1 (Chair), Princeton Plasma Physics Laboratory.2 University of California, Los Angeles.3 University of California, San Diego.4 General Atomics.5 Fusion Power Associates.6 MIT Plasma Science and Fusion Center.7 CH2M Hill.8 University of Washington.9 Lawrence Livermore National Laboratory.
10 Lawrence Berkeley National Laboratory.11 Idaho National Engineering and Environmental Laboratory.12 Sandia National Laboratory, New Mexico.13 University of Wisconsin.14 Princeton Plasma Physics Laboratory.15 Naval Research Laboratory.16 ORNL, and UT Joint Institute for Energy and Environment.17 Oak Ridge National Laboratory.18 To whom correspondence should be addressed. E-mail: rgoldston@
pppl.gov
A Plan for the Development of Fusion Energy
Robert Goldston,1,18 Mohamed Abdou,2 Charles Baker,3 Michael Campbell,4
Vincent Chan,4 Stephen Dean,5 Amanda Hubbard,6 Robert Iotti,7 Thomas Jarboe,8
John Lindl,9 B. Grant Logan,10 Kathryn McCarthy,11 Farrokh Najmabadi,3 Craig Olson,12
Stewart Prager,13 Ned Sauthoff,14 John Sethian,15 John Sheffield,16 and Steven Zinkle17
This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion EnergySciences Advisory Committee (FESAC) in response to a charge letter dated September 10, 2002from Dr. Ray Orbach, Director of the DOE’s Office of Science. In that letter, Dr. Orbach askedFESAC to develop a plan with the end goal of the start of operation of a demonstration powerplant in approximately 35 years. This report, submitted March 5, 2003, presents such a plan,leading to commercial application of fusion energy by mid-century. The plan is derived fromthe necessary features of a demonstration fusion power plant and from the time scale definedby President Bush. It identifies critical milestones, key decision points, needed major facilitiesand required budgets. The report also responds to a request from DOE to FESAC to describewhat new or upgraded fusion facilities will “best serve our purposes” over a time frame of thenext twenty years.
KEY WORDS: Fusion energy, fusion program plan.
“This [progress in fusion science] is an enormous change thatis enough to change the attitudes of nations toward theinvestments required to bring fusion devices into practicalapplication and power generation.”
Presidential Science Advisor John Marburger.
“By the time our young children reach middle age, fusionmay begin to deliver energy independence. . . and energyabundance. . . to all nations rich and poor. Fusion is apromise for the future we must not ignore. But let me beclear, our decision to join ITER in no way means a lesserrole for the fusion programs we undertake here at home. Itis imperative that we maintain and enhance our strongdomestic research program. . . . Critical science needs tobe done in the U.S., in parallel with ITER, to strengthen ourcompetitive position in fusion technology.”
Secretary of Energy, Spencer Abraham
“The results of ITER will advance the effort to produce clean,safe, renewable, and commercially-available fusion energy bythe middle of this century. Commercialization of fusion hasthe potential to dramatically improve America’s energy secu-rity while significantly reducing air pollution and emissionsof greenhouse gases.”
President George W. Bush
EXECUTIVE SUMMARY
This report presents a plan for the deploymentof a fusion demonstration power plant within 35 years,
62 Goldston et al.
leading to commercial application of fusion energy bymid-century. The plan is derived from the necessaryfeatures of a demonstration fusion power plant andfrom the time scale defined by President Bush. It iden-tifies critical milestones, key decision points, neededmajor facilities and required budgets.
Recent Advances and Anticipated Major Milestones
Recent advances in the science and technology offusion energy have dramatically improved the prospectfor practical fusion power. The goal of a self-sustaining,burning fusion plasma is planned to be achieved both ininertial fusion with the National Ignition Facility (Fig. 1)and in magnetic fusion with the international ITERexperiment (Fig. 2). These experiments form a basisfor this plan, and the need for their full exploitationunderlies its near-term urgency.
Fusion powers the sun and the stars, and is nowwithin reach for use on Earth. In the fusion processlighter elements are “fused” together making heavierelements and producing prodigious amounts of energy.Fusion offers very attractive features as a sustainablebroadly available energy source, including no emis-sions of greenhouse gases or other polluting gases,no risk of a severe accident, no severe consequencesof a terrorist attack and no long-lived radioactive
waste. Furthermore fusion does not require largeland use, very long-distance transmission or large-scale energy storage. Fusion energy can be used toproduce electricity and hydrogen, and for desalina-tion. The successful development of fusion energyover the next few decades will complement othernew energy sources and support the President’shydrogen initiative, making a major, timely contri-bution to reduction of the build-up of greenhousegases in the earth’s atmosphere. Currently escalat-ing international tensions underscore the importanceof fusion’s ultimate contribution to U.S. energysecurity.
The plan presented here addresses the develop-ment path both for Magnetic Fusion Energy (MFE)and for Inertial Fusion Energy (IFE). In MFE, mag-netic fields produced by coils carrying electric cur-rents confine a plasma (a superhot gas) that producesfusion energy continuously. In IFE, continuouspower is produced by using repetitive pulses of energyto compress and heat small dense plasmas very rap-idly, in order to produce fusion energy during thebrief period that the plasmas are held in place by theirown inertia.
The last decade has seen dramatic advances in thescience and technology of both magnetic and inertialfusion energy, made possible by advances in detailed
Fig. 1. The National Ignition Facility, presently under construction, is designed to achieve ignition and moderate gain in inertial fusion.
A Plan for the Development of Fusion Energy 63
Fig. 2. The ITER facility, presently in international negotiation, isdesigned to integrate magnetic fusion burning plasma physics withfusion technologies, producing hundreds of megawatts of fusionpower for long pulses.
plasma measurement technique and in advancedcomputing.
● Within MFE, the underlying turbulence thatcauses loss of heat from high-temperature mag-netically confined ions has been identified, andin some cases quenched, in good agreementwith computational models. Theoretical andcomputational models of the global stabilityof magnetically confined plasmas have beenvalidated, and new techniques to stabilize highpressure plasmas, desirable for economic powerproduction, have been demonstrated. Techniqueshave been developed to quench magnetic turbu-lence in self-organized systems with attractivepower plant properties, and new configurationshave been shown to sustain very high plasmapressure relative to magnetic pressure. Newplasma configurations have been designed capa-ble of operating at high plasma pressure withpassive stability.
● Within IFE, multi-dimensional computationalmodeling of both direct and x-ray driven tar-gets has successfully predicted experimentalresults with both laser and z-pinch drivers,and has been used to design high-gain IFEtargets. Significant advances have been madein the repetitively pulsed “drivers” required
for IFE. Large increases have been made inthe production of x-rays with z-pinches, andmegajoules of z-pinch x-rays have been usedto drive high-quality capsule implosions.Cryogenic target implosions energy-scaled tosimulate NIF experiments have begun. Exper-iments using a petawatt laser have demon-strated efficient heating of pre-compressedcores, a step towards higher gain inertialfusion energy.
● In the fusion technology program, materialsoriginally developed for the fission breederprogram have been reformulated for bothenhanced performance and greatly reducedactivation. Multi-scale modeling of neutroneffects now captures the essential physics ofneutron interactions in materials, allowingbetter understanding of the full range fromnanophysics to large scale material properties.New designs for fusion blankets employing con-figurations featuring innovative combinations ofmaterials open the way to higher temperaturecoolants and so higher efficiency power plantoperation. Important advances have been madein both solid and liquid chamber wall technolo-gies for IFE and MFE, as well as in IFE finalfocusing systems and target fabrication.
Building on these accomplishments, exciting re-sults are anticipated from major new fusion facilitiesin the decade 2010–2020:
● Early in the decade powerful beams of light willflash through 192 laser channels in the NIF,converging on a diminutive pellet of fusionfuel. The core of the fuel will be compressed topressures comparable to and heated to tempera-tures higher than the center of the sun. Anintense brief fusion flame will be ignited andwill propagate into the bulk of the fusion fuel,releasing a burst of fusion energy substantiallygreater than the applied laser energy.
● In the middle of the decade an internationalcoalition will bring on line a fusion system,ITER, capable of producing power plant lev-els of fusion energy. Superconducting coilswill produce magnetic fields 100,000 timesstronger than the Earth’s, capable of confiningthe superhot plasma in steady fusion condi-tions. A fusion power level of 500 millionWatts will be produced in a steady flow up toan hour long. Should ITER not move forward,
64 Goldston et al.
the plan calls for construction of the domesticburning plasma experiment, FIRE.
● By the end of the decade an international teamwill obtain the first results on high-performancematerials exposed to a fusion-relevant neu-tron environment in the International FusionMaterials Irradiation Facility (IFMIF). Theseaccelerated exposure data will be used to vali-date experimentally emerging materials sciencemodels and to qualify specific materials forfusion application.
These accomplishments will form a strong basisfor the development of practical, economically com-petitive fusion energy. A strong parallel effort in thescience and technology of fusion energy is required toguide research on these experimental facilities andto take advantage of their outcome.
The Plan
In response to a charge from the Director of theDOE Office of Science, Dr. Raymond Orbach, aFusion Energy Sciences Advisory Committee Panelwas established to provide a plan for the developmentof fusion energy and specifically for the deploymentof a fusion demonstration power plant (Demo) capableof producing net electricity within approximately35 years. The demonstration power plant must openthe way for a first generation of attractive commercialfusion power systems to be brought on line by mid-century. Consistent with the Charge to the Panel, thisFinal Report builds on recent work of FESAC and the2002 Fusion Snowmass Summer Study and providessuch a plan. Key features of the plan are:
● It works from a set of principles derived fromthe end goal of a Demo operating within35 years that will lead directly to commercialfusion energy.
● It presents a development path for fusion energythat identifies development periods, key deci-sion points, required facilities and estimatedcosts.
Key conclusions of the plan are:
● To develop fusion energy on this timescale, it isimperative to have a strong balanced programthat develops fusion science and technology inparallel, for both IFE and MFE.
● Additional funding, starting now, is required
to participate in the construction and utiliza-tion of ITER, or, if ITER does not advance toconstruction, to complete the design of andto construct the domestic FIRE experiment,
● to exploit NNSA’s investment in inertialfusion,
● to participate in the design of IFMIF,● to establish a research and development
program that will lead to a demonstrationpower plant within 35 years.
A set of overlapping scientific and technologicalchallenges was found to determine the developmentpath for both magnetic and inertial fusion energy.These challenges define a sequenced set of decisionsfor the construction of major facilities. As shown inFigure 3, these challenges are:
● Configuration Optimization, in which a rangeof potentially attractive configurations istested and optimized for both MFE and IFE;
● Burning Plasma, in which a plasma is broughtsimultaneously to conditions of high tempera-ture, density and confinement, so that thefusion process can be self-sustaining;
● Materials Testing, in which materials arequalified for use in the energetic neutronenvironment associated with fusion energy;
● Component Testing, in which near full-scalefusion power technologies such as chambercomponents are qualified in a realistic fusionenvironment;
● Demonstration, in which fusion is demon-strated to be an environmentally and eco-nomically attractive energy source.
● Scientific and Technology Development Pro-grams in theory and simulation, basic plasmascience, concept exploration and proof ofprinciple experimentation, materials develop-ment and plasma, fusion chamber and powertechnologies form the foundation for thisresearch.
This fusion development plan is guided by a seriesof specific, defined decisions. It also provides pathwaysfor “breakthrough” developments that significantly im-prove the end product. Finally it assumes that difficultchoices will be made on a timely basis, taking intoaccount the key parameters of quality, performanceand relevance to the plan. Such timely decisions arerequired for this plan to succeed.
The overlapping scientific and technological chal-lenges will be met during four development periods,
A Plan for the Development of Fusion Energy 65
Fig. 3. Overlapping scientific and technological challenges define the sequence of major facilities needed in the fusion development path.Programs in theory and simulation, basic plasma science, concept exploration and proof of principle experimentation, materials developmentand plasma, fusion chamber, and power technologies form the foundation for research on the major facilities.
whose decision-driven goals and approximate timeperiods are:
● Present–2008: Acquire Science and Tech-nology Data to Support MFE and IFE Burn-ing Plasma Experiments and to Decide onKey New MFE and IFE Domestic Facilities;Design the International Fusion MaterialsIrradiation Facility
● 2009–2019: Study Burning Plasmas, Opti-mize MFE and IFE Fusion Configurations,Test Materials and Develop Key Technolo-gies in order to Select between MFE andIFE for Demo
● 2020–2029: Qualify Materials and Technol-ogy in Fusion Environment
● 2030–2037: Construct Demo
Each of these development periods is characterizedby specific scientific and technological objectives, aswell as by key decisions required for the transition tothe activities of the next period, as shown in Table 1 andFigure 4. The Table and Figure indicate the decisionsassumed in the scenario used to define the cost of thedevelopment path (the cost-basis scenario), but it shouldbe recognized that these decisions also provide oppor-tunities for “off-ramps” for technologies, and thus thedecision could be taken at these points not to proceed tothe next stage of development of a given technology.
It is the judgment of the Panel that the overalldecisions to make the major transitions (i.e., inapproximately 2008, 2019 and 2029) should be guided
by an outside group, such as the National ResearchCouncil or the President’s Council of Advisors onScience and Technology, while the specific decisionson particular facilities need to be made through peerreview by technical experts. The panels of technicalexperts should increasingly include participants fromthe U.S. energy industry with a clear focus on keypractical issues of economics and licensing.
The total cost to the U.S. of the plan to bring on linea first-generation Demonstration fusion power plant thatwill lead to commercial application of fusion energy bymid-century is approximately $24B in FY2002 dollars.The plan assumes an ongoing level of highly coordinatedinternational programmatic activities, and internationalparticipation in ITER and IFMIF, but assumes U.S.-onlysupport for the MFE Component Test Facility (CTF) orthe IFE Engineering Test Facility (ETF), and for Demo.It assumes continuing strong NNSA support of InertialConfinement Fusion.
To achieve the goals of this plan, the program mustbe directed by strong management. Given constrainedbudgets, the wide variety of options and the linkagesof one issue to another, increasingly sophisticated man-agement of the program will be required.
Additional funding that would be needed in thesecond half of the development plan to maintain astrong core scientific capability, and to provide con-tinued innovation aimed at improved configurationsbeyond Demo, is not included. The panel believes thatthese are necessary elements of an overall fusion R&Dprogram. The panel has not attempted to analyze these
66 Goldston et al.
Table 1. Goals, Specific Objectives, and Key Decisions
● Present–2009: Acquire Science and Technology Data to Support MFE and IFE Burning Plasma Experiments and to Decide on KeyNew MFE and IFE Domestic Facilities; Design the International Fusion Materials Irradiation Facility
Specific Objectives:● Begin construction of ITER, and develop science and technology to support and utilize this facility. If ITER does not
move forward to construction, then complete the design and begin construction of the domestic FIRE experiment.● Complete NIF and ZR (Z Refurbishment) (funded by NNSA).● Study attractive MFE configurations and advanced operation regimes in preparation for new MFE Performance Extension (PE)
facilities required to advance configurations to Demo.● Develop configuration options for MFE Component Test Facility (CTF).● Participate in design of International Fusion Materials Irradiation Facility (IFMIF)● Test fusion technologies in non-fusion facilities in preparation for early testing in ITER, including first blanket modules, and to
support configuration optimization.● Develop critical science and technologies that can meet IFE requirements for efficiency, rep-rate and durability, including drivers,
final power feed to target, target fabrication, target injection and tracking, chambers and target design/target physics.● Explore fast ignition for IFE (funded largely by NNSA).● Conduct energy-scaled direct-drive cryogenic implosions and high intensity planar experiments (funded by NNSA).● Conduct z-pinch indirect-drive target implosions (funded by NNSA).● Provide up-to-date conceptual designs for MFE and IFE power plants.● Validate key theoretical and computational models of plasma behavior.
2008 Decisions: Assuming successful accomplishment of goals, the cost-basis scenario assumes that by this time decisions aretaken to construct:
● International Fusion Materials Irradiation Facility● First New MFE Performance Extension Facility● First IFE Integrated Research Experiment Facility
● 2009–2019: Study Burning Plasmas, Optimize MFE and IFE Fusion Configurations, Test Materials and Develop Key Technologies inorder to Select between MFE and IFE for Demo
Specific Objectives:● Demonstrate burning plasma performance in NIF and ITER (or FIRE).● Obtain plasma and fusion technology data for MFE CTF design, including initial data from ITER test blanket modules.● Obtain sufficient yield and physics data for IFE Engineering Test Facility (ETF) decision.● Optimize MFE and IFE configurations for CRG/ETF and Demo.● Demonstrate efficient long-life operation of IFE and MFE systems, including liquid walls.● Demonstrate power plant technologies, some for qualification in CTF/ETF.● Begin operation of IFMIF and produce initial materials data for CTF/ETF and Demo.● Validate integrated predictive computational models of MFE and IFE systems.
Intermediate Decisions: Assuming successful accomplishment of goals, the cost-basis scenario assumes a decision to construct twoadditional configuration optimization facilities, which may be either MFE or IFE.
● MFE Performance Extension Facility● IFE Integrated Research Experiment
2019 Decision: Assuming successful accomplishment of goals, the cost-basis scenario assumes a selection between MFE and IFEfor the first generation of attractive fusion systems.
● Construction of MFE Component Test Facility (CTF)or
● Construction of IFE Engineering Test Facility (ETF)
● 2020–2029 Qualify Materials and Technologies in Fusion EnvironmentSpecific Objectives:
● Operate ITER with steady-state burning plasmas providing both physics and technology data.● Qualify materials on IFMIF with interactive component testing in CTF or ETF, for implementation in Demo.● Construct CTF or ETF; develop and qualify fusion technologies for Demo.● On the basis of ITER and CTF/ETF develop licensing procedures for Demo.● Use integrated computational models to optimize Demo design.
2029 Decision:● Construction of U.S. Demonstration Fusion Power Plant
● 2030–2035: Construct DemoSpecific Objective: Operation of an attractive demonstration fusion power plant.
A Plan for the Development of Fusion Energy 67
Fig. 4. Fusion Development Path including programs, major facilities, and key decision points.
costs in a systematic manner but estimates they wouldsum to a few billion dollars.
Why Now?
There have been dramatic scientific and technolog-ical advances in fusion in the last decade, and majoraccomplishments are expected in NIF and ITER in thenext. A ramp-up in domestic fusion research and devel-opment is required now to impact the direction of theseupcoming burning plasma research experiments, in orderto guide them in addressing critical issues in the devel-opment of practical fusion energy. Rapid progress isalso needed in configuration optimization experimentsfor both MFE and IFE, because critical decisions mustbe made on key future investments by 2008 in order tomaintain the needed schedule. The design of IFMIF andthe domestic fusion technology program must moveforward as well, if materials and technologies are tobe available for testing in ITER and in CTF/ETF andfor application in Demo. A program funded at presentlevels cannot accomplish these essential schedule-drivensteps, which are needed to provide fusion energy on thetimescale envisioned by President Bush.
The U.S. fusion energy sciences program is stillsuffering from the severe budget cuts of the mid-1990s and the loss of a clear national commitment todevelop fusion energy. The result is that despite theexciting scientific advances of the last decade it isbecoming difficult to retain technical expertise in keyareas. The President’s fusion initiative has the poten-tial to reverse this trend, and indeed to motivate a newcadre of young people not only to enter fusion energyresearch, but also to participate in the physical sci-ences broadly. With the addition of the funding rec-ommended here, an exciting, focused and realisticprogram can be implemented to make fusion energyavailable on a practical time scale. On the contrary,delay in starting this plan will cause the loss of keyneeded expertise and result in disproportionate delayin reaching the goal.
The required funding over the next five years inconstant $FY2002, including the High Average PowerLaser program and the z-pinch IFE studies currentlyfunded within the NNSA, is:
In 2011–2018 the budget requirement reaches apeak value of $800–900M/year. This is approximatelyequal to the buying power of the fusion program in thelate 1970’s and early 1980’s.
