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"Magnetic Fusion: Issues, Metrics, Gaps and a Road Map to Energy "

Dale Meade

Fusion Innovation Research and Energy®

Princeton, NJ

ARIES Project MeetingBethesda, MD July 29, 2010

Fusion GainQ ~ 25 - 50

nET ~ 6x1021 m-3skeVP/Pheat = f ≈ 90%

Steady-State65 - 90% Bootstrap

Efficient Current Drive

ARIES Studies have Identified Desired Characteristics of an Attractive Fusion Power Plant

Plasma ExhaustPheat/Rx ~ 10-20 MW/m2

Ash RemovalT Retention < 0.025%

Plasma ControlGlobal Burn Control

Profile ControlFuel mix, Impurity Control

Disruption MitigationELM,RWM Stabilization

Significant advances are needed in each area.

Tritium BreedingTBR > 1

Low Inventory (< 1kg-T)

Energy Recoveryn ~ 2 - 4 MWm-2

Efficiency ~ 40-60 %Operating T ~ 500-1100 °C

FW/Blkt MaterialsFluence ~ 150 dpa

Low activation (Class C)Volume

Power DensityPf/V~ 3 - 6 MWm-3

<p> ~ 10 atmn ≈ 2 - 4 MWm-2

High Availability75%

Constructing a Fusion Roadmap

• Start with EPRI Requirements

• Guiding Principles• Identify the Goal and Characteristics• Determine key issues/processes/coupling• Establish meaningful quantifiable metrics• Determine present status (e.g. TRLs) • Quantify gaps, and identify steps (milestones) to close gaps Establish logic diagrams with links to coupled issues

Identify Credibility Milestones (Litmus Tests)Address key issues early at the lowest size/costOptimize technical risk for steps

• Look for key issues and processes that are coupled• Identify possible mission elements

• Establish a draft Roadmap(s) from the Present to Power Plant Goal• Arrange Mission elements in natural order with coupling links• Evaluate the capability of possible facilities to address mission elements

• Identify candidate facilities and layout draft plan • Activities need to have target cost and duration estimates • Fundable Steps/Stages that bootstrap funding for next phase

avoid Mountain of Death (PCAST ‘97)

Composite Themes/Issues for Fusion (Rev 1)FESAC Greenwald Panel Start May31, 2007

Assessment of Fusion Confinement Configurations and Plasma TechnologyThe non-burning Program (includes new machines)

Creating a Star on Earth (ITER Baseline)Achieving Burning Plasma Conditions Determining Basic confinement, stability, wave-particle, power handling

Sustaining the Fusion Heat Source Advanced burning regimes (e.g., higher Q)- GreenwaldSustained Plasma configuration (e.g., lower fcd ,-htg, CD, magnets)- Mike ZLong pulse power handling - UlricksonFueling, ash removal and and impurity control - DorlandPlasma control - Gates

Closing the Fusion Fuel Cycle - UlricksonTritium breedingTritium recoveryTritium retention

Harnessing the Power of FusionPower densities of interest - MeadeRobust to off normal events - UlricksonHigh temp blankets for reasonable efficiencies -CallisBreeding Blanket Heat recovery - Callis

Nano Engineering (Design) of Materials for the Fusion Bottle

Realizing the Safety and Environmental Benefits of Fusion - McCarthy

Addressing the Practicality and Economics of Fusion - Maintainability (remote handling, availability, reliability,waste)

Fusion Research Themes (FESAC 2007)

Theme A – Creating a High-Performance Steady-State ( Burning) Plasma (a heat source from magnetic fusion)

Theme B – Taming the Plasma Materials Interface (interface between heat source and furnace wall, and

extracting plasma exhaust power)

Theme C – Harnessing the Power of Fusion (extracting neutron power, breeding tritium, remote handling, safety/environment)

• These themes follow a systems or process based approach, sometimes called Holistic approach to the R&D of complex systems - eg space craft.

