1 "Magnetic Fusion: Issues, Metrics, Gaps and a Road Map to Energy " Dale Meade Fusion Innovation Research and Energy® Princeton, NJ ARIES Project Meeting Bethesda, MD July 29, 2010

Fusion Gain Q ~ n  E T ~ 6x10 21 m -3 skeV P  /P heat = f  ≈ 90% Steady-State % Bootstrap Efficient Current Drive ARIES Studies have Identified Desired Characteristics of an Attractive Fusion Power Plant Plasma Exhaust P heat / R x ~ MW/m 2 Ash Removal T Retention < 0.025% Plasma Control Global Burn Control Profile Control Fuel mix, Impurity Control Disruption Mitigation ELM,RWM Stabilization Significant advances are needed in each area. Tritium Breeding TBR > 1 Low Inventory (< 1kg-T) Energy Recovery  n ~ MWm -2 Efficiency ~ % Operating T ~ °C FW/Blkt Materials Fluence ~ 150 dpa Low activation (Class C) Volume Power Density P f /V~ MWm -3 ~ 10 atm  n ≈ MWm -2 High Availability 75%

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/cost Optimize 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 Technology The 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)- Greenwald Sustained Plasma configuration (e.g., lower f cd,-htg, CD, magnets)- Mike Z Long pulse power handling - Ulrickson Fueling, ash removal and and impurity control - Dorland Plasma control - Gates Closing the Fusion Fuel Cycle - Ulrickson Tritium breeding Tritium recovery Tritium retention Harnessing the Power of Fusion Power densities of interest - Meade Robust to off normal events - Ulrickson High temp blankets for reasonable efficiencies -Callis Breeding 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

6 Theme A - High Performance: Q => n  E =>  Plasma Temperature (keV) ‘58 Alcator C (10 20 m -3 s) n i (0)  E n i (0)  E T i increased by ~10 7 since 1958 JAEA

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

Theme A - High Performance => Power Density =>  2 B 4 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  /P ext = 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 P cd ≤ 5P  /Q. High Fusion Power Density (  2 B 4 /T 2 ) - to provide high neutron wall loading. Can near optimum  be attained for alpha-defined profiles? Plasma Control (P cd + P cont = 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  ? 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  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 Need to incorporate duration/steady-state Metrics and Gaps to MFPP 7

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)

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 1Stage 2Stage 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) Construct Cost Cumulative C-1C-2C-3O-1O-2O-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 $

From discussions in 1999

Configuration Optimization MFE CTF ITER Phase II Materials Testing Materials Science/Development IFMIF First RunSecond Run 47 IFE NIF MFE ITER (or FIRE) Burning Plasma Indirect Drive Direct Drive Key Decisions: IFE IREs MFE PEs IFMIF MFE or IFE Demo Fiscal 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 47 Theory, Simulation and Basic Plasma Science Configuration Optimization US “FESAC 35 Year Plan” for Fusion (May 2003)

19 ITERNIF Facilities to Produce Fusion Energy are under Construction First D-T ~2027? Fusion Gain, Q 10 Fusion Energy/pulse200,000 MJ First D-T ~2010 Fusion Gain, Q Fusion Energy/pulse40 MJ

Progress and Projections for Controlled Fusion Energy

21 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.

22 Why Couldn’t US MFE Take the Next Step? Logic III became the basis for the MFE Act of 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$ +