Establishing a program now to develop fusionenergy on a practical time scale will maximize thecapitalization on the burning plasma investments inNIF and ITER, and ultimately will position the U.S. toexport rather than import fusion energy systems.Failure to do so will relegate the U.S. to a second orthird tier role in the development of fusion energy.Europe and Japan, which have much stronger fusionenergy development programs than the U.S., and whichare vying to host ITER, will be much better positionedto market fusion energy systems than the U.S.–unlessaggressive action is taken now.
A PLAN FOR THE DEVELOPMENT OF FUSION ENERGY
A. Introduction
This report presents a plan for the deployment ofa fusion demonstration power plant within 35 years,leading to commercial application of fusion energy bymid-century. The plan is derived from the necessaryfeatures of a demonstration fusion power plant andfrom the time scale defined by President Bush. It iden-tifies critical milestones, key decision points, neededmajor facilities and required budgets.
Recent Advances and Anticipated Major Milestones
Recent advances in the science and technology offusion energy have dramatically improved the prospectfor practical fusion power. The goal of a self-sustaining,burning fusion plasma is planned to be achieved both ininertial fusion with the National Ignition Facility and inmagnetic fusion with the international ITER experi-ment. These experiments form a basis for this plan, andthe need for their full exploitation underlies its near-term urgency.
The plan presented here addresses the develop-ment path both for Magnetic Fusion Energy (MFE)and for Inertial Fusion Energy (IFE). In MFE, mag-netic fields produced by coils carrying electriccurrents confine a plasma (a superhot gas) that pro-duces fusion energy continuously. In IFE, continuouspower is produced by using repetitive pulses ofenergy to compress and heat small dense plasmasvery rapidly, in order to produce fusion energy during
the brief period that the plasmas are held in place bytheir own inertia.
The last decade has seen dramatic advances inthe science and technology of both magnetic andinertial fusion energy, made possible by advancesin detailed plasma measurement technique and inadvanced computing.
● Within MFE, the underlying turbulence thatcauses loss of heat from high-temperature mag-netically confined ions has been identified, andin some cases quenched, in good agreement withcomputational models. Theoretical and compu-tational models of the global stability of mag-netically confined plasmas have been validated,and new techniques to stabilize high pressureplasmas, desirable for economic power produc-tion, have been demonstrated. Techniques havebeen developed to quench magnetic turbulencein self-organized systems with attractive powerplant properties, and new configurations havebeen shown to sustain very high plasma pressurerelative to magnetic pressure. New plasma con-figurations have been designed capable of oper-ating at high plasma pressure with passivestability.
● Within IFE, multi-dimensional computationalmodeling of both direct and x-ray driven tar-gets has successfully predicted experimentalresults with both laser and z-pinch drivers,and has been used to design high-gain IFEtargets. Significant advances have been madein the repetitively pulsed “drivers” required forIFE. Large increases have been made in theproduction of x-rays with z-pinches, and mega-joules of z-pinch x-rays have been used todrive high-quality capsule implosions. Cryogenictarget implosions energy-scaled to simulate NIFexperiments have begun. Experiments usinga petawatt laser have demonstrated efficientheating of pre-compressed cores, a step towardshigher gain inertial fusion energy.
● In the fusion technology program, materialsoriginally developed for the fission breeder pro-gram have been reformulated for both enhancedperformance and greatly reduced activation.Multi-scale modeling of neutron effects nowcaptures the essential physics of neutron inter-actions in materials, allowing better under-standing of the full range from nanophysicsto large scale material properties. New designsfor fusion blankets employing configurations
A Plan for the Development of Fusion Energy 69
featuring innovative combinations of materialsopen the way to higher temperature coolantsand so higher efficiency power plant operation.Important advances have been made in bothsolid and liquid chamber wall technologiesfor IFE and MFE, as well as in IFE final focus-ing systems and target fabrication.
Building on these accomplishments, exciting re-sults are anticipated from major new fusion facilitiesin the decade 2010–2020:
● Early in the decade powerful beams of light willflash through 192 laser channels in the NIF,converging on a diminutive pellet of fusionfuel. The core of the fuel will be compressed topressures comparable to and heated to tempera-tures higher than the center of the sun. Anintense brief fusion flame will be ignited andwill propagate into the bulk of the fusion fuel,releasing a burst of fusion energy substantiallygreater than the applied laser energy.
● In the middle of the decade an internationalcoalition will bring on line a fusion system,ITER, capable of producing power plant lev-els of fusion energy. Superconducting coilswill produce magnetic fields 100,000 timesstronger than the Earth’s, capable of confiningthe superhot plasma in steady fusion condi-tions. A fusion power level of 500 millionWatts will be produced in a steady flow up toan hour long. Should ITER not move forward,the plan calls for construction of the domesticburning plasma experiment, FIRE.
● By the end of the decade an international teamwill obtain the first results on high-perform-ance materials exposed to a fusion-relevantneutron environment in the InternationalFusion Materials Irradiation Facility (IFMIF).These accelerated exposure data will be usedto validate experimentally emerging materialsscience models and to qualify specific materi-als for fusion application.
These accomplishments will form a strong basisfor the development of practical, economically com-petitive fusion energy. A strong parallel effort in thescience and technology of fusion energy is required toguide research on these experimental facilities and totake advantage of their outcome.
The plan presented here prepares the United Statesto take advantage of these scientific developments, withthe goal of bringing practical fusion power on line
within 35 years, leading to commercial exploitation offusion power by the middle of the century.
Forty-two years ago, when President Kennedycommitted the United States to put a man on themoon he inspired a generation of young people to pur-sue careers in science and technology. He drove thenation to develop important new technologies. And heopened up the path not only for human spaceflight, butalso for practical, commercial applications that havebenefited our nation and the world.
The plan presented here envisions a science-basedsolution for the nation’s and the world’s need for aplentiful and environmentally benign new energysource. It will inspire new interest in the physical sci-ences and result in the accelerated development of newtechnologies. Ultimately this plan will provide the na-tion and the world with a crucially needed new cleancommercial energy source, available to all nations formillions of years.
President Kennedy promised a man on the moon inless than a decade, and the nation committed resourcesof $125B, as measured in today’s dollars, to achieve thatgoal. This plan for the development of fusion energylasts for approximately 35 years, takes advantage ofstrong international cooperation, and requires much lesstotal U.S. resources, approximately $24B. The purposeis to provide the world with the capability to harnessfusion energy for practical commercial application.
The world will change dramatically, and unpre-dictably, over the next few decades. The plan presentedhere provides a clearly defined development path forpractical fusion energy. This plan takes advantage ofthe most developed approaches to fusion energy, whileanticipating and encouraging new insights and devel-opments that can result in improvements in the attrac-tiveness of the ultimate product.
It is a major challenge for political systems to thinkin terms of decades, but human families easily comprisethree or even four generations, and still look forward tothe future beyond. Our children and our grandchildrenwill thank us if we invest in their lives, and succeed inproviding them with a new technology that will maketheir world a much better, and a much safer place.
This Final Report responds to the Charge to FESACto provide “a plan with the end goal of the start of oper-ation of a demonstration power plant in approximately35 years.” Section 2 outlines the potential of Fusion asan attractive long-term energy source. Section 3 presentsa set of principles of the plan established by the Panelfor the fusion energy development path. Section 4overviews the elements of the plan (described in moredetail in Appendix B). Section 5 presents a Cost-Basis
70 Goldston et al.
Scenario for the development of fusion energy, includ-ing high-level goals, specific objectives and key deci-sions. Section 6 presents the Panel’s overall conclusionsin response to the Charge.
Appendix A presents an overview of the scientificand technological challenges for the development offusion energy, as previously defined by FESAC.Appendix B provides details on the Programs andMajor Facilities within the Plan. Appendix C repro-duces the primary Charge to FESAC. Appendix Dreproduces the FESAC response letter to DOE, trans-mitting this report. Appendix E presents the processesused by the Panel in developing the present report.Appendix F is a glossary. Appendix G reproduces asecond Charge submitted to FESAC, asking for thedefinition of major new facilities to be operated withinthe next twenty years. Appendix H is the specificresponse to the second Charge.
B. Fusion as an Attractive Long-term Energy Source
Fusion powers the sun and the stars. Lighter ele-ments are “fused” together making heavier elementsand prodigious amounts of energy. Fusion offers veryattractive features as an energy source. The basic fuelsfor the first generation of fusion systems are mostlikely to be deuterium, a naturally occurring heavyform of hydrogen, and lithium, from which tritium, anartificial heavy form of hydrogen, is derived for thefusion reaction. These fuels are abundantly availableto all nations for millions of years. There are no chem-ical pollutants or carbon dioxide emissions from thefusion process or from its fuel production. Radioactivebyproducts from fusion, determined by the materialchoices for the power plant, are relatively short-lived,with the promise of requiring only near-surface burial.There is no risk of a criticality or melt-down accidentbecause only a small amount of fusion fuel is presentin a fusion system at any time. As a result no publicevacuation plan is required in the vicinity of a fusionpower plant. The consequences of a terrorist attack arenot anticipated to be severe. In addition, althoughneutrons are produced from fusion, the risk of nuclearproliferation is greatly reduced relative to fissionsystems because no fissionable or fertile materialssuch as uranium, plutonium or thorium are present ina fusion system, and surreptitious inclusion of evensmall amounts of such elements can easily be detected.
Fusion offers the promise of a steady non-carbon-emitting power source that can be located close to
population centers, and is not subject to daily or seasonalweather variations. Large land-use, massive energy stor-age or very long distance transmission are not requiredfor fusion systems. As population centers grow, accord-ing to projections for the U.S. and abroad, such steady,concentrated power sources will be important elementsin the world’s energy mix. Fusion systems will supplybase load electricity, and could cost-effectively power afuture energy supply chain for transportation based onhydrogen and fuel cells, by producing hydrogen duringoff-peak hours or in dedicated facilities. Energy from thefusion process could also be used for desalination. Thusfusion has the potential to satisfy a substantial fractionof the world’s energy needs in an environmentally at-tractive manner for a long time to come.
Analyses of the build-up of atmospheric carbondioxide indicate that the time scale for atmospheric sta-bilization of carbon dioxide at realistically achievablelevels (550–750 ppm) is in the range of 100 to 200 years.As a result, the greatest need for non-carbon-emittingenergy sources will come in the latter half of the 21st
century and beyond. In order to stabilize carbon dioxideconcentrations, the world’s energy economy must bedramatically transformed beginning in this century, andmust reach a radically different state in the next. In addi-tion, escalating international tensions underscore the im-portance of long-term national energy security. Given thetime scale for the introduction of new energy technolo-gies, a strong program for the development of attractivenew energy sources such as fusion is required now.
C. Principles of the Plan
Against the background described above, thePanel has established a set of principles for a plan todevelop fusion energy.
1. The goal of the plan is operation of a U.S.demonstration power plant (Demo), whichwill enable the commercialization of fusionenergy. The target date is about 35 years.Early in its operation the Demo will show netelectric power production, and ultimately itwill demonstrate the commercial practicalityof fusion power. It is anticipated that severalsuch fusion demonstration devices will bebuilt around the world. In order for a futureU.S. fusion industry to be competitive, theU.S. Demo must:
a. be safe and environmentally attractive,b. extrapolate to competitive cost for elec-
tricity in the U.S. market, as well as for
A Plan for the Development of Fusion Energy 71
other applications of fusion power suchas hydrogen production,
c. use the same physics and technology as thefirst generation of competitive commercialpower plants to follow, and
d. ultimately achieve availability of �50%,and extrapolate to commercially practicallevels.
2. The plan recognizes that difficult scientificand technological questions remain for fusiondevelopment. A diversified research portfolio isrequired for both the science and technology offusion, because this gives a robust path to thesuccessful development of an economicallycompetitive and environmentally attractive en-ergy source. In particular both Magnetic FusionEnergy (MFE) and Inertial Fusion Energy (IFE)portfolios are pursued because they presentmajor opportunities for moving forward withfusion energy and while they share a commongoal they face, in some areas, significantlydifferent scientific and technological challenges.The criteria for investment, in order to optimizecost-effectiveness, are:
a. Quality:i. Excellence and innovation in both
science and technology are central.ii. Development of fundamental plasma
science and technology is a criticalunderpinning.
iii. The U.S. must be among the worldleaders in fusion research for the U.S.fusion industry to be competitive.
b. Performance:i. The plan is structured to allow for cost-
effective staged investments basedupon proven results. Decision pointsare established for moving approachesforward, as well as for “off-ramps.”
ii. Technically credible alternative sci-ence and technology pathways thatare judged to reduce risk substantiallyor to offer substantially higher payoff(“breakthroughs”) are pursued.
It is not a requirment, however,that every pathway be funded atthe level needed for developmentin 35 years.
iii. Inevitably later elements of the planare less well defined at this time thanearlier ones; a goal of earlier elementsis to help define later ones.
c. Relevance (this topic is elaborated insection 5.9):i. Technical credibility
ii. Environmental attractivenessiii. Economic competitiveness
3. The plan recognizes and takes full advantageof external leverages.
a. The plan depends upon the internationaleffort to develop fusion energy, posi-tioning the U.S. to contribute to thisdevelopment and ultimately to take aleadership position in the commercializa-tion and deployment of fusion energysystems.
b. The plan takes full advantage of develop-ments in related fields of science andtechnology, such as advanced computingand materials nanoscience.
c. The high quality of the science and tech-nology developed for fusion gives rise toopportunities for broader benefits to so-ciety. Thus connections to other areasof science and technology are activelypursued.
d. For Inertial Fusion Energy, the plan takesfull advantage of advances supported bythe U.S. National Security Administration(NNSA) in the area of Inertial Confine-ment Fusion (ICF).
D. Elements of the Plan
The plan presented here addresses the develop-ment path both for Magnetic Fusion Energy (MFE)and for Inertial Fusion Energy (IFE). In MFE, mag-netic fields produced by coils carrying electric cur-rents confine a plasma (a superhot gas) that producesfusion energy continuously. In IFE, continuous poweris produced by using repetitive pulses of energy tocompress and heat small dense plasmas very rapidly,in order to produce fusion energy during the briefperiod that the plasmas are held in place by their owninertia.
A set of overlapping scientific and technologicalchallenges defines the sequence of major facilities in thefusion development path, as illustrated in Figure 3. Thissequence is similar between MFE and IFE. Programs intheory and simulation, basic plasma science, conceptexploration / proof of principle, materials developmentand fusion energy technology form the foundation forresearch on the major facilities.
72 Goldston et al.
Fig. 5. Fusion Development Path including programs, major facilities, and key decision points.
Figures 5–7 provide more detailed timelines of theprograms and facilities required to meet the series ofchallenges shown schematically in Figure 3. The un-derlying scientific and technological challenges, andassociated milestones, are described in Appendix A.A more detailed description of each of the program andproject elements is provided in Appendix B.
A concise description of the program and projectelements is given below.
1. Configuration Optimization
For MFE, the development of a comprehensiveunderstanding of magnetic confinement is required toevolve optimized magnetic configurations. The inves-tigation of a range of configurations is needed both toprovide a broad base for this comprehensive under-standing, and also to advance particular configurationstowards fusion power application. Desirable featuresfor optimization include reliable plasma operation athigh mass power density, with low recirculating powerfraction. Reliability is a critical issue for any complex
fusion system. Mass power density in effect measuresthe cost of a power plant core against its fusion powerproduction. The recirculating power fraction is thatfraction of the plant electrical output power needed tosustain the plasma configuration.
The tokamak is the most developed plasma con-figuration for magnetic fusion and is widely agreed tobe well enough understood to allow the step to a burn-ing plasma. Many experiments worldwide routinelyobtain similar operating regimes with energy confine-ment projected to meet the needs of a burning plasmaexperiment. Progress in fundamental understanding ofplasma transport and stability has also improvedconfidence in extrapolating present results to futuredevices. In parallel, an aggressive effort is underwayin U.S. and international experiments to increasethe attractiveness of the tokamak as a fusion powerplant. Key features of such an “advanced tokamak”are steady-state operation with a high fraction of self-generated current to reduce recirculating power, andincreased pressure limits to raise fusion power density.These features will be enabled largely through activecontrol of current, transport and pressure profiles.
A Plan for the Development of Fusion Energy 73
Fig. 6. MFE Fusion Development Path including programs, major facilities, and key decision points, with more detail in earlier years andkey dependencies.
Tokamak experiments are making good progress instudying key aspects of the advanced regimes for limiteddurations. Major new international facilities are beingdesigned and constructed to demonstrate advanced per-formance in steady-state. It is a major challenge, how-ever, to achieve simultaneously all of the most desirablefeatures with high reliability. Thus other less-developedconfigurations are pursued in parallel with the tokamak,potentially rising to the performance extension (PE)level of experimentation and ultimately to realization asDemo. Indeed a billion-dollar class superconductingstellarator is currently operating in Japan, and one isunder construction in Germany. New configurations,building on the growing understanding of fusion plas-mas, including quantitative numerical simulations, offerthe potential for improved performance as fusion sys-tems. Progress with these configurations has been veryimpressive as well. The understanding that arises fromexperimentation coupled closely with theory and ad-vanced computing should make the step to Demo possi-ble for non-tokamak configurations if merited.
It is important to recognize that there is an ongoingneed for enabling technology development to support the
configuration optimization experiments at all levels,through the burning plasma, component testing andDemo stages. Work on techniques to drive current, to fuelplasmas, to heat them, and to efficiently remove powerand particles are necessary components of this effort.
For IFE, the challenge of configuration optimiza-tion is similar to that of MFE, with the exception that thecriterion of mass power density is replaced predomi-nantly by that of driver cost. Configuration optimizationexperiments focus on the development of reprateddrivers and associated target physics, as well as targetfabrication, target injection/placement, final optics/powerfocusing and chamber technologies. Target physics ex-periments of relevance to IFE are ongoing on the NNSAfacilities Omega, Nike and Z, on facilities in Europeand Japan, and will be conducted on the NIF and LaserMegajoule (LMJ) in France in the future.
For the laser IFE approach, the work is carried outthrough the High Average Power Laser program. Thisincludes development of two types of lasers, kryptonfluoride and diode pumped solid state, methods tofabricate direct drive targets on a mass productionbasis, a system to study target injection and tracking of
74 Goldston et al.
the target, final optics, and chamber developmentwork. The last includes exposing candidate first wallchamber materials to relevant x-ray and ion fluxes, aswell as experiments to look at long term issues such ashelium retention.
The heavy ion IFE work is carrying out driverdevelopment with three smaller scale machines thatinvestigate the crucial issues of ion source develop-ment and beam injection (Source Test Stand), transport(High Current Experiment) and focusing (NeutralizedTransport Experiment). These experiments need to befollowed by an Integrated Beam Experiment (IBX),which will perform an integrated test of ion beamphysics from formation to placement on target. Theheavy ion program is also developing techniques tofabricate targets that meet both the physics require-ments and requirements for low cost production. Theheavy ion program will use the same target injectorbeing developed in the HAPL program.
For the z-pinch IFE approach, experiments are un-derway to test the materials proposed for recyclabletransmission lines (RTLs) needed for repetitivelypulsed operation. Studies are in progress on RTL struc-
tural properties, RTL manufacturing and costing, thickliquid wall chambers, and power plant optimization.Z-pinch driven hohlraum capsule implosion experimentsto optimize capsule compression ratios and compres-sion symmetry are in progress on Z. A set of experi-ments (optimization of RTL’s, rep-rated pulsed power,blast mitigation, and scaled RTL cycle demonstration)have been proposed for the PoP phase.
The fast ignition approach is, in principle, com-patible with all IFE drivers. Programs to study fast ig-nition are underway in Japan and at a lower level atpresent, in the U.S.