• They form a natural overlapping sequence

Theme A- Create Fusion Heat Source

Theme B-Tame Plasma Materials Interface

Theme C - Harness the Power of Fusion

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Theme A - High Performance: Q => nE =>

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Ignition Power Plant Break-Even Tokamak '60’Tokamak 70LHD(JA)GAMMA-10(JA)Helical '00JFT-2M(JA)Tokamak '80TFTR(US)FTU(EU)C-Mod(US)ASDEX-U(EU)DIII-D(US)JT-60 (JA)JT-60 (JA)TFTR(US)JET(EU) Reverse Field Pinch

Tokamak '90Tokamak '90

Plasma Temperature (keV)10-1 1 10 1 10 2

‘58

Alcator C - 1983

10 -3

10 -1

10 0

10 -4

10 -2

10 1

(1020 m-3 s)

ni(0)Eni(0)ETi

increased by ~107

since 1958

JAEA

Need to add dimension of duration to metric (many like this)

Economic Reactors Will Require Efficient Magnetic Utilization⟨p⟩

( )atm

0.1110301101001000TPXIGNITOR-ARIES AT2ASSTRH2 O Cu Coil ST Ops MaxBcoil2 (T2)ProjectedAchieved1 %βfusion = 2 %LN2 Cu Coil, Bitter Wedged Ops Max-ARIES ST0.5%NSTX-FIRE AT-ARIES RS-FIRE H- & -ITER H ITER ATTFTR-C Mod- C Mod AT- ( )Alc C OHJET -PBX M• “ ” , Attractive fusion systems require both high field highβ and efficient utilization.

• Advanced tokamaks offer the best combination of highβ .and achievable high field

NSTX≈ 5 MWm-3≈ 0.5 MWm-3 Nb SnCIC

3 CSCoil

Ops Max βfusion = ⟨p⟩ / Bcoil2 60JT U -DIII D Theme A - High Performance => Power Density => β2B4

Need to add dimension of duration to metric

Is ITER Sufficient to Resolve Burning-Plasma Issues for MFPP?

High Fusion Gain - attain good confinement with profiles defined by alpha heating(P/Pext = Q/5), possible non-linear dependence of transport on gradients, coupled to edge plasma by pedestal, optimum temperature for fusion ~ 15 keV and high density but efficient current drive favors higher T ~ 30 keV and lower density.

Sustainment (100% NI) - produce large bootstrap current with pressure profiles defined by alpha heating and residual current driven efficiently by low power Pcd ≤ 5P/Q.

High Fusion Power Density (β2 B4 <v>/T2) - to provide high neutron wall loading. Can near optimum β be attained for alpha-defined profiles?

Plasma Control (Pcd + Pcont = 5P/Q ) - maintain plasma control (esp. disruptions) with low power typically < 0.15P. Will a burning plasma evolve to a self-organized state with good confinement, high bootstrap and high β?

Exhaust Power Density - can high exhaust power densities be handled while maintaining edge plasma for high Q and efficient CD with long PFC lifetime?

Self- Conditioned PFCs - will the PFCs self-condition that is consistent with high Q and β and long PFC lifetime?

High-Performance Steady-State Burning-Plasma

• ARIES-I And ARIES-AT span the range of a possible MFPP.

• Individual gaps between ITER (scenario 4) and ARIES range between 2.5 - 10

• Need to incorporate duration/steady-state

Metrics and Gaps to MFPP

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High-Performance Steady-State Burning-Plasma

• The individual gaps are taken to be independent, therefore the Integration Gap is the product of individual gaps.

• The Integration Gap for Fusion Gain, Sustainment and Exhaust Power density is ≈ 200

Integration Issue Gaps (an example)Integrate Fusion Gain, Sustainment and Exhaust Power Density

Table I. Individual Issue (Metric) Today*(>10E)

ITER ARIES-I

ARIES-AT

<Gap>IT t o AR

Fusion Gain ( )Q < 0.2 5 20 50 7 Sel -f heati ng(%) 4 50 80 91 1.7Sustainment (100% N )I ** (Pcd/P ) >25 1 0.25 0.1 6 Curren tDrive fracti on (1-fbs) (%) ~30 ~50 32 9 2.5Neutr onWall Loadi ng (MWm-2) 0.1 0.5 2.5 3.3 6 Plasma Press (ure atm) 1.6 2.5 10 10 4 Fusion Pow er density (MWm-3) 0.3 0.5 4 4.7 8Plasma Control* (Pcont/P) >25 1 0.25 0.1 6Exhaus t Power Density (Pheat/Aps

(MWm-2)0.85 0.2 1 1 5

Sel -f Conditi onPFCs & F W f(tpulse, T, φ, No ? Yes Yes ?* Not all simultaneous** Curren tDrive Power + Plasma Control Powe r= 5 P/QAssumes ITER will be upgraded with addition of Lower Hybri d current drive forScenari 4o .

