1. Material System Design Studies of High Temperature Gas-Cooled Solid Breeder Blanket Module A.Hasegawa (Tohoku Univ.) A.Shimizu, T.Yokomine (Kyushu Univ.) ITER TBM Project Meeting UCLA, USA 2/23-25, 2004

2. Summary of Current Status for TBMs WSG1 (Helium-cooled/Be (F/M steel, SiC/SiC) Blankets - TBM of F/M steel has been proposed - SiC/SiC Blaket: DEMO Design Study (DREAM), SiC/SiC Material Tests, Specimen Irradiation Test, Research on Cooling, Some of them by JUPITER-II WSG2 (Helium-cooled Lithium Lead (F/M steel, SiC/SiC) Blankets - Demo Design Study (Vector), Many activities existed. Interesting aloso for ICF blanket, Proposal will be made WSG3 (Water-Cooled Ceramic/Be (F/M steel) Blankets - Demo Design Study, R&Ds on corrosion, heat transfer, material irradiation being conducted WSG4 (Self-Cooled Lithium (V) Blankets - Network activities in Universities/NIFS, Evaluation of Russian Design, Going to design Japanese Blanket, Planning of R&D, Researches on vanadium alloy, coating, impurity control, tritium recovery, cooling, some of them by JUPITER- II and by IFMIF. WSG5 (Self-Cooled Molten Salt Blankets) - Network activities in Universities/NIFS, Demo Design Sudy of FFHR, R&Ds on many parts (redox control, cooling, tritium recovery, …) some of them by JUPITER-II, by TNT-loop, planning of R&D for TBM.

3. Expected Participants Dpt. of Quantum Science and Energy Engineering Tohoku University Structure materials : Hasegawa (Tohoku Univ.) Kohyama( Kyoto Univ.) Solid breeding materials : Enoeda (JAERI) Shikama( Tohoku Univ.) Neutron multiplier : TBD (JAERI) Shibayama(Hokkaido Univ.) Thermomechanis : Shimizu (Kyushu Univ.) System design : Konishi (Kyoto Univ.) Tritium recovery system : TBD The advanced Helium cooled blankets will be studied by collaborative works by universities and JAERI.

4. Current interests in various blankets by parties PartiesJAEUUSRFChinaKorea PB/He○○○○○○ LiPb/He △ ○○○○○ Pb/Water○○ Li/V○○○○○ Salts○○

5. Roadmap for Materials and Blanket Development in Japan Materials and Blanket System Development Reference Material (RAFM) and System Design Construction Operation ITER Power Generation Plant Irradiation Test, Materials Qualification and System Performance Test IFMIF 1 st commercial plant Design (Staged construction and operation) (Licencing)(Blanket test) Blanket Module Test Approximate calendar year 2015 2020 2030 2040 Advanced Materials (V-alloy, Flibe, SiC/SiC --) and System Reference Blanket (Mostly JAERI responsibility) Advanced option (Mostly NIFS/University responsibility) modification

6. Back Ground of this Activities Dpt. of Quantum Science and Energy Engineering Tohoku University ●Based on irradiation behavior of SiC, advanced SiC/SiC composites were developed using stoichiometric SiC fibers. ・ increase radiation resistance using advance fiber no mechanical degradation up to 10dpa at 800C high size stability Recent achievement of SiC/SiC composites -1-

7. Back Ground of this Activities Dpt. of Quantum Science and Energy Engineering Tohoku University ●Development of new matrix processing, NITE, enabled to increase matrix density. The lower porosity and near theoretical density realized high hermeticity and good thermal conductivity of SiC/SiC composites. Joining between SiC/SiC composites was also successful by the NITE process. It is almost ready to fabricate complex shape structure made of SiC/SiC composite such as gas cooling blanket. To start design activity of the blanket system, the technical issues will be discussed in this working group. Recent achievement of SiC/SiC composites -2-

8. NITE: Nano-Infiltration Transient Eutectic Phase Process Dense and robust structures (cf. PIP, CVI, …) Fairly high thermal conductivity Chemical stability Thin plate production, surface smoothness, potential gas tightness Applicability of existing net-shaping techniques Low production cost What is NITE Process ?

9. Shape-Variability of NITE Composites Kohyama et al.,(2002) Qualification of these composite is in progress under collaboration with high temperature gas turbine program.

10. Hino et al.,(2003) Monolithic SiC by NITE SiC/SiC by NITE #1 Pilot SiC/SiC by NITE (Ube ) Permeability of NITE Composites at RT

11. Research Area for High Temperature Gas Blanket System Dpt. of Quantum Science and Energy Engineering Tohoku University ●Study on blanket system design for high temperature gas-cooling system is started in Japan to realize high efficiency energy source of fusion power plant. Design and feasibility studies base on the following fields will be discussed in this working group. Material development, Thermomechanics, Tritium recovery system Material Design for High Temperature Blanket System Structural Materials, Sold Breeding Materials, Neutron Multiplier Materials

12. Bulk-flow type （ DREAM ） Channel type （ DEMO, HCPB ） Advanced Gas Cooling System There are two types of gas cooling system 1) Bulk-flow type : one major gas loop 2) Channel type : two major gas loops ( T purge gas loop + He gas cooling loop) Dpt. of Quantum Science and Energy Engineering Tohoku University

13. Bulk-Flow Type Heat Efficiency Blanket Heat Exchanger Tritium Recovery System ＞ 900 ℃ DREAM Tritium Recovery Efficiency High

14. Channel type Blanket Cooling Loop Tritium Recovery Loop ＞ 900 ℃ ＞ 1000 ℃ High Heat Efficiency High Tritium Recovery Efficiency

15. Key issues of this Blanket System Dpt. of Quantum Science and Energy Engineering Tohoku University ●To realize high energy efficiency of blanket, higher temperature (900 ℃ ) outlet-gas is required. ●New breeding material which has higher temperature resistance is needed to utilize high temperature capability of SiC/SiC composite. ex. coating or dendrite structure breeding materials ●Upper limit of current solid breeding materials : < 900C ●High temperature performance of solid breeding materials such as resistance to sintering and creep deformation become important. ●To obtain higher temperature outlet gas, temperature of wall and solid breeder becomes much higher than the gas temperature.

16. Sumary Dpt. of Quantum Science and Energy Engineering Tohoku University ●In the high temperature gas cooling system, many material and system issues remain and some break- through of high temperature resistance of breeding material are required. ●Japan proposes to include testing of SiC/SiC composite and high temperature blanket concepts in TBMs. ●Considering about limited resources and timeframe, this advanced blanket module is expected to join later phase of ITER.

17. Title Dpt. of Quantum Science and Energy Engineering Tohoku University