In both heavy-ion and z-pinch approaches to fusiona thick liquid first wall may alleviate materials and com-ponents issues associated with intense fluxes of high-energy neutrons, and so shorten the transition time froman IFE Engineering Test Facility (ETF) to Demo. Rela-tively low cost non-nuclear facilities are required tostudy thick liquid wall issues such as x-ray and ion fluxeffects, scaled hydrodynamics for jets and streams,shock mitigation to the structural wall, vapor condensa-tion and chamber clearing, molten salt fluid flow loopsand materials/nozzles erosion/corrosion issues.
Fig. 7. IFE Fusion Development Path including programs, major facilities, and key decision points, with more detail in earlier years and keydependencies.
A Plan for the Development of Fusion Energy 75
2. Burning Plasmas
The burning plasma step is critical for both MFEand IFE. The defining feature of a burning plasma is thatit is sustained primarily by the heat generated through itsown internal fusion reactions.
Within MFE the fundamental issue is to determinethe response of a magnetically confined fusion plasmato continuous heating by the products of its own inter-nal fusion reactions. While measurable fusion self-heating has been produced in experiments both in theU.S. and abroad, no experiment has yet penetrated intothe regime where self-heating dominates the plasmadynamics. A facility to investigate this physics willprovide critical information with application across arange of magnetic configurations.
A burning plasma is a crucial and missing ele-ment in the world magnetic fusion program. In presentexperiments most of the plasma heating is appliedexternally. In a burning plasma, intense fusion reac-tions occur and energetic alpha particles (heliumnuclei) are generated and are then confined by themagnetic field and slow down, transferring their en-ergy to maintain the high temperature of the plasma.When such fusion alpha heating dominates the plasmadynamics, important new scientific frontiers will becrossed. The creation of a burning plasma will enablemajor advances in many of the key areas of plasmascience and technology, and contribute to the demon-stration of magnetic fusion as a source of practicalenergy. While delivering the fusion-sustaining heat,the alpha particles also represent a new dynamicsource of energy to change the plasma pressure profile.Such changes in the plasma structure and dynamicscan potentially increase the loss of heat and particlesfrom the plasma, and consequently lead to a reductionin fusion power. Alternatively, these changes may leadto a further increase in temperature and fusion powerproduction. Understanding and controlling theseeffects on heat and particle transport, the subject of“burn control,” are essential elements of power plantdevelopment.
The U.S. has decided to join the negotiations forthe construction of ITER, as recommended by FESAC.If ITER goes forward it will fulfill all of the require-ments for an MFE burning plasma experiment. On theother hand, if the international negotiations do not suc-ceed, and ITER does not go forward, the domesticallydesigned experiment, FIRE, would be an attractiveoption for the study of burning plasma science, asdiscussed by FESAC. Either ITER or FIRE couldserve as the primary burning plasma facility, although
they lead to different fusion energy developmentpaths. Both devices are designed to achieve theirtechnical goals on the basis of conventional pulsedtokamak physics, but have capability to investigateadvanced tokamak modes of operation. In the ITERcase, the capability for long pulse and steady-stateoperation is provided. Moreover, a substantial amountof fusion technology development and testing is pro-vided as well. In the FIRE case an additional high-performance (but non-burning) steady-state experimentwould be required in parallel. A scenario includingFIRE, rather than ITER, is considered in Section 5.8.
Within IFE the critical issue addressed in theburning plasma step is whether a sufficiently symmet-rical, well-timed implosion, with adequate control ofhydrodynamic instabilities can be produced, using amegajoule class driver, so that a small fraction of thefuel can be heated to the point where it initiates a prop-agating burn in the remainder of the colder fuel. (In thecase of fast ignition the “hot spot” would be created byan external fast energy source, such as a petawattlaser.) The burning plasma step for IFE will beaddressed in the National Ignition Facility (NIF), cur-rently under construction. This step is a critical issuefor all approaches to IFE, and its results can be trans-ferred to other configurations beyond those testabledirectly on the NIF, through the use of advancednumerical simulations.
The configuration to be pursued initially on NIFis the best developed at present: a laser-driven x-rayhohlraum imploding a fusion capsule. Althoughtargets in this configuration are not presently projectedto have adequate gain for IFE with lasers, such targetswill provide much of the needed physics basis for IFEtargets driven with the three types of drivers underconsideration: ion beams, z-pinches and direct-drivelasers. NIF is also reconfigurable to study in moredetail laser direct drive and fast ignition. The resultsfrom NIF, coupled with results from configurationoptimization experiments at Omega, Nike and Z aswell as those abroad, and improved fundamental un-derstanding, can lead to an Engineering Test Facility(ETF) configured differently from the NIF.
3. Materials Testing
Due to the diverse technological requirementsof fusion power systems, a broad-based materialsR&D program encompassing neutron-interactive andnon-irradiation aspects is needed. For example highthermal-conductivity radiation-resistant materials are
76 Goldston et al.
needed for both MFE plasma facing components andIFE dry wall chamber surfaces.
The development of radiation-resistant, low-activation materials for fusion applications is a criticalelement in both the MFE and IFE development paths.While heavy-ion and z-pinch IFE configurations usingthick liquid walls face significantly less severe issueswith respect to neutron-interactive materials than otherapproaches, it is clear that materials issues for solid-wall laser-driven IFE and for MFE are comparable.
Guided by coordination from the InternationalEnergy Agency fusion materials working groups, thefusion materials science program has developed a suiteof high-performance reduced-activation metallic andceramic composite materials systems. In particularferritic steels evolved from those developed for thefission breeder program appear to be promising candi-dates to withstand the intense neutron fluence whileretaining low activation properties. However, just as inthe configuration optimization programs, a range ofmaterials needs to be developed in order to haveconfidence that one or more attractive materials will beavailable for Demo. Furthermore these materials needto be tested in an intense, realistic energetic neutronenvironment, which will be made available through aspecial-built facility, capable of providing an intenseneutron flux with an appropriate energy spectrumonto an area of 100 cm2. The international community(including the U.S.) has been involved in the concep-tual design of the International Fusion Materials Irradi-ation Facility, which would address this need.
4. Component Testing
Fusion power and fuel cycle components requiretesting, development and qualification in the fusionenvironment prior to Demo for both IFE and MFE.This activity includes testing and qualification of firstwall/blanket modules that both breed tritium and convertthe fusion energy flux to high grade heat, as well asplasma interactive and high-heat flux components suchas the divertor, tritium processing, IFE target fabricationand delivery system, and remote maintenance systems.Since the world supply of tritium is very limited, thisactivity must be carried out in very much reduced-scalefacilities until tritium breeding technology is reliablydeveloped.
Within the MFE path, significant experience isanticipated from testing plasma support technologies(e.g., superconducting magnets and plasma heating)in ITER. However testing of chamber technology in
ITER, while important, will be limited to initial func-tional tests and screening due to the relatively lowplasma duty cycle and the lower flux and neutronfluence than encountered in Demo. Thus a ComponentTest Facility (CTF) is judged to be necessary in additionto a burning plasma experiment in order for Demo tomeet its goals of tritium self-sufficiency, and practical,safe, and reliable engineering operation with high ther-modynamic efficiency, rapid remote maintenance andhigh availability.
The mission of the CTF in the MFE path isintegrated testing and development of fusion power andfuel cycle technologies in prototypical fusion powerconditions. This will require iteration and coordinationwith materials qualification in IFMIF. The CTF facilityis to provide substantial neutron wall load (�1 MW/m2)and fluence (�6 MWyr/m2) at minimum overall fusionpower (�150 MW) in order to enable integrated testingand optimization of a series of components at minimumtritium consumption and overall cost. An importantgoal of MFE configuration optimization experimentsthrough 2019 is to provide an optimized configurationfor the CTF.
Within the IFE path, an Engineering Test Facility(ETF) is needed to (1) produce repetitive pulses forcomponent testing and (2) demonstrate (for the first timefor some drivers) high yield targets. For component test-ing the approach favored is to use reduced-yield targetsrelative to Demo, and a proportionally reduced distanceto the chamber components in order to minimize tritiumconsumption and simplify component development.
Since the Demo is to demonstrate the operation ofan attractive fusion system, it must not itself be devotedto testing components for the first time in a fully realis-tic fusion environment. Furthermore the tritium con-sumption of a large facility such as Demo makes itimpractical for developing tritium breeding components,as only very little operation without full breeding wouldbe possible. Instead, reliable designs qualified in CTFfor MFE or ETF for IFE must be implemented in Demo.
5. Demonstration
The U.S. fusion demonstration power plant(Demo) is the last step before commercialization offusion. It must open the way to commercialization offusion power, if fusion is to have the desired impact onthe world energy system. Demo is built and operated inorder to assure the power producers and the generalpublic that fusion is ready to enter the commercialarena. As such, Demo begins the transition from science
A Plan for the Development of Fusion Energy 77
and technology research facilities to a field-operatedcommercial system. Demo must provide energy pro-ducers with the confidence to invest in commercialfusion as their next generation power plant, i.e., demon-strate that fusion is affordable, reliable, profitable, andmeets public acceptance. Demo must also convincepublic and government agencies that fusion is secure,safe, has a low environmental impact, and does notdeplete limited natural resources. In sum, Demo mustoperate reliably and safely on the power grid for aperiod of years so that industry gains confidence fromoperational experience and the public is convinced thatfusion is a “good neighbor.”
To provide consistent focus and integration of theprogram elements of this plan toward the end goal,systems analysis and design studies of possible powerplants must be carried out continuously. These de-signs, maintained current with the progress of the var-ious program elements of this plan, provide guidanceto the overall program.
6. Underlying Scientific and TechnologyDevelopment Programs
Programs in theory and simulation, basic plasmascience, concept exploration and proof of principleexperimentation, materials development and plasma,fusion chamber and power technologies form the foun-dation for research on the major facilities.
Fundamental scientific understanding is a criticalunderpinning of all aspects of the fusion developmentpath, from the definition and understanding of smallinnovative concept exploration experiments withinboth MFE and IFE to the design of the Demo based onthe results from previous experiments. Fundamentalengineering and materials science is critical as well tothe development of both materials and chamber tech-nologies.
E. Cost-Basis Scenario
The purpose of this section of the Report is topresent a scenario for the development of fusion en-ergy on the time scale envisioned by President GeorgeW. Bush and by Energy Secretary Spencer Abraham.For fusion energy to begin to be commercially avail-able by mid-century, a demonstration power plant, asit has been defined in this Report, will be requiredabout 35 years from today.
The scenario presented in this section builds onthe descriptions of the projects and programs defined
in Section 4, and elaborated in Appendix B. Thisscenario also builds on the principles presented inSection 3. In particular, in order to have acceptableassurance of success, it provides for the developmentof portfolios within both magnetic and inertial fusionenergy. The development of these portfolios is guidedby a series of specific, defined decisions on whether ornot to construct significant new facilities. It alsoprovides pathways for “breakthrough” developmentsthat significantly improve the end product. Finally itassumes that difficult choices will be made on a timelybasis, taking into account the key parameters ofquality, performance and relevance to the plan. Thisscenario is used to estimate a U.S. cost for the devel-opment of a fusion demonstration power plant.
Four time periods are envisioned along the path-way to Demo, as shown in Table 2. Each of these timeperiods is characterized by scientific and technologicalgoals, specific objectives, and key decisions requiredfor the transition to the activities of the next period.Necessarily the level of detail that can be provided atthis time is much greater for the earlier periods anddecisions than for the later ones, but the Panel believesthat this overall structure provides a valuable guide tothe needed activities.
At the transition between periods major decisionsand commitments must be made. It is the judgmentof the Panel that the overall decisions to make themajor transitions (i.e., in approximately 2008, 2019and 2029) should be guided by an outside group, suchas the National Research Council or the President’sCouncil of Advisors on Science and Technology,while the specific decisions on particular facilities needto be made through peer review by technical experts.The panels of technical experts should increasinglyinclude participants from the U.S. energy industry witha clear focus on key practical issues of economics andlicensing.
An overview of the plan is provided in Table 2,and detailed in the subsections 5.1–5.4. Figures 5–7illustrate the structure of the plan graphically.
1. Acquire Science and Technology Data to SupportMFE and IFE Burning Plasma Experiments andto Decide on Key New MFE and IFE DomesticFacilities; Design the International FusionMaterials Irradiation Facility (Present – 2008)
Over this time period existing projects and programsare strengthened in order to produce timely results. Thespecific goal is to be prepared for the major decisions
78 Goldston et al.
Table 2. Goals, Specific Objectives, and Key Decisions
● Present – 2008: Acquire Science and Technology Data to Support MFE and IFE Burning Plasma Experiments and to Decide on KeyNew MFE and IFE Domestic Facilities; Design the International Fusion Materials Irradiation Facility
Specific Objectives:● Begin construction of ITER, and develop science and technology to support and utilize this facility. If ITER does not
move forward to construction, then complete the design and begin construction of the domestic FIRE experiment.
● Complete NIF and ZR (Z Refurbishment) (funded by NNSA).● Study attractive MFE configurations and advanced operation regimes in preparation for new MFE Performance Extension (PE)
facilities required to advance configurations to Demo.● Develop configuration options for MFE Component Test Facility (CTF).● Participate in design of International Fusion Materials Irradiation Facility (IFMIF)● Test fusion technologies in non-fusion facilities in preparation for early testing in ITER, including first blanket modules, and to
support configuration optimization.● Develop critical science and technologies that can meet IFE requirements for efficiency, rep-rate and durability,
including drivers, final power feed to target, target fabrication, target injection and tracking, chambers and target design/target physics.
● Explore fast ignition for IFE (funded largely by NNSA).● Conduct energy-scaled direct-drive cryogenic implosions and high intensity planar experiments
(funded by NNSA). ● Conduct z-pinch indirect-drive target implosions (funded by NNSA). ● Provide up-to-date conceptual designs for MFE and IFE power plants.● Validate key theoretical and computational models of plasma behavior.
2008 Decisions: Assuming successful accomplishment of goals, the cost-basis scenario assumes that by this time decisions are taken to construct:
● International Fusion Materials Irradiation Facility● First New MFE Performance Extension Facility● First IFE Integrated Research Experiment Facility
● 2009–2019: Study Burning Plasmas, Optimize MFE and IFE Fusion Configurations, Test Materials and Develop Key Technologies inorder to Select between MFE and IFE for Demo
Specific Objectives:● Demonstrate burning plasma performance in NIF and ITER (or FIRE).● Obtain plasma and fusion technology data for MFE CTF design, including initial data from ITER
test blanket modules.● Obtain sufficient yield and physics data for IFE Engineering Test Facility (ETF) decision.● Optimize MFE and IFE configurations for CTF/ETF and Demo.● Demonstrate efficient long-life operation of IFE and MFE systems, including liquid walls.● Demonstrate power plant technologies, some for qualification in CTF/ETF.● Begin operation of IFMIF and produce initial materials data for CTF/ETF and Demo.● Validate integrated predictive computational models of MFE and IFE systems
Intermediate Decisions: Assuming successful accomplishment of goals, the cost-basis scenario assumes a decision to construct twoadditional configuration optimization facilities, which may be either MFE or IFE.
● MFE Performance Extension Facility● IFE Integrated Research Experiment
2019 Decision: Assuming successful accomplishment of goals, the cost-basis scenario assumes a selection between MFE and IFEfor the first generation of attractive fusion systems.
● Construction of MFE Component Test Facility (CTF) or
● Construction of IFE Engineering Test Facility (ETF)● 2020–2029: Qualify Materials and Technologies in Fusion EnvironmentSpecific Objectives:
● Operate ITER with steady-state burning plasmas providing both physics and technology data.● Qualify materials on IFMIF with interactive component testing in CTF or ETF, for
implementation in Demo.● Construct CTF or ETF; develop and qualify fusion technologies for Demo.● On the basis of ITER and CTF/ETF develop licensing procedures for Demo.● Use integrated computational models to optimize Demo design.
2029 Decision:● Construction of U.S. Demonstration Fusion Power Plant
● 2030–2035: Construct DemoSpecific Objective: Operation of an attractive demonstration fusion power plant.
A Plan for the Development of Fusion Energy 79
that will be required in 2008. It is assumed that ITERnegotiations lead expeditiously to a construction project.Other than ITER, during this time period there are noconstruction decisions made on major projects (PE-classMFE facilities or IRE-class IFE facilities) that carrymajor out-year commitments, but some commitmentsare made, as warranted, to new facilities at the PoP level.
The Cost-Basis Scenario assumes that the follow-ing activities are undertaken during this period:
Design Studies/Demo● Design studies are strengthened, in order to
help guide future programmatic decisions. Par-ticular focus is required during this time periodon laser inertial fusion energy and on configu-ration options for the Component Test Facility(CTF), since decisions relative to these twoareas (IFE laser IRE, MFE PE with possibleapplication to CTF) will be required at the endof this time period.
Engineering Science/Technology Development● Engineering science and technology develop-
ment are strengthened from their current lev-els in order to more fully support configurationoptimization experiments, to support inertialfusion IRE and ITER issues as they develop, toprepare for ITER blanket testing even duringits initial operation, and ultimately to preparefor CTF.
IFMIF● The U.S. engages in the Engineering Validation
and Engineering Design Activity for the Inter-national Fusion Materials Irradiation Facility(IFMIF), in order to be prepared for a construc-tion decision at the end of this time period.
Materials Science/Development● Materials science activities are strengthened to
prepare for the use of IFMIF, ITER and CTF.
MFE Burning Plasma● Construction of ITER commences.
IFE Burning Plasma● Initial megajoule-class compression results on
non-cryogenic targets are obtained from theNIF, giving new information on laser-plasmainteractions, relevant for both direct and indirectdrive, and on the degree of symmetry achievablewith high energy laser driven hohlraums.
● High compression “energy scaled” cryogenicdirect drive implosions are conducted at Omegaand high intensity planar experiments are carried
out at Nike, playing a major role for evaluatingthe prospects of high gain direct drive at the NIF.
● Z-pinch driven indirect drive target experimentson Z/ZR demonstrate high capsule compressionratios and symmetry that scales to that requiredfor high yield and substantial DD neutron pro-duction, using megajoules of z-pinch x-rays.
ments are strengthened in the U.S. to supportdecisions on ITER advanced features, CTF de-sign, and to contribute to basic understandingof toroidal magnetic confinement.
● Assuming continuing success in ongoing MFEPoP and PE experiments, design work is com-menced on a new Performance Extension (PE)MFE experiment, with interest potentially bothfor application for Demo and for CTF, inpreparation for a 2008 decision. PoP activitieson the Spherical Torus (ST) and Reversed FieldPinch (RFP) configurations are strengthenedboth in preparation for this decision and tocontribute to basic understanding of toroidalmagnetic confinement.
Concept Exploration/Proof of Principle● The Proof-of-Principle (PoP) HAPL laser
fusion work currently underway continues andis brought to a favorable conclusion. Assum-ing that this work is successful, design workis commenced on a laser Integrated ResearchExperiment.
● The construction of the PoP-class NationalCompact Stellarator Experiment proceeds, alongwith the associated national stellarator pro-gram, in order to prepare for the possibility ofa CS configuration for the 2nd new MFE PEexperiment.
● A PoP-class heavy ion fusion experiment, theIntegrated Beam Experiment, is brought toa Physics Validation Review, confirmed byFESAC for Proof-of-Principle status, passes aDOE Conceptual Design Review, and movesinto construction during this time period.
● Concept exploration activity is strengthenedfor the Z-pinch and Fast Ignition IFE conceptsand for MFE configurations at Concept Explo-ration (CE) level of development in order toprepare for expeditious transition to PoP scale.This will allow selected approaches to bemoved forward more rapidly. It is assumed inthe Cost-Basis Scenario that success at the CE
80 Goldston et al.
level of development leads to construction oftwo further configurations at the PoP scale(either MFE or IFE) during this time period.
