy-ionaccelerator. Using laser-diode arraysunder development for industrialapplications, DPSSL drivers mayultimately improve the efficiency,pulse rate, and cost of solid-statelasers enough for use as IFE drivers.Figure 4 shows a schematic DPSSLdriver layout that, except for thediode pump arrays, has anarchitecture similar to that beingdeveloped for the NIF.

Fusion chambers. IFE needsfusion chambers where target fusionenergy can be captured in suitablecoolants for conversion intoelectricity. To allow high pulse rates,these chambers will have to be builtso they can be cleared of target debrisin fractions of a second. Further, theymust be reliable enough to withstandthe pulsed stresses of one billionshots (30 years of operation) withoutstructural failure. They should also

Inertial Fusion Energy E&TR December 1994

36

Heavy-ionbeams

DT fuelcapsule

0.35-µm laser beamsin two cone arrays

Dopedplastic

Hohlraum

Hohlraum

Shield

ShieldCapsule

Doped gas

14–1

6 m

m

Figure 3. The NIF cantest important heavy-ion physics issues,such as soft-x-raytransport and drivesymmetry, hohlraumplasma dynamics,capsule-implosionhydrodynamics, andmix. Here the modifiedlaser-driven target in(b) shows how the NIFcould use a laser totest x-ray transport andplasma dynamics in ahohlraum geometrylike that shown in (a).

(a) (b)

use low-activation materials (such asmolten salt coolants or carbon-composite materials) to minimize thegeneration of radioactive waste.Many IFE power plant studies havealready found conceptual designs thatmeet these goals, but actual tests willbe required. What we learn from theNIF fusion chamber can provide datato benchmark design codes for futureIFE chamber designs.

Other Needs. In addition to fusionignition, the NIF will provideimportant data on other key IFEpower plant needs. These needsinclude wall protection from targetdebris and radiation damage, chamberclearing, rapid target injection, andprecision tracking. The NIF will also be used to provide data that can benchmark and improve thepredictive capability of variouscomputer codes that will be needed todesign future IFE power plants, toselect among possible IFE technologyoptions, and to improve ourunderstanding of IFE target andchamber physics.

One predictive capability that cancalculate and interpret materialresponses to neutron damage is atechnique called molecular dynamicsimulation (MDS).10 MDS calculatesresponses at the atomic level byquantifying how a three-dimensionalarray of atoms responds to knock-onatoms that impinge on the matrixfrom a range of angles and with arange of energies as a result of anincident neutron flux. Potentially,MDS capabilities may includepredicting, for a material, the numberof vacancies and interstitials that willresult from a neutron irradiationpulse, as well as the cluster fractionof defects, atomic mixing and solute precipitation, and phasetransformations. Figure 5 shows howsamples of materials exposed to thetarget neutron emission in a NIF shotcan provide data that confirm theMDS model calculations.

E&TR December 1994 Inertial Fusion Energy

37

Heated fusedsilica final optic Reactor

chamber

First wall

Spatial filter

PulseinjectionPolarizer

Diodes

Output pulse

Gas-cooledharmonic

conversion

Gas-cooled gain medium

Gas-cooled Pockels cell

Neutronabsorber

Dichroicmirror

Figure 4. The diode-pumped, solid-state laser driver for IFE is similar in design to thatbeing developed for the NIF. Although the NIF architecture will not include the diode pumparrays shown here, it will serve as an experience and technology base for the IFE driver. Thisfigure shows a DPSSL IFE laser designed like the NIF in that it uses a multipass laseramplifier in which the laser beam is amplified by passing back and forth between the cavitymirrors four times before a Pockels cell optical switch sends the amplified beam out to thefinal optics and the target. However, the DPSSL uses light from arrays of efficient diodelasers to pump the amplifier from the ends rather than using light generated from flashlamps on the sides of the amplifier as in the present NIF design.

