Chamber Technology (CT) and Why Now? General Atomics, San Diego Mohamed Abdou Presented to: VLT-PAC General Atomics, San Diego February 25, 2003 Note: specifics are for MFE Chamber. See Wayne Meier for specifics on IFE Chamber

Outline What is Chamber Technology? and its central role in fusion devices, burning plasma devices, and fusion energy systems Past achievements and tremendous impact on plasma physics research and fusion energy development (prior to Restructuring) Recent achievements and Impact on fusion program (post restructuring) Critical Technical Issues for Chamber Technology and their Central Role in the Fusion Program for the next few years and beyond. Plans for immediate future FY04/05/06 and Role of Chamber Technology in Recent Initiatives: ITER, Energy-Based Policy, and 35-yr Plan Disastrous consequences to the Fusion Program of “close out” of CT Note: Prior to the Restructuring of the Fusion Program of 1997, Chamber Technology was divided into several programs (Neutrons, Blanket/FW, Fuel Cycle, etc.) After restructuring, these programs were combined under a Chamber Technology Program.

Scope of Chamber Technology Research Chamber Technology (CT) Research embodies the scientific and engineering disciplines required to understand, design, develop, test, build, and operate safely and reliably the systems that surround a burning plasma. CT includes all components and functions from the edge of the plasma to the magnets, including: first wall blanket (breeding and non-breeding) conducting shells vacuum vessel radiation shielding nuclear part of RF antenna, etc. cooling systems electric/thermal insulators tritium barriers and processing tritium fuel cycle support structure & remote maintenance CT also includes design and integration for Chamber Components

Chamber Technology Embodies Two of the Three Fundamental Functions of Fusion Energy Systems Fusion Energy Systems Fundamental Functions: 1- Producing energy from the DT fusion reaction in the plasma 2- High-temperature power extraction in a practical, safe, and economical fusion energy system (extracting heat in any plasma device) 3- Breeding sufficient tritium to assure that the plasma is self-sustained and that fusion is a “renewable” energy source with a closed fuel cycle The Chamber Technology Program includes all components required to achieve functions #2 and #3 Chamber Technology also embodies the systems that hold, provide the vacuum and fuel the plasma, which are essential to achieving function #1

The CT Program is responsible for advancing and providing state-of-the-art predictive capabilities for many technical disciplines required for the fusion program (to support, for example, Safety, Materials, PFC, Advanced Design Studies, fusion devices, burning plasma experiments, etc.) Modeling, experiments, codes and analysis for: neutron/photon transport neutron-material interactions heat/mass transfer thermofluid physics and MHD thermal hydraulics Tritium release, extraction, inventory and control structural mechanics thermomechanics chemistry radioactivity and decay heat engineering scaling reliability analysis methods

Neutrons (fluence, spectrum, spatial and temporal gradients) R&D for Chamber Technology is a “Grand Challenge” not only because of the multi-function, multi-physics, multi-engineering requirements and issues but also because of the complex and unique thermo-magneto-vacu-tritu-nuclear environment of fusion Neutrons (fluence, spectrum, spatial and temporal gradients) - Radiation Effects (at relevant temperatures, stresses, and loading) - Bulk Heating - Tritium Production - Activation and Decay Heat Heat Sources (magnitude, gradient) - Bulk (from neutrons) - Surface (from particles and radiation) Particle Flux (energy, density, gradients) Magnetic Field (3-component with gradients) - Steady Field - Time-Varying Field Mechanical Forces - Normal (steady, cyclic) - Off-Normal (pulsed) Thermal/Chemical/Mechanical/Electrical/Magnetic/Nuclear Interactions and Synergistic Effects Combined environmental loading conditions Interactions among physical elements of components  The kind of training needed to perform research and engineering within this highly constrained fusion chamber system takes many years of education and experience.

Technology Programs are Highly Interrelated and Interactive (Take as an analogy a “three-legged stool”: PFC, Chamber Tech, and Materials) (Many Other “3-legged stool” examples can be shown with other parts of the fusion program, e.g. with Safety and Design Studies Programs) S P Tritium retention Methods, analysis, and R&D (failure modes, effects, and rates; reliability growth; maintenance and availability; etc.) Reliability, Availability, and Maintainability Thermofluid MHD PFC heat sink development and heat removal, coolant compatibility Erosion of PFM and impurity control Joining of Plasma Facing Materials (PFM) to heat sink, thermal fatigue life Plasma materials interactions R&D (effects of PFM on core plasma) PFM and heat sink materials (development, properties and irradiation) Vacuum Vessel Configuration and engineering design Structural material (development, properties and irradiation) Plasma Facing Components Thermofluid effects (heat transfer, fluid mechanics, MHD) Tritium extraction, inventory, and control Heat removal and thermal efficiency Tritium breeding and neutron multiplier materials R&D First Wall/Blanket/Shield Fusion Materials Chamber Tech PFC Key Issue Radiation shielding (components and personnel radiation protection, design and R&D) Neutronics, photonics, and neutron material interactions (transport, DPA, He, H, transmutation, etc.) Blanket structural materials (development, properties and irradiation) Coolant/Multiplier/Breeder/Structure interactions and compatibility Remote maintenance technology Materials Program Fusion Technology Plasma Technology Area P - Primary role for resolving issue, S - Supporting role in resolving issue