Theory, Simulation and Basic Fusion Experiments● Theory and advanced computing are strength-
ened, and the Fusion Simulation Project is ini-tiated, in collaboration with the DOE-SCOffice of Advanced Scientific Computing Re-search, taking advantage of advances in com-puting technology to both support ITERdirectly and also to provide the basis for ex-trapolating results from ITER to other MFEconfigurations.
● Credible IFE targets are designed with sufficientgain and stability using 2 and 3D modeling.Underlying codes are benchmarked against ex-periments.
● Fusion Frontier Centers, as recommended bythe NRC FuSAC Panel, are opened in collabo-ration with the NSF.
In the Cost-Basis Scenario it is assumed that thedecisions at the end of this time period lead to the fol-lowing outcomes:
● Results from the Engineering Design Activitylead to construction of the IFMIF beginningin 2009.
● Results from the ongoing HAPL laser PoP pro-gram, cryogenic target implosion results fromOmega, high-intensity planar target resultsfrom Nike, initial 120 beam implosion resultsfrom the NIF, and initial design studies lead tothe start of construction of a laser IntegratedResearch Experiment.
● Results from the current MFE PoP and PE pro-grams lead to the start of construction of a firstnew MFE PE experiment. Likely configura-tions for this facility could be the RFP, the ST,or a specialized tokamak. A potential goal forthis facility would be scientific developmentfor a cost-effective CTF.
2. Study Burning Plasmas, Optimize MFE and IFEFusion Configurations, Test Materials andDevelop Key Technologies in order to Selectbetween MFE and IFE for Demo (2009–2019)
During this period, in the MFE area there will beresults from ITER, in which it is anticipated that powerplant levels of fusion power will be produced for long
durations. Coupled with this will be results from ex-isting tokamaks, and up to two additional PerformanceExtension experiments. In the IFE area there will beignition and moderate gain results from the NIF, cou-pled with results from up to three Integrated ResearchExperiments demonstrating technology for IFE. Theremay be high-yield results from a new z-pinch facility.In both the MFE and IFE cases, the first PerformanceExtension or IRE facility is anticipated to be based ona configuration currently being developed at the PoPor PE scale, but in both cases the second such facilitycould also be based on new ideas, or ideas currently atthe Concept Exploration stage.
The experience with ITER will have blazed thetrail for licensing of fusion systems, and initial resultsfrom IFMIF will provide critical information on the per-formance of materials in a fusion neutron environment.
Key project decisions that will be required duringthis time period include:
● The construction of further PoP experimentswithin either MFE or IFE. In the Cost-BasisScenario it is assumed that two new PoP’s (eitherMFE or IFE) are constructed early in this timeperiod, and the currently existing PoP’s are shutdown during this period.
● The construction of other IFE Integrated Re-search Experiment(s). In the Cost-Basis Scenarioit is assumed that one or two further IREs areconstructed during this time period. Thus twoor three IFE configurations are assumed to bewell enough developed to contribute to thedesign of an Engineering Test Facility andthence to Demo. It is assumed that if a third IREis constructed, a second new MFE PE is notconstructed.
● Research on Fast Ignition may lead to a decisionto incorporate this feature into IFE facilities.
● The construction of other MFE PerformanceExtension experiment(s). In the Cost-BasisScenario it is assumed that one further suchexperiment is constructed during this timeperiod. Possible candidates include an RFP,ST, Compact Stellarator, a specialized tokamakor a configuration currently at the CE level,which, most likely, has been tested by this timeat the PoP scale. It is assumed that if a secondnew MFE PE is constructed, a third IFE IRE isnot constructed.
● It is anticipated that current U.S. PE-classtokamak facilities will have completed theirresearch programs midway through this period,
A Plan for the Development of Fusion Energy 81
demonstating the extent to which key advancedoperation features can be achieved in an inte-grated manner. Their results contribute to ITERoperational scenarios and to optimized designswhich may compete for the new PE experiment.U.S. participation on long-pulse superconduct-ing tokamaks abroad increases.
In order to prepare for the transition to theQualification of Materials and Technology in FusionEnvironment period it will be necessary to:
● Strengthen considerably efforts in engineeringscience and technology development.
● Begin design of both the MFE ComponentTest Facility and the IFE Engineering TestFacility.
On the basis of the information available at theend of this time period, it is assumed in this plan thata decision will be made on whether the Demo thatwill lead to the first generation of attractive fusionpower plants will be based on Magnetic or on Iner-tial Fusion Energy. This will form the basis for thedecision between an MFE Component Test Facilityand an IFE Engineering Test Facility.
3. Qualify Materials and Technologies in FusionEnvironment (2020–2029)
During this time period either the MFE Compo-nent Test Facility or the IFE Engineering Test Facilitywill be constructed and begin operation, providingcritical technological information for the final designand construction of the Demo. An aggressive materialsand technology qualification program will be required.The configuration of the Demo is decided during thistime period and design commences.
4. Construct Demo (2030–2035)
During this time period a Demonstration PowerPlant is constructed and then begins operation, leadingto the commercial deployment of fusion energy bymid-century.
5. Cost Profile
Input was collected from technical experts in eachrelevant area, in order to develop cost profiles for theprograms and major facilities included within the plan.In the case of MFE theory, configuration optimization
and technology development, as well as materialsdevelopment for both MFE and IFE, it is assumed thatcoordinated programmatic activities of similar scaleare undertaken in Europe and Japan. For IFE, it isassumed that strong support by the NNSA for InertialConfinment Fusion continues. For the major facilitiesin the plan, the following assumptions are made withrespect to Total Project Costs (all costs are in$FY2002). Operating costs are also included in thecost profile.
● The overall cost for the construction of ITER isestimated at $5B. The total U.S. contribution toITER construction, including also U.S. contin-gency, R&D and design of diagnostics, heatingand current drive systems, and U.S. oversightof industrial activities, is taken to be $1B, con-sistent with FESAC estimates.
● The Total Project Cost for construction of theInternational Fusion Materials Irradiation Fa-cility, IFMIF, is estimated at $600M, based oncurrent international estimates, including 20%contingency. It is assumed that the U.S. con-tributes 25% of the cost of IFMIF.
● The Total Project Cost for construction of thefirst new Performance Extension MFE facilityis taken to be $400M taking into account arange of estimates provided to the Panel.
● The Total Project Cost for construction of aLaser Integrated Research Experiment is as-sumed to be $320M, based on estimates providedto the Panel for either a KrF or a DPSSL basedsystem. Associated laser IFE technology devel-opment is included within the Engineering Sci-ence/Technology Development program line.
● The Total Project Cost for a second IFE Inte-grated Research Experiment is estimated to be$300M, taking into account a range of esti-mates provided to the Panel.
● The Total Project Cost for construction of thesecond new Performance Extension MFE faci-lity is taken to be $400M taking into account arange of estimates provided to the Panel.
● Note that the overall plan logic allows for up tothree new MFE PE’s and up to three IFE IRE’s,but only a total of four such facilities is in thecost basis.
● During the 2009–2019 time period, the cur-rently existing MFE PE’s and PoP’s completeoperation.
In 2019 a decision will be made to proceed witheither MFE (Component Test Facility leading to MFE
82 Goldston et al.
Demo) or IFE (Engineering Test Facility leading toIFE Demo). For the purpose of estimating a cost pro-file for the development path, therefore, the costs areaveraged between these two options. The cost profilefor the IFE path peaks earlier than that for MFE. Itshould be recognized that accurate estimations aredifficult for facilities to be constructed in this timeframe.
● The Total Project Cost for an MFE ComponentTest Facility is taken to be $1.5B, taking intoaccount a range of estimates provided to thePanel. All costs are assumed to be borne by theU.S.
● The Total Project Cost for a U.S. MFE Demois set at $5B. All costs are assumed to be borneby the U.S.
● The Total Project Cost for an IFE EngineeringTest Facility is estimated at $4.5B, taking into ac-count a range of estimates provided to the Panel.All costs are assumed to be borne by the U.S.
● The Total Project Cost for a U.S. IFE Demo isset at $1B, taking into account a range of esti-mates provided to the panel, assuming that the
ETF facility can be upgraded to function as theDemo. All costs are assumed to be borne bythe U.S.
Additional funding that would be needed in thesecond half of the development path plan for theoptimization of a second generation of fusion powersystems and to sustain a strong program in high-temperature plasma science and associated science andtechnology expertise is not included. MFE and IFE con-figurations not selected for Demo and first generationcommercial application should be funded, if merited, atan appropriate level to contribute to a second generationof attractive fusion systems. The Panel has not attemptedto analyze these costs in a systematic manner, but esti-mates they would sum to a few billion dollars.
Decommisioning costs for ITER, IFMIF and CTF,which would fall outside of the time-window of thisplan are not included in its cost.
The cost profile for the development of Demo, basedon this scenario, is presented in Figure 8 and Table 3.
Several specific issues of importance relative tothe structure and execution of the plan are discussed inthe following sections:
Fig. 8. Cost profile for fusion development plan to provide a Demonstration Power Plant.
A Plan for the Development of Fusion Energy 83
Table 3. Cost Profile for Fusion Development Plan (FY2002 $M)
6. Criteria for Advancement of Fusion Configurations
For both MFE and IFE, the decision to proceedfrom one stage of development to the next is based onthe maturity of the configuration, in order to be as-sured that (1) the next-stage program will be success-ful, and (2) the anticipated benefits of the next stage ofresearch justifies the increased level of effort.
Common criteria for each level of any approachto proceed to the next stage are given in Table 4. Inaddition to these common criteria for all approaches,there are additional criteria for judging resolution ofscientific and technical issues that are unique to eachapproach at each level that are described in Appendix Aand Appendix B. In all cases, rigorous peer review isessential before proceeding to a higher stage.
7. The Plasma Configuration of the MFE Demo
The tokamak is the only plasma configuration thatis currently well enough developed to allow confidentextrapolation into the burning plasma domain. As aresult ITER is designed as a tokamak. An attractiveoperating mode for the tokamak, called the “advancedtokamak,” offers the promise of steady state operationwith moderate recirculating power and acceptablemass power density. However there are still significantphysics and technology issues that remain to be resolvedfor a Demo based on the advanced tokamak. On-goingtokamak research and ITER plan to resolve these issuesin time for the design of the Demo. It is uncertain, how-ever, how much of the promise of the advanced tokamakcan be realized in a practical system. It is also uncertainwhat the demands of the market will be 30� years intothe future. Thus the advanced tokamak may prove to bethe correct configuration for the first generation of U.S.commercial fusion power plants, but it is also possiblethat a more attractive alternative may become available,or may be required for commercial practicality.
This plan supports research on a range of magneticconfigurations, which will also support the developmentof the tokamak by contributing to innovation and scien-tific understanding of magnetic confinement. These con-figurations include the Spherical Torus, Reversed FieldPinch and Compact Stellarator, which are closely relatedto the tokamak and are being investigated at the Proof ofPrinciple (PoP) scale. A number of other configurations,which are significantly more distant from the tokamak,are currently under investigation at the smaller ConceptExploration (CE) scale.
The plan includes the option for two MFE con-figurations to be tested at the larger PerformanceExtension (PE) scale, in parallel with ITER. The firstof these experiments must be based on a configurationcurrently at the PoP or PE scale, and could also helpto provide the basis for a cost-effective ComponentTest Facility. With success in the Concept Explorationprogram, and test at the PoP scale, the second suchPerformance Extension experiment could be basedeither on a configuration currently under investigationat the PoP level, or on a configuration currently atthe CE scale–or possible even a very successfulnew idea. This explicit allowance for “breakthroughs”is consistent with the overall Principles articulated inSection 3. This approach requires, however, a vigorousU.S. Concept Exploration and Proof-of-Principle pro-gram as well as advanced numerical simulation andplasma diagnostics.
A flexible and well-diagnosed Performance Exten-sion experiment, coupled through theory and advancedcomputing with burning plasma results from ITER,should provide the physics basis for the step to Demo.Whether the experiment will require deuterium-tritiumoperation (as in TFTR and JET) is a matter that willdepend on the configuration being considered and onthe degree of confidence that can be placed at thattime in theoretical calculations and experimental simu-lations using, for example, high-energy beams. A firm
84 Goldston et al.
Table 4. Common Decision Criteria for Up-selection of Fusion Approaches to Next Development Levels
● New configuration defined with potential for fusion energy or experiment proposed for improving existing configuration.● Basic analysis shows potential for scientific feasibility.
If the above criteria are satisfied, the configuration is a candidate for:
Concept Exploration (for fusion approaches, not for basic plasma science experiments)● Clear potential to improve some important aspect of fusion power systems.● Experiments and modeling show basic scientific feasibility of the concept.
If the above criteria are satisfied, the configuration is a candidate for:
Proof-of-Principle● Conceptual study shows attractive (economic/environmental) power plant example.● Experiments and modeling show broad understanding of physical principles of concept, and key physics issues favorably resolved for
the next (PE/IRE) stage.● Small-scale experiments show power plant technologies feasible to develop.● Organized national team with development plan to DEMO decision.
If the above criteria are satisfied, the configuration is a candidate for:
MFE Performance Extension/IFE Integrated Research Experiment● Detailed power plant design updated with PE/IRE data confirms attractive power plant.● Well-diagnosed physics and technology demonstrated at sufficient scale, integration, and duration show that cost, performance, and
reliability goals can be met.● Data available from a burning plasma experiment from which reasonable extrapolation can be made to CTF/ETF and/or Demo.● Theory and modeling proves adequate predictive capability for CTF/ETF and Demo.● Development plan through DEMO to commercialization with the participation of U.S. industry.
If the above criteria are satisfied, the configuration is a candidate for advancement to the Component Testing and/or Demo stage:
Component Testing (MFE CTF/IFE ETF)● Individual component reliability and integrated operation of fusion chamber and power technologies demonstrated.● Safety and environmental requirements for U.S. licensing demonstrated.● Sufficient fuel cycle closure demonstrated.● For IFE, integrated near full scale driver demonstrated.● For IFE, high yield targets optimized.
If the above criteria are satisfied, demonstrated technologies are candidates for application in:
Demonstration Power Plant● Acceptable safety and environmental impacts demonstrated.● Attractive economics projected for U.S. market.● Technology is prepared for commercialization.● 50% availability is demonstrated, extrapolable to commercial practicality.
If the above criteria are satisfied, fusion will be prepared for commercialization.
technology basis for the step to Demo will be suppliedby ITER, IFMIF and CTF.
The cost-basis scenario as articulated provides forthe option that Demo can be configured differentlyfrom the advanced tokamak as it is presently under-stood. It should be anticipated, however, that the ini-tial operation of Demo will require more learning inthis case and the initial production of electricity wouldbe somewhat delayed as a result.
8. The FIRE Scenario
The U.S. is considering two options for a burningplasma experiment: ITER and FIRE, as discussed
in Section 4. For simplicity, only the ITER option isused for the cost basis scenario presented above. BothITER and FIRE would make significant scientific andtechnological contributions in burning plasma science.However there are differences in the opportunitiesoffered by the two approaches. As discussed by FESACin A Burning Plasma Program to Advance FusionEnergy (2002),
● FIRE offers an opportunity for the study ofburning plasma physics in conventional con-figurations for a few plasma current redistribu-tion time periods and in advanced tokamakconfigurations under quasi-stationary condi-tions (several plasma current redistribution
A Plan for the Development of Fusion Energy 85
time periods), and would contribute to plasmatechnology.
● ITER offers an opportunity for the study ofburning plasma physics in conventional con-figurations for a few plasma current redistribu-tion time periods and in advanced tokamakconfigurations for long durations (many cur-rent redistribution time periods) with steadystate as the ultimate goal, and would contributeto the development and integration of plasmaand fusion technology.
The FESAC report also discussed differences inthe roles of the two approaches within the develop-ment paths for fusion energy, as follows:
● A FIRE-based development plan reduces initialfacility investment costs and allows optimiza-tion of experiments for separable missions. Thisoption aims at smaller extrapolations in physicsand technology. Assuming a successful outcome,a FIRE-based development path provides foradditional optimization before further integra-tion steps are needed, allowing a more advancedand/or less costly integration step that willfollow.
● An international tokamak research programcentered around ITER, which includes otherperformance-extension devices throughout theworld, has the highest chance of success inexploring burning plasma physics in steady-state. ITER will provide valuable data on inte-gration at power-plant relevant plasma supporttechnologies. Assuming a successful outcome(demonstration of high-performance AT burn-ing plasma), an ITER-based development pathwould lead to the shortest development time toa demonstration power plant.
From the perspective of the total cost to the U.S.for the development of commercial fusion energy, thedifference between the FIRE and ITER paths is rela-tively minor. However there are some differences in theprogram schedule. Since ITER can operate essentiallyin steady-state, it would be the first test of an integratedDemo-scale fusion device operating in a nuclearenvironment, with initial tests of some fusion chambertechnologies. Since the FIRE pulse length is about20–40 seconds, in the FIRE path a steady-state DDexperiment operating in parallel with FIRE is relied onto address steady-state issues. The KSTAR tokamakbeing constructed in South Korea and the JT60-SCtokamak under discussion in Japan are examples of such
steady-state devices, which are assumed to be fullyaccessible to U.S. researchers. In the FIRE path theintegration of burning plasmas with steady state opera-tion is deferred to a later time. One impact of the defer-ral is that the integration would then first occur in theComponent Test Facility. Thus an initial period of CTFoperation, likely of several year duration, would berequired to acquire operating experience with steady-state deuterium-tritium plasmas and fusion chambertechnology. Similarly the start-up time of the DEMOmight be extended for integration at large scale.
9. Management Considerations
In its August 1999 report “Realizing the Promiseof Fusion Energy,” the DOE Secretary of EnergyAdvisory Board (SEAB) stated “To achieve its goal, theprogram must be directed by strong management–amanagement that leads the effort toward the fusionenergy goal at a reasonable pace, with sufficient budget,with solid accountability, and high-quality scienceand technology.” This is especially true if the programseeks to operate a demonstration power plant on aset timetable within constrained financial resources. Asstated by SEAB, “Given constrained budgets, the widevariety of options and the linkages of one issue toanother, increasingly sophisticated management of theprogram will be required.”
A successful fusion program requires the solutionand integration of many disparate scientific, techno-logical, economic and systems issues. As stated bySEAB, “Although each task could be initiated inde-pendently, conducting the tasks in parallel (through anintegrated planning process) allows better cross-linkingand integration of tools, understanding, and expertise.”This approach is sometimes referred to as systemsmanagement and its adoption is essential to properlyimplement the development plan described in thisreport. The recent Integrated Program Planning Activ-ity (IPPA) is a positive step in this direction.
The approach to fusion program planning today is,however, primarily “roll-forward” in nature, i.e, scien-tific and technological results from the ongoing programare weighed and, largely based on such considerations,the nature and timing of future decisions and steps isdetermined. This gives especial weight to the criteriaof Quality and Performance discussed in Section 3. Asuccessful fusion power development program requires,in addition, increased emphasis on Relevance of eachstep to the Plan described here and its ultimate goal, anattractive demonstration fusion power plant. This is
86 Goldston et al.
sometimes referred to as a “roll-back” approach, i.e., onein which the nature of the desired end-product (a fusionpower demonstration plant that extrapolates readily tocommercial power plants) is defined sufficiently that thephysics, technology and engineering required for theDemo are identified and programs established andjudged with respect to the goal of providing the requireddata. Clearly “roll-forward” and “roll-back” planningmust be used in a complementary fashion for fusionultimately to be successful. Quality, Performance andRelevance to the plan and its ultimate goal must all bekey decision criteria.
Top level power plant objectives include, amongothers, minimization of projected cost of electricity,maximization of investment protection, minimizationof capital costs, minimization of operating costs, max-imization of availability, minimization of developmentcosts, and maximization of public safety. Such tar-gets, as well as relevance to the Plan presented here,should be incorporated into the fusion decision makingprocess as a way to formally incorporate “roll-back”planning into fusion program management. Many as-pects of this approach have been incorporated inthe ARIES power plant design studies program. Suchconsiderations should be formally used in guiding theevolution of the fusion program as a whole.
