Future Plasma Facing Components (PFCs) & In-vessel Components (IVCs): The Need for a Strong Sustained & Integra

1. Future Plasma Facing Components (PFCs) & In-vessel Components (IVCs): The Need for a Strong Sustained & Integrated Approach for Modeling and Testing R.E. Nygren Fusion Technology Department Sandia National Laboratories • Deputy Director, Virtual Laboratory for Technology • Member, Power Extraction Subpanel in HFP Presentation at the ReNeW Joint Workshop 2-6 March 2009 for the themes of Harnessing Fusion Power and Taming the Plasma Interface Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company,for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

2. OUTLINE High Heat Flux Components include Plasma Facing Components and some In-Vessel Components • Gaps & Needs (“Greenwald” Panel) • Compelling schedule for actively-cooled PFCs and IVCs • Proposal: emphasize and include strong sustained & well integrated program in technology in thrusts for PFCs, IVCs, PMI, Power Extraction, … others that starts now!

3. An HHFC Program – Guiding Principles • At each of the stages of development toward a DEMO there is a critical set of capabilities in fusion nuclear technology that need to be in place to proceed further. • Progress will occur through a well integrated program of computational models and benchmark experiments, (well instrumented)first in labs, later in dedicated facilities. • We (fusion) require authoritative information on technology to identify paths toward a successful DEMO. This in turn requires an understanding informed by in-depth studies of possible design alternatives and enabling technologies, integrated predictive modeling of PFC/IC performance, and supporting experiments.

4. “Greenwald” Panel Report Theme B. Taming the Plasma Material Interface: .. knowledge sufficient to design and build, with high confidence, 8. PWI: Understand and control of all processes that couple the plasma and nearby materials. 9. PFCs: Understand .. materials and processes that can be used to design replaceable components that can survive .. 10. .. Other .. : .. necessary understanding of plasma interactions, neutron loading and materials to allow design of .. any other diagnostic equipment that can survive ... “The themes were defined in terms of knowledge required prior to Demo. ... based on sound scientific principles and rigorously tested in the lab so that the step to a [DEMO] .. taken with high confidence of success.” “The Report also characterized PFCs and materials as “Tier 1 solution not in hand, major extrapolation ..”

5. “Greenwald” Panel Report Theme C. Harnessing fusion power: knowledge .. sufficient to design and build, with high confidence, 11. Fuel Cycle: .. manage the flow of tritium ... 12. Power: .. temperatures sufficiently high for efficient production of electricity or hydrogen. 13. Materials ..: Understand the basic materials science for fusion breeding blankets, structural components, plasma diagnostics and heating components .. high neutron fluence .. 14. Safety: Demonstrate .. safety …. minimize environmental burdens .. 15. RAMI [Reliability, Availability, Maintainability & Inspectability]: Demonstrate .. productive capacity …. validate economic assumptions ….

6. “Greenwald” Panel Report Finding 6. Evaluation of current and planned programs and summary of gaps ….. The most significant gaps were:G1. …. G2. … G-5. Ability to predict and avoid, or detect and mitigate, off-normal plasma events … G-9. Sufficient understanding of all plasma-wall interactions …. The science underlying the interaction of plasma and material needs to be significantly strengthened to .. G-10. Understanding of the use of low activation solid and liquid materials, joining technologies and cooling strategies ... G-11. Understanding .. the complete fuel cycle, particularly .. G-12. An engineering science base .. effective removal of heat ... G-13. Understanding .. low activation materials .. G-14. .. guarantee safety over the plant life cycle - including .. G-15. .. efficient maintainability of in-vessel components ..

7. “Greenwald” Panel Report Recommendation 4. .... nine major initiatives. I-1. .. predictive plasma modeling and validation .., I-2. Extensions to ITER AT capabilities .. burning AT regimes I-3. Integrated advanced burning physics …facility .. dedicated I-5. .. disruption-free concepts .. performance extension device .. I-6. .. advanced computer modeling and laboratory testing .. single-effects science for major fusion technology issues, I-8. Component development/testing program … multi-effect issues in critical technology .. breeding/blanket .. first wall I-4. Integrated experiment for PWI/PFCs .. steady-state .. non-DT I-7. Materials qualification facility … (IFMIF). I-9. Component qualification facility.. high availability.. heat flux .. neutron fluence .. DT device .... (CTF).

