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Coordinating Meeting on R&D for Tritium and Safety Issues in Lead-Lithium Breeders (PbLi-T 2007)

Coordinating Meeting on R&D for Tritium and Safety Issues in Lead-Lithium Breeders (PbLi-T 2007). PbLi research activities at Kyoto University. June 11,2007 Satoshi Konishi, Institute of Advanced Energy, Kyoto University. Institute of Advanced Energy, Kyoto University.

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Coordinating Meeting on R&D for Tritium and Safety Issues in Lead-Lithium Breeders (PbLi-T 2007)

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  1. Coordinating Meeting on R&D forTritium and Safety Issues in Lead-Lithium Breeders (PbLi-T 2007) PbLi research activities at Kyoto University June 11,2007 Satoshi Konishi, Institute of Advanced Energy, Kyoto University

  2. Institute of Advanced Energy, Kyoto University Activity in Kyoto University Objective Kyoto University pursues advanced blanket concept based on LiPb – SiC – He combination to be opearated at 900 degree or above. Research objective includes, -to Establish a possible advanced blanket concept with supporting technology -to Demonstrate the attractiveness of fusion energy with safety and effectiveness i.e. high temperature efficient generation and hydrogen production, minimal waste generation and tritium release, technical feasibility, adoptability to attractive reactor designs. Research Items Current researtch efforts are on the following tasks Conceptual design with neutronics and thermo-hydraulics, MHD LiPb-SiC-hydrogen system study: compatibility, solubility, permeability LiPb technology : Loop experiment, purity control, high temperature handling SiC component development : cooling panel, tubings, fittings and IHX Mockup development : heat transfer, tritium recovery and control

  3. Li-Pb Flow SiC-LiPb Blanket Concept Outer blanket calculation model • Module box temperature made of the RAFS must keep under 500 ºC. • Li-Pb outlet temperature target 900 ºC. • We propose the new model of active cooling in Li-Pb blanket. • This concept is equipped He coolant channels in SiC/SiC composite and provides more efficient isolation between the RAFS and high temperature Li-Pb. • We evaluate the feasibility of high temperature blanket in this model. 1.RAFS module box (~500ºC) 2.SiC/SiC active cooling panel 3.High temp. outlet (~900ºC)

  4. Research Update and Hilights • Concept verification • - neutronics and heat balance

  5. Typical configuration multiplier Neutron Flux 1MW/m2 Plasma Li17-Pb83 SiC/SiC：1.5 [cm] w/cooling channel • One Dimensional Neutron Transport Code (ANISN) • TBR • Neutron Shield • Nuclear Heating FW（F82H):1.5 [cm] w/cooling channel Vacuum vessel

  6. Tritium Breeding Tritium Breeding Rate Relation with Thickness (Li-Pb) and TBR 6Li = 7.4%, TBR TBR Thickness (Li-Pb) [cm] Li-Pb thickness [cm] 6Li = 7.4 ～ 90% • Contribution to 7Li for TBR is less than 5% of all. • 6Li concentration is needed. • With VV, ca.0.1 increases. TBR >= 1.2 6Li 70%55cm 6Li 90%50cm

  7. F82H He SiC/SiC Li-Pb Evaluation of Nuclear Heating Distribution of nuclear heating • Distribution of nuclear heating was calculated. • Intense nuclear heating by neutron was observed at the front of Li-Pb • Heat removal must be within a reasonable He flow range. Heat generation per unit volume [W/cm3] Wall thickness [cm] 6Li = 90%, TBR = 1.2, Li-Pb = 50cm

  8. Heat Transfer Analysis Temperature of RAFS side must keep under 500ºC. Temperature of Li-Pb is determined by active cooling of SiC/SiC composite panel with He channels. He Channel RAFS side ~500 [ºC] Li-Pb side v SiC/SiC Layer d1 For example : THe=350 [ºC], VHe = 8 [m/s] L Max 500 [ºC] 600 [ºC] 1. High Temperature Li-Pb 2. Large Nuclear Heating

  9. Results of Heat Transfer Analysis • Max Li-Pb temperature is obtained as a function of He coolant flow speed. He Coolant Temp. = 350 ºC Relation with Li-Pb side temperature and He velocity　（PHe = 8 [MPa]） • 900 ºC Li-Pb is possible with moderate He velocity. SiC/SiC 1.5 cm, He channel 0.5x0.5cm