F. Conclusion
There have been dramatic scientific and technolog-ical advances in fusion in the last decade, and majoraccomplishments are expected with NIF and ITER(or FIRE) in the next. A ramp-up in domestic fusionresearch and development is required now to impact thedirection of these upcoming burning plasma researchexperiments, in order to guide them in addressing criti-cal issues in the development of practical fusion energy.Rapid progress is also needed in configuration optimiza-tion experiments for both MFE and IFE, because criticaldecisions must be made on key future investments by2008 in order to maintain the needed schedule. Thedesign of IFMIF and the domestic fusion technologyprogram must move forward as well, if technologies areto be available for testing in ITER and materials are tobe made available for testing in CTF/ETF and Demo.A program funded at present levels cannot accomplishthese essential schedule-driven steps.
The total cost to the U.S. of the plan to bring on linea first-generation Demonstration fusion power plant thatwill lead to commercial application of fusion energy bymid-century is approximately $24B in FY2002 dollars.
The plan assumes an ongoing level of highly coordinatedinternational programmatic activities, and internationalparticipation in ITER and IFMIF, but assumes U.S.-onlysupport for CTF or ETF, and Demo. It assumes con-tinuing strong NNSA support of Inertial ConfinementFusion.
To achieve the goals of this plan, the program mustbe directed by strong management. Given constrainedbudgets, the wide variety of options and the linkagesof one issue to another, increasingly sophisticated man-agement of the program will be required.
Additional funding that would be needed in thesecond half of the development plan to maintain astrong core scientific capability, and to provide con-tinued innovation aimed at improved configurationsbeyond Demo, is not included. The panel believes thatthese are necessary elements of an overall fusion R&Dprogram. The panel has not attempted to analyze thesecosts in a systematic manner but estimates they wouldsum to a few billion dollars.
The U.S. fusion energy sciences program is stillsuffering from the severe budget cuts of the mid-1990sand the loss of a clear national commitment to developfusion energy. The result is that despite the excitingscientific advances of the last decade it is becomingdifficult to retain technical expertise in key areas. ThePresident’s fusion initiative has the potential to reversethis trend, and indeed to motivate a new cadre of youngpeople not only to enter fusion energy research, butalso to participate in the physical sciences broadly.With the addition of the funding recommended here,an exciting, focused and realistic program can beimplemented to make fusion energy available on apractical time scale. On the contrary, delay in startingthis plan will cause the loss of key needed expertise andresult in disproportionate delay in reaching the goal.
Establishing a program now to develop fusionenergy on a practical time scale will maximize thecapitalization on the burning plasma investments in NIFand ITER, and ultimately will position the U.S. to exportrather than import fusion energy systems. Failure to do sowill relegate the U.S. to a second or third tier role in thedevelopment of fusion energy. Europe and Japan, whichhave much stronger fusion energy development programsthan the U.S., and which are vying to host ITER, will bemuch better positioned to market fusion energy systemsthan the U.S.–unless aggressive action is taken now.
It is the judgment of the Panel that the plan pre-sented here can lead to the operation of a demonstra-tion fusion power plant in about 35 years, enablingthe commercialization of attractive fusion power bymid-century as envisioned by President Bush.
A Plan for the Development of Fusion Energy 87
APPENDIX A: SCIENTIFIC AND TECHNOLOGICAL CHALLENGES
The plan laid out in this report leads to a demon-stration fusion power plant. A key feature is that thereare many major accomplishments and discoveries thatwill occur along the way. These accomplishments arepart of a coordinated plan to provide key informationneeded for design of a DEMO. However, they will them-selves constitute major advances in plasma science,technology, and fusion energy science. These advanceswill provide, to both fusion scientists and the public,crucial information on the feasibility and characteristicsof fusion power. Below are summarized some of thesemajor goals for MFE and IFE, building on previous workby FESAC.
A.1 Magnetic Fusion Energy
In December, 2000, the Integrated Program Plan-ning Activity (IPPA) carried out by the fusion commu-nity identified challenges for magnetic fusion energy infour areas: fundamental plasma science, configurationoptimization, burning plasma science, and materialsand technology. We discuss each of these major areasin turn, focusing only on selected grand challenges.Fundamental plasma science underlies all of the endeav-ors. However, to connect advances in fundamentalplasma science to specific milestones, we merge itsdiscussion with that of configuration optimization.Other areas of science, in particular materials andengineering science, underlie the materials and technol-ogy endeavor.
A.1.1 Fundamental Plasma Scienceand Configuration Optimization
The overarching goals, stated in the IPPA report is
Advance the fundamental understanding of plasma,the fourth state of matter, and enhance predictive capa-bilities, through the comparison of well-diagnosedexperiments, theory, and numerical simulation.
Resolve outstanding scientific issues and establishreduced-cost paths to more attractive fusion energysystems by investigating a broad range of innovativemagnetic confinement configurations.
Advances in fusion energy rely upon discoveriesin fundamental plasma physics. These advances are, inpart, used to evolve magnetic configurations to con-fine fusion plasmas. Research on a variety of magnetic
configurations are planned for two reasons. First,the optimal fusion system will be evolved, and criti-cal fusion science issues will be resolved, throughresearch on a spectrum of configurations, linkedthrough theoretical understanding and advanced com-puting. Second, specific configurations have potentialto extrapolate into fusion systems with favorableattributes, either for the first DEMO or for the secondgeneration DEMO.
Three dominant scientific challenges are:
i. What is the fundamental upper limit to theplasma pressure, and how can it be optimized?The fusion power increases with plasma pressure.The plasma pressure is gauged relative to themagnetic pressure that contains the plasma. Allplasmas are subject to a pressure limit, beyondwhich the plasma will disassemble or lose itsenergy. The scientific challenge is to understandthe mechanisms that limit the pressure and howthe plasma behaves at the limit. Confinementconfigurations are being developed that optimizethe pressure limit.
ii. What is the mechanism for energy transportfrom electric and magnetic turbulence, andhow can the transport be minimized?Plasmas tend spontaneously to develop turbu-lence in which the electric and/or magnetic fieldsfluctuate, releasing energy from the plasma. Thisenergy loss cools the plasma, inhibiting fusion.Treatment of plasma turbulence in fusion plas-mas has been revolutionized in recent yearsthrough new understanding of its cause and newtechniques for its control.
iii. How can plasmas be sustained in steady-stateagainst resistive decay?It is desirable that a plasma in a fusion systempersist in a steady-state. In recent years it hasbeen discovered that a tokamak plasma current isspontaneously generated in the plasma–a formof a thermo-electric effect unique to a plasma in acomplex magnetic field. This “bootstrap current”has the potential to sustain a tokamak or spheri-cal torus in steady-state. Other configurations areunder study that do not require plasma current forconfinement (the magnetic field is producedentirely by external magnets), and are therebyinherently steady-state devices. Self-organizedconfigurations such as the RFP and spheromakmay take advantage of reconnection and magnetichelicity conservation for non-inductive startupand steady-state sustainment.
88 Goldston et al.
A.1.2 Burning Plasma Science
Advance understanding and innovation inhigh-performance plasmas, optimizing for projectedpower-plant requirements, and participate in aburning plasma experiment
A crucial step in fusion energy research is thestudy of a high-performance (i.e., well-confined, highpressure, parameters in the reactor range), burningplasma. The defining feature of a burning plasma isthat it is self-heated: the 200 million degree tempera-ture in the core of the plasma is maintained mainly bythe heat generated by the fusion reactions themselves,as occurs in burning stars. The fusion-generated alphaparticles produce new physical phenomena that arestrongly coupled together as a nonlinear complexsystem. Understanding all elements of this systemposes a major challenge to fundamental plasmaphysics. The technology needed to produce and con-trol a burning plasma presents challenges in engineer-ing science similarly essential to the development offusion energy.
A.1.3 Technology
Develop enabling technologies to advancefusion science; pursue innovative technologies andmaterials to improve the vision for fusion energy;and apply systems analysis to optimize fusiondevelopment.
The technological challenges of containing andcontrolling a fusion plasma, and producing the tritiumfuel, are large and require both fundamental technolog-ical development and innovation. These challengesinclude the development of new low-activation materi-als that can withstand the fusion neutron environmentand new technologies including plasma facing compo-nents, chamber technologies, current drive and heatingsystems, tritium technology and superconductingmagnets. Systems studies guide both the technologyand physics research, providing information on theimpact of specific design elements on fusion reactorattractiveness.
A.2 Inertial Fusion Energy
In December, 2000, the Integrated Program Plan-ning Activity (IPPA) carried out by the fusion commu-nity identified challenges for inertial fusion energy in twoareas: inertial fusion energy targets, and repetitive driverpower plants. We discuss these major areas in turn.
A.2.1 Inertial Fusion Energy Targets
Advance the fundamental understanding andpredictability of high energy density plasmas forIFE, leveraging from the ICF target physics worksponsored by the National Nuclear Security Agency’sOffice of Defense Programs.
A crucial step in inertial fusion energy research isthe development and demonstration of target physicsleading to ignition and high-yield/high-gain targets.The target categories include direct-drive (where thedriver energy couples directly to the target), indirect-drive (where the driver energy is converted to x-rays,which then couple to the target), and fast ignition(where an intense petawatt driver ignites a spot in atarget compressed by a main driver–laser, heavy ion, orz-pinch). Target physics challenges include driver/tar-get interaction and coupling, energy transport and sym-metry to the target, implosion dynamics and equationof state (EOS) of materials, hydrodynamic instabilityand mix, and ignition and burn propagation. Thedevelopment of target physics research in NNSA leadsnaturally into the development of high-yield/high-gaintargets needed for IFE.
A.2.2 Repetitive Driver Power Plants
Develop the science and technology of attractiverep-rated IFE power systems, leveraging from thework sponsored by the National Nuclear SecurityAgency’s Office of Defense Programs.
An IFE system consists of a main driver (laser,heavy ion, z-pinch), a target (indirect-drive, direct-drive, fast ignition), and a chamber concept (dry-wall,wetted-wall, thick liquid wall). The mainline approachfor lasers is to use a rep-rated KrF laser or rep-rateddiode-pumped solid-state laser, a direct-drive target,and a solid-wall power chamber. The mainline approachfor heavy ions is to use a rep-rated induction linac heavyion driver, an indirect-drive target, and a thick liquidwall chamber. The mainline approach for z-pinches is touse a rep-rated z-pinch driver, an indirect-drive target,and a number of thick liquid wall chambers. A fastignition target is an option for any of the three maindrivers.
Each driver concept must pass through the proof-of-principle (PoP) phase of development and theIntegrated Research Experiment (IRE) phase of devel-opment. Each phase of development includes R&Don rep-rated drivers, energy transport to the target(final focus magnets for heavy ions, final optics forlasers, and recyclable transmission line placement for
A Plan for the Development of Fusion Energy 89
z-pinches), IFE target physics, target fabrication, targetinjection or placement, chamber walls, and power plantsystem optimization.
Following the PoP and IRE phases of develop-ment, the three approaches will then compete for devel-opment of a single Engineering Test Facility (ETF) thatwill lead to a DEMO. This ETF will be in competitionwith an MFE Component Test Facility (CTF), and inthis plan, only one of these will go forward to supportDemo.
APPENDIX B: PROGRAMS AND MAJOR FACILITIES
This appendix provides descriptions of each of theprograms and major facilities in the plan shown inFigures 5–7.
B.1 Theory, simulation, and basic plasma science
The goal of theory and simulation in the fusionenergy development path is to provide the theoreticalunderpinning for understanding and predicting thebehavior of fusion plasmas, and to develop a compre-hensive simulation capability for carrying out “virtualexperiments” of fusion core systems. This capabilityis essential for rapid scientific and technologicalprogress in all plasma experiments from conceptexploration through Demo, as well as in other criticalareas, such as materials development, in order to reachthe plan’s goal.
Improvements in physics understanding andtheoretical descriptions for all physical processesin key areas that govern the performance of fusionsystems will be needed. This should translate into acapability to perform detailed numerical simulationsof individual components utilizing high performancecomputers, which will be used to quantitativelyvalidate against experimental measurements. ForMFE, this effort has been accelerated under the DOEScientific Discovery through Advanced Computinginitiative (SciDAC), and further development ofintegrative capabilities is being proposed by theIntegrated Simulation of Fusion Systems (ISOFS)FESAC Panel. A key long-term deliverable is theFusion Plasma Simulator that is capable of compre-hensive simulation of all relevant processes in fusionsystems. It will also serve the important purposeof transferring knowledge gained from more maturesystems to exploratory configurations. Within the
National Nuclear Security Administration advancedcomputing for Inertial Confinement Fusion is incor-porated within the Advanced Scientific ComputingInitiative (ASCI), but increased efforts are requiredin parallel with ASCI to understand ion beamdynamics and to optimize target designs for IFEincluding the fast ignition approach.
The progress of the theory and simulation programwill be measured by the quality of its scientific publi-cations including impact on related fields of science;effectiveness in supporting the understanding, interpre-tation, and planning of ongoing fusion experiments;means to enable the exploration of new concepts andconfigurations to improve the prospects for economicalfusion power and enhanced ability to predict theperformance of future fusion devices.
The primary goal of basic plasma experimentsis to study fundamental plasma phenomena in thesimplest and most flexible situation possible andover a wide range of relevant plasma parameters.Although basic plasma experiments are not intendedto focus directly on a particular application, they canbe expected to provide a quantitative understandingof the underlying physical principles and to have sig-nificant impacts on an entire spectrum of applicationsincluding, but not limited to, fusion energy develop-ment. The interconnections to other areas of scienceand technology broaden the impact of fusion researchand bring new ideas and techniques into the fusionarena. Another important consequence of this effortis the training of future plasma experimentalistsneeded for implementing the fusion energy develop-ment plan.
The success of the basic plasma experimentalprogram can be measured by its contributions to theunderstanding of basic plasma processes such as chaos,turbulence and magnetic reconnection; and to spin-off technologies such as plasma processing of com-puter chips, space thrusters and waste remediation. It isexpected that new knowledge and technology will alsodirectly benefit fusion energy development. The qual-ity of the plasma scientists entering the field will beanother indicator of success.
To maintain a strong basic plasma experimen-tal program in the most efficient and cost-effectiveway, emphasis should be placed on university-scaleresearch programs. The on-going Partnership in BasicPlasma Science and Engineering, funded jointly byDOE and NSF, is an effective way to ensure thecontinued availability of the basic knowledge that isneeded for the development of applications. Thecreation of the joint DOE/NSF Centers of Excellence in
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Fusion Plasma Science recommended by the NAS/NRCin its 2001 fusion Report would be extremely beneficial.In addition, creation of joint programs between theOffice of Fusion Energy Science and the Office ofBasic Energy Science would further leverage DOE’sinvestment in plasma science and strengthen investiga-tions in other energy-related areas of plasma scienceand technology.
B.2 Configuration optimization
Configuration optimization is required in orderto have confidence that an attractive fusion config-uration will be available for Demo. In the MFE casethis includes the advanced tokamak, the most devel-oped configuration, as well as the spherical torus, thecompact stellarator, the reversed-field pinch and arange of more self-organized systems, typically atlower levels of investment. Some Concept Explorationfacilities, particularly in the tokamak, stellaratorand ST areas, examine specialized issues in supportof larger facilities. There is strong scientific cross-fertilization between configurations, ideas are ex-changed and hybrid configurations emerge. A broadportfolio strengthens the quality of fusion science, andwidens its application beyond the fusion arena. An im-portant aspect of this research is the development andapplication of innovative plasma measurement tools sothat theory and simulation can be validated againstexperiment in specific detail.
In the IFE case driver systems include diode-pumped solid-state lasers and krypton fluoride lasers,heavy ion beams and Z pinches. A range of compres-sion and heating schemes is under study (indirectdrive, direct drive and fast ignition), as well as arange of chamber technologies (dry wall, thin wettedwall and thick liquid wall). Specific combinationsare considered most compatible based on physics,engineering and economic viewpoints and are beingpursued as integrated approaches.
B.2.1 MFE Concept Exploration/Proof of PrincipleExperiments
A peer review process ensures that the most inno-vative and potentially attractive systems are constantlybeing evaluated at the introductory Concept Explorationstage. Two illustrative examples are the Spheromakand the Levitated Dipole. The Spheromak is highlyself-organized plasma, in which plasma ejected froman electromagnetic “gun” forms itself into a toroidal
configuration within a conducting shell. The interest-ing aspect of this configuration from a power plantperspective is that no material structure links the torus,simplifying the fusion chamber considerably. Theplasma science challenges are great, however, as con-trol of the strong magnetic turbulence within theplasma, which spoils confinement, is needed to makethis an attractive candidate for fusion energy applica-tion. The goal of present experiments is to understandthis turbulence and determine if higher temperatureplasmas will be more quiescent. The Levitated Dipolein many ways examines an extreme opposite configu-ration. In this case most of the magnetic field isformed by a levitated superconducting ring, which issurrounded by a plasma with such weak pressure gra-dients that it is calculated to be very stable, in analogyto the high pressure plasma atmosphere found aroundJupiter. For fusion application the greatest challengeswill be to maintain such a floating ring in a fusionenvironment, even using advanced low-neutronic fuelssuch as D-3He, and to collect fusion power efficientlyat low overall power density.
Two systems are currently being investigatedwithin MFE at the next level of development, Proof ofPrinciple. These are the Spherical Torus and theReversed Field Pinch. The Spherical Torus is the low-aspect ratio limit of the tokamak, in which the centraldoughnut hole is minimized. This configuration offersvery high �t, the ratio of the plasma pressure to theapplied toroidal magnetic field pressure. As a result itcan employ rather low magnetic fields, with the resultthat the potential impacts of plasma “disruptions” arereduced, and the magnets can be made simpler. Theslender center column of such a system can beremoved easily for maintenance, providing simpleraccess to the core of the system. This system is a pos-sible candidate for use as a Component Test Facility(see below). Its application to Demo would requireminimization of the recirculating power needed tomaintain the electric current in the copper centercolumn. The other system under investigation, theReversed Field Pinch, is similar to a tokamak, butwith a very low toroidal magnetic field. Recentexperiments have shown transient techniques to stabi-lize the magnetic turbulence in such systems, givingtokamak-like confinement. If long-pulse approachesto turbulence stabilization can be devised, this approachcould lead to significantly less expensive fusion sys-tems. A third system has been approved by FESACfor Proof of Principle, the Compact Stellarator, and iscurrently under construction. It is similar in manyways to the advanced tokamak, but uses complex
A Plan for the Development of Fusion Energy 91
asymmetric magnetic coils to provide stability andconfinement. This system does not require externaldrive to maintain its magnetic configuration, as doesthe tokamak, and experimentally stellarators arefound to disrupt only under very unusual circum-stances. Through the exploitation of a new form ofunderlying symmetry this system is calculated tocombine the high power density of a tokamak with thestability and steady-state features of stellarators, thuspotentially providing improvements in all three keyareas: reliability, mass power density and recirculat-ing power.
B.2.2 MFE Performance Extension (PE) Experiments
The next level of development beyond Proof ofPrinciple is Performance Extension (PE). At thislevel configurations are tested at more fusion-likeplasma conditions. While there are PE-class stellara-tors in construction and operation abroad, the onlyPE devices in the U.S. are tokamaks. These devicesare productive experiments providing critical resultsfor the final design and then operation of a burningplasma experiment. Examples include control andamelioration of instabilities that limit the achiev-able fusion power density or potentially damage theplasma facing components; and disruption avoidanceand mitigation. Many experiments worldwide rou-tinely obtain similar operating regimes with energyconfinement scaling meeting the needs of a burningplasma experiment. Progress in fundamental under-standing of plasma transport and stability has pro-vided confidence in extrapolating present results tofuture devices. In addition PE-class facilities havea strong focus on developing improved performanceoperating modes. In tokamaks this is called “AdvancedTokamak” operation. Desirable features are steady-state operation with a high fraction of self-generatedcurrent, to reduce recirculating power, and increasedpressure limits to increase fusion power density. Inthe advanced tokamak these will be accomplishedlargely through active control of current, transportand pressure profiles. This mode offers the potentialto resolve key issues facing the tokamak, allowingit to progress confidently to the CTF and/or Demostage.