100

50

0

–50

–100

Sample array

Shield

Capsule1015 n/shot

–100

2–5 cm

–50 0 50 100

Leng

th, Å

Length, Å

t = 4.61 ps

Cu 25 keV PKA (a)

Figure 5. A molecular-dynamic simulation experiment on the NIF. Samples of 2- to 5-cm-widthmaterial placed within 20 cm of a NIF yield capsule (at left) will receive a significant exposure to14-MeV neutrons (1015 neutrons per shot per square centimeter of sample area). The tantalumshield will stop most x rays. Electron microscope images of the damage sites will be comparedto MDS code predictions as shown at right. The figure shows a typical damage site in a coppersample due to primary knock-on copper atoms (25 keV primary knock-on atoms [PKA]) arisingfrom collisions of fast neutrons with copper atoms in the sample.

Inertial Fusion Energy E&TR December 1994

38

An inertial confinement fusion (ICF) capsule ortarget is a small, millimeter-sized, spherical capsulewhose hollow interior contains a thin annular layer ofliquid or solid DT fuel (a mixture of deuterium andtritium isotopes of hydrogen). The outer surface of thecapsule is rapidly heated and ablated either directly byintense laser or ion particle beams (drivers), calleddirect drive (a below), or indirectly by absorption ofsoft x-rays in the outer capsule surface. These soft x-rays are generated by driver beams hitting a nearbymetal surface, a process called indirect drive (b below).

The rocket effect caused by the ablated outer capsulematerial creates an inward pressure causing the capsuleto implode in about 4 nanoseconds (a nanosecond isone billionth of a second). The implosion heats the DTfuel in the core of the capsule to a temperature of about 50 million degrees Celsius, sufficient to cause theinnermost core of the DT fuel to undergo fusion. Thefusion reaction products deposit energy in the capsule,further increasing the fuel temperature and the fusionreaction rate. Core fuel ignition occurs when the self-heating of the core DT fuel due to the fusion reactionproduct deposition becomes faster than the heating dueto compression. The ignition of the core will thenpropagate the fusion burn into the compressed fuellayer around the core. This will result in the release ofmuch more fusion energy than the energy required tocompress and implode the core.

An inertial fusion power plant would typically fire acontinuous series of targets at a pulse rate of 6 Hz. Theseries of fusion energy releases thus created in the formof fast reaction products (helium alpha particles andneutrons) would be absorbed as heat in the low-activation coolants (fusion chamber) that surround thetargets. Once heated, the coolants would be transferredto heat exchangers for turbine generators that produceelectricity. The inertial fusion power plant exampleshown below uses jets of molten salt, called Flibe,surrounding the targets inserted into the fusionchamber. The molten salt jets absorb the fusion energypulses from each target while flowing from the top tothe bottom. The molten salt is collected from thebottom of the chamber and circulated to steamgenerators (not shown) to produce steam for standardturbine generators. This particular power plant exampleuses a ring-shaped ion beam accelerator as a driver, butthere are also laser driver possibilities.

The minimum driver energy required to implode thecapsule fast enough for ignition to occur is typicallyabout a megajoule, the caloric equivalent of a largedoughnut. Since this driver energy must be delivered in a few nanoseconds, however, a power of severalhundred terawatts (1 terawatt = 1 million megawatts)will be needed. For reference, the entire electricalgenerating capacity of the United States is about one-half terawatt.

Producing Inertial Fusion Energy

(a) Direct-drive targets are directly heated and implodedby intense driver beams.

Ionparticle

orlaser

beams

Ignition fusion reaction products (alpha particles)heat the compressed fuel

core to fusion temperature causing implosion

Fuel capsule

DT fuel layer

Hea

vy-io

nbe

am

High-Z radiation case

Indirect-drivelaser target

Indirect-driveheavy-ion target

Vacuum Fuel capsuleSoft x ray

Lase

rbe

ams

High-Z radiator

(b) Indirect-drive target fuel capsules are imploded by soft x rays generated by intense lasers or ion beams at the ends of a high-Z radiation case (“hohlraum”).

(a) Direct-drive targets are directly heated and imploded (b) Indirect-drive target fuel capsules are imploded by soft x raysby intense driver beams. generated by intense lasers or ion beams at the ends of a high-Z

radiation case (“hohlraum”).

