Evaluation Methodology for Fusion R&D: Applying Readiness Levels to Fusion Energy

1. Progress developing an evaluation methodology for fusion R&D M. S. Tillack ARIES Project Meeting March 4, 2008

2. We have adopted readiness levels as the basis for our evaluation methodology

3. GAO encouraged DOE and other government agencies to use TRL’s (a direct quote), to… • “Provide a common language among the technology developers, engineers who will adopt/use the technology, and other stakeholders; • Improve stakeholder communication regarding technology develop-ment – a by-product of the discussion among stakeholders that is needed to negotiate a TRL value; • Reveal the gap between a technology’s current readiness level and the readiness level needed for successful inclusion in the intended product; • Identify at-risk technologies that need increased management attention or additional resources for technology development to initiate risk-reduction measures; and • Increase transparency of critical decisions by identifying key technologies that have been demonstrated to work or by highlighting still immature or unproven technologies that might result in high project risk”

4. How can we apply this to fusion energy? • Use criteria from utility advisory committee (and not physical components) to derive issues • Relate the issues criteria to fusion-specific, designindependent technical and R&D needs • Define “Technical Readiness Levels” for the key issues and R&D needs • Define the end goal (design or facility) in enough detail to evaluate progress • Evaluate status, gaps, R&D facilities and pathways

5. 1) Utility Advisory Committee“Criteria for practical fusion power systems” J. Fusion Energy 13 (2/3) 1994. • Have an economically competitive life-cycle cost of electricity • Gain public acceptance by having excellent safety and environmental characteristics • No disturbance of public’s day-to-day activities • No local or global atmospheric impact • No need for evacuation plan • No high-level waste • Ease of licensing • Operate as a reliable, available, and stable electrical power source • Have operational reliability and high availability • Closed, on-site fuel cycle • High fuel availability • Capable of partial load operation • Available in a range of unit sizes

6. 2) The criteria for attractive fusion suggest three categories of technology readiness • Economic Power Production (Tillack) • Control of plasma power flows • Heat and particle flux handling • High temperature operation and power conversion • Power core fabrication • Power core lifetime • Safety and Environmental Attractiveness (Steiner) • Tritium inventory and control • Activation product inventory and control • Waste management • Reliable Plant Operations (Waganer) • Plasma diagnosis and control • Plant integrated control • Fuel cycle control • Maintenance 12 top-level issues

7. The intent is to be comprehensive based on functions rather than physical elements • Economic Power Production • Control of plasma power flows • Heat and particle flux handling • High temperature operation and power conversion • Power core fabrication • Power core lifetime Power deposition Power flows Power conversion

8. 3) Example TRL table: 1c. High temperature

9. 4) An evaluation of readiness requires identification of an end goal • For the sake of illustration, we are considering Demo’s based on mid-term and long-term ARIES power plant design concepts, e.g. • Diverted high confinement mode tokamak burning plasma • Low-temperature or high-temperature superconducting magnets • He-cooled W or PbLi-cooled SiCf/SiC divertors • Dual-cooled He/PbLi/ferritic steel blankets or single-coolant PbLi with SiCf/SiC • 700˚C or 1100˚C outlet temperature with Brayton power cycle

10. 5) Example evaluation: High temperature operation and power conversion • Concept development is largely completed for DCLL. Limited data on ex-vessel parts of power conversion system (e.g., HX) • For TRL4: Need full loop operation at high temperature in a laboratory environment • This is typical of many issues; some are more advanced, but most are stuck at TRL=3 • ARIES-AT power conversion TRL is probably at 2.

11. Status of documentation • TRL tables have been drafted, to be presented today • Report: • Outline, Introduction, Methodology complete • Description of issues nearing completion • Definition of the end goal for the evaluation needs completion • Preparing to run through an example evaluation of the whole system • We should obtain community input on TRL definitions to ensure accuracy and buy-in. Town meeting? • PPT progress report to DOE in preparation