1. Approach for a High Performance Fusion Power Source Pathway Dale Meade Fusion Innovation Research and Energy ARIES Team Meeting March 3-4, 2008 UCSD, San Diego, CA

2. Outline Fusion Power Source Goals (i.e., Define TRL 9) 1st Generation Power Plant (e.g., ARIES-I’) nth Generation Power Plant (e.g., ARIES-AT’) Fusion Power Source Characteristics/Status/Gaps Fusion Power Gain Fusion Power Density Fusion Power Sustainment Fusion Power Control Fusion Plasma Interface Integration Possible Pathways Series-? Parallel-? Optimized to address critical issues early-?

3. Issues for Commercial Fusion Energy

4. Fusion Power Source - Issues and Metrics 1. Fusion Power Gain ( P f => Q p => n  E, T i, Lawson) 2. Fusion Power Density (  n => P f /Vp => p 2, p/B 0 2, p/B max 2 ) 3. Fusion Power Sustainment (  duration =>  dur /  char, ) (P cd /P f => f BS, T e ) 4. Fusion Power Control (P max, P min => n T /n D, Q p, P heat,P CD ) (  P loss,  loss Transient Events ) 5. Fusion Plasma Interface Hi T e for CD Lo T for divertor, Hi T i at edge pedestal materials - T retention, Impurity Rad to disperse P exhaust self-conditioning of walls at long pulse, impact of hi T wall is existing confinement data base for C PFCs relevant? 6. Integration - How to measure? e.g., multiplicative How to display? e.g., radar plot

5. Fusion Power Source Gain Metric and Gap Q Gap: Today to FPP ~ 50, ITER to FPP ~ 6 Q FPP ≈ 30 Note: Duration Also

6. Fusion Power Density Metric and Gap Need to update and identify AT modes Plasma Pressure Gap: from today ~ 6 and 10 6 in duration (non-burning) from ITER ~ 3 and 10 3 in duration

7. Fusion Power Source Sustainment Metric and Gap Need a metric for coupling of hi Q(alpha defined profile) and f BS Also need high T e for high  cd Gap: Today to FPP is very large, ITER to FPP ~ 10 4 Contributions from EAST,KSTAR, JT-60SA for non-burning plasma M Kikuchi - IAEA 2006 FPP

8. Fusion Power Source Control Metric and Gap 1. Operation must be on the thermally stable branch of PopCon ITER should be able to establish this for H-Mode ITER do something for modest AT regime 2. Need to establish how far the AT regime (negative shear) can be pushed toward high bootstrap % with a pressure profile defined by strong alpha heating. 3. A highly reliable disruption avoidance system compatible with item 2 must be developed. 4. Develop techniques to eliminate large ELMs.

9. Fusion Power Source Interface Issues The AT regimes envisioned require high T e in the core for efficient current drive, and highish T i at the plasma edge pedestal but low T in the divertor plasma to reduce erosion. Significant radiation is required near the plasma edge and on the divertor to spread the thermal exhaust power over a larger area. Impact of self-conditioning of PFCs at long pulses and impact of hi T wall on edge plasma and hence confinement. Are the existing confinement data base and associated scaling relations for Carbon PFCs relevant to DEMO or FPP?

10. Fusion Power Source Issue Integration In an FPP, all these issues will be important and are strongly coupled together. Presently - the sequence is Gain, Power Density, then Sustainment are drivers with Control and PFC Interface facilitating the first three. Is this the optimal sequence for addressing these issues? How about - Gain, Sustainment then Power Density? Gain Sustainment PFC Interface Control Power Density Drivers Facilitators

11. Example of TRL for Fusion Power Sources

12. Example of TRL for Fusion Power Sources (2)

13. TRL Graphic - Time Bar Chart TRL 1 TRL 2 TRL 3 TRL 4 TRL 5 TRL 6 TRL 7 TRL 8 TRL 9 time line for a single issue, also add TRL time line for other closely coupled issues indicating links

15. Questions Related to a Pathway to Fusion Power What is the minimum performance FPP that would be of interest? Is it close to ARIES-1’ or EU Model A? What is the minimum performance DEMO that would be of interest? Is DEMO a protoype? Can it be upgraded? What could the fusion program do near term that would convince the system that fusion R&D is worth Big Bucks? Can we incorporate elements of a “business plan” in the Fusion Pathway analysis that will encourage the required investment at each step? (Enterprise Partners Venture Capital http://www.epvc.com/venture_capital_resources/venture_capital_plan.asp) Answers to these questions would help define a Pathway to Fusion Power.