The rapid thermal motion of the deuterium andtritium nuclei will cause a significant fraction of them tocollide and fuse into helium ash before the compressedfuel mass from the implosion has had time to reboundand expand. The reaction products will fly away withseveral hundred times more kinetic energy than thethermal energy of the deuterium–tritium ion pair beforefusion occurred. If some inefficiency in coupling thedriver laser or ion-beam energy into compressing andheating the capsule is taken into account, the ratio offusion energy produced by the target to the driver beamenergy input to the target—called the target gain—canrange from 50 to 100 in a typical power plant. Once thisfusion heat is converted into electricity, the averageamount of electricity needed to energize the driverwould be 5 to 10% of the total plant output.

Inertial fusion targets are of two basic types: directdrive and indirect drive, both of which will be tested bythe NIF to determine the best target for inertial fusionenergy. A direct-drive target consists of a sphericalcapsule driven directly by laser or ion beams. So that thecapsule will implode symmetrically and achieve highgain, it must be illuminated uniformly, from all directions,

by many driver beams. In indirect-drive targets, the fuelcapsule is placed inside a thin-walled cylindrical container(hohlraum) made from a high-atomic-number material,such as lead. Here a smaller number of driver beams (witha total energy similar to that required for direct drive) aredirected at the two ends of the hohlraum cylinder, wherethe driver beam energy is converted to soft x rays, which,in turn, lead to the compression of the fuel capsule. Thehohlraum spreads the soft x rays uniformly around thecapsule to achieve a symmetric implosion.

For its driver, the NIF will use a solid-state glasslaser to deposit the externally directed energy. Thislaser will deliver 1.8 MJ of laser light energy (in pulsesspaced several hours apart) to test the minimum energyrequired for target ignition and the scaling of target gainso that any type of target optimized for future powerplants can be designed with confidence. DOE–EnergyResearch is developing heavy-ion beam accelerators asits leading candidate drivers for future IFE powerplants, while DOE–Defense Programs is developingother driver technologies for ICF research, includingadvanced solid-state lasers, that could lead to alternativeIFE drivers as well.

E&TR December 1994 Inertial Fusion Energy

39

Recirculating heavy-ion induction accelerator Bypass pumps

Rotatingshutter

OscillatingFlibe jets

Developing Fusion PowerTechnology

The NIF can also help developfusion power technology (FPT),which includes the technologiesneeded to remove the heat of fusionand deliver it to the power plant. Theprimary functions of such componentsin IFE power plants are to convertenergy, to produce and processtritium, and to provide radiationshielding. The dominant issues forFPT in IFE power plants concerncomponent performance (both nuclearand material) so as to achieveeconomic competitiveness and torealize safety and environmentaladvantages. In this regard, NIF willprovide valuable FPT informationgained from the demonstratedperformance and operation of the NIF facility itself, as well as fromexperiments designed specifically

to test FPT issues. NIF’s relevance to FPT has to do with both itsprototypical size and configurationand its prototypical radiation-field(neutrons, x rays, and debris) spectraand intensity per shot. The mostimportant limitation of NIF for FPTexperiments is its low repetition rate(low neutron fluence), and its mostimportant contributions to FPTdevelopment for IFE are related to:• Fusion ignition.• Design, construction, and operationof the NIF (integration of manyprototypical IFE subsystems).• Viability of first-wall protectionschemes.• Dose-rate effects on radiationdamage in materials.• Data on tritium burnup fractions inthe target, tritium inventory and flow-rate parameters, and the achievabletritium breeding rate in samples.

• Neutronics data on radioactivity,nuclear heating, and radiationshielding.

The NIF will also be able todemonstrate the safe andenvironmentally benign operationthat is important for IFE, includinghandling tritium safely andmaintaining minimum inventories of low-activation materials. It isdesigned to keep radioactiveinventories low enough to qualify asa low-hazard, non-nuclear facilityaccording to current DOE and federalguidelines, thus setting the pattern forfuture IFE plants. Similar non-nucleardesign goals will also be met for IFEpower plants if the design selected for the fusion chamber is carefullyfollowed and the low activationmaterials for it are used. The NIF will also demonstrate proper qualityassurance in minimizing both

Inertial Fusion Energy E&TR December 1994

40

Figure 6. The timeline for IFE development includes ICF ignition and gain, IFE technologies, and the IFE power plant.