  10. Outlet Temp. and Velocity of Li-Pb • Required Li-Pb velocity is calculated. Heat value [J/cm3] Outlet [deg.] Outlet [deg.] Total accepted heat value on outlet [J/cm3] Li-Pb velocity [cm/s] Relation with outlet temperature and Li-Pb flow velocity The MHD pressure drop is considered to be negligible in this condition ( ~1 cm/s). Net thickness 54.5 cm, Li-Pb thickness 50 cm 6Li = 90%, TBR = 1.2 Li-Pb inlet ： 300ºC Mean Flow Path 100 cm, Flow path height 10cm

  11. Research Update and Hilights 2. Tritium Permeation through Structural materials

  12. Institute of Advanced Energy, Kyoto University Permeation experiments sample The device consists of two lines with high and low pressure divided with disk sample Permeation of deuterium was measured by using quadrupole mass spectrometer. manometer manometer high pressure line QMS low pressure line heater IG TMP D2 RP Fig. 1 A schematic diagram of the experimental setup.

  13. Sample The method for fixing sample Before experiment After experiment • Disc samples 20 mm in diameter and 2.79 mm thick were used. • The sample is fixed between two VCR Couplings with metal gaskets. • Outside of this test section was vacuum. Low pressure line High pressure line

  14. Hydrogen permeability through SiC Institute of Advanced Energy, Kyoto University Sample: CVD SiC Thickness: 2.79 [mm] Temp: 800 [ºC] Gas: 100%Ｄ2 1.0x105 [Pa] x200 Permeation flow rate of CVD was larger than that of Hexoloy by 2 orders

  15. Institute of Advanced Energy, Kyoto University Temperature dependence of Permeability Comparative arrhenius plot of the obtained permeability. [mol・Pa-1/2・s-1・m-1] K: permeability n: permeation flow rate d: thickness of the sample Ph: the pressure of high pressure line A: geometrical area of the sample

  16. Institute of Advanced Energy, Kyoto University Diffusivity It is considered that the time taken to start the permeation is related to diffusivity. The time required to start the detection of permeation gas is… SUS316: a few seconds CVD: a few minutes Hexoloy: a few hours Activation energy of the diffusion of Hexoloy is 110 kJ/mol.

  17. Institute of Advanced Energy, Kyoto University Solubility Solubility was calculated by permeability and diffusivity. The solubility in SiC material is ranging 10-4 to 10-3 [mol m-3 Pa-1/2 ] at the temperature above 700 degree C

  18. Permeation in FAFM Institute of Advanced Energy, Kyoto University -8 10 -9 10 -10 10 -11 10 -12 10 0.8 1 1.2 1.4 1.6 1.8 700 900 800 600 500 400 300 ℃ ] -1 0.93mm F82H m 1.93mm F82H -1 Ni sec -1/2 permeability [mol Pa fcc bcc -1 1000/T [K ]

  19. Institute of Advanced Energy, Kyoto University -6 10 -7 10 -8 10 -9 10 0.8 1 1.2 1.4 1.6 1.8 bcc fcc Diffusion in RAFM ℃ 900 800 700 600 500 400 0.93mm F82H 1.93mm ] F82H -1 Ni sec 2 [m Diffusion coefficient -1 1000/T [K ] Difference understood as the change in crystal structure

  20. Research Update and Hilights 3. Compatibility

  21. Compatibility tests Kyoto UniversityInstitute of Advanced Energy SiC/SiC composite tube was installed in the LiPb loop Tube section was heated above 600 degree C with LiPb flow Possible corrosion is observed with mucroscopes. SiC/SiC tube Inner surface of SiC after exposure Test section : heated and cooled

  22. Reaction between LiPb and SiC SiC/SiC composites Pb mapping LiPb SiC/SiC did not react with LiPb below 750 degree C. Siのmapping Kyoto University

  23. Corrosion of stainless steel Institute of Advanced Energy, Kyoto University Inside of tube Welding x100 Tube surface、x100 welding、x100

  24. Institute of Advanced Energy, Kyoto University Corroded steel X500 SEM elements (x10000) elements analyses : Cr,Ni missing

  25. Institute of Advanced Energy, Kyoto University Microstructure of ＳｉＣ SEM observation of SiC : deposit of Cr and Fe found