Why Chamber Technology Research Now? “Why Now?!” It is not just needed now! It was needed 30 years ago! It was started 30 years ago! It would have been impossible for the fusion program to make the progress we have made without Chamber Technology Research over the past 30 years. No Credible plans for future fusion development are possible without Chamber Technology Research NOW. One way to understand “why now” is to learn how Chamber Technology Research was crucial in making progress over the past 30 years.

Since the Early 1970’s, Chamber Technology Research has had a Fundamental and Major Impact on: The Direction and Emphasis of Plasma Physics R&D The Direction and Emphasis of other Fusion Technology Programs Identifying and Resolving Critical Issues in Fusion, many of which are “Go, No-Go” issues Shaping our vision today of a burning plasma device and fusion power plant This impact is illustrated by some “historical” examples given in a separate handout.

Remaining Critical R&D Issues for Chamber Technology (FNT) Remaining Engineering Feasibility Issues, e.g. feasibility, reliability and MHD crack tolerance of electric insulators tritium permeation barriers and tritium control tritium extraction and inventory in the solid/liquid breeders thermomechanics interactions of material systems materials interactions and compatibility synergistic effects and response to transients D-T fuel cycle tritium self-sufficiency in a practical system depends on many physics and engineering parameters/details: e.g. fractional burn-up in plasma, tritium inventories, FW thickness, penetrations, passive coils, and many more variables. A related issue is how to supply Tritium for burning plasma experiments, such as ITER. Reliability/Maintainability/Availability: failure modes, effects, and rates in blankets and PFC’s under nuclear/thermal/mechanical/electrical/ magnetic/integrated loadings with high temperature and stress gradients. Maintainability with acceptable shutdown time. Lifetime of blanket, PFC, and other FNT components

NOW is the time to develop tritium breeding blanket for extended ITER Operation and beyond Tritium Supply considerations are a critical factor in Fusion Energy Development Experimental DT Devices for Fusion Energy Development Will Need a Tritium Breeding Blanket The world maximum tritium supply (from CANDU) over the next 40 years is 27 kg. This tritium decays at 5.47% per year. Cost is high ($30M-$200M/kg) A DT facility with 1000 MW fusion power burns tritium at a rate of 55.8 kg/yr. Large power DT facilities must breed their own tritium. (It is ironic that our major problem is “tritium fuel supply”, while the fundamental premise of Fusion is an “inexhaustible” energy source) This is why testing of breeding blanket module is Planned in ITER from Day 1 of Operation (2013), since ITER can not run in the extended phase without breeding The Fusion Program needs to show that “tritium self sufficiency in a practical engineering system” is indeed attainable in a real fusion device. This is a challenge, involves > 20 physics, engineering, and material variables.

See calculation assumptions in Table S/Z The Lack of Adequate Tritium Supply and the Need for Tritium Breeding Blanket are Already Having a Major Impact NOW on ITER Operational Plans and Fusion Energy Development Plans See calculation assumptions in Table S/Z Without a tritium breeding capability, ITER cannot run in an extended phase. Large power DT facilities must breed their own tritium Breeding Blanket must be developed NOW - We cannot wait very long for blanket development even if we want to delay DEMO

We must proceed quickly to participate in ITER Technology Testing Program ITER was conceived not only as a burning plasma experiment but also as an experiment to test fusion technologies in a real fusion environment. The Chamber Technology Program has a leading role in both the basic device and the blanket test module missions. ITER can provide important functional and screening tests for vital tritium breeding technologies Notion: It doesn’t make sense to pay billions to build ITER, and not spend millions to utilize ITER to acquire key technology data and experience

ITER Operational Plan Calls for Testing Breeding Blankets from Day 1 of Operation H-Plasma Phase D Phase First DT plasma phase Accumulated fluence = 0.09 MWa/m2 Blanket Test

