1. Overview of the ARIES “Pathways” Program Farrokh Najmabadi UC San Diego 8th International Symposium on Fusion Nuclear Technology Heidelberg, Germany 01– 05 October 2007,

2. US DOE has made no Commitment to Fusion Demo • US Fusion program is viewed as a Science Program and not an energy program. • FESAC activities • FESAC Fusion Development Path Panel (2003) • FESAC Strategic Planning Panel (2007) • Community activities • Proposal for many devices. • ARIES pathways program • A 3-year activity started in 2007.

3. A 35,000 ft viewof fusion development landscape

4. Early US Fusion Development Path Partially integrated test of fusion plasmas and fusion technologies (Testing in “prototypical” environment) Full Integration of fusion plasma with fusion technologies (Test in “actual” environment) A “1st of the kind” Power Plant! “Fusion Power: Research and Development Requirements.” Division of Controlled Thermonuclear Research (AEC).

5. 03 05 07 09 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 US Fusion Development Path (FESAC Report, 2003) Theory, Simulation and Basic Plasma Science Configuration Optimization Concept Exploration/Proof of Principle MFE Program MFE PE(s) Burning Plasma Complete ITER Ops Phase 1 MFE ITER (or FIRE) Materials Testing Materials Science/Development Complete IFMIF Ops 80 dpa Prelim. IFMIF Ops 150 dpa MFE IFMIF Component Testing Internal Components Design Engineering Science/ Technology Development MFE CTF Demonstration Design Studies US Demo 03 05 07 09 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47

6. Demo Mission From FESAC Development Path Panel • US Demo Mission: “Successful operation of the Demo convinces the users (Public, Regulators, Industry, power producers) that a commercial power plant can successfully meet all its objectives.” • The ``first-generation'' plant MUST be attractive in terms of economics, safety, regulation, and environmental characteristics. • Demo is used to label different devices with different mission among parties. • The “perceived” required characteristics of an attractive power plant are different among parties. • What is needed to convince the funding agencies that fusion is a viable power source are different among parties.

7. In the ITER area,we need to develop a 5,000 ft view of Fusion Development Landscape

8. The ARIES “Pathways” Program • What are the remaining major R&D areas? • What is the data base needed to field a Demo and a commercial power plant? • What is the impact of each R&D item on the attractiveness of the final product (metrics for prioritization of R&D)? • Which of the remaining major R&D areas can be explored in existing devices or simulation facilities (i.e., fission reactors)? • What other major facilities are needed (CTF, Fast track, etc.) • We need to create the data base and experience necessary to convince investors and regulators that fusion is a viable power source. • Validation in an integrated, prototypical environment is needed before proceeding to Demo.

9. Elements of ARIES Pathways Program • Required data base: • A system-based (concurrent physics/engineering) approach to identify interconnected physics/engineering constraints and issues , e.g., Power and particle management, Fuel management, Operation (reliability, maintenance, off-normal events), Safety, etc. • “Technical Readiness Level” approach to judge the maturity of the technology • Metrics for prioritization of R&D: • A new approach to Systems Analysis, surveying the design space (instead of finding only an optimum design point) • Industrial advisory Committee

10. Our system-based approach has Highlighted several operation issues • Acceptable variations in plasma power (n, T, …) during normal operation and impact on power handling equipment (Blankets are currently designed for steady loads.) • Impact of power plant start-up scenarios (regulations dictate certification tests at different power levels) on plasma scenarios and power handling equipment. • Precise, in-situ control of tritium breeding (too much breeding leads to very large inventories). • Characterization of the Impact of off-normal events on power plant operation. • Industrial approach to testing to develop highly reliable components.

11. Excess T production is a concern

12. Technical Readiness Levels provides a basis for development path analysis • TRLs are a set of 9 levels for assessing the maturity of a technology (level1: “Basis principles observed” to level 9: “Total system used successfully in project operations”). • Developed by NASA and are adopted by US DOD and DOE. • Provide a framework for assessing a development strategy. • Initial application of TRLs to fusion system clearly underlines the relative immaturity of fusion technologies compare to plasma physics. • TRLs are very helpful in defining R&D steps and facilities.

13. Example: Fuel performance development in GNEP project

14. A new approach to System analysis to better understand the trade-offs • Typical system analysis of fusion system seek an optimum set of parameters (minimum cost) based on a set of constraints. • Our experience indicates that such “optimum” design points are usually driven by the constraints. • In some cases, a large design window is available when the constraint is “slightly” relaxed, allowing a more “robust” and credible design. • Our new approach is to develop a large data base of candidate design points for a power plant and examine the available design space using modern visualization and data mining techniques. • The data bases currently contains over 106 self-consistent physics points and undergoing detailed analysis with engineering and costing packages.

15. Example of Design space for fusion power plants Contours of COE

16. The first meeting of the ARIES Industrial advisory Committee meeting was held in June 2007. • ARIES Program had a “utility advisory committee” in 90s. • Their input was used subsequently in all ARIES Designs. • They helped define mission of a Demonstration Power Plant (used in FESAC Development Path Panel report) • Our new Industrial Advisory Committee includes members from US utilities, Vendors, Architect/Engineers, and regulatory agencies. • Discussions in the first meeting of our new Industrial Advisory Committee revolved around the following two questions.

17. Are the Prior EPRI Criteria for Practical Fusion Power Systems still valid? • EPRI Criteria for Practical Fusion Power include: economics, public acceptance, and regulatory simplicity. Economics: • Utilities will only be motivated to build a fusion power plant if it offers better economics than other options. The impact of environmental concerns on future energy prices, however, is not known. • High reliability and availability are critical: Suggested targets are 70% for Demo and 90% for commercial plant. • Steady state operation is essential. The Balance of Plant of a pulsed power source would be very expensive. • There is a large effort in developing high-efficiency power conversion system for fossil fuels. Fusion should try to capitalize on these efforts. Public Acceptance: There is a large public sensitivity toward tritium.

18. What are the feature of a Demo relative to a commercial plant? • What are the feature of a Demo relative to a commercial plant? • DEMO must have essentially all the features of the commercial plant. It is the role of the DEMO to demonstrate those features and technologies so that the risk of the commercial plant is acceptable for private investment.

19. IAC observations on fusion development • Relies on large scale, expensive facilities • Limited scope of data in relevant conditions • Difficult learning period between facilities (long lead times, $$$) • Solution may be to use smaller facilities, integrated with large scale simulations to minimize risk for DEMO.

20. Can we use massive simulations to shorten the development time? • A major shift to modeling and simulation to minimize testing requirements and development costs in engineering disciplines. • Relying on 3-D multi-physics codes which are based on first principle to analyze components. • This approach, however, requires a different development approach: • Accurate understanding of fundamental physics principles (single effect issues) • Experiment planning such that it highlights multi-physics interaction (instead of traditional approach of testing integrated systems to failure repeatedly). • Final validation in an integrated, prototypical environment.

21. Thank you!Any Questions?