Is ITER Sufficient to Resolve Nuclear Technology Issues for a DEMO?

Tritium fueling, recovery from plasma exhaust and isotope separation - will be carried out at Demo scale.

Tritium Breeding - ITER will not breed it’s own tritium fuel. A number (~4) tritium blanket modules will be installed to testing various concepts

Neutron Wall Loading - ~ 0.5 MWm-2, about a factor of 5 below Demo requirements.

Neutron fluence is expected to be < 0.5 dpa at end of program, more than an order of magnitude below a Demo.

Remote Handling - while major contributions will be made, the in-vessel remote handling of blanket/shield modules chosen by ITER is generally considered to be problematic for a Demo.

Safety, Licensing, Waste Disposal - ITER will make major contributions in this area. Some issues related to qualification of materials for Demo.

Elements of a Strategic Plan for Fusion Energy

Personal thoughts on potential elements of US fusion Program

• There are significant gaps in the Demo-like burning plasma and fusion technology areas that will not be covered by ITER or any other planned facility. This represents an opportunity for the US.

• Extend the concept of a “Broadened Approach to Fusion” , developed by Europe and Japan, with a major US Fusion Energy initiative to complement ITER and strengthen the basis for Demo.

• This initiative should be a fully national effort that is planned from the beginning as a staged/phased initiative to reduce risk, cost impact and allow success in early stages to bootstrap funding.

Theme A- Create Fusion Heat Source

Theme B-Tame Plasma Materials Interface

Theme C - Harness the Power of Fusion

FESAC Planning Panel Report to FPA: December 5, 2007

Relationship of Initiatives to Gaps

Staged Mission Elements for Fusion Energy Plan

Theme A- Create Fusion Heat Source

Theme B-Tame Plasma Materials Interface

Theme C - Harness the Power of Fusion

Stage 1 Stage 2 Stage 3

• Mission elements included within themes

• Issues are coupled across themes and must be addressed in an integrated manner.

• Plan should go all the way to a Power Plant. Three stages is an illustration.

Staged Fusion Energy Initiative (Facility)

ConstructCost

Cumulative

C-1 C-2 C-3O-1 O-2 O-3

Time

• have the full plan in mind from the beginning• upgrade/replace fusion core while building on existing infrastructure

(fusion core typically ≤ 30% of total project)• avoids one of fusions biggest roadblocks - Mountain of Death (PCAST ‘97)

Will lead to a National Fusion Energy Laboratory

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From discussions in 1999

Configuration Optimization

MFE CTF

ITER Phase II

Materials Testing

Materials Science/Development

IFMIFFirst Run Second Run

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IFE NIF

MFE ITER (or FIRE)

Burning Plasma

Indirect Drive Direct Drive

03 05 07 09 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45

Key Decisions:

IFE IREs

MFE PEs

IFMIF

MFE or IFE

Demo

03 05 07 09 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45Fiscal Year

Design

Construction

Operation

Concept Exploration/Proof of Principle

IFE IREs

MFE PE Exp’ts

Engineering Science/ Technology Development

Component Testing

IFE ETF

US Demo

Demonstration

Systems Analysis / Design Studies

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Theory, Simulation and Basic Plasma Science

Configuration Optimization

US “FESAC 35 Year Plan” for Fusion (May 2003)

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ITER NIF

Facilities to Produce Fusion Energy are under Construction

First D-T ~2027?Fusion Gain, Q 10Fusion Energy/pulse 200,000 MJ

First D-T ~2010Fusion Gain, Q 10 - 20Fusion Energy/pulse 40 MJ

Progress and Projections for Controlled Fusion Energy

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Concluding Thoughts

• Magnetic Fusion Needs a Road Map with quantifiable metrics that lead to major deliverables on a once every decade time scale.

• While we have been down this path many times, lets look hard for the optimum way to resolve the major issues in a staged manner that allows us to build on success.

• Extend the concept of a “Broadened Approach to Fusion”, developed by Europe and Japan, with a major US Fusion Energy initiative to complement ITER and strengthen the basis for Demo.

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Why Couldn’t US MFE Take the Next Step?

• Logic III became the basis for the MFE Act of 1980.

• The US Fusion Program evolved on to Logic I - we never get there!

Fusion Power by Magnetic Fusion Program Plan July 1976 ERDA – 76/110/1

FY 1978$

Actual FY-1978$

+