Defense Programs (ICF) National ignition Facility (NIF)

Energy Research (IFE) Heavy-ion driver technology (ILSE Facility at LBL)

Target fabrication andfusion chambertechnologies

Power plant demonstration Engineering Test Facility (ETF) and DEMO

Design

Tests ILSE experiments

Technology development and tests

Stage 1 Stage 2 Tests DEMOTechnologyintegration

Construct Target physicsexperiments

ETFPowerplant

Target andfusion

chamber

1995 2000 2005 2010 2015 2020 2025

Energyapplicationsdecision

Driver feasibilitydemonstration

Ignition and gaindemonstration

occupational and public exposures toradiation.

An Integrated IFE DevelopmentPlan

To capitalize on the success offusion ignition in the NIF, which isexpected to occur around the year2005, an Engineering Test Facility(ETF) will be needed. This facilitywill test the fusion power planttechnologies called for in the 1990Fusion Policy Advisory Committee7

the 1992 National Energy Policy Actof 19922 plans. A decision to moveforward with the ETF will alsodepend on the timely demonstrationof a feasible, efficient, high-repetitionIFE driver.

Figure 6 shows existing andproposed facilities in an integratedplan for IFE development. In additionto the NIF, they include:• The Induction Linac SystemsExperiment (ILSE). Plans call forthis proposed heavy-ion acceleratortest facility to be built at theLawrence Berkeley Laboratory. Itsmission will be to demonstrate thefeasibility of a heavy-ion driver forIFE by testing critical, high-current,ion-beam-induction accelerator andfocusing physics with properlyscaled-down ion energy and mass.ILSE may be built in two stages for a total construction cost of about $46 million. The ILSE experimentsshould also be completed by the year2005.• The ETF/LaboratoryMicrofusion Facility (ETF/LMF).This multiuser facility for bothdefense experiments and IFEtechnology development will be ableto produce target-fusion energyyields at full-power plant scale (200to 400 MJ) and high pulse rates (5 to

10 Hz). As indicated, it will alsodrive multiple test fusion chambersfor defense, IFE (ETF), basicscience, and materials research, usinga single driver to save costs. Its totalconstruction cost is expected to be $2 billion in today’s dollars, and itslife-cycle costs to the year 2020 areexpected to be $3 billion. Then asuccessful IFE chamber fromprevious tests will be upgraded to ahigher average fusion power level.This upgrade, which is expected toprovide a DEMO (net electric-powerdemonstration) by the year 2025, is shown as the last phase of theupgradable ETF/LMF facility.

Note in Figure 6 that the decisionto initiate the ETF/LMF facility,including selecting an ETF/LMFdriver, will be made after ignition isdemonstrated in the NIF. An ETFwith a single driver can be designedto test several types of fusionchambers at reduced power, greatlyreducing the cost of IFE developmentthrough a demonstration power plant. This parallel approach to IFE development has already been endorsed by many reviewcommittees, including the NationalAcademy of Sciences,11 the FusionPolicy Advisory Committee,7 theFusion Energy Advisory Committee,and the Inertial Confinement Fusion Advisory Committee.12

DOE–Defense Programs (using theNIF for fusion ignition and gaindemonstration) and DOE–EnergyResearch will play complementaryroles in driver development and otherIFE technologies.

Chairman Robert Conn, inreporting the recommendations of the 1993 Fusion Energy AdvisoryCommittee to then DOE EnergyResearch Director Will Happer,wrote: “We recognize the great

opportunity for fusion developmentafforded the DOE by a modestheavy-ion driver program thatleverages off the extensive targetprogram being conducted by DefensePrograms. Consequently, we urge the DOE to reexamine its manyprograms, both inside and outside ofEnergy Research, with the view toembark more realistically on aheavy-ion program. Such a programwould have the ILSE as acenterpiece, and be done incoordination with the program todemonstrate ignition and gain byDefense Programs.”8

Summary

When the NIF demonstrates fusionignition, which is central to provingthe feasibility of IFE, it will tell usmuch about IFE target optimizationand fabrication, provide importantdata on fusion-chamber phenomenaand technologies, and demonstratethe safe and environmentally benignoperation of an IFE power plant. Inaccomplishing these tasks, the NIFwill also provide the basis for futuredecisions about IFE developmentprograms and facilities such as theETF. Furthermore, it will allow theU.S. to expand its expertise in inertialfusion and supporting industrialtechnology, as well as promote U.S.leadership in energy technologies,provide clean, viable alternatives tooil and other polluting fossil fuels,and reduce energy-related emissionsof greenhouse gases.

