Fusion Nuclear Technology Research and Opportunities for ITER Utilization

1. Fusion Nuclear Technology Research and Opportunities for ITER Utilization Neil B. MORLEY and Mohamed ABDOU University of California, Los Angeles Fusion Power Associates Annual Meeting and Symposium Washington D.C. October 11 and 12, 2005

2. Fusion Nuclear Technology (FNT) Fusion Power & Fuel Cycle Technology FNT Components and Materials from the edge of the Plasma to TF Coils(Reactor “Core”) 1. Blanket Components (FW) 2. Plasma Interactive and High Heat Flux Components a. divertor, limiter b. rf antennas, launchers, wave guides, etc. 3. Vacuum Vessel & Shield Components Other Components affected by the Nuclear Environment 4. Tritium Processing Systems 5. Instrumentation and Control Systems 6. Remote Maintenance Components 7. Heat Transport and Power Conversion

3. Fusion Nuclear Technology Critical Issues for Fusion Energy • Tritium Supply & Tritium Self-Sufficiency • High Power Density • High Temperature • MHD for Liquid Breeders / Coolants • Tritium Control (Permeation) • Reliability / Availability / Maintainability • Testing in Fusion Facilities

4. n n p p p n n n p DT fusion is usually depicted to laymen by the reaction in the plasma Inexhaustible Limitless Physics Confinement Current Drive Heating … n Tritium Consumption in Fusion is HUGE! Unprecedented! 55.8 kg per 1000 MW fusion power per year

5. 30 CANDU Supply w/o Fusion 25 20 Projected Ontario (OPG) Tritium Inventory (kg) 15 1000 MW Fusion 10% Avail, TBR 0.0 10 ITER-FEAT (2004 start) 5 0 1995 2000 2010 2015 2020 2025 2030 2035 2040 2045 2005 Year Tritium supply for the development of fusion – where does it come from? • Production & Cost: • CANDU Reactors:27 kg from over40 years, $30M/kg (current) • Fission reactors:2–3 kg / year. at a cost of $84M-$130M per kg, per DOE Inspector General* Conclusions • Availability of tritium supplyfor fusion development beyond ITER first phase is an issue • Large power D-T facilities must breed their own tritium (this is why ITER’s extended phase was planned to include the installation of a tritium breeding blanket) • FW/Blanket are necessary in the near term to allow continued development of D-T fusion

6. n Breeding n p p p n n The DT FUSION ENERGY picture requires a closed fuel cycle and nuclear technology • Blanket / Shield Components and Materials: • Absorption • Activation • Multiplication • Energy Extraction • Shielding • R/A/M • Tritium Fuel Cycle: • Processing • Decay • Permeation • Inventory Physics n

7. Tritium Self-Sufficiency :Λa > Λr Λr = Required tritium breeding ratio • Λr is 1 + G, where G is the margin required to account for : • tritium losses, radioactive decay • inventory in plant components • inventory in tritium processing system • inventory stockpile for outages and for start-up of other plants • Λris dependent on many system physics and technology parameters. Λa = Achievable tritium breeding ratio • Λa is a function of technology, material and physics requirements, e.g. • Efficient energy extraction • FW armor and thickness • Conducting shells, embedded coils, heating ports, etc. • Reliability/maintainability concerns

8. Current physics and technology concepts lead to a “narrow window” for attaining tritium self-sufficiency for DT fusion energy • Tritium inventory in processing systems and reserves are closely tied to fueling rate and fractional burn-up in plasma – strong influence on required TBR: Λr • 3D Analysis of current worldwide FW/Blanket concepts accounting for plasma support systems estimates an achievable TBR:Λa ≤ 1.15 • Integral neutronics experiments in Japan and the EU showed that calculations consistently OVERESTIMATEexperiments by an average factor of ~ 1.14 td = doubling time Required TBR td=1 yr td=5 yr td=10 yr Fractional burn-up [%] “Window” for Tritium self sufficiency Fusion power - 1.5GW Reserve time - 2 days Waste removal efficiency - 0.9 (Sawan and Abdou, ISNFT-7)

9. Physics and Technology R&D partnership needed to determine the potential for achieving “Tritium Self-Sufficiency” How do we Establish the conditions governing the scientific feasibility of the D-T cycle, i.e., determine the “phase-space” of plasma, nuclear, material, and technological conditions in which tritium self-sufficiency can be attained R&D on FW/Blanket/PFC and Tritium Processing Systems that emphasize: • Understanding and predicting behavior of components and materials in the integrated fusion environment under relevant conditions • Minimizing Tritium inventory in components • Faster tritium processing system, particularly processing of the plasma exhaust • Improve reliability of tritium-producing (blanket) and tritium processing systems R&D on physics concepts and operating modes that: • Maximize tritium fractional burn-up • Reduce the requirements on space needed in the breeding region for heating, stabilization coils and conductors, etc. • Ease peak requirements on surface heat loads and disruptions loads, etc.

