Research Mission & Goals of FNSF-ST and FDF/FNSF-AT Are on Critical R&D Path to Fusion Energy

1. Work in support of testimony by ORNL Director Thom Mason to the House Committee on Science and Technology, 10/29/2009

2. Research Mission & Goals of FNSF-ST and FDF/FNSF-AT Are on Critical R&D Path to Fusion Energy FNSF & requisite R&D complement ITER, BA & support DEMO R&D • Guided by FESAC Greenwald Panel & ReNeW reports: • Tests, discovers, understands, & innovates solutions. • Synergistic effects of PMI, tritium cycle, power extraction, and fusion material damage in a continuous fusion nuclear environment. • Blankets that make electricity & sufficient tritium. • RAMI: modular components, remote handling (RH), hot cells  low Mean Time to Replace (MTTR). • Integrates & controls reliable AT burning plasmas. • Initially to 1 MW-yr/m2 & 10 dpa @ ≤10% duty cycle. • Allows upgrade to CTF (≤6 MW-yr/m2 & 60 dpa; ≤30%). • Material synergies to 2-6 MW-yr/m2, 20-60 dpa. FNSF-ST: R = 1.3m; QDT 3 FDF / FNSF-AT: R = 2.7m; QDT 6.9

3. “Coupling the Non-Nuclear with the Nuclear” – Plasma Material Interaction & Neutron Material Interaction (PMI+NMI) • Coincidence & juxtaposition of otherwise disparate physics mechanisms of similar activation energies  likely new science. • Example – formation and dynamics of clusters of defects: • Use Ferric Steel: firm database for ≤ 10 dpa & 100 appm He. • Fusion neutron  displacement cascades of >103 atoms over ~102 nm. • Clusters of ≥20 point defects and ≤20 nm are formed with energy ~1eV. • These clusters undergo 1D motion with activation barriers of ~0.1eV. • Observed to move at 1-5 nm/s at ~300 oC, affected by impurity atoms. • How would such clusters affect PMI if and when they migrate near & to plasma facing surface, & vice versa? Molecular dynamics simulations of neutron induced displacement cascades [Zinkle, Stoller, 2005]. 1D movements of defect cluster in bcc iron observed via TEM [Arakawa et al, 2007].

4. FNSF Mission: to Investigate New Synergistic Science & Engineering of Fusion Environment • Discovery-Driven Mission: • Provide a continuously driven fusion nuclear environment of copious neutrons, to test, discover, and understand the multiscale interacting phenomena involving plasma material interactions, tritium fuel cycle, power extraction, and nuclear effects on materials. (for MFE and IFE.) • Scale of interactions: • ps to years, nm to meters, involving four states of matter. • R&D cycles: • Test and improve internal components until nuclear science and engineering basis are established for DEMO. • Complementary to ITER Mission & in parallel: • Low Q  interpolate from ITER projections • Fusion neutron fluence ≤1 MW-yr/m2 (≤10 dpa)  3 x ITER plan • tpulse ≤ 2 wks  1000 x ITER plan • Duty factor ≤10%  higher than ITER

5. Required Capabilities: to Address the FNSF Mission • Required capabilities: • WL 1 MW/m2at the outboard mid-plane. • Solenoid-free & non-inductiveplasma operation. • Reliable plasma: e.g., Hot-Ion H-Mode, bN 0.75 bNno-wall; qcyl 4. • Divertors to handle peak heat flux  10 MW/m2and particle removal. • Reliable center post: peak JTFC≤ 4 kA/cm2. • Low MTTR: modular components & remote handling (RH) to. • Ab initio & ex post facto research: hot cell labs with RH. • Accompanying R&D – to manage risks inherent to FNSF: • Modular internal test components: divertors, blankets, FW, NBI systems, RF launchers, diagnostic systems & TF center post. • Plasma dynamics and control: database, predictability, and enabling capabilities, including the AT regime. • RH, hot cells research systems and tools. • Integrated modeling and simulation of FNSF.

6. Staging R&D Starting with Conservative JET-level DD Plasma through DT WL=2MW/m2 Are Recommended for FNS Program I-DD: JET-level DD plasma operation, PFC, neutronics, shielding, safety, RH system II-DT: JET-level DT operation & FNS research: PMI-NMI, tritium cycle, power extraction III-DT: full plasma & FNS research, basis for CTF IV-DT: “stretch” plasma & FNS research • R0 = 1.3m, A = 1.6 • Mid-plane test area ≥ 10m2 • Total blanket area ~ 60 m2

7. FNSF Internal Components Assembly/Disassembly Capability

8. Anticipating Component Replacements, Shielded Vacuum Seals and Bi-Directional Sliding Joint Are Considered To reduce MTTR and achieve 10% Duty Cycle for 1 MW-yr/m2 Mid-Plane Test Module Access Top TF Conductor Lid 1D Neutronics: 5x10-6 dpa 10 dpa 0.05 dpa Bi-Directional Sliding Joint

9. To Manage the Risks Facing FNSF-ST & AT, Requisite R&D Will be Determined for Specific Design Concepts • FNSF-ST: • Solenoid-free plasma start up (e.g., ECW/EBW, Helicity Injection) and predictive start up modeling. • Single-turn TF coil center post engineering & fabrication. • Low dissipation, low voltage, high current, dc power supply with stiff control of current. • FNSF-ST & FNSF-AT: • Hot-Ion H-Mode operational scenarios and predictive modeling. • SOL-Divertor with improved configurations to limit heat fluxes ≤10 MW/m2 and predictive modeling. • Continuous, disruption-minimized, non-inductive operation, including Advanced Tokamak, in strongly stable plasma regimes. • RH systems, made compatible with internal component modules, to minimize MTTR toward a duty factor of 10%. • RH-enabled hot-cells for maintenance and research.

10. FNSF-ST and FNSF-AT are Options that Parallel and Complement ITER, BA in Support of DEMO R&D • In concert with accompanying R&D to reduce risks, develop basis for DEMO. • Cost effective – compact; low Pfusion; moderate Q; low net tritium usage. • Start with conservative plasma physics & enabling technology for a reliable fusion nuclear environment. • Example: JET-level Q<1 plasma and low WL~0.25MW/m2. • Test, discover, and understand multi-scale synergistic phenomena to innovate and develop component solutions. • Requires fast component replacements. • Use modular components, remote handling, hot cells, shielded vacuum seals, bi-directional sliding joint, etc. to reduce MTTR. • Advance in concert plasma and component performances, from DD to DT; from FNS to component testing. FDF / FNST-AT FNSF-ST ITER

11. How many FNSF? – a Discovery-Driven Fusion Nuclear Science and Engineering Research Users’ Facility • How many fission critical nuclear testing facilities were built and operated in the U.S. between 1945 and 1965, that presaged naval propulsion and commercial power? • About 50 at the Idaho Reactor Testing Station (INL), and • Several times more as part of Defense Program. •  Rapid and worldwide realization of practical fission energy (1958: Shippingport, 60 MWe) • How many fusion nuclear science and engineering testing facilities, in concert with ITER, will be needed before practical fusion energy can be realized? • We hope to answer this question after the first Low-Q FNSF starts operation. • Of Interest to other applications of volumetric fusion neutrons.