High Temperature Blanket and Its Socio-Economic Issues Institute of Advanced Energy, Kyoto University High Temperature Blanket and Its Socio-Economic Issues Satoshi Konishi Institute of Advanced Energy, Kyoto University Contents - Fast track and Development Strategy in Japan 　- Power plant design - Hydrogen production - Safety and environmental impact

Fast Track : the next step Institute of Advanced Energy, Kyoto University Fast Track : the next step Fusion study is in the phase to show a concrete plan for Energy. -Power plant design and strategy following ITER are required. Common understanding ・Resource constraint (Energy) ・Global warming problem (Environment) ・Growth in developing countries (Economy) Energy Demonstration in 2030? Technical feasibility Combined Demo-Proto steps Social feasibility Strategy varies in each Parties due to different social requirements.

Fast Track Discussion in Japan Institute of Advanced Energy, Kyoto University Fast Track Discussion in Japan 2000 2010 2020 2030 Power Demo ITER TBM Tokamak IFMIF Concept Design Const. Test BPP Generation EPP module1 module2 High beta, long pulse KEP EVEDA New line 10dpa/y 20dpa/y RAF In pile irradiation Full irrad. 1/2 irrad. Evolution required In a same facility Drawn from Fast track working group in Japan, 2002,Dec.

Researchers’ viewpoint Socio-Economic Aspect of Fusion Institute of Advanced Energy, Kyoto University ・Future energy must respond to the demand of the society. ・Social and Economical feasibility of fusion depends on high temperature blanket and its feature. Fusion Other Energy Outcome/benefit Energy Supply Present Programs Social viewpoint Damage/cost/ ”Externality” Future Social Demand Government Public funding Socially Required Government Outcome funding Fusion Development Previous Programs Researchers’ viewpoint Technically feasible Generation

Power Plant Design Near Future Plants Institute of Advanced Energy, Kyoto University Near Future Plants -Reduced Activation Ferritic steels (RAFs) are expected as blanket material candidates. -Considering temperature range for RAFs, 500 C range is maximum, and desirable for efficiency. -From the aspect of thermal plant design, ONLY supercritical water turbine is the available option From fire-powered plant technology. -No steam plants available above 650 degree C.

Flow diagram of indirect cycle Institute of Advanced Energy, Kyoto University Blanket Reheater Turbines Tritiated water processing Steam Generator Booster pump 　Feed water heater （divertor heat） CVCS Feed water pump

Thermal plant efficiency Institute of Advanced Energy, Kyoto University Direct cycle turbine train generates 1160MW of electricity. Thermal efficiency is estimated to be 41%.

Comparison of Generation Cycles Institute of Advanced Energy, Kyoto University 　　　　　　　　　　direct　　 indirect He gas Main steam pressure　 25MPa 16.3MPa 10MPa Turbine temp. 500℃ 480℃ 500 ℃ Coolant flow rate　　 　1250kg/s 1260kg/s 1865kg/s Vapor flow rate 1250kg/s 1037kg/s 908kg/s Total generation 1200MW 1090MW 1028MW Thermal efficiency 41.4% 38.5% 35.3% Technical issues　　 tritium in　 steam expansion 　　　　　　　　　 coolant generator volume Other thermal Plants: BWRs – 33% PWRs – 34% Supercritical Fire – 47% Combined gas turbine - >60%

Findings Institute of Advanced Energy, Kyoto University -Supercritical water cycles is desirable and possible (technically difficult). - No gas turbine system is effective in temperature ~500 C. - With steam generator, gas cooled is less effective than water. - Plant design limited above 650 C. High temperature material does not guarantee economy. Improvements may be required in the DEMO generation. Possible Advanced Plant Options High temperature cycle can be planned with He gas turbine at ~900 C. Only dual coolant LiPb blanket has possibility for high temperature in ITER/TBM. At high temperature, use of heat for hydrogen production may be an attractive choice.

Fusion Contribution with hydrogen Institute of Advanced Energy, Kyoto University 30 actual estimated Renewable hydrogen renewables 20 Gton oil equivalent/year nuclear Fusion hydrogen gas Fusion electricity hydro 10 Unconventional gas oil Unconventional oil coal 1900 1950 2000 2050 2100 year

Hydrogen Production by Fusion Institute of Advanced Energy, Kyoto University Hydrogen Production by Fusion Fusion can provide both high temperature heat and electricity - Applicable for most of hydrogen production processes As Electricity 　-water electrolysis, SPE electrolysis　: renewables, LWR 　-Vapor electrolysis : HTGR As heat 　 -Steam reforming:HTGR(800C), -membrane reactor:FBR(600C) 　 -IS process :HTGR(950C) 　-biomass decomposition: HTGR

Energy Eficiency Institute of Advanced Energy, Kyoto University ◯amount of produced hydrogen from unit heat 　 ・low temperature（３００℃）generation　　　 → conventional electrolysis 　 ・high temperature（９００℃）generation 　　　→ vapor electrolysis 　 ・ high temperature（９００℃） → thermochemical production 　 Hydrogen production From 3GW heat electricity Energy consumption efficiency 300C-electrolysis 3 3 % 1 G W 2 8 6 kJ/ m o l 2 5 t / h 900C-electrolysis 5 % 1 . 5 G W 2 3 1 kJ/ m o l 4 4t /h 900C-vapor electrolysis 5 % 1 . 5 G W 1 8 1 kJ/ m o l 5 6t /h ー 6 kJ/ m o l 3 4 0t / h 900C-biomass ー