TBM Roll Back from ITER 1st Plasma Shows CT R&D must be accelerated now for TBM Selection in 2005 EU schedule for Helium-Cooled Pebble Bed TBM (1 of 4 TBMs Planned) ITER First Plasma a final decision on blanket test modules selection by 2005 in order to initiate design, fabrication and out-of-pile testing (Reference: S. Malang, L.V. Boccaccini, ANNEX 2, "EFDA Technology Workprogramme 2002 Field: Tritium Breeding and Materials 2002 activities- Task Area: Breeding Blanket (HCPB), Sep. 2000)

C × i + replacement cost + O & M COE = P × Availability × M × h fusion Reliability/Maintainability/Availability is one of the remaining “Grand Challenges” to Fusion Energy Development. Chamber Technology R&D is necessary to meet this Grand Challenge. Need High Power Density/Physics-Technology Partnership - High-Performance Plasma - Need Low - Chamber Technology Capabilities Failure Rate C × i + replacement cost + O & M COE = P × Availability × M × h fusion th Energy Need High Temp. Multiplication Energy Extraction Need High Availability / Simpler Technological and Material Constraints · Need Low Failure Rate: - Innovative Chamber Technology t time replacemen rate failure / 1 ) ( + · Need Short Maintenance Time: - Simple Configuration Confinement - Easier to Maintain Chamber Technology

C = Potential improvements with aggressive R&D The reliability requirements on the Blanket/FW (in current confinement concepts that have long MTTR > 1 week) are most challenging and pose critical concerns. These must be seriously addressed as an integral part of the R&D pathway to DEMO. Impact on ITER is predicted to be serious. It is a DRIVER for CTF. The Chamber Technology Program NOW is leading the way to resolving this challenge. A = Expected with extensive R&D (based on mature technology and no fusion-specific failure modes C = Potential improvements with aggressive R&D

Why do research now on Chamber Technology? Utilization of ITER technology testing environment Develop needed tritium breeding and recovery technologies for burning plasma experiments and to demonstrate fusion fuel self-sufficiency Impact on current and future physics program Vital Interactions with other technology programs Key predictive capabilities needed by all programs Access to the broader international technology research / data though existing collaborations Training young technology researchers that will be running ITER and CTF experiments in 10 years Tough technology problems require long testing and development times – e.g. Reliability Growth

CT Plans for FY 04/05 A Chamber Technology Program is Essential to the New Presidential Initiatives to join ITER and Implement an Energy-Based Policy for Fusion The Chamber Technology Community is ready to move to a new emphasis: 1. Re-Start ITER Test Blanket Module Program 2. Support ITER Basic Device in the FNT area 3. Continue research on Advanced Chamber Configurations with re-adjusted scope 4. Maintain vital efforts to advance fundamental Predictive Capabilities and tools needed by other Fusion Programs 5. FNT Experimental Techniques and testing to support the energy development plans Learn from proven successful APEX Features 1) Multidisciplinary, multi-institution integrated TEAM 2) Close Coupling to the Plasma Community 3) Direct Participation of Scientists from Materials, PFC, Safety, and AD Programs 4) Direct Coupling to IFE CT Community 5) Direct participation with International programs 6) Encourage Innovation Note: Balance among these elements in a constrained budget will be derived from community deliberations.

Chamber Technology Plan for FY 04/05 CT Plans for FY 04/05 (cont’d) Chamber Technology Plan for FY 04/05 1. Blanket Test Module Program (for ITER and other devices) Lead US community to evaluate blanket options for DEMO, evaluate R&D results for key issues to select TWO Primary Blanket Concepts for testing in ITER (must reach a decision by 2005). [This effort will also involve interactions with EU, Japan, and China for coordinated, cost effective efforts]. In addition to the CT community, this effort will involve participation by many US programs (e.g. Materials, Safety, PFC, and Advanced Design Studies Programs and industry) Perform concurrently R&D on the most critical issues required to make prudent selection by 2005 (e.g. self-healing coatings and other types of MHD insulators, tritium permeation barriers, SiC inserts, solid breeder/multiplier/structure/coolant interactions)

Blanket Test Module Program (cont’d) Enhance and focus current international collaborative R&D to provide data to ITER Blanket Test Module Selection: a) Thermomechanics material interactions for SB/multiplier/structure/coolant (ongoing under IEA) b) Enhanced heat transfer techniques for molten salts to determine if there is a temperature window with ferritic steel structure and/or advanced high-temperature ferritic steel (ongoing under JUPITER-II) Participate in international “unit cell” experiment in fission reactors (tritium release and breeder/multiplier/structure/purge interactions) Develop Engineering Scaling and design blanket test articles in the ITER environment for the blanket concepts selected for testing in ITER

