Opportunities for research on material compatibility and tritium behavior at the STAR laboratory

1. Opportunities for research on material compatibility and tritium behavior at the STAR laboratory Pattrick Calderoni Fusion Safety Program Idaho National Laboratory, USA HAPL Program Meeting GA San Diego 8-9 August 2006

2. Objectives Introduce the INL Safety and Tritium Applied Research facilities and research capabilities in the areas of compatibility and tritium behavior for fusion chamber and blanket materials Summarize recent and ongoing activities at INL that are relevant to the HAPL program Present a preliminary plan to integrate HAPL chamber and blanket R&D with the current and planned STAR activities Collect directives, comments, suggestions, impressions, desires, … on technical and programmatic aspects to consolidate the preliminary plan into an R&D proposal

3. Provide laboratory infrastructure to study tritium science and technology issues associated with the development of safe and environmentally friendly fusion energy Designated a National User Facility Research thrust areas Plasma-material interactions of PFC materials with energetic tritium and deuterium ions Fusion safety: chemical reactivity, activation product mobilization and dust/debris characterization for PFC materials; tritium behavior in fusion systems (in-vessel source term) Molten salts and fusion liquids for tritium breeder and coolant applications Fission reactor tritium production permeation issues; AGR fuel tritium retention and release studies Tritium plant and fuel cycle issues for MFE and IFE STAR Mission and Research

4. Glovebox TCS Chemical reactivity experiment Tritium SAS Tritium Stack monitor D ion implantation experiment Glovebox exhaust manifold Tritium Plasma Exp Flibe preparation purification & testing Flibe-tritium experiment Flibe Salt 2Lif-BeF2 Flibe-corrosion experiment 15,000 Ci tritium limit Segregation of operations/ventilation Once-through room ventilation Gloveboxes and hoods Tritium cleanup system (TCS) Tritium storage and assay system (SAS) STAR Floor-plan Layout 15,000 Ci tritium limit Segregation of operations Gloveboxes and hoods Tritium cleanup system Once-through room ventilation

5. Key systems in STAR Molten Salt Tritium Behavior Experiment Tritium Storage and Assay System Tritium Plasma Experiment and Enclosure Steam and air chemical reactivity test apparatus Molten Salt Preparation, Purification, and REDOX Experiments Tritium Cleanup System

6. STAR is Ready for Operation of Tritium Experiments • Useable tritium inventory currently 1300 Ci • 300 Ci in equimolar H2:D2:T2 calibration standard • 1000 Ci T2 available for experiments • shipments from SRS limited to 1000 Ci with standard TYPE-A container • Molten Salt Tritium Permeation Experiment: • 100 to 300 Ci transferred as D2/T2 in vessel loaded with SAS • diagnostics to include QMS, gas chromatograph, on-line ion chamber, and catalytic recovery • effluent will exhaust via facility stack • TPE Tritium Experiments: • 700 to 900 Ci transferred as T2 in vessel loaded with SAS • local U-Bed capture in TPE; effluent routed to TCS for complete cleanup

7. Experiments at Kyoto and Tokyo Un with fast neutrons (Moriyama, Oishi 97/89, Suzuki 98/00) showed that tritium is generated in Flibe as TF without the addition of H2 TF reacts with structural materials generating high solubility fluorides Need to control fluorine potential to minimize corrosion Of the three options (purge H2/HF mixtures, add metal element, add ternary salt) the use of metallic Be is best for fusion applications when considering the complexity of ternary salts chemistry and T permeation issues Molten salts R&DRedox, the control of fluorine potential D. Olander, letter to the editors of J Nuc Mat (02) The redox condition of molten fluoride salts is quantitatively described by the fluorine potential. The fluorine potential, however applied, controls the equilibrium concentration of structural materials dissolved in flibe.

8. Be rod Molten salts R&D: redox experiments Measure HF in the gas phase as a signature of REDOX potential • On-line detection of HF in the gas with titrator and mass spectrometer allows dynamic time dependent analysis • Controlled parameters: HF/H2 concentration, temperature, Be exposure time Inject HF into the Flibe • Hydrofluorination is first used to purify the salt from oxides and metal impurities: • M + 2HF <--> MF2 + H2 • BeO + 2HF = BeF2 + H2O When equilibrium is reached (pure salt) a metallic Be rod is inserted in the salt for a specified time Available Be reacts with HF until initial conditions are restored

9. Hydro-fluorination approach Bubble H2/HF/He thru melt (530ºC) Chemical Analysis of Flibe On components Pre and post purification Techniques: Metals: ICP-AES, ICP-MS, acid dissolution C, N, O: LECO Flibe purification facilities Control instruments & He-HF gas cabinet Pot/heater assembly Titration cell Gas manifolds HF traps Processed Flibe