Use of Heat for Hydrogen Production Institute of Advanced Energy, Kyoto University ◯Processing capacity: 3GWt 　 ・2500t／h waste 340t of H2 1.3x106 fuel cell vehicles (6kg/day) or 6.4 GWe (70% fc) H2 340 t/h Heat exchange, Shift reaction CO2 3.7E+06 kg/h 2500 t/h biomass CO 2.4E+06 kg/h Fusion Reactor 3ＧＷｔｈ H2 1.7E+05 kg/h H2O Chemical Reactor cooler Steam He (770 t/h) Turbine 1.38E+07 kg/h 600℃

Hydrogen from biomass and heat Institute of Advanced Energy, Kyoto University The experimental results of the change in carbon atoms combined in carbonized gases [mol.%] 5 10 15 20 25 30 CO 2 CH 4 0.0005 0.0010 0.0015 0.0020 0.0025 0.0030 35 65 85 H by measurement by calculation [cm 3 /min] A mount of hydrogen production [mol] flow rate st eam concentration [%]

Fusion safety and environmental impact Institute of Advanced Energy, Kyoto University E X H A U S T F L N SOLID WASTE B K R P C M I Y O D RELEASE W G V i g h t e m p r a u , s o c f y n l v : 1 / 　①Solid Waste Impact pathway ②Tritium Release from Coolant ③Fuel Processing exhaust

Inventory distribution compared with ITER Institute of Advanced Energy, Kyoto University OFF-SITE FUEL STORAGE 550 g* FUELING 50 g ISOTOPE SEPARATION 　 190 g PURIFICATION 100 g EFFLUENT PROCESSING ～1 g WATER DETRITIATION COOLANT HOT CELL 500 g WASTE TEMPORARY VACUUM VESSEL 1100 g COOLING SYSTEMS PRIMARY FUEL SYSTEM STACK LOAD IN EFFLUENTS ITER SITE INVENTORY：2800 g TORUS EXHAUST 130 g POWER REACTOR：probably less <100g 〜10g LOAD OUT

POWER BLANKET (example) Institute of Advanced Energy, Kyoto University 780K supercritical water Li ceramic pebbles He/H2 sweep for tritium recovery High Temperature High Pressure Fine tubings Tritium Production 1st wall Cooling tubes Tritium Permeation could be ~100g day

Normal release from Fusion Facility Institute of Advanced Energy, Kyoto University 　・ Normal tritium will be dominated by release from coolant 　・ Largest detritiation system will be for coolant 　・ Fusion safety depends on ACTIVE system. Generalized fusion plant T R I U M E C O V Y P A L G N S D B K r e a c t o b u n d y s f i m l g - T R I U M H O G P ( k g / d a y ) A L N V E Y C S 1 3 6 . 5 t r i u m f l o w e a k / p n

Generalized detritiation system Institute of Advanced Energy, Kyoto University Generalized detritiation system 　・Detritiation for power train will depends on blanket types. 　・Normal detritiation for coolant will handle emergency spill. 　・Safety control with active system is not site specific. HX Blanket Turbine tritium tritium Heat Heat Heat Heat Tritium recovery Tritium recovery Low concentration Tritium recovery Large throughput Large enrichment -broad concentration range Closed cycle cascade High concentration Quick return Once through

Detritiation systems of Plant Institute of Advanced Energy, Kyoto University   Processes large throughput, lower concentration Controls environmental release Operational continuously (including maintenance) Air Detritiation : - 1000 m3 / hour, possibly ci/m3 level - leak from generator, secondary loops, hot cell Water Detritiation : (isotope separation) - 100 m3 / day, possibly 1000 ci/m3 level, 100g/day? - driving turbine Solid Waste Detritiation : - 1 ton / day, possibly g / piece? - materials (lithium, berylium, Steel) recycle - needed both for resource and waste aspects.

Tritium confinement Institute of Advanced Energy, Kyoto University Power train will be driven with tritium containing medium. T R I U M S C O N F E D W H L A Y B U I L D N G F E O P V A C M S T R Y H X Cryostat High temperature blanket will require improved permeation control. Pressurized gas may require additional expansion volume. For gas driven system, large Expanson volume may be needed. Expansion pool Expansion pool

Emission from Fusion and Dose Institute of Advanced Energy, Kyoto University Emission from Fusion and Dose Impact pathway of tritium suggests ingestion will be dominant.

Findings Institute of Advanced Energy, Kyoto University Fusion plant detritiation will be dominated by power plant configuration. - Normal tritium release will be controlled actively. - Off-normal spill can be recovered with normal detritiation. - High temperature plant will require improved tritium system. Measurable tritium will be released in airborne form. Tritium accumulates in environment (far smaller natural BG). Ingestion dose will be dominant. For long run, C-14 may be a concern.

Conclusion Institute of Advanced Energy, Kyoto University Fusion development is in the phase to study market ・Fusion must find customers and meet their requests. ・Fusion must satisfy environmental and social issues. Development of advanced blanket is a key issue for fusion ・Economy - not just temperature, but to maximize market ・Environment - not just low activation, but best total cost and social value / least risk(Externality) Development strategy (road map) for blanket is needed. ・ITER and DEMO require 2 or more generations of blankets. ・staged improvement of blanket is planned with water-PB, and LiPb dual coolant concepts.

Conclusion 2 Institute of Advanced Energy, Kyoto University Possible blanket improvement ・Independent from large