Existing PE tokamaks are making good progressin studying key aspects of the advanced regimes forlimited durations, in parallel with efforts to mitigatethe impact and frequency of plasma disruptions. Majornew international facilities in China, Japan and Korea
are being designed and constructed to demonstrateadvanced performance in steady-state for plasmas withminimal self-heating. It is a major challenge to achievesimultaneously all desirable features with high reli-ability, which is a necessary step for the tokamak toproceed to a Demo.
In the period before Demo it is anticipated thatone or more of the configurations currently at theProof-of-Principle stage could graduate to Perform-ance Extension. It should not be excluded even that anattractive configuration currently at the Concept Ex-ploration stage could advance rapidly. Together withresults from a burning plasma, and advanced compu-tation, a successful Performance Extension experimentcould allow Demo to take on a configuration differentfrom the advanced tokamak.
B.2.3 IFE Concept Exploration/Proof of PrincipleExperiments
Smaller scale experiments evaluate selected sci-entific and technical feasibility issues for promisingIFE approaches. Current experiments in this categoryinclude the Electra krypton fluoride (KrF) laser, theMercury diode pumped solid-state laser (DPSSL), aset of high-current heavy-ion beam experiments thataddress three key aspects of a heavy-ion accelerator-injection (Source Test Stand), transport (High CurrentExperiment) and focusing (Neutralized TransportExperiment). For heavy ions, an Integrated BeamExperiment (IBX) that in effect combines the currentset of three beam experiments is required before aheavy-ion Integrated Research Experiment (IRE, seediscussion below). For z-Pinch IFE, following presentexperiments to test the recyclable transmission line(RTL) concept on the Saturn z-pinch facility, a setof experiments (RTL optimization, rep-rated pulsedpower, blast mitigation, scaled RTL cycle) is requiredbefore a z-pinch IRE. There are concept-explorationlevel experiments on the physics of fast ignition beingcarried out by U.S. researchers on the Gekko-XII laserfacility in Japan, the LULI laser facility in France, andon the Vulcan laser facility in the Rutherford-AppletonLaboratory in the UK. Also capsule compressionexperiments for the fast ignition approach are beingcarried out on Z and Omega.
To qualify for the IRE level, each IFE approachmust (a) resolve key proof-of-principle driver issues(efficiency, reliability, focusability, cost) that arespecific to each approach, (b) have adequate gain IFEtarget designs with 2-D hydrostability for plausible
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beam non-uniformities, (c) show plausible pathwaysfor target fabrication and injection or placement, (d)have a chamber design concept that is self-consistentwith target illumination geometry, final focus andbeam propagation or RTL placement, chamber clear-ing, and adequate lifetime. Target physics experimentsrelevant to (b) are currently being carried out onOmega, Nike and Z. Target fabrication/injection R&Dis carried out leveraging existing NNSA target R&Dfacilities, as well as a new target injection experiment,for both direct and indirect drive targets. Universitiescarry out a number of small scale chamber experi-ments to benchmark models for both liquid anddry wall chamber concepts, and IFE materials testingis being performed on Z (for x-rays) and on RHEPP(for ions).
B.2.4 IFE Integrated Research Experiments (IREs)
Integrated Research Experiments (IREs) are non-nuclear facilities for qualifying approaches to IFEwhose objective is to validate driver and chambertechnologies required for an Engineering Test Facility(ETF). Both full scale and subscale components aretested in the IRE programs, which are designed toensure that key driver, chamber and target compo-nents can work together with the required efficiency,pulse-rate, durability and precision, and at costs thatscale to economical fusion energy. The IRE programs,together with target physics results from the NationalIgnition Facility (NIF), Omega, and Z, are to providethe scientific and technical basis for the EngineeringTest Facility (ETF, see below). Initial megajoule-class implosion results from the NIF are expected atabout the earliest time that a construction decisionwould be required for an IRE. Current research fo-cuses on three approaches: (1) krypton-fluoride (KrF)or diode-pumped solid state (DPSSL) laser driverswith direct-drive targets and dry-wall chambers, (2)heavy ion accelerator driver with X-ray indirect-drivetargets and thick-liquid protected chambers, and (3) z-pinch driver with X-ray indirect-drive targets andthick-liquid protected chambers. Fast ignition, if suc-cessful, may enhance the gain of either direct-drive orindirect-drive targets, and may relax driver and targetrequirements in each approach.
To qualify for the ETF, each IRE program mustresolve the key issues that enable an ETF: for thelaser approaches–laser efficiency, durability, cost andbeam quality, target fabrication and injection, firstchamber wall materials and protection, and final optics
durability; for the heavy ion approach–focal spot sizeunder fusion chamber relevant conditions, acceleratorcost, target fabrication, thick liquid protected cham-bers with target material recovery and focus magnetlifetime; for the z-pinch approach–economical RTLs,blast mitigation effects for the first wall, rep-ratedpulsed power, target fabrication, and thick liquidprotected chambers with target material recovery. Inaddition to these IRE outputs, the ETF would requireadequate target physics data from NIF and other ICFfacilities on implosion symmetry and capsule/fuellayer smoothness, and high confidence 3D calcula-tions for IFE targets, validated with data from NIF,Omega, and Z.
B.3 Burning plasma
Burning plasma experiments are required in orderto provide understanding of the physics of self-heatedplasmas. In both MFE and IFE a burning plasmaexperiment will contribute basic physics informationof relevance to a range of fusion configurations.
The world effort to develop fusion energy isat the threshold of a new stage in its research: theinvestigation of burning plasmas. This investigation,at the frontier of the physics of complex systems,would be a dramatic step in establishing the poten-tial of fusion energy to contribute to the world’senergy security.
The defining feature of a burning plasma is that itis self-heated: the 100 million degree temperature ofthe plasma is maintained mainly by the heat generatedby the fusion reactions themselves, as occurs in burn-ing stars. The fusion-generated alpha particles producenew physical phenomena that are strongly coupled to-gether as a nonlinear complex system. Understandingall elements of this system poses a major challenge tofundamental plasma physics. The technology neededto produce and control a burning plasma presents chal-lenges in engineering science largely along the path tothe development of fusion energy.
B.3.1 MFE Burning Plasma
A burning plasma is a crucial and missingelement in the world magnetic fusion program. Thedefining feature of a burning plasma is that it issustained primarily by the heat generated through itsown internal fusion reactions. This is in contrast toprevious experiments in which most of the heating wasapplied from outside the plasma. When these reactions
A Plan for the Development of Fusion Energy 93
occur in a fusion power system, energetic alpha parti-cles (helium nuclei) and neutrons are generated. Thealpha particles are confined by the magnetic field andslow down, transferring their energy to maintain thehigh temperature of the plasma. When fusion alphaheating dominates the plasma dynamics, importantnew scientific frontiers will be crossed. To create aburning plasma on Earth and systematically determineits properties will be an enormous step forward forfusion energy research. It will enable major advancesin all of the key areas of plasma science and technol-ogy, and contribute to the demonstration of magneticfusion as a source of practical energy. While deliver-ing the fusion-sustaining heat, the alpha particles alsorepresent a new dynamic source of energy to changethe plasma pressure profile. Such changes in theplasma structure and dynamics can increase the loss ofheat and particles from the plasma, and consequentlylead to a reduction in fusion power. Alternatively,these changes may lead to a further increase in tem-perature and fusion power production. Understandingand controlling these effects on heat and particletransport, the subject of “burn control,” are essentialelements of power plant development.
The U.S. has decided to join the negotiations forthe construction of ITER, as recommended by FESAC.If ITER goes forward it will fulfill all of the require-ments for an MFE burning plasma experiment. On theother hand, if the international negotiations do notsucceed, and ITER does not go forward, FIRE is anattractive option for the study of burning plasmascience as discussed by FESAC. Either ITER or FIREcould serve as the primary burning plasma facility,although they lead to different fusion energy develop-ment paths. Both devices are designed to achieve theirtechnical goals on the basis of conventional pulsedtokamak physics, but have capability to investigateadvanced tokamak modes of operation. In the ITERcase, the capability for long pulse and steady-stateoperation is provided. Moreover, a substantial amountof fusion technology development and testing isprovided as well. In the FIRE case an additional high-performance (but non-burning) steady-state experi-ment would be required in parallel. A scenarioincluding FIRE, rather than ITER, is considered inSection 5.7.
B.3.2 IFE Burning Plasma
The National Ignition Facility (NIF), a NationalNuclear Security Administration (NNSA) facility sched-
uled for completion in 2008, is tasked with achievingthermonuclear ignition. The NIF experimental programwill begin soon after first light with the first 4 beams,which is currently expected toward the end of FY03.As more beams are added, increasingly complex targetexperiments will be possible. By the end of FY07 itshould be possible to begin high quality symmetryexperiments in support of ignition. The full capability ofNIF for ignition experiments is planned to be availableat the end of FY08. Direct drive capability is anticipatedto be available in 2013.
NIF will be capable of testing a variety of igni-tion target approaches. In all IFE targets the fusionfuel is compressed before it is ignited. There are twobroad methods of compression and two methods ofignition. The fuel is compressed either through animplosion driven directly by the driver beams (directdrive) or by converting the driver energy to x raysthat then drive the implosion (indirect drive). Thetwo classes of ignition are central hot-spot ignitionand fast ignition. In hot-spot ignition, the implosionboth compresses and heats a hot spot in the center ofthe fuel. This spot ignites and subsequently burns therest of the fuel. These target designs are the mostmature. In fast ignition, the target is compressed byone driver, and a spark is ignited by a separate, veryhigh intensity source such as a short pulse laser. Fastignition could be used with any of the main driverconcepts.
NIF will initially be configured for indirectdrive with hot spot ignition, and can later be config-ured for direct drive. With the development of newtechnology, it could also be configured for fast igni-tion. Although NIF will be carrying out laser drivenignition experiments, much of the physics is applica-ble to targets imploded with other drivers. This isparticularly true for indirect drive where almost allthe physics, except the process of x-ray generation,applies to targets imploded with ion beams orZ-pinch pulsed power drivers. In addition to NIF,over the next decade, critical physics data for ignitionphysics including fast ignition will be provided byother NNSA facilities (Omega, Nike and Z) as wellas international facilities.
NIF employs a flash-lamp pumped glass laserwhich is quite flexible as a research facility, but isdesigned only to explore single-shot target physics.Hence the NIF will provide relatively little informa-tion on the repetitive high average power driveror chamber technology required for IFE, althoughsome specific data, e.g., on debris creation, will berelevant.
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B.4 Materials
B.4.1 Materials Science/Development
The neutrons produced by fusion reactions,which are more energetic than those produced bynuclear fission, lead to unique damage problems forthe materials surrounding the fusing plasma. Thedevelopment of advanced materials is required forMFE and for the IFE development pathways that donot make use of a thick liquid wall, and even in thelatter case some materials development and testingwill be required. Accelerated lifetime testing of mate-rials to be used in a fusion power plant must be avail-able in order to have confidence in the materialsemployed for Demo.
One of the main technical challenges for thesuccessful development of fusion energy is thedevelopment and qualification of materials for thefirst wall, high heat flux components, breedingblanket components, and various special purposematerials (optical materials, insulators, mirrors,etc.). The overarching goals of the fusion materialsR&D program are 1) to establish the technical andeconomic feasibility of environmentally attractivefusion energy systems, and 2) to improve the attrac-tiveness of fusion energy by utilization of improved,innovative materials systems.
Due to the wide range of performance require-ments for the various individual materials needed indiverse assemblies in a fusion power plant, a broad-based R&D program is required to guide power plantdesign and provide key input for integrated componenttests. The final product is the validated database (andassociated knowledge base) required for Demo approvaldecisions. At the present time there are over ten dif-ferent fusion power conversion (blanket) conceptsthat have been identified as viable candidates for MFEand IFE. The underlying knowledge base from thefusion materials R&D effort will be key in the initialdown-selection to a handful of the most promisingconcepts. The R&D program must include both non-irradiation and irradiation tests, along with underlyingtheory and modeling that guide the interpretation andextrapolation of experimental results. Both structuraland non-structural materials systems must be exam-ined, as well as chemical compatibility issues. Theperformance capabilities of irradiated materials willlargely determine the allowable temperature (andtherefore thermodynamic efficiency, which directlyaffects cost of electricity), power density, and lifetime.Utilization of high-performance radiation-resistantreduced activation materials can significantly improve
the safety aspects and waste disposal burden of fusionpower plants.
The time scale to develop fully a new materialfor commercial use is typically well over 10 years. An -enhanced, sustained and focused materials research pro-gram is essential to meet the specialized materials needsof the demanding environment in Demo 35 years fromnow. The most promising materials systems would besubjected to integrated component testing.
B.4.2 International Fusion Materials IrradiationFacility (IFMIF)
Since the development and qualification ofradiation-resistant structural materials that can sur-vive exposures to �10 MW yr/m2 (essential for thetechnological viability of fusion) is considered to bethe most challenging and schedule-controlling materi-als issue, a dedicated intense fusion neutron source isneeded early in the 35 year fusion development path.
Fundamental experimental and modeling studiesperformed over the past 20 years have established thatmost of the key atomic displacement features for DTfusion neutrons interacting with materials are similar tothose found with fission neutrons. This validates muchof the fission test reactor database as a valuable initialscreening tool for evaluating the radiation stability offusion materials. However the higher production oftransmutation products such as H and He by energeticfusion neutrons is predicted to have significant influ-ence on the microstructural stability of materials for flu-ences above �0.5�1 MW yr/m2 (�5�10 displacementsper atom). Therefore an intense high-energy neutronsource is an essential facility for development and qual-ification of the materials of the first wall, plasma fac-ing components, and breeding blanket components ofDemo concepts that do not utilize a thick liquid wall.International assessments have concluded that the min-imum requirements for this facility include: �0.5 litervolume with �2 MW/m2 equivalent neutron flux toenable accelerated testing up to at least 10 MW yr/m2
(and larger volumes at lower neutron fluences), avail-ability �70%, and flux gradients 20%/cm. Internationalassessments have concluded an accelerator-driven D-Listripping neutron source, with two 125 mA deuteronbeams of 40 MeV energy focused onto a flowing Litarget (5 � 20 cm beam footprint) would meet therequirements. The international conceptual design ofsuch a facility, called the International Fusion MaterialsIrradiation Facility is now complete, with a stage ofengineering validation required before engineering
A Plan for the Development of Fusion Energy 95
design can commence. In order to obtain the requiredinformation for the design of a Demo reactor that wouldoperate in 2037, this engineering validation phaseshould be entered expeditiously and engineering designshould begin with five years.
B.5 Engineering Science/Technology Development
B.5.1 Plasma Technologies
It is important to recognize that there is an ongo-ing need for enabling plasma technologies to supportthe configuration optimization experiments at alllevels as well as the burning plasma and componenttesting stages. Continued innovation and long-termdevelopment for Demo are required as well. Most ofthe improvements in plasma performance were madepossible by improved plasma technologies such asplasma facing components, plasma fueling methods,and better heating technologies.
The development of the technological tools to heat,fuel and control high-temperature plasmas has beencrucial to progress in plasma science. Next generationconfinement devices will need improved tools such asmore efficient plasma heating systems, more robust in-vessel components (e.g., RF antennas), high-throughputfueling systems, plasma facing components able towithstand higher heat and particle fluxes and improvedand less expensive magnets. The development of theplasma technologies proceeds hand-in-hand with plasmaconfinement improvements. Burning plasma devicesin particular carry plasma technologies into the scalerequired for fusion energy systems and require thedevelopment of plasma technologies that will function ina fusion environment.
The successful development of high performanceplasma facing components (PFCs) is central to theoverall development of fusion, and has posed progres-sively more difficult challenges as the power of fusiondevices has increased. Helium ash removal requiresparticle flow to the first wall region (e.g., divertor)and with the particles comes intense heat. PFCs arebombarded by energetic neutrals, ions, electrons andphotons and must survive intense plasma-materialsinteractions, without contaminating the plasma. In longpulse devices, PFCs must continuously remove highheat fluxes while withstanding off-normal heating tran-sients. In DT devices, remotely maintained PFCs mustsurvive neutron radiation and cyclic thermal heat loadswhile avoiding unacceptable tritium inventories.
In order to complete the R&D for ITER, it willbe necessary to demonstrate reliable operation of a
prototype, multimegawatt, 170 GHz gyrotron, win-dow, power supply, transmission line and launcher. Adevelopment path would consist of final developmentof each component, construction of a test stand andlifetime testing of the system. Cost reduction in manu-facturing would also be an objective.
Present day ion-cyclotron heating (ICH) systemshave demonstrated the viability of this technology, butsubstantial R&D will be required to make robustlyreliable systems that could be used on ITER andpotentially DEMO. Prototypes of antenna launchersshould be built to validate the mechanical and electric-al designs. It is necessary for these antenna systems tooperate reliably at the required voltage levels. R&D isneeded to understand the fundamental reasons forbreakdown, to develop techniques to avoid it, and toacquire the desired confidence level in the projectedperformance. Advanced antenna designs encompassesseveral innovative ideas that should improve the oper-ation and reliability of the ICH system. Testing ofthese new concepts will be needed in dedicated teststands as well as in a real plasma environment.
Future fueling (and, for tokamaks, related disrup-tion mitigation) systems will require significant extra-polations beyond present-day performance in boththroughput (ie. approaching steady state), velocity(ie. to the burning plasma regime) and reliability andflexibility. A progression in development objectivesfor ITER, CTF, and DEMO is envisaged along withincreasing-scale dedicated test stands for prototypetesting with full DT capability.
Superconducting magnet systems represent amajor cost element for long-pulse or burning-plasmadevices. While dramatic progress has been made indevelopment of large-scale DC and pulsed Nb3Snmagnets for ITER at up to 13 T, further increases inperformance (16T) and reductions in cost should berealized by development of higher performance super-conductor (both low and high temperature), higherstrength structural materials, more radiation-resistantinsulators, improved quench detection techniques, andrelated R&D on joints, leads, feedthroughs, refrigera-tion etc. Dedicated test stands such as a PulsedSuperconducting Magnet Facility and full-scale proto-types will complement this component developmentprogram.
B.5.2 Fusion Chamber and Power Technologies
The fusion chamber is the core of the fusionpower plant that surrounds the plasma in MFE (or the
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target in IFE) and includes the blanket and plasmafacing components that must breed the tritium fueland convert the high fluxes of neutrons and alphapower from the fusion reaction into high grade heat.The goal of the Chamber Technology Program is todevelop the technologies required to attain tritium selfsufficiency, operate at high temperatures to achievehigh thermodynamic efficiency, and provide the par-ticle pumping, impurity control and vacuum condi-tions necessary for stable plasma operation. Highperformance, safety, reliability, and maintainabilityare key objectives of the program as they are funda-mental to the development of attractive fusion energysystems.
Several concepts for the chamber are beingpursued in the U.S., Japan and Europe. The lithium-containing tritium breeder can be a liquid metal,ceramic, or molten salt. Liquid metals, molten saltsand helium are options for cooling. Ferritic steels,vanadium alloys and SiC/SiC composites are optionsfor structural materials. Beryllium is required as aneutron multiplier in most concepts. Tungsten, tanta-lum, molybdenum and copper are options for theplasma facing components. The chamber may alsoinclude a variety of electric and thermal insulators andtritium permeation barriers. All these concepts havesome common and many widely different feasibilityand attractiveness issues that must be addressed in anextensive R&D program.