8. PFC & IVC operations edge modeling HHFC modeling & testing PMI modeling & testing Current Status of HHFC Program Excluding PMI and edge programs #1 Support ITER PFC design & R&D and develop component fabrication processes, QA, and operation. excellentrelations with IPO, IP, DAs; US R&D & testing (for all DAs) ongoing; US role in design expanding; valuable insight into design/machine interfaces gap: test capabilities (old & frail); design integration & interfaces; participation in divertor R&D 2. Support physics missions of existing, upgraded and new US confinement experiments. current need but little R&D[NSTX Liquid Li divertor is really PMI] gap: program organization; integration with machines; test capabilities (He, probes, disruption simulation) MAU 3. Develop and prove robust PFCs for future confinement devices. limited but sustained work on He cooled W and on liquid surfaces gap: expanded test capabilities; stronger integrated modeling; test capabilities (He, liq. met.) DLY

9. robust actively-cooled PFCs & IVCs • component development • extensive instrumentation • - design confirmation [modeling, testing] • - fabrication (?dev.) • - QA & acceptance An HHFC Program to address the gaps Integrated with PMI models & tests, edge modeling, and operations • Well integrated technology program: • Supporting HHF tests & other experiments: • Comprehensive confirmed predictive models: • Development of instrumentation:

10. robust actively-cooled PFCs & IVCs • component development • extensive instrumentation • - design confirmation [modeling, testing] • - fabrication (?dev.) • - QA & acceptance An HHFC Program to address the gaps Integrated with PMI models & tests, edge modeling, and operations • Well integrated technology program: support ongoing physics missions and future devices with strong integration and coordination with devices, PMI and edge. • Supporting HHF tests & other experiments: confirm performance and enable deployment of new PFCs & IVCs • Comprehensive confirmed predictive models: PMI, edge plasmas, thermal-hydraulics, materials behavior • Development of instrumentation: needed for safe operation and to evaluate performance;“smart tiles,” actively-cooled PFCs and IVCs (and TBMs, etc.) DIII-D, C-MOD, NSTX, Upgrades,ITER, CTF, DEMO

11. robust actively-cooled PFCs & IVCs • component development • extensive instrumentation • - design confirmation [modeling, testing] • - fabrication (?dev.) • - QA & acceptance An HHFC Program to address the gaps Integrated with PMI models & tests, edge modeling, and operations • Comprehensive and predictive models:PMI, edge plasmas, TH & mat’ls behavior • Supporting HHF & other experiments:confirm performance,enable deployment of new PFCs/IVCs in & future devices • Well integrated technology program:support ongoing physics missions and future devices … • Development of instrumentation: actively-cooled PFCs/IVCs(+TBMs,..), “smart tiles”, probes, … Partnership of modelers & experimenters & PFC users e.g., critical roles of test design and measurements Technologists understand machine interfaces & req’mts Existing “work horse” lab facilities need upgrades, expansion and support

12. robust actively-cooled PFCs & IVCs • component development • extensive instrumentation • - design confirmation [modeling, testing] • - fabrication (?dev.) • - QA & acceptance An HHFC Program to address the gaps Integrated with PMI models & tests, edge modeling, and operations Fundamental Point 1: HHFC R&D is challenging & time-consuming. It requires strong coordination with confinement projects on interfaces and with industrial suppliers on fabrication development, QA and acceptance.

13. robust actively-cooled PFCs & IVCs • component development • extensive instrumentation • - design confirmation [modeling, testing] • - fabrication (?dev.) • - QA & acceptance An HHFC Program to address the gaps Integrated with PMI models & tests, edge modeling, and operations • ~25y - fusion-specific water-cooled heat sinks • ~15y - ITER PFC R&D • ~10y detailed R&D • ITER design changing • ~ 4y FWQ mockups • ?US vendors engaged • 3-5y final design to fab Fundamental Point 1: HHFC R&D is challenging & time-consuming. It requires strong coordination with confinement projects on interfaces and with industrial suppliers on fabrication development, QA and acceptance. Tore Supra water cooled PFCs • modular limiters in 1990s failed • very good history working closely with Plansee on fabrication • yet still had quality problems • rebuilt PFCs - CIEL completed 2002 FWQM Testing Status US & EU Mockups Date: End of May 8, 2008 Cycles Completed: 3447

15. We develop PFCs using single effects tests Testing Hierarchy ITER & CTF for “integrated” tests. HHFC/PMI facilities for single & multiple effects. These “work horse” lab facilities will continue and need upgrades, expansion & sustained support. J. Linke et al., JNM 367–370 (2007) 1422–1431

16. robust actively-cooled PFCs & IVCs • component development • extensive instrumentation • - design confirmation [modeling, testing] • - fabrication (?dev.) • - QA & acceptance An HHFC Program to address the gaps Integrated with PMI models & tests, edge modeling, and operations Fundamental Point 2: A strong well integrated HHFC program (near term) could enable new PFCs and IVCs in upgrades for longer shots, higher power or hot walls. Consider deploying He-cooled probes or guards to postpone water cooling. Cooling with room temperature He (not high T, lower density) is a less challenging adaption of the technology.

