An ITER-TBM Experimental Thrust for ReNeW Themes III and IV Neil B. Morley, Mohamed Abdou, Alice Ying (UCLA); Mohamed Sawan, Jake Blanchard (UW); Clement Wong (GA); Brad J. Merrill, Pattrick Calderoni (INL) Yutai Katoh (ORNL) ReNeW Theme III and IV Workshops UCLA March 2-6,

The biggest Gap to DEMO is… …the Fusion Nuclear Science and Technology (FNST) capability needed to harness fusion power  All the components and technologies from the edge of the plasma to the magnets  And the systems that support the power extraction and fuel cycle The most important priority for the US, other than ITER, must be a strong, coordinated program on FNST with all its elements: PeX, PFC, Blanket, Materials, Fuel Cycle, RAMI, and Safety 2

3 Theory/Modeling/Database Basic Separate Effects Multiple Interactions Partially Integrated Property Measurement Phenomena Exploration Non-Fusion Facilities A Framework for Fusion Nuclear Science and Technology Development Design Codes, Predictive Cap. Component Fusion Env. Exploration Concept Screening Performance Verification Design Verification & Reliability Data Testing in Fusion Facilities (non neutron test stands, fission reactors and accelerator-based neutron sources, plasma physics devices) Experiments in non-fusion facilities are essential and are prerequisites Testing in Fusion Facilities is NECESSARY to uncover new phenomena, validate the science, establish engineering feasibility, and develop components

4 Three Three Stages of FNST Testing in Fusion Facilities Are Required Prior to DEMO Initial exploration of coupled, prompt, phenomena in fusion environment Screen and narrow blanket design concepts Develop test methods and diagnostic capabilities Establish engineering feasibility of blankets (satisfy basic functions & performance, up to 10 to 20 % of lifetime) Principles of tritium self- sufficiency Select 2 or 3 concepts for further development Failure modes, effects, and rates and mean time to replace/fix components (for random failures and planned outage) Iterative design / test / fail / analyze / improve programs aimed at reliability growth and safety Verify design and predict availability of FNT components in DEMO Sub-Modules/Modules Stage I Fusion “Break-in” & Scientific Exploration Stage IIStage III Engineering Feasibility & Performance Verification Component Engineering Development & Reliability Growth Modules Modules/Sectors DEMODEMO MW-y/m 2 > MW-y/m MW/m 2, burn > 200 s 1-2 MW/m 2 steady state or long burn COT ~ 1-2 weeks 1-2 MW/m 2 steady state or long burn COT ~ 1-2 weeks MW-y/m 2 Where to do Stages I, II, and III ?

Why do “Fusion Break-in” experiments in ITER? 1.ITER will provide the first such integrated magnetic confinement fusion environment 2.ITER has a FNST testing capability and supporting systems built into the machine – three mid-plane ports, hot cells, remote handling, heat rejection, tritium systems, control systems... (already paid for!!) 3.The ITER test module size, neutron flux, magnetic field and pulse length are all significant and well suited for fusion break-in experiments 4.ITER is less dependent on the successful function of these first-of-a-kind blanket experiments, reducing the bootstrap problem of requiring the successful operation of the very components that are being tested. 5.Good synergy and a basis for collaboration/cost sharing among the international community for scoping of the many blanket concept, configuration, materials choices 6.Advance the US primary blanket option, the Dual Coolant Lead Lithium (DCLL) blanket, which is not being tested by any other party 7.Help Congress understand how “ITER is promoting progress toward fusion as a reliable and affordable source of power” 5

ITER Provides Substantial Hardware Capabilities for Testing of Blanket System Equatorial Port Plug Assy. TBM Assy Port Frame  ITER has allocated 3 ITER equatorial ports (1.75 x 2.2 m 2 ) for TBM testing  Each port can accommodate only 2 Modules (i.e. 6 TBMs at a time, with competition for Space (EU and China requesting full ports, all other parties except the US requesting half-port)  Hot cell, remote handling, heat and tritium sinking, control equipment, power, atmosphere, … 6

TBM experiments involve a whole TBM System  “Prompt” behavior and phenomena in the testing module  System wide responses and functions – power and tritium extraction TBM AEU He pipes to main He blowers PbLi loop Bio- shield VV Port Extension TBM Port Frame

What are the possible concerns? Is TBM really a part of ITER? Yes, ITER-TBM has been planned for many years and is approved by the ITER Council ITER Operation Schedule Version as of 2 years Ago, new version in development

Concerns: What can be tested in ITER? –The ITER test module size, NWL, magnetic field and pulse length are all significant Es pecially the combined strong, spatially complex, nuclear heating and magnetic field important for liquid metal breeder blankets –“Prompt” phenomena that reach near steady state during the ITER burn (minutes to an hour) Tritium/heating profiles First wall surface temp MHD thermofluid behavior Thermomechanical state and temperature profiles –Cyclic equilibrium over many pulses Tritium concentration and permeation Corrosion and activated product transport Impact of early life radiation damage in ceramic insulators Time, s Pulse Flat Top Transit time PbLi FCI Fe ITER Pulse Time, s DCLL Temperauture, C DCLL TBM rear channel temperature Temperature reaches steady state in about 1 PbLi transit time through the module

10 Example: Interaction between MHD flow and FCI behavior are highly coupled and require fusion environment PbLi flow is strongly influenced by MHD interaction with plasma confinement field and buoyancy-driven convection driven by spatially non-uniform volumetric nuclear heating Temperature and thermal stress of SiC FCI are determined by this MHD flow and convective heat transport processes Deformation and cracking of the FCI depend on FCI temperature and thermal stress coupled with early- life radiation damage effects in ceramics Cracking and movement of the FCIs will strongly influence MHD flow behavior by opening up new conduction paths that change electric current profiles  Simulation of 2D MHD turbulence in PbLi flow  FCI temperature, stress and deformation Similarly, coupled phenomena in tritium permeation, corrosion, ceramic breeder thermomechanics, and many other blanket and material behaviors

Concerns: Isn’t an ITER-TBM program too costly? −Why are we doing ReNeW? Why are we talking about FNF? −The R&D, predictive capabilities, and test facilities needed to prepare for, license, and interpret integrated fusion environment experiments in ITER are the same as those needed to reinvigorate the US FNST program, and are the same as will be needed for any fusion environment testing and tritium breeding enabling technology development. −If we accept we need to do the basic FNST R&D and need a strong FNST program, then cost is really a modest increment  the cost of the modules (a few $M each), the one time cost of the cooling loops (~$10M), and the cost of the PIE −Different lead/collaborate options with other Parties are also possible at different cost, timing, and commitment levels 11

Concerns: Why not wait for FNF? (CTF/FDF/VNS) −ITER is under construction and paid for. −Get multiple data-sets from different machines −Save FNF operating time (and significant cost) from early screening in collaboration with all ITER parties −Learn from ITER (R&D and testing) to enable a better FNF to meet its high availability requirements −Switch to FNF if/when available – not much could be considered wasted 12

Visions of a ITER-TBM thrust for the US The US should actively participate in the international ITER-TBM program. Two Main Possibilities 1.Advocate a strong leadership role in ITER-TBM for the US, and then use it as a driver for immediate and essential FNST R&D –Thrust would include a strong, coordinated R&D effort with near term milestones 2.Partner with other parties on different TBMs and contribute software and hardware specific to the US technical interests −Thrust would have a flexible cost and timing, but requires near term R&D be supported in some other way −One example idea: partner on another PbLi blanket concept, and contribute a DT module based on the DCLL concept 13