10. A technology/physics partnership is clearly already a part of ITER Many FNT components & capabilities needed for ITER basic machine • 1. Blanket Components • 2. Plasma Interactive and High Heat Flux Components • a. divertor, limiter • b. rf antennas, launchers, wave guides, etc. • 3. Vacuum Vessel & Shield • 4. Tritium Processing Systems • 5. Instrumentation and Control • 6. Remote Maintenance • 7. Heat Transport and Power Conversion But FEW technology solutions for ITER are compatible with TRITIUM SELF-SUFFICIENCY and ENERGY NEEDS

11. n n p p p n n n p The ITER Test Blanket Module (TBM) Program is a vehicle for utilizing ITER to advance the scientific principals of tritium self-sufficiency! “The ITER should serve as a test facility for neutronics, blanket modules, tritium production and advanced plasma technologies. The important objectives will be the extraction of high-grade heat from reactor relevant blanket modules appropriate for generation of electricity.” —The ITER Quadripartite Initiative Committee (QIC), IEA Vienna 18–19 October 1987 Studying burning plasma physics ITER Studying breeding & energy relevant technologies n “ITER should test design concepts of tritium breeding blankets relevant to a reactor. The tests foreseen in modules include the demonstration of a breeding capability that would lead to tritium self sufficiency in a reactor, the extraction of high-grade heat and electricity generation.” • —SWG1, reaffirmed by ITER Council, IC-7 Records (14–15 December 1994), and stated again in forming the Test Blanket Working Group (TBWG) ITER’s Principal Objectives Have Always Included studying ENERGY relevant technologies and materials

12. TBM Mission Perform first wall and tritium breeding module experiments to advance the understanding of the competing requirements of tritium self-sufficiency, extraction of high grade heat, and controlled, ignited plasma operation. The TBM in ITER is essential to: • Achieve a key element of the ITER Mission “demonstrate the scientific and technological feasibility of fusion power for peaceful purposes” • Achieve the most critical milestone in fusion nuclear technology research: testing in the integrated fusion environment. • Resolve the critical “tritium supply” issue for ignited plasma experiments and fusion development beyond ITER - and at a fraction of the cost to buy tritium for a large D-T burning plasma • Access R&D information from much larger ($10-20M per year) blanket/PFC programs (EU and Japan) and other international partners • Maximinize the return on the >$1B of US investment and capitalize on the >$10B of investment by international partners in ITER

13. TBM Preparation and R&D is proceeding aggressively in the International Community View of a typical TBM test port cell arrangement TBM location in a ITER test port • Several TBM proposals have • been made by ITER Parties: • Helium-cooled Li-based Ceramic/Beryllium TBM (4 variations) • Helium-cooled liquid Lithium-Lead TBM (3 variations) • Water-cooled Li-based Ceramic/Beryllium TBM (1 variation) • Liquid natural Lithium TBM (2 variations)

14. ITER plan includes the TBM – Activities are coordinated by the Test Blanket Working Group • TBMs are to be installed from the first day ofH-H operation to check interfaces & main operations, compatibility with ITER operations and to support to safety dossier • 3 Midplane ports are reserved for TBM use, as well as space at the port cell, TCWS building, tritium building, and hot cell for necessary ancillary systems such as coolant loops, tritium processing, etc.