CT Plans for FY 04/05 (cont’d) 2. FNT Support for the ITER Basic Device As ITER moves toward construction it will need more accurate predictions in the nuclear area e.g. computation of radiation field, radiation shielding, nuclear heating, penetrations, materials radiation damage, dose to insulators in superconducting magnets, decay heat, radwaste, maintenance dose, tritium fuel cycle, tritium permeation and inventories, basic device non- breeding blanket issues and performance Help resolve remaining issues in ITER design e.g - flexibility in non-breeding blanket design to ensure feasibility for change to breeding blanket in the extended phase - providing for auxiliary and ancillary equipment to support the ITER Blanket test module program - diagnostics to monitor in-situ FW/Blanket operating conditions

CT Plans for FY 04/05 (cont’d) 3. Advanced Chamber Configurations and High Pay-Off Concepts (Emphasis on Innovation and Engineering Sciences - Similar to Plasma Confinement Alternate Concepts and Configuration Optimization) Thin liquid wall concepts: R&D on critical issues to evaluate feasibility, attractiveness (including plasma-chamber interactions) Provide thermofluid MHD and design support for the NSTX liquid-surface test module (joint activity between PFC/ALPS and Chamber Technology) and MHD channel flow tests Evaluate the potential of advanced blanket concepts with attractive combinations of materials and configurations. This activity will be aimed at GEN-II in US DEMO (see 35-yr plan) and possibly hydrogen production, but successful results may have profound near-term impact on the fusion program

CT Plans for FY 04/05 (cont’d) 4. Fundamental Predictive Capabilities (Computational Models and Codes and Tools Needed by Other Key Fusion Programs, e.g. Safety, Materials, PFC, Advanced Design Studies) Heat Transfer/Fluid Mechanics/MHD Radioactivity and Decay Heat Tritium Transport/Recovery/Control, Tritium Fuel Cycle Dynamics Reliability and Availability Neutronics and Neutron-Material Interactions 5. FNT Experimental Techniques and Diagnostics Develop experimental techniques and engineering scaling for testing Chamber Technology on fusion devices Develop diagnostic techniques for operation in the magneto-nuclear environment of fusion devices (ITER, CTF, etc.) Evolve technical and programmatic strategies for Fusion Nuclear Technology testing and development on ITER, CTF, and other devices leading to DEMO (support the 35-yr Plan)

Consequences of Terminating Chamber Technology Program Loss of Credibility to the fusion program and to any fusion energy plan It undermines the initiative to rejoin ITER It makes the “35-yr” US Plan “dead on arrival” At odds with the President’s New Policy for Fusion Demoralizing to fusion’s advocates Heartening to fusion’s critics Confusing and frustrating message to the International Fusion Programs Devastating consequences to the US Fusion Program’s ability to make progress

Consequences of Terminating Chamber Technology Program (cont’d) Moving forward with fusion requires many diverse skills in Chamber Technology. After the 1996 restructuring, only a “bare minimum” of critical skills remain – skills that took 30 years to develop. Termination of the CT Program will set fusion energy back by decades. Loss of FNT “headlights”: Enormous risk that near term fusion research may not ultimately bear the fruit of a practical fusion energy source.

Specific and Immediate Consequences: No participation in ITER test program or possibility to test US blanket modules. Loss of ability to influence ITER decisions on the test program, scheduled to be finalized in 2005. Loss of capability for timely demonstration of tritium self sufficiency - the fundamental premise of fusion as an “inexhaustible” energy source. Loss of vital expertise needed to design and test in ITER, CTF, and DEMO. Great harm to important elements of the US fusion technology program. CT Research, Materials, Safety, and Advanced Design studies interact very strongly. How can we do safety analysis without radioactivity calculations and technologies for tritium containment? How do we develop structural materials for the blanket if we do not know what the blanket is? How do we predict MHD induced motion of lithium in DiMES/DIIID during plasma operation? Loss of critical interaction with the plasma community to solve the plasma-chamber interface issues and to provide innovative Chamber solutions to improve plasma performance.

Specific and Immediate Consequences (Cont.): No research on innovative technology ideas that may have the most significant impact on the attractiveness of fusion energy or hydrogen producing systems. Loss of access to foreign research/data from existing CT international collaborations. (also loss of funding from Japan) Loss of investment in unique new experimental facilities recently constructed. Drastic reduction in university involvement and serious impact on many Professors, Fusion Researchers and PhD students Loss of training for the “seed of the future” – graduate students and young researchers. CT Research provides training and development of skills for people that go on to lead other programs. The head of the US Safety Program, the Head of the Vacuum Vessel Division in KSTAR, and the Head of the PFC components in Europe and ITER, for example, were all students trained in the US Chamber Technology Research Program. Many fusion leaders and university professors in the US, Europe and Japan were trained as part of the US CT Research Program. Loss of current CT leadership at a time when the program needs more technology emphasis as we move toward ITER, CTF, and demonstration.