17. robust actively-cooled PFCs & IVCs • component development • extensive instrumentation • - design confirmation [modeling, testing] • - fabrication (?dev.) • - QA & acceptance An HHFC Program to address the gaps Integrated with PMI models & tests, edge modeling, and operations Fundamental Point 2: A strong well integrated HHFC program (near term) could enable new PFCs and IVCs in upgrades for longer shots, higher power or hot walls. Consider deploying He-cooled probes or guards to postpone water cooling. Cooling with room temperature He (not high T, lower density) is a less challenging adaption of the technology. Heat pipes and helium cooling technology have both progressed significantly in the last decade. US He-cooled PFC target >20MW/m2

18. Compelling schedule for actively-cooled HHFCs Tokamak/AT Focus: 1. tokamak divertors 2. solid surface PFCs 3. present/ITER-DEMO gap Other: 4. alternates 5. liquid surface 6. other fusion pathways Alternates Non-electric or hybrid applications

19. ReNeW PFCs Tokamak/AT DEMO-A divertor ITER divertor DEMO-B divertor JET DIII-D JT-60U ??? C-MOD ASDEX-U TEXTOR ??? Tore Supra TFTR ???/CTF Alternates MAST ?? primary alternate ??? NSTX LHD ??? W7X Wendelstein ??? Non-electric or hybrid applications

20. D/T plasma • solid surface • long pulse • good efficiency • high availability • damage resistance ReNeW PFCs Tokamak/AT DEMO-A divertor ITER divertor DEMO-B divertor JET DIII-D JT-60U ??? C-MOD ASDEX-U TEXTOR ??? Tore Supra TFTR Alternates MAST ?? primary alternate • ?liquid surface NSTX ??? LHD ??? W7X Wendelstein ??? Non-electric of hybrid applications

21. D/T plasma • solid surface • long pulse • good efficiency • high availability • damage resistance • tritium retention • active cooling • high temperature • high reliability • neutron damage ReNeW PFCs GAP 2 GAP 1 Tokamak/AT DEMO-A divertor ITER divertor DEMO-B divertor JET DIII-D JT-60U ??? C-MOD ASDEX-U TEXTOR ??? Tore Supra TFTR Alternates MAST ?? primary alternate • ?liquid surface NSTX ??? LHD ??? W7X Wendelstein Non-electric of hybrid applications

22. D/T plasma • solid surface • long pulse • good efficiency • high availability • damage resistance • tritium retention • active cooling • high temperature • high reliability • neutron damage ReNeW PFCs GAP 2 GAP 1 Tokamak/AT DEMO-A divertor ITER divertor DEMO-B divertor JET DIII-D JT-60U ??? C-MOD ASDEX-U TEXTOR ??? Tore Supra TFTR ???/CTF Alternates MAST ?? primary alternate • ?liquid surface NSTX ??? LHD ??? W7X Wendelstein Non-electric of hybrid applications

23. D/T plasma • solid surface • long pulse • good efficiency • high availability • damage resistance • tritium retention • active cooling • high temperature • high reliability • neutron damage ReNeW PFCs GAP 2 GAP 1 Tokamak/AT DEMO-A divertor ITER divertor DEMO-B divertor JET DIII-D JT-60U ??? or upgrade C-MOD ASDEX-U TEXTOR ??? actively cooled launchers, probes (IVCs) Tore Supra TFTR ???/CTF Alternates engineering instrumentation MAST ?? primary alternate • ?liquid surface NSTX ??? LHD ??? W7X Wendelstein Non-electric of hybrid applications Analog thinker in a digital age.

24. E N D

25. An HHFC Program – Guiding Principles • At each of the stages of development toward a DEMO there is a critical set of capabilities in fusion nuclear technology that need to be in place to proceed further. • Progress will occur through a well integrated program of computational models and benchmark experiments, (well instrumented)first in labs, later in dedicated facilities. • We (fusion) require authoritative information on technology to identify paths toward a successful DEMO. This in turn requires an understanding informed by in-depth studies of possible design alternatives and enabling technologies, integrated predictive modeling of PFC/IC performance, and supporting experiments.

26. An HHFC Program – Guiding Principles We will need to proceed through several stages of readiness in PFCs, ICs and all of FNST to build a DEMO. 1st stage development: minimum set of capabilitiesto support the understanding of science-based engineering principles • Experimental facilities with hot fluids and hot walls and adequate instrumentation • Integrated computational models • Appropriate materials • Appropriate experience with design integration and safety

27. An HHFC Program – Guiding Principles The first level of readiness enables the following activities: • Development of PFCs and In-vessel Components for upgrades and new devices • Preparation of initial integrated experiments in ITER, i.e., TBMs and appropriate instrumentation • Serious evaluations of possible designs for a CTF-type device and for the supporting effort to develop components • Decisions about successful paths for future devices (e.g., upgrades, D/D and D/T CTFs and DEMO)