Key issues include sufficient tritium breeding in ahighly heterogonous system, in-situ tritium release andrecovery, tritium containment, thermomechanicalloadings and responses, MHD effects, integrity ofinsulators and structure, materials interactions, syner-gistic effects, resistance to off-normal events, failuremodes, effects and rates, and rapid remote mainte-nance. Interestingly, promising new concepts for MFEchambers, based on flowing liquid metals along thechamber walls, have emerged based on interactionswith the IFE community.
The R&D program includes developing phe-nomenological and computational models; exploringdesign options with emphasis on innovation, funda-mental understanding, and comprehensive engineeringanalysis. Experiments in laboratory scale non-neutrontest stands, fission reactors, and accelerator-basedneutron sources are able to simulate single effectphenomena and a limited number of multiple effectphenomena. Hence they are useful in narrowingmaterial and design concept options but they cannotestablish the engineering feasibility of the fusion
chamber for Demo. Testing in the fusion environmentis required.
A fusion chamber must operate under intensefluxes of neutrons, surface heat loads, and particles, me-chanical and electrical forces, and, for MFE, magneticfields. There are large gradients in the loading condi-tions and responses (e.g. radiation field, magnetic field,nuclear heating, temperature, stress, atomic displace-ment, tritium concentration) that make numerical andexperimental simulations challenging. Synergistic ef-fects due to combined environmental conditions (neu-tron/magnetic/electrical/thermomchanical/chemicalinteractions) and interactions among the physical ele-ments of the chamber components (e.g. tritium pro-ducer/multiplier/structure/coolant/ insulators) result innew phenomena unique to the fusion environment. Suchnew interactive phenomena and synergistic effects re-quire testing in the fusion environment. Multiple inter-action and integrated tests in the fusion environment arenecessary to resolve the key issues, establish the engi-neering feasibility, select the most promising concept,and to improve the performance, safety, reliability, andmaintainability toward an attractive and competitive fu-sion energy system.
For heavy-ion and z-pinch IFE (and possibly someMFE configurations), the primary approach is thickliquid wall concept, in which about 1m of lithium con-taining molten salt (FLiBe) is formed around the targetcavity. Liquid walls allow high heat and neutron fluxesand do not experience permanent deformation in theintense radiation field. Most materials are locatedbehind the thick liquid in a lower radiation field envi-ronment where they may last the lifetime of the plantand long-term radioactivity is low even for currentlyavailable austenic stainless steels. Fission tests maysuffice to determine the neutron-damage lifetime ofsuch structures.
The key issues for the thick liquid wall conceptare fluid hydrodynamics (including shock mitigation),reliable operation of the oscillating nozzles used toform the liquid wall and vapor condensation andchamber clearing. These issues can be largely resolvedby computational modeling and testing in low-costlaboratory experiments. Final validation of the conceptwill be performed in the integrated fusion environmentof the ETF.
The dry wall chamber concept for laser IFEhas similarities to those considered for MFE. Many ofthe key issues are similar, except for the absence ofmagnetic field interactions and the presence of pulsedx-ray, heat, neutron and debris-ion effects.
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B.5.3 MFE Component Test Facility (CTF)
For MFE, the Component Test Facility, CTF, isan experimental DT-fusion facility which is to provide afusion environment for affordable testing, optimization,and qualification of prototypes of fusion chamber sub-systems for Demo, including first wall/blanket modulesthat both breed tritium and convert fusion power tohigh-grade heat, plasma-interactive and high-heat-fluxcomponents such as the divertor, and tritium processingand remote maintenance systems. The facility’s conceptwill be optimized to provide high neutron wall loadand fluence at minimum overall fusion power in orderto enable integrated testing and optimization of a seriesof components at minimum tritium consumption andoverall cost.
The CTF will enable a Demo with performancesufficiently attractive to motivate rapid deployment offusion as a commercial energy source. A developmentpath with a CTF provides a significant competitiveadvantage over development paths that perform compo-nent testing on Demo, because the flexibility of thesmaller, lower power facility enables more rapid andbroader-ranging prototyping. The facility must enabletesting at a neutron wall load of 1 MW/m2 and cumula-tive neutron fluence greater than 6 MW years/m2 overa testing area greater than 10 m2 and volume greater than5 m3, with duty cycle greater than 80%, and overall avail-ability above 30%. To enable cost-effective operationwith affordable tritium consumption, the facility is opti-mized for minimum size and fusion power (�150 MW)and would likely be operated in a driven mode. In laterstages, the facility may achieve a tritium-breeding rationsufficient for the facility to be a supplier of tritium forthe start-up of Demo, and could also achieve higher out-put power, potentially even leading to net electric pro-duction. Candidate concepts for the facility include thesteady-state tokamak, the spherical torus and the gas-dynamic trap. High power density and high availabilityare challenging metrics for the success of the CTF.
CTF will be a full nuclear facility, and the deci-sion to take this step will depend upon success in theinitial phases of the burning plasma experiment andthe development of an attractive cost-effective config-uration for this device.
B.5.4 IFE Engineering Test Facility (ETF)
The ETF, or Engineering Test Facility, is the finalstep in the development of inertial fusion energybefore building the DEMO. It may be capable of
generating net electrical power at low levels (between100 and 300 MW) and low availability. The ETF willhave operational flexibility and will carry out threemajor functions:
1. Demonstrate and integrate a near full scaledriver.
2. Optimize targets for high yield. It is anticipatedthat NIF will map out parts of the gain curve, butwill not provide the required data to optimizetargets for IFE.
3. Test, develop, and optimize the chamber con-figuration in a full nuclear environment. Thisincludes the first wall and blanket, tritiumbreeding, tritium recovery, and thermal man-agement.
For Tasks 1 and 2 the ETF will need a driver, andfinal optics/power focusing system for lasers or heavyions, or recyclable transmission line (RTL) forz-pinches, that is roughly on the same scale as thatneeded for the DEMO. The ETF will have a targetfactory and target injection/placement system that is ca-pable of producing and injecting full targets on a repet-itive (5–10 Hz) long-term basis for lasers or heavy ions,or on a repetitive (0.1 Hz/chamber) long term basis forz-pinches. These are expensive components, and it isanticipated they will be carried over to the Demo withlittle modification, although technological developmentmay provide improved options. For Task 3 (chamberoptimization) the ETF will use reduced yield targets(about 1/4 to 1/9 full yield), and a chamber that is about1/2 to 1/3 the linear dimension expected for DEMO.This keeps the wall loading at power plant levels, butreduces the total fusion power in the system, which inturn lowers development costs as well as minimizesheat transfer and tritium handling issues. At this pointIFE would be ready to proceed to the DEMO phase.Under some approaches the DEMO might only requirethe addition of an advanced chamber to the ETF. It isrecognized that the ETF is a major step. It is a full nu-clear facility of a scale comparable to Demo and at mostone IFE concept will be carried to this phase.
B.6 Systems Analysis, Design, and Demo
B.6.1 Systems Analysis and Design
Systems analysis and design supports major pro-gram evaluation and decision points and guides fusionresearch and development toward practical products.
98 Goldston et al.
System designs for all configurations, magnetic andinertial, need to be updated in a timely manner as newadvances are made in fusion science and technology.Objectives of such activities include (1) establish,standardize and maintain codes for evaluating costsand systems issues for fusion designs, (2) evaluatevarious potential commercial applications, (3) prepareand evaluate designs of Demo, power plant and otherapplications for all credible fusion concepts andapproaches, (4) identify high leverage issues, (5) eval-uate and optimize various possible development paths,(6) identify and evaluate issues associated with safety,environment and licensing, (7) establish and maintainan engineering database, (8) evaluate the potential ofnon-DT fuel cycles, and (9) maintain and criticallyevaluate market factors and status of competitivetechnologies.
B.6.2 Demo
The U.S. fusion demonstration power plant (Demo)is the last step before commercialization of a fusion
concept. It must open the way to rapid commercializa-tion of fusion power, if fusion is to have the desiredimpact on the world energy system. Demo is built andoperated in order to assure power producers and thegeneral public that fusion is ready to enter the com-mercial arena. As such, Demo represents the transitionfrom a laboratory experiment to a field-operated com-mercial system. Demo must provide energy producerswith the confidence to invest in commercial fusion astheir next generation power plant, i.e., demonstratethat fusion is affordable, reliable, profitable, and meetspublic acceptance. Demo must also convince publicand government agencies that fusion is secure, safe,has a low environmental impact, and does not depletelimited natural resources. In addition, Demo mustoperate reliably and safely on the power grid for longperiods of times (i.e., years) so that power producersgain operational experience and the public is con-vinced that fusion is a “good neighbor.” To instill thislevel of confidence in both the investor and the public,Demo must achieve high standards in safety, low envi-ronmental impact, reliability, and economics. Table 5presents the top-level goals for the U.S. Demo.
Table 5. Top-Level Goals for the U.S. Fusion Demo
Safety and environmental impact:1. Not require an evacuation plan.2. Generate only low-level waste.3. Not disturb the public’s day-to-day activities.4. Not expose workers to a higher risk than other power plants.5. Demonstrate a closed tritium fuel cycle.
Economics:6. Demonstrate that the cost of electricity from a commercial fusion power plant will be competitive, and that other applications such as
hydrogen production are also attractive.
Scalability:7. Use the physics and technology anticipated for the first generation of commercial power plants.8. Be of sufficient size for confident scalability (�50%–75% of commercial).
Reliability9. Demonstrate robotic or remote maintenance of fusion core.
10. Demonstrate routine operation with minimum number of unscheduled shutdowns per year.11. Ultimately achieve an availability � 50% and extrapolate to commercially practical levels.
A Plan for the Development of Fusion Energy 99
APPENDIX C: PRIMARY CHARGE LETTER
September 10, 2002
Professor Richard D. Hazeltine, ChairFusion Energy Sciences Advisory CommitteeInstitute for Fusion StudiesUniversity of Texas at AustinAustin, TX 78712
Dear Professor Hazeltine:
I would like the Fusion Energy Sciences Advisory Committee (FESAC) to comment, from our present state ofunderstanding of fusion, on the prospects and practicability of electricity into the U.S. grid from fusion in 35 years.
In addition, I would like FESAC to develop a plan with the end goal of the start of operation of a demonstrationpower plant in approximately 35 years. The plan should recognize the capabilities of all fusion facilities aroundthe world, and include both magnetic fusion energy (MFE) and inertial fusion energy (IFE), as both MFE and IFEprovide major opportunities for moving forward with fusion energy.
The report would be most helpful if it could be done in two phases. Building as much as possible on previous workof FESAC, the first phase would be a preliminary report, completed by December 1, 2002, which would bothprovide a general plan to achieve the aforementioned goal and identify those significant issues that deserveimmediate attention. As a second phase, I would like by March 2003, or earlier, a more detailed plan upon whichbudgeting exercises can be based. This detailed plan would be most useful if it:
● Identifies all important technical and scientific issues, the tasks that would lead to their resolution, and thesequence in which these tasks should be accomplished in order to reach the program goal most effectively;
● Identifies specifically all of the major facilities needed to support the tasks, and provides the mission andapproximate cost of each facility;
● Provides a set of general performance measures by which the progress toward the accomplishment of thetasks and/or the mission of related facilities can be measure;
● Identifies key decision points where choices can be made among the various concepts and technologiesbeing pursued; and
● To the extent possible, an estimate of the overall cost of such a plan, and optimum funding scenario(s).
These are historic times for the fusion program, and the work of FESAC will help ensure that the policy issuesbefore us are fully informed.
Sincerely,
Raymond L. OrbachDirectorOffice of Science
APPENDIX D: FESAC RESPONSE TO CHARGE
March 5, 2003
Dr. Ray OrbachDirector, Office of ScienceU.S. Department of Energy1000 Independence Avenue, S.W.Washington, D.C. 20585
Dear Dr. Orbach:
The Fusion Energy Sciences Advisory Committee (FESAC) here submits the final report of the Fusion Develop-ment Path Panel, with FESAC’s strongest, unanimous endorsement. In response to your charge of September 10,2002, the Panel has constructed a plan to provide what the President has described as “commercially available fu-sion energy by the middle of this century.” The first stage of the report, which outlined the key scientific and tech-nical issues, was submitted to you on December 12, also with unanimous FESAC endorsement. The present, finalstage of the report brings additional structure and detail to the information of Stage 1; in particular, it includes costestimates.
On December 18, after the Development Path Panel had begun its work, you submitted a second charge to FESAC,to study new and upgraded facilities within the fusion program, as part of the Twenty Year Facilities Plan being con-structed by the Office of Science. Because this charge overlapped in several respects the Development Path work al-ready underway, I asked the Development Path Panel to respond to both charges in a single report. Hence the presentReport includes, beginning on page 77, a detailed response to the facilities charge. Of course FESAC’s unqualifiedendorsement applies equally to this segment of the Report.
In endorsing this report, FESAC congratulates and thanks the members of the Development Path Panel and itsChair, Professor Goldston, for their extraordinary effort. Despite the complexity of the task and the rigorous sched-ule that was imposed, the Panel completed a thorough, systematic study, identifying “critical milestones, key de-cision points, needed major facilities and required budgets.” FESAC finds the Report to be rational, impressivelydetailed and altogether convincing.
Beginning with the observation that “recent advances in the science and technology of fusion energy have dra-matically improved the prospect for practical fusion power,” the Report identifies key tasks whose accomplishment“will form a strong basis for the development of practical, economically competitive fusion energy.” It concludesthat “establishing a program now to develop fusion energy on a practical time scale will maximize the capitaliza-tion on the burning plasma investments in NIF and ITER, and ultimately will position the US to export rather thanimport fusion energy systems.”
Yours truly,
Richard HazeltineChair. Fusion Energy Sciences Advisory Committee
100 Goldston et al.
APPENDIX E: PROCESSES USED BY THEPANEL
October 3–4A panel, Appendix E, was set up by FESAC. It heldits first meeting at PPPL on October 3–4 and dis-cussed the approach to preparing the reports includingthe key factors determining the timeline for electric-ity generation and how best to obtain fusion commu-nity input. A first attempt was made at identifying thekey factors which could affect the logic and timelinefor electricity production in a Demo power plant forboth IFE and MFE. A preliminary definition of aDemo was made.
It was noted that there was a very short time avail-able to prepare the Preliminary Report. Therefore thePanel determined to concentrate its efforts in preparingthe Preliminary Report on the key factors which affectthe logic and timeline, and determined that it was notpractical to hold a large community meeting before thecompletion of the Preliminary Report. A more com-plete analysis, including all of the items requested inthe Charge letter, along with broader community input,will be undertaken in preparation for the Final Report.It was agreed to hold a meeting to obtain input on thekey factors, then to complete the Preliminary Reportand to start preparation of the Final Report.
October 28–30A Panel meeting was held at LLNL on October 28–30first to hear from experts on some of the key factorsdetermining the logic and timeline and then to preparedrafts of Preliminary Report sections. European andJapanese views on the fusion development path wereprovided as well.
November 11–12Public meetings were held at the American PhysicalSociety, Division of Plasma Physics meeting duringNovember 11–12 to inform the fusion communityabout the Panel’s progress in preparing the Prelimi-nary Report and to obtain input. These meetings wereheld in association with the University Fusion Associ-ation annual meeting and at a general discussion of theSnowmass and FESAC processes. Input was alsoreceived through a publicly announced email reflector:[email protected]. Very valuable input was obtainedand taken into account in this report.
November 15–16The Panel met at the end of the APS Division of PlasmaPhysics meeting (November 15–16) to complete the
Preliminary Report, and made final refinements inthe following few days. Public comment was receivedon the morning of November 15. The report was sub-mitted to FESAC on November 21.
November 25–26The Fusion Energy Sciences Advisory Committee met inGaithersburg, MD, reviewed the Preliminary Report,concluding that “The present Preliminary Report has theunanimous, unqualified endorsement of FESAC.”
January 13–16An open community meeting was held at GeneralAtomics in San Diego on January 13–14, in whichinvited speakers presented cost and schedule require-ments for the major project elements of the Plan andcontributed speakers also made oral presentationsto the Panel. A substantial fraction of the time onthe agenda was devoted to public discussion with thefusion community present. Written submissions werereceived as well. The Panel then met on January15–16 and discussed Program elements and worked todevelop the Cost-Basis Scenario.
February 9–10A Panel meeting was held at the Princeton PlasmaPhysics Laboratory focused on completing the responseto the second Charge Letter and moving towards closureon the Final Report.
February 27–28The Panel completed its work through two extensiveconference calls.
APPENDIX F: GLOSSARY
Advanced Tokamak (AT): A tokamak operatingmode currently under investigation which dependspredominantly on the self-sustained “bootstrap” cur-rent to provide steady-state operation and on feedbackstabilization to allow high plasma pressure.
Compact Stellarator (CS): A new MFE configurationthat is designed to achieve the favorable features of thestellarator in a more compact configuration.
Component Test Facility (CTF): A small steady stateMFE fusion facility to test components at neutronfluxes representative of first-wall values in fusionpower systems. Could be funded internationally.
A Plan for the Development of Fusion Energy 101
102 Goldston et al.
Configuration Exploration (CE): Experiments inboth MFE and IFE that provide initial investigation ofa new fusion configuration.
Demo: A demonstration fusion power plant. Likelyseveral Demo’s will be built around the world.
Diode Pumped Solid State Laser (DPPSL): One ofthe candidate laser IFE drivers. DPPSLs are solid statelasers that use high intensity diodes to pump the lasercrystal medium.
Direct Drive: The pellet is compressed directly by thedriver beams. This is the current choice for laser IFE.
Driver: The source of intense, pulsed energy used tocompress and heat an IFE target. Current driver choicesare lasers, heavy ions, or z-pinches.
Dry Wall IFE: Use of a solid wall to protect thechamber in IFE. These chambers may contain gasto protect the wall from x-rays, charged particles,and target debris. This is the favored approach forlaser IFE.
Engineering Test Facility (ETF): The last compo-nent in the IFE development path before Demo. TheETF will demonstrate and integrate a near full scaledriver, will be used to optimize targets for high yield,and will develop and evaluate chamber configurations.
Fast Ignition: An IFE target is compressed by onedriver, and a spark is ignited by a separate very highintensity source such as a short pulse laser, eliminatingthe need for hot-spot formation.
Fusion Ignition Research Experiment (FIRE): Acopper-coil burning MFE plasma physics facility, tobe funded primarily nationally if the U.S. does notparticipate in ITER.
Heavy Ion Beams: One of the three driver choices forIFE. High current beams of low charge state ions areaccelerated to high energies and focused onto an IFEtarget.
High Average Power Laser Program (HAPL): Theenabling technology Proof-of-Principle program forlaser IFE. Includes development of lasers, target fabri-cation and injection, final optics, and chamber con-cepts and materials.
Hohlraum: The hohlraum, which is heated by adriver, is an “oven” that bathes a target symmetricallyin x-rays. Used in indirect drive IFE targets.
Hot Spot Ignition: The IFE target implosion bothcompresses and heats a hot spot in the center of thefuel. This hot spot ignites and initiates a propagatingburn.
Indirect Drive: The IFE capsule containing DT isimploded by x-rays in a hohlraum. This is the currentchoice for heavy ion IFE and for z-pinch IFE
Integrated Beam Experiment (IBX): A proof-of-principle class facility designed to perform an inte-grated test of heavy ion beam physics for IFE fromformation to placement on target.
Integrated Research Experiments (IREs): One ormore facilities which demonstrate that key driver,chamber and target components can work togetherwith the efficiency, durability and precision requiredfor inertial fusion energy.
International Fusion Materials Irradiation Facility(IFMIF): Accelerator-based energetic neutron sourcefor testing material samples at fluxes close to first-wall values in fusion power systems, to be fundedinternationally.
International Thermonuclear Experimental Reactor(ITER): A long-pulse MFE burning plasma physics andengineering test facility, to be funded internationally.
Krypton fluoride (KrF) laser: One of the candidatelaser IFE drivers. KrF is a gas laser medium that ispumped by electron beams.