Key Words: drivers—laser drivers, heavy-iondrivers; energy sources—fission breeder reactors,fossil fuels, inertial fusion energy, magnetic fusionenergy, solar energy; fusion chambers; fusionpower technology; International ThermonuclearExperiment; National Ignition Facility; targets—direct-drive targets, indirect-drive targets.

E&TR December 1994 Inertial Fusion Energy

41

References1. Sources, Effects, and Risks of Ionizing

Radiation, United Nations Scientific Committeeon the Effects of Atomic Radiation, 1988Report to the General Assembly, UnitedNations, ISBN-92-1-142143-8, 090000P(1988), Table 33, p. 114 and Table 72, p. 232.

2. The National Energy Policy Act of 1992, PublicLaw 102-486 (1992).

3. E. M. Campbell and D. L. Correll, “Lasers,”Energy and Technology Review, LawrenceLivermore National Laboratory, Livermore,CA, UCRL-52000-94-1/2, (1994), pp. 53–55.

4. B. G. Logan, R. W. Moir, and M. A. Hoffman,Requirements for Low Cost Electricity andHydrogen Fuel Production from Multi-UnitInertial Fusion Energy Plants with a SharedDriver and Target Factory, LawrenceLivermore National Laboratory, Livermore,CA, UCRL-JC-115787 (1994), to be publishedin Fusion Technology.

5. R. W. Moir, R. L. Bieri, X. M. Chen, T. J.Dolan, M. A. Hoffman, P. A. House, R. L.Leber, J. D. Lee, Y. T. Lee, J. C. Liu, G. R.Longhurst, W. R. Meier, P. F. Peterson, R. W.Petzoldt, V. E. Schrock, M. T. Tobin, and W.H. Williams, “HYLIFE-II: A Molten-SaltInertial Fusion Energy Power Plant Design—Final Report,” Fusion Technology 25, 5–25(1994).

6. J. H. Pitts, R. F. Bourque, W. J. Hogan, W. M.Meier, and M. T. Tobin, The Cascade InertialConfinement Fusion Reactor Concept,Lawrence Livermore National Laboratory,Livermore, CA, UCRL-LR-104546 (1990).

7. Fusion Policy Advisory Committee, Review ofthe U.S. Fusion Program, Final Report,Washington, DC (1990).

8. “Findings and Recommendations for the Heavy-Ion Fusion Program,” Report of the FusionEnergy Advisory Committee (FEAC) to DOE

Energy Research Director William Happer(April 1993).

9. C. D. Orth, S. A. Payne, and W. F. Krupke, ADiode-Pumped Solid-State Laser Driver forInertial Fusion Energy, Lawrence LivermoreNational Laboratory, Livermore, CA, UCRL-JC-116173 (1994).

10. J. Wong, T. Diaz de la Rubia, M. W. Guinan,M. Tobin, J. M. Perlado, A. S. Perez, and J.Sanz, The Threshold Energy for DefectProduction and FIC: A Molecular DynamicsStudy, Lawrence Livermore NationalLaboratory, Livermore, CA, UCRL-JC-114789(1993). Also see Procedures 6th InternationalConference on Fusion Reactor Materials,Stresa, Italy (1993).

11. National Research Council, Second Review of the Department of Energy’s InertialConfinement Fusion Program, Final Report,(National Academy Press, Washington, DC,1990).

12. Inertial Confinement Fusion AdvisoryCommittee for Defense Programs, letter toAssistant Secretary for Defense Programs (May 20, 1994).

Inertial Fusion Energy E&TR December 1994

42

For further information contact B. Grant Logan (510) 422-9816 orMichael T. Tobin (510) 423-1168.