Next Step Options for Advancing Fusion Energy: The FIRE Collaboration

1. FIRE Collaboration http://fire.pppl.gov AES, ANL, Boeing, Columbia U., CTD, GA, GIT, LLNL, INEEL, MIT, ORNL, PPPL, SNL, SRS, UCLA, UCSD, UIIC, UWisc Next Step Option (NSO) Dale Meade US ITER Project/VLT Meeting Princeton, NJ October 21, 2004

2. The Next Step Option (NSO) Activity • The purpose of the Next Step Options activity is to investigate and assess various opportunities for advancing the scientific understanding of fusion energy, with emphasis on plasma behavior at high energy gain and for long duration. The Next Step Options (NSO) study has been organized as a national integrated physics/engineering design activity within the Virtual Laboratory for Technology (VLT). The NSO program’s objective is to develop design options and strategies for burning plasmas in the restructured fusion sciences program, considering the international context. Examples of specific tasks to be pursued include investigation of a modular program pathway, with initial emphasis on the burning plasma module. The initial effort has been focused on a design concept called the Fusion Ignition Research Experiment (FIRE) that includes both burning plasma physics and advanced toroidal physics mission objectives. • NSO-PAC: 15 members, Chaired by Tony Taylor, 5 meetings, all reports are on the web at http://fire.pppl.gov/nso_pac5.html • FIRE effort evolved form the US ITER Design Home Team,and involved >15 institutions and >50 individuals. • FIRE has been engaged in a PreConceptual design activity at a budget of ≈ $2M/year with FY04 =FY05 = $0.6 M. The FIRE PreConceptual design was completed in FY04.

3. NSO/FIRE Status • FIRE followed recommendations of Snowmass and FESAC (BPPS & 35 Yr Plan) • Developed “Steady-state” High- AT Mode for FIRE • Expanded Operating Range for H-Mode and AT, longer pulse, faster rep rate • AT duration limited by first wall more than TF in present design • PVR March 29-30, 2004 • Strong positive recommendations from the PVR Committee • Technically Ready to begin Conceptual Design • Identified areas for more R&D – (most in common with ITER) • Pre-Conceptual Design Completed - September 30, 2004 • Original Goals Exceeded • Excellent Technology support from VLT Team • Strong Support from the Base Program (both Technology and Physics) • Documentation is on web (needs to organized/indexed)

4. “Steady-State” High-b Advanced Tokamak Discharge on FIRE 0 1 2 3 4 time,(current redistributions)

5. Q = 5 ARIES-like AT Mode Operating Range Greatly Expanded Nominal operating point • Q = 5 • Pf = 150 MW, • Pf/Vp = 5.5 MWm-3 (ARIES) • ≈ steady-state 4 to 5 tCR Physics basis improving (ITPA) • required confinement H factor and bN attained transiently • C-Mod LHCD experiments will be very important First Wall is the main limit • Improve cooling • revisit FW design Opportunity for additional improvement.

6. NSO/FIRE Status • FIRE followed recommendations of Snowmass and FESAC (BPPS & 35 Yr Plan) • Developed “Steady-state” High- AT Mode for FIRE • Expanded Operating Range for H-Mode and AT, longer pulse, faster rep rate • AT duration limited by first wall more than TF in present design • PVR March 29-30, 2004 • Strong positive recommendations from the PVR Committee • Technically Ready to begin Conceptual Design • Identified areas for more R&D – (most in common with ITER) • Pre-Conceptual Design Completed - September 30, 2004 • Original Goals Exceeded • Excellent Technology support from VLT Team • Strong Support from the Base Program (both Technology and Physics) • Documentation is on web (needs to organized/indexed)