  26. Research Update and Hilights 4. Chemistry control - With ion conductor cells

  27. Solid electrolyte cells for LiPb chemistry control Institute of Advanced Energy, Kyoto University Ceramics tubes of YSZ for oxygen • YSZ (Yttria-stabilized zirconia) • Inside electrode was made of Pt mesh and Pt paste exposed to air as a standard gas • Liquid LiPb was used as outside electrode SrCeYbO3 for proton conductivity

  28. Experiments Institute of Advanced Energy, Kyoto University Solid electrolyte cell

  29. Oxygen Potential in LiPb Institute of Advanced Energy, Kyoto University Pb⇔PbO Temperature[℃] • The cell generates EMF • EMF is converted into aO2 with Nernst equation • The theoretical aO2 is calculated from Gibbs free energy equation • Observed aO2 for LiPb by the EMF agreed well with theoretical value. Pb-17Li⇔Pb-17Li-O* lnaO2 Li⇔Li2O Measurement Oxygen activity in LiPb * * *Peter Hubberstey; Pb-17Li and lithium: A thermodynamic rationalisation of their radically different chemistry

  30. Interaction with O2 in cover gas • Cover gas on LiPb is replaced with He-10%O2 • Absorption of O2 in LiPb was observed • Absorbed oxygen corresponds to O/Li=0.17. • Increase of oxygen potential in LiPb was detected at the EMF plot EMF [V] Oxygen concentration[%] time [sec] at 450℃ Relationship between EMF and oxygen concentration of cover gas Fig. State before and after measurement

  31. Hydrogen Potential in LiPb Institute of Advanced Energy, Kyoto University hydrogen activity in LiPb measured with Proton conductor cell.

  32. Research Update and Hilights 5. Loop, Engineering Development and MHD

  33. Fabrication test of cooling panel Kyoto UniversityInstitute of Advanced Energy Fabrication technique for cooling panel and other blanket parts such as FCI and HX are being tested. cutting junction SiC cooling panel unit 0.5mm 15.12 mm 15.12 mm Fabrication process 17.89 mm 17.89 mm 6 mm 6 mm

  34. Institute of Advanced Energy, Kyoto University Cooling channel structure

  35. LiPb loop and SiC insert Kyoto UniversityInstitute of Advanced Energy SiC/SiC Tube 149mm SUS316 Tube

  36. LiPb/SiC loop operated at 900C Institute of Advanced Energy, Kyoto University 流速：0.7～1.0 [cm/s] ・operated at 900℃ maximum ・Heat transfer and removal requires improvement

  37. Glovebox for LiPb experiment Kyoto UniversityInstitute of Advanced Energy

  38. He loop for LiPb blanket GC GC F Expansion tank Heater SiC tube T T T IHX MHD section ９００℃ ７００℃ P cooler F 断熱材 ～200℃ T Test module T 耐熱合金 ＥＭＰ HEATER ９００℃ ７００℃ P T Vacuum vessel T T hygrometer MSB Used for Other project Zr He loop Dump tank Original LiPb loop He-LiPb loop

  39. MHD measurement with SiC/LiPb. Compatibility test at various flow velocity. Hydrogen/Tritium permeation through composite. Hydrogen isotherm with LiPb. Better purity and precise composition with controlled atmosphere(glovebox). Instrumentation:EM flowmeter, emf sensor. Secondary 900C He loop and heat transfer test. Development of RAFM enclosure , square SiC duct and flange. 3-D neutronics and module design. Planned test in 2007 Kyoto UniversityInstitute of Advanced Energy

  40. Ultimate goal of this program in Kyoto is to develop a concept of high temperature blanket. Small scale blanket module will be demonstrated in 4 years. System and component design will be made. Small neutron source will be used for tritium transfer experiment. Possible collaboration on DCLL and further SiC-LiPb configuration under TBM programs. Reactor design with near term high temperature blanket. Long term plan Kyoto UniversityInstitute of Advanced Energy

  41. LiPb-SiC blanket concept is now actively studied in Japan at Kyoto University. Both experimental and design studies are open for international collaboration. Some of the experiments are unique and valuable for international efforts for liquid blanket development. Conclusion Kyoto UniversityInstitute of Advanced Energy

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