10. Simple model Be dissolves as Be0 HF input (1000 ppm) > dissolution rate Exposure time does not influence recovery (only HF concentration) but Solubility of Be0 from integration of titrator data higher than MSRE Complex model Be dissolves as Be0 and enters the salt by galvanic mechanism as ionic Be2+ (demonstrated by recent tests with insulated Be rod) Initial ionic migration > HF input and Be deposits on Ni crucible Exposure time does not influence recovery (only HF concentration and available deposition surface for ions) Currently measuring ionic migration by electrochemical analysis to decouple processes Redox experiments: analysis and complexities

11. He He+H2+HF TC He He He He+H2+HF Ferritic steel corrosion tests FSCT #1 and #2 concluded Analysis of results ongoing at INL and in Japan - stay tuned for Jupiter II final reports

12. Tritium permeation experiments Experiments are designed to investigate tritium behavior in flibe / Ni systems with Redox control Previous experiments in Japan under irradiation complicated by oxide layer formation Chamber designed and constructed in Japan, tested with H2 to verify negligible convection effects Gas supply system, glove-box, instruments and control already tested with previous D2 permeation experiment

13. Vacuum pump Pressure gauge HF trap Flow meter exhaust Flow meter Gas chromatograph + ionization chamber And QMS Flow meter Cap High temperature salt Flibe Ni Ar D2 T2 Be insertion Tritium permeation experiments • Tritium provided in pressurized vessel containing D2/T2 mixture • Glovebox setup to contain potential leaks, connected with tritium clean-up system • GC column coupled with ionization chamber has been tested with tritium • Develop DF/TF generator to compare with T2 permeation results • Builds on success of TMAP modeling with D2 permeation experiment • 1-D axial model with sink terms to simulate radial loss

14. Flibe and Sn-Li alloy mobilization studies for blanket safety analysis Objectives: measure the vaporization and mobilization properties of molten Sn­25at%Li (in argon) and flibe (in argon, air and air+water vapor) from 600 to 1400K Approach: use a mass spectrometer equipped with a Knudsen effusion source to measure the partial pressure of condensable vapors. Partial pressures are derived from spectral line intensities after calibration with Li metal. Mobilized deposits were analyzed by ICP-AES.

15. Pb-Bi corrosion test for Fast Breeder Reactor

16. Corrosion mechanism in liquid metals

17. Corrosion mechanism in liquid metals

18. Pb-Bi corrosion test for Fast Breeder Reactor

19. Integration of HAPL chamber and blanket R&D with current and planned STAR activities • A gradual integration would be beneficial to: • minimize budget for research activities and facilities • allow maximum flexibility to accommodate design changes and leverage on other R&D programs with common objectives (ITER-TBM, Z-IFE, GNEP, etc) • incorporate INL Fusion Safety Program expertise in the HAPL chamber and blanket design and analysis • start a collaborative program that could lead to a full utilization of the STAR laboratory capabilities, including applied research on tritium behavior in blanket materials, tritium inventory assessment and blanket safety analysis

20. Integration of HAPL chamber and blanket R&D with current and planned STAR activities SiC / flibe material compatibility tests and Redox control assessment and optimization Task 1 Flibe batch preparation Requires minimal modification of available STAR facilities for T < 700C Utilizes available state-of-the-art analytical techniques, including electrochemical measurements, and extensive expertise of scientific and technical personnel Allows comparison with static compatibility tests of Pb-17Li for TBM program ongoing at ORNL (B. Pint)

21. Integration of HAPL chamber and blanket R&D with current and planned STAR activities SiC / Pb-17Li material compatibility tests and corrosion control assessment and optimization Task 2 Requires re-assembly and modification of Pb-Bi alloy experiment Utilizes available state-of-the-art analytical techniques and expertise of scientific and technical personnel Start could wait until completion of Task 1 to leverage on other R&D and continued analysis and design of HAPL chamber and blanket system (ie, choice of coolant)

22. Integration of HAPL chamber and blanket R&D with current and planned STAR activities T permeation experiments in SiC / flibe systems and SiC / Pb-17Li systems Task 3 Requires modification of planned T permeation experiments in flibe / Ni systems for T < 700 C Utilizes available state-of-the-art analytical techniques and expertise of scientific and technical personnel Start would depend on Task 1 and 2 results, as well as continued HAPL blanket analysis and design (ie, coolant material choice) If comparison of material properties is needed research activities for flibe and Pb-17Li could be carried out in parallel depending on research budget and personnel availability

23. Opportunities for research on material compatibility and tritium behavior at the STAR laboratory Pattrick Calderoni Fusion Safety Program Idaho National Laboratory, USA HAPL Program Meeting GA San Diego 8-9 August 2006