7. FIRE PVR • FIRE Physics Validation Review (PVR) was held March 30-31 in Germantown. • The Committee included: S. Prager, (Chair) Univ of Wisc, Earl Marmar, MIT, N. Sauthoff PPPL, F. Najmabadi, UCSD, Jerry Navratil, Columbia (unable to attend), John Menard PPPL, R. Boivin GA, P.  Mioduszewski ORNL, Michael Bell, PPPL, S. Parker Univ of Co, C. Petty GA, P. Bonoli MIT, B. Breizman Texas, • PVR Committee Consensus Report: • The FIRE team is on track for completing the pre-conceptual design within FY 04. FIRE would then be ready to launch the conceptual design. The product of the FIRE work, and their contributions to and leadership within the overall burning plasma effort, is stellar. • Is the proposed physical device sufficiently capable and flexible to answer the critical burning plasma science issues proposed above? • The 2002 Snowmass study also provided a strong affirmative answer to this question. Since the Snowmass meeting the evolution of the FIRE design has only strengthened ability of FIRE to contribute to burning plasma science.

8. FIRE PVR (2) • • The panel identified FIRE-specific areas that can benefit from further pre-conceptual design work including: alpha driven instabilities, generic port plug design, more modeling of particle exhaust, n>1 resistive wall modes and neoclassical modes. • The panel also identified generic burning plasma areas that can benefit from further work : investigation of the suppression of neoclassical tearing modes (NTM) by RF current drive, development of modified and new diagnostics for burning plasma research, development of an integrated simulation capability applicable to burning plasmas, investigation of effects of ELMs on tungsten divertor components and systematic antenna development. Possible elements in a US burning plasma program. • Nearly all these items are also on the ITER task list.

9. NSO/FIRE Status • FIRE followed recommendations of Snowmass and FESAC (BPPS & 35 Yr Plan) • Developed “Steady-state” High- AT Mode for FIRE • Expanded Operating Range for H-Mode and AT, longer pulse, faster rep rate • AT duration limited by first wall more than TF in present design • PVR March 29-30, 2004 • Strong positive recommendations from the PVR Committee • Technically Ready to begin Conceptual Design • Identified areas for more R&D – (most in common with ITER) • Pre-Conceptual Design Completed - September 30, 2004 • Original Goals Exceeded • Excellent Technology support from VLT Team • Strong Support from the Base Program (both Technology and Physics) • Documentation is on web (needs to organized/indexed)

10. Issues and Recommended Approach • Uncertainty of ITER Construction Decision (This is no surprise) • Follow FESAC recommendations • Support the ITER process, more aggressive outreach is needed to get greater community involvement in ITER. • Stay on track, and “Hold our FIRE” as per FESAC/NRC • NSO was chartered for this situation • Proposed Option “extend performance of ITER using Advanced Tokamak operation” • Fully exploit the capability of ITER (increase power to ~1GW at steady-state) • Would address several physics tasks requested by IT Leader • Coincident with US program emphasis on advanced physics and technology • Aligns with FIRE mission if ITER does not go forward

11. (TAE instabilities in Steady-state scenarios) Physics Tasks Requested by the International Team Leader[US ITER Project Status @ TOFE , 9/04] • Magnets and PFCs (power and particle-handling, including tritium inventory): • How disruptions/VDEs which may affect the ITER design. • Characterization of thermal energy load during disruption • Model development of halo current width during VDEs based on experiments • Simulations of VDEs in ITER with 3D MHD code • Disruption mitigation by noble gas injection • Oxygen baking experiment, which could be possible during spring 2005 at D III-D and is under discussion at GA, may be one of the possible tasks. • Heating and Current-drive and advanced control: • ITER Plasma Integrated Model for ITER for Control • Feasibility study of ITER SS scenarios with high confinement, NBCD, ECCD, LHCD, ICCD and fueling by pellet injection. • RF launchers • Validation of enhanced confinement models and application to ITER. • Development of Steady State Scenarios in ITER • RWM in Steady State Scenario in ITER • Evaluation of Fast Particle Confinement of ITER • Diagnostics: • Specific diagnostic design tasks, including updating procurement packages[activities related to the diagnostics for which the US is responsible]