National Ignition Facility (NIF): A large glass laserfacility currently under construction. This NNSAfacility is tasked with achieving thermonuclear ignitionusing laser-compressed targets.
Nike: A krypton fluoride laser that accelerates planartargets to study the physics of direct-drive IFE.
NNSA: National Nuclear Security Agency. TheDepartment of Energy Agency that is responsiblefor maintaining and securing the nuclear stockpile.The Agency’s mission includes the goal of achiev-ing fusion ignition by inertial confinement in thelaboratory.
A Plan for the Development of Fusion Energy 103
Omega: Omega is a glass laser capable of sphericalimplosions to study direct-drive inertial confinement.
Performance Extension (PE): Experiments in MFEthat study a fusion configuration at near-fusionparameters.
Proof of Principle (PoP): Experiments in MFE andIFE that study a fusion configuration in an integratedmanner.
Recyclable Transmission Line (RTL): For z-pinchIFE, a low-mass transmission line structure conductscurrent from the pulsed power driver to the z-pinchload. In operation, an RTL is vaporized and thematerials are recycled to make subsequent RTLs.
Repetitive High Energy Pulsed Power (RHEPP): Arepetitive pulsed power source. For IFE, RHEPP isconfigured to produce high energy ions that mimic theemissions from a fusion target, to evaluate the effectof such ions on candidate wall materials.
Reversed Field Pinch (REP): A toroidal MFEconfiguration with a very low magnetic field the longaway around the torus, leading to the potential for low-cost magnets in a fusion power plant.
Spherical Torus (ST): A toroidal MFE configurationin which the hole in the center of the doughnut isshrunken nearly to zero, resulting in capability to
sustain relatively high plasma pressures and so fusionpower density at a given magnetic field.
Stellarator: A toroidal MFE configuration whosecross-sectional shape varies around the torus, allowingdisruption-free operation and no need for externalsustainment of plasma current.
Target: For laser direct-drive IFE, the DT capsule; forheavy ion and z-pinch IFE, a hohlraum containing aDT capsule.
Tokamak: An axisymmetric toroidal MFE system witha much stronger magnetic field directed around the torusthe long way than the short way. Conventional tokamakshave a ratio of the major to the minor radius of �3. Thetokamak is the most developed MFE configuration, andis prepared for testing in a burning plasma.
Z: A large z-pinch machine that produces intense,energetic pulses of x-rays. The primary role for “Z” inIFE is to investigate indirect drive. The Z-machine isalso used to evaluate the response of candidate wallmaterials to x-rays.
Z-pinch: One of the three driver choices for IFE. Itdelivers a large electrical current to an annular wirearray, gas puff, or foil that becomes a plasma andcollapses radially under its self-magnetic forces. Whenthe plasma stagnates on axis, the kinetic energy isconverted into an intense x-ray burst.
104 Goldston et al.
APPENDIX G: ADDITIONAL CHARGE LETTER
December 18, 2002
Professor Richard D. HazeltineUniversity of Texas at AustinInstitute for Fusion StudiesOne University Station-C-15 00Austin, TX 78712-0262
Dear Professor Hazeltine:
For more than a half-century the Department of Energy’s Office of Science has envisioned, designed, constructed andoperated many of the premiere scientific research facilities in the world. More than 17,000 researchers and their stu-dents from universities, other government agencies, private industry and from abroad use Office of Science facilitieseach year-and this number is growing. For example, the light sources built and operated by DOE now serve more thanthree times the total number of users, and twenty times as many users from the life sciences, as they did in 1990.
Creating these facilities for the benefit of science is at the core of our mission and is part of our unique contributionto our Nation’s scientific strength. It is important that we continue to do what we do best: build facilities that cre-ate institutional capacity for strengthening multidisciplinary science, provide world class research tools that attractthe best minds, create new capabilities for exploring the frontiers of the natural and physical sciences, and stimu-late scientific discovery through computer simulation of complex systems.
To this end, I am asking all the Office of Science’s advisory committees to join me in taking a new look at ourscientific horizon, and to discuss with me what new or upgraded facilities will best serve our purposes over atimeframe of the next twenty years. More specifically, I charge the committees to establish a subcommittee to:
A. Consider what new or upgraded facilities in your discipline will be necessary to position the Office ofFusion Energy Sciences at the forefront of scientific discovery. Please start by reviewing the attached listof facilities, assembled by Dr. Anne Davies and her team, subtracting or adding as you feel appropriate,with prudence as to cost and timeframe. For this exercise please consider only facilities/ upgrades requir-ing a minimum investment of $50 million.
B. Provide me with a report that discusses each of these facilities in terms of two criteria:1. The importance of the science that the facility would support. Please consider, for example: the extent
to which the proposed facility would answer the most important scientific questions; whether there areother ways or other facilities that would be able to answer these questions; whether the facility wouldcontribute to many or few areas of research; whether construction of the facility will create new syn-ergies within a field or among fields of research; and what level of demand exists within the scientificcommunity for the facility. In your report to me please categorize the facilities in three tiers, such as“absolutely central,” “Important,” and “don’t know enough yet,” according to the potential importanceof their contribution. Please do not rank order the facilities.
2. The readiness of the facility for construction. Please think about questions such as: whether theconcept of the facility has been formally studied in any way; the level of confidence that the technicalchallenges involved in building the facility can be met; the sufficiency of R&D performed to-date toassure technical feasibility of the facility; and the extent to which the cost to build and operate thefacility is understood. Group the facilities into three tiers according to their readiness, using categoriessuch as “ready to initiate construction,” “significant scientific/engineering challenges to resolvebefore initiating construction,” and “mission and technical requirements not yet fully defined.”
Many additional criteria, such as expected funding levels, are important when considering a possible portfolio offuture facilities, however for the moment I ask that you focus your thoughts on the two criteria discussed above.
A Plan for the Development of Fusion Energy 105
I look forward to hearing your findings and discussing these with you in the future. I would appreciate at least apreliminary report by March, 2003.
Sincerely,
Dr. Raymond L. OrbachDirectorOffice of Science
106 Goldston et al.
APPENDIX H: RESPONSE TO ADDITIONAL CHARGE
The facilities described here are those considered to be essential elements of a fusion energy development paththat provides acceptable confidence of achieving a Demonstration power plant within 35 years, leading to commer-cialization of a generation of attractive fusion power systems.
For this goal to be achieved, each of these facilities must operate during the time window of the Charge. Otherfacilities which must begin construction during the next twenty years, but will not operate during this time window,have not been detailed here. The overall cost profile for the fusion energy development program is included in themain body of the report in response to the Charge to FESAC of September 10, 2002.
PROJECT: MFE BURNING PLASMA (ITER OR FIRE)—COST CATEGORY: ABOUT $1B US COST
Mission:Demonstrate the scientific and technological feasibility of magnetic fusion power.
Importance of the Science:Burning plasmas at near power plant scale will present new scientific challenges that must be explored
and understood to enable the development of fusion energy. Research on a burning plasma, where the plasma ismainly self-heated by fusion reaction products, explores the complexity of the nonlinear behavior of magneti-cally confined plasma at high temperature and pressure, a behavior that in turn may be modified by the fusion-generated alpha-particle heating. Scientific topics include turbulent confinement of the plasma, the spectrum ofenergetic particle modes and Alfvénic modes, alpha particle-effects on MHD modes, and plasma-material inter-actions. Operation of the power plant at high plasma pressure in steady state, which would lead to an efficient,robust energy-production system, will be more challenging at the larger scale of a burning plasma and in thepresence of nonlinear alpha-particle heating, where new phenomena and changes in previously studied behaviorare expected.
A burning plasma experiment will offer an early opportunity to apply technologies needed for a fusion powerplant, at a level depending on its scope and scale: heating, current drive, and fueling systems; hardened diagnos-tics; remote handling, superconducting coils of unprecedented size and energy; tritium-processing of the effluentand re-injection as fuel; high-heat-flux components at reactor-relevant loads; and tritium-producing blanketdesigns, which both handle the fusion power and create tritium via interaction of the fusion-produced 14 MeV neu-trons with lithium. A burning plasma experiment will provide an integrated demonstration of the reliability andeffectiveness of the subsystems. In addition a burning plasma experiment can demonstrate the favorable safetycharacteristics of a fusion power plant.
Readiness:Scientific Readiness
1. There is high confidence in confinement projections.2. Operational boundaries (e.g., plasma pressure and current limits) are well-understood, and feedback
control techniques are being developed.3. There is confidence that abnormal events can be avoided or mitigated, although further R&D is needed to
present less stringent heat loads to plasma-facing components.4. There is confidence that the required plasma purity can be obtained, including helium removal and the in-
hibition of impurity influx from the first wall and divertor.5. Diagnostic techniques are available to characterize and evaluate most of the important parameters in a burn-
ing plasma.6. Plasma control techniques are available to produce and evaluate burning plasma physics and to explore
steady-state advanced operational regimes.
Technical Readiness
1. The ITER design is prepared to enter construction, based on comprehensive international EngineeringDesign Activities and extensive associated R&D. The FIRE design will complete a Physics ValidationReview in FY2003.
2. It is clear that the necessary components, including magnetic field coils, the vacuum vessel, the divertor, andthe first-wall components, can be manufactured.
3. Major components can operate within the design requirements in the expected nuclear environments.4. There has been adequate progress in the construction of plasma-facing components that can accept high heat
flux, particle flux, and mechanical stresses, including during disruptions.5. There is confidence in the ability to minimize tritium retention. However, further research is needed to
increase the operational duty cycle of the device.6. The required remote maintenance for a burning plasma experiment has been demonstrated.7. There must be adequate fueling, heating, and current drive techniques to control and explore burning plas-
mas. There is high confidence that these can be provided.
The mission of the IBX is to validate the key physics of high current heavy-ion beams with injection, accelera-tion, longitudinal pulse compression and focusing to spot sizes necessary for energy-producing targets.
● The IBX would be the first of three integrated facilities, the next being the Integrated Research Experiment,a prototype accelerator to validate an intense ion-beam driver, and the last being the inertial fusion Engineer-ing Test Facility (ETF) that would demonstrate the viability of inertial fusion energy.
● The IBX would provide well-diagnosed beam data essential to benchmark and improve the physics used inthe development of an integrated beam model, which in turn would optimize the designs for IRE, ETF, andpower plant drivers.
Importance of the science:
● For heavy-ion fusion accelerators as well as for many high ion current accelerators in the world such as the PSRat LANL, the SNS at Oak Ridge, and the GSI-SIS-18 storage ring at Darmstadt, Germany, the scientificresearch in IBX will provide new insight into the behavior of high current beams which are non-neutral plas-mas with sufficient space charge to exhibit many collective effects, such as longitudinal space charge waves,production and loss of halo ions, and electron-ion two-stream instabilities. Understanding these issues willbenefit the success of high current ion accelerators world-wide.
● In heavy-ion fusion in particular, the IBX would provide the first proof-of-principle test of source-to-targetheavy-ion fusion-relevant beam physics needed to predict the focal spot size in the following IRE and ETF.
● The IBX is the essential proof-of-principle facility for the next step in heavy-ion fusion research, and wouldbe unique in the world due to the high-current capability of its induction accelerator. It would providecapability for a variety of beam transport, compression and focusing experiments by researchers from sev-eral U.S. fusion laboratories and universities, and collaborations with scientists from heavy-ion physicslaboratories in Germany and Japan.
Readiness of the facility for construction:
● The technical basis for the IBX is presently being developed by three separate, modest-scale experiments thataddress, by FY04, the source, transport, and final focus issues that will each contribute to understanding partsof the beam quality evolution (for beam focusing) in IBX.
● Existing induction accelerator technology largely satisfies the hardware needs to build IBX, in the inductionmodules of the Experimental Test Accelerator at LLNL, in the injector of the Relativistic-Two-beam Acceler-ator at LBNL, and in prototype beam transport magnets that have been built and tested at MIT and LBNL.
● The mission, scope and general pre-conceptual design principles of IBX are well understood. The project costestimate of $50–70M is benchmarked against earlier accelerator designs of similar scale. The project will beready to proceed to a Physics Validation review and FESAC approval for PoP status leading to CD-0 in FY04,assuming adequate funding for preconceptual design.
108 Goldston et al.
PROJECT: INTERNATIONAL FUSION MATERIALS IRRADIATION FACILITY (IFMIF)—U.S. COST: $150M
Mission:
The mission of the IFMIF, developed by the international fusion community, is to qualify materials for fusionapplication. IFMIF will experimentally validate emerging models of the effects of exposure of materials to fusion-relevant environments and identify potentially new physical phenomena associated with intense high energy fusionneutron irradiation not achievable with existing or other planned fission, fusion or spallation neutron facilities.IFMIF will qualify materials for use in an MFE Component Test Facility or an IFE Engineering Test Facility, aswell as a fusion Demo power plant.
Importance of the science:
● A major long-standing critical issue for fusion energy is the development of materials that can adequatelyfunction in the intense DT fusion neutron environment. Fundamental experimental and modeling studies per-formed over the past 20 years have established that most of the key atomic displacement features for DTfusion neutrons interacting with materials are similar to those found with fission neutrons. This validatesmuch of the fission test reactor database as a valuable initial screening tool for evaluating the radiationstability of fusion materials. However the higher production of transmutation products such as H and He infusion is predicted to have significant influence on the microstructural stability of materials for fluencesabove �0.5–1 MW yr m�2 (�5 to 10 displacements per atom). Therefore, an intense high-energy neutronsource is essential for development and qualification of the materials for the first wall, plasma facing compo-nents, and breeding blanket components of Demo configurations that do not utilize a thick liquid wall.
● In addition to providing key scientific insight into the microstructural stability of materials in a fusionenvironment, this facility will enable important experimental validation of current materials science radia-tion effects models. This information will be valuable for establishing comprehensive radiation effects mod-els that can be usefully applied to a wide range of future nuclear facilities including Gen IV fission reactors,spallation neutron sources, etc.
● IFMIF is the key materials science facility for fusion, and timely deployment of the facility is required inorder to develop fusion energy within the next 35 years. This facility will leverage and enhance currentinternational materials science collaborations.
Readiness of the facility for construction:
The international design team has completed a conceptual design for IFMIF. The team has proposed a five-year engineering validation phase in parallel with a detailed engineering design activity, to commence in 2004.This activity is intended to resolve the remaining key technology issues for the facility and to provide a robust costestimate for construction. The technology for IFMIF is based on state-of-the-art accelerator design. IFMIF is anaccelerator-driven D-Li stripping neutron source, with two 125 mA deuteron beams of 40 MeV energy focusedonto a flowing Li target (5 � 20 cm beam footprint). Work at recent facilities such as LEDA at Los Alamos andthe Spallation Neutron Source project has been instrumental in validating much of the physics and resolving costissues. Preliminary cost estimates for construction of this international facility are �0.6 B$ over a period of 6 years.Construction of the facility should commence in FY2009 to meet the goal of deploying a fusion demonstrationpower plant in 35 years.
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PROJECT: MAGNETIC FUSION ENERGY PERFORMANCE EXTENSION FACILITIES—COST RANGE: 2 � 1 FACILITIES @ $200M-$600M EACH
Mission:
A Performance Extension class experiment in magnetic fusion energy is a facility designed to test a mag-netic confinement configuration in plasma parameter regimes close to those which would be encountered in aburning plasma. This will provide good understanding of the science and performance potential of the configur-ation as a fusion power source. The fusion development path towards Demo envisions two new such facilities,one to begin construction in approximately FY2009, and a second in approximately FY2013. The configurationtested in either could be employed in Demo, through use of burning plasma data from ITER and advanced com-putation. Whether the experiment will require deuterium-tritium operation (as in TFTR and JET) is a matterwhich will depend on the configuration being considered and on the degree of confidence that can be placed atthat time in theoretical calculations and experimental simulations using, for example, high-energy beams. Thefirst facility could have the mission of preparing the physics basis for a compact Component Test Facility (CTF).
Importance of the Science
A range of magnetic confinement configurations is being explored in the laboratory. Small-scale ConceptExploration and mid-scale Proof of Principle experiments are able to test many aspects of the basic physics ofa new configuration. However dimensionless parameters such as �* (ion gyroradius/system size) are sufficientlydifferent from fusion energy systems that confident extrapolation is not possible. A Performance Extensionexperiment addresses such critical fusion science issues as turbulence and resulting energy and particle transport,MHD stability limits, discharge initiation and sustainment and plasma-material interactions at fusion-relevantplasma parameters. Key configuration-specific technologies are also developed and tested.
Examples of attractive configurations which could compete for the first future MFE PE experiment includethose now being tested at the Proof-of-Principle level, such as the reversed field pinch and the spherical torus, andthose which already are being tested at the PE level, such as the advanced tokamak, but would propose to explorenew operation regimes, for example in support of the CTF. The second future MFE PE experiment, in addition tothe above, could be based on a configuration currently at the concept exploration level, such as the spheromak orFRC after a successful Proof-of-Principle scale test, or could follow on from the proof-of-principle compact stel-larator experiment currently under construction.
Readiness for construction
At present there is no proposed facility in this category designed to a level of detail sufficient for a near-termconstruction decision. Several pre-conceptual designs exist, but await confirmatory physics results from currentexperiments and more detailed engineering design studies. Further consideration of application to the CTF missionis required. Clear criteria have been defined by FESAC to assess readiness for PE class experiments. These includeplasma science and technology benefit, likelihood of resolving key physics and technology issues, and the attrac-tiveness of the energy vision for the configuration. The decision making process would include a peer-basedPhysics Validation Review, approval by FESAC for PE status, and then peer-based Conceptual, Preliminary andFinal Design reviews.
110 Goldston et al.
PROJECT: INERTIAL FUSION ENERGY INTEGRATED RESEARCH EXPERIMENTS—COST RANGE: 2 � 1 FACILITIES @ $150M-$350M
Mission:
The Integrated Research Experiments (IRE) will establish the science and technology required to justify and buildthe Engineering Test Facility (ETF) for inertial fusion energy (IFE). The development of each IFE concept (Z-Pinch,Heavy Ions, and Lasers) requires an IRE.
Importance of the Science:
The IREs integrate both full scale and subscale components to ensure the key driver, chamber, target and finaloptics components can work together with the required efficiency, precision, and durability. The IREs, coupledwith target physics results from the National Ignition Facility (NIF), Omega, and Z, will answer all the importantscientific and technical questions needed to proceed to the ETF.
The ETF is a multi-billion dollar class nuclear facility that will be the last step before a commercially viable Demo.It will be used to demonstrate and optimize high gain and it will demonstrate power plant scale final optics/powerfocusing, target production, and target injection. It will operate at pulse repetition rates suitable for a fusion power plant.It will optimize blanket/chamber technologies, and potentially produce net electricity.
To start such a major program, the underlying science and technology must be mature enough that we can con-fidently predict they will lead to an economically viable fusion power plant. The goal of the IRE is to establish thatscience and technology.
The IRE and its associated research program are essential for developing a given IFE configuration intoa fusion power source. The IRE will require research and development in a wide range of scientific disciplines,including the physics of plasmas, particle beams, lasers and z-pinches; the science of materials and related nano-technologies; the behavior of complex fluid flows; and low temperature physics, optics and chemistry. Thus theunderlying science will contribute to a wide range of research and technology development both inside and outsidefusion research.
Readiness:
None of the IFE configurations is now ready to proceed to the IRE, as significant scientific and technical chal-lenges must be resolved. However the mission and technical requirements for the IRE are well defined and the presentR&D programs will validate the technical feasibility of the IREs and fully establish their cost.
The technical goals for justifying the IREs are similar for all three IFE approaches. Each approach must meetspecific criteria for each of the principal components: Driver, final optics/power focusing system, target fabrication,target injection, chamber, and target physics. Each must produce a viable point design as well. The decision makingprocess would include a peer-based Physics Validation Review, approval by FESAC for PE status, and then peer-based Conceptual, Preliminary and Final Design reviews.