15. ITER Environment for TBM Experiments • large geometry of the test ports. (maximum height of TBM ~ 2m, similar to the size of typical blanket modules in a power plant); • plasma exposure with typical particle loads and off normal plasma events; • strong magnetic field (~ 4 T), same order of magnitude as in power plants; • similar neutron energy spectrum as in power plants, however lower neutron flux (~25- 30 % of neutron wall loading in DEMO plant) and much lower fluence; • generation and confinement of radioactivity

16. US TBM Selected Concepts 1. The Dual-Coolant Pb-17Li Liquid Breeder Blanket concept with self-cooled Pb-Li breeding zone and flow channel inserts (FCIs) as MHD and thermal insulator -- Innovative concept that provides “pathway” to higher outlettemperature/higher thermal efficiency while using ferritic steel. --US lead role in collaboration with other parties (most parties are interested in Pb-Li as a liquid breeder, especially EU and China). -- Plan an TBM that will occupy half an ITER test port with corresponding ancillary equipment. 2. The Helium-Cooled Solid Breeder Blanket concept with ferritic steel structure and beryllium neutron multiplier, but without an independent TBM -- Support EU and Japan efforts using their TBM structure & ancillary equipment -- Contribute only unit cell /submodule test articles that focus on particular technical issues

17. Dual Coolant Lead-Lithium (DCLL) FW/Blanket Concept Idea of “Dual Coolant” concept – Push towards higher performance with present generation materials (FS) • Ferritic steel first wall and structure cooled with helium • Breeding zone is self-cooled Pb-17Li • Structure and Breeding zone separated by SiCf/SiC composite flow channel inserts (FCIs) that DCLL Typical Unit Cell Self-cooled Pb-17Li Breeding Zone SiC FCI He-cooled steelstructure • Provide thermal insulation to decouple Pb-17Li bulk flow temperature from ferritic steel wall • Provide electrical insulation to reduce MHD pressure drop in the flowing liquid metal Pb-17Li exit temperature can be significantly higher than the operating temperature of the steel structure  High Efficiency

18. Pb-Li Outlet Pipe FW He Coolant Manifolds Pb-Li Inlet Pipe Pb-Li Flow Separation Plate with He coolant Channels Pb-Li Inlet Manifold Pb-Li Return Flow Channel FCI Plasma Facing First Wall Pb-Li Inlet Flow Channel FW He Coolant Channels Bottom Plate He Coolant Channels

19. Side Wall Helium-Cooled Ceramic Breeder (HCCB) Blanket/First Wall Concept for TBM Idea of “Ceramic Breeder” concepts – Tritium produced in immobile lithium ceramic and removed by diffusion into purge gas flow • First wall / structure / multiplier /breeder all cooled with helium • Beryllium multiplier and lithium ceramic breeder in separate particle beds separated by cooling plates • Temperature window of the ceramic breeder and beryllium for the release of tritium is a key issue for solid breeder blanket. Schematic view of an example ITER HCCB test blanket submodule showing typical configuration layout of ceramic breeder, beryllium multiplier and cooling structures and manifolds • Thermomechanical behavior of breeder and beryllium particle beds under temperature and stress (and irradiation) loading affects the thermal contact with cooled structure and impacts blanket performance • Nuclear performance and geometry is highly coupled and must be balanced for tritium production and temperature control

20. Electromagnetics/Neutronics unit cell design Unit (mm) Ceramic Breeder TBM: Inserting “US” unit cells into the EU HCPB structural box

21. Specific TBM Test Objectives in ITER • validation of TBM structural integrity under combined and relevant thermal, mechanical and electromagnetic loads • validation of Tritium breeding predictions • validation of Tritium recovery process efficiency, tritium control and inventories • validation of thermofluid predictions for strongly heterogeneous breeding blanket concepts with volumetric heat sources and strong MHD interactions • demonstration and understanding of the integral performance of the blanket components and material systems

22. Summary Remarks • There are many remaining challenging FNT issues that need to be resolved for successful fusion development • The D-T cycle is the basis of the current world plasma physics and technology program. If the D-T cycle is not feasible the plasma physics and technology research would be very different. • “Tritium self-sufficiency” is a complex issue that depends on many system physics and technology parameters / conditions. • Availability of external tritium supply for continued fusion development beyond ITER’s first phase is an issue • There is only a “window” of physics and technology parameters in which the D-T cycle is feasible. We need to determine this “window.” • Conducting an effective Test Blanket Module (TBM) program is one of the main objectives of ITER and necessary to advance the understanding tritium breeding and tritium self sufficiency in fusion systems • ITER will be the first real opportunity to apply the results of R&D from the past 30 years on many aspects of blankets, materials, PFC, etc.