12. FY05 Plans Highlighting ITER Support • Develop higher performance steady-state AT mode for ITER (NINBCD, FWCD,LHCD) • Initial results to be presented at IAEA and ITPA • N ≈ 3.3, fbs ≈ 50% with 100% non-inductive drive (NINB, LHCD, bootstrap) • LH for off-axis CD can put qmin at r/a ~0.8, compare with ECCD • Lots of opportunity for improvement!! • Optimize NIND, ICFW, ECCD and LHCD mix and plasma startup(ITPA) • Evaluate RWM feedback stabilization requirements and integrate with first wall • Initial results from Columbia (VALEN, DIII-D) look promising • stable up to N = 3.7, for coils inside VV, integrated with shield modules • Key issue is the technical feasibility of coils near the plasma • Interest expressed by G. Janeshitz in RWM in port plug first wall • Resources for design of integrated first wall and coil are already over committed.

13. IAEA Paper FT/P7-23 Optimize CD mix & startup to flatten q profile First Results from ITER-AT Studies Using TSC,TRANSP and NOVA-K Goal is Steady-State, bN ≈ 3.5, fbs > 60% fbs , Q > 5 using NINB, ICFW and LHCD This case has bN ≈ 3.3, fbs ≈ 44%, ≈ 100% non-inductive and Q ≈ 5. Invited to join ITPA Integrated Modeling paper at IAEA and Nuclear Fusion.

14. FY05 Plans Highlighting ITER Support • Develop higher performance steady-state AT mode for ITER (NINBCD, FWCD,LHCD) • Initial results to be presented at IAEA and ITPA • N ≈ 3.3, fbs ≈ 50% with 100% non-inductive drive (NINB, LHCD, bootstrap) • LH for off-axis CD can put qmin at r/a ~0.8, compare with ECCD • Lots of opportunity for improvement!! • Optimize NIND, ICFW, ECCD and LHCD mix and plasma startup(ITPA) • Evaluate RWM feedback stabilization requirements and integrate with first wall • Initial results from Columbia (VALEN, DIII-D) look promising • stable up to N = 3.7, for coils inside VV, integrated with shield modules • Key issue is the technical feasibility of coils near the plasma • Interest expressed by G. Janeshitz in RWM in port plug first wall • Resources for design of integrated first wall and coil are already over committed.

15. IAEA Paper FT/P7-23 Applying FIRE-Like RWM Coils to ITER Increases b-limit from bN = 2.5 to 3.7 VALEN Analysis- Columbia ITER RWM coils located outside TF coils Engineering feasibility needs to be determined G. Janeschitz has expressed interest in RWM coils integrated with first wall

16. FY05 Plans Highlighting ITER Support(2) Coordinate with PFC and TBM activities on design issues for higher power densities if AT scenario yields extended performance (~1,000+ MW), ITER will need a first wall capable of higher power (~ 1MWm-2) recovering performance approaching the original ITER is the ultimate goal More Proactive Outreach for ITER and Burning Plasma Program US ITER Project Info on web at http://fire.pppl.gov/iter_us_news.html Two Symposia at AAAS Annual Meeting (Feb 2005) in Washington, DC on Energy and Fusion (Talk on ITER-NRS) KPS-DP: Special Lecture on Burning Plasmas Community Workshop next Spring on Burning Plasma Activities

17. FY06 Plans Follow up on themes started in FY05 Use output of Spring 2005 Burning Plasma workshop to refine directions Recommended Approaches to Increased Effectiveness Greater involvement of the fusion community in ITER Establish a National Burning Plasma Program Been proposed since December 2000 at Austin BP Workshop Increase outreach to the fusion community as well as scientific community Community Workshop next Spring on Burning Plasma Activities

18. Concluding Remarks • FIRE Pre-Conceptual Design has been completed - exceeding original goals. • Special thanks and a debt of gratitude to the VLT/FIRE team members for their “stellar” work on/under FIRE. • Maintain FIRE at a holding position to be put forward as an attractive burning plasma experiment if the ITER negotiations remain deadlocked. • Transition of NSO activities to supporting the “option” of extending ITER performance using AT operation has been accomplished without missing a step. The goal is to recover most of the capability of the larger ITER. Already some progress. • Need to stay the course with community strategy as events unfold. • We must expand the fusion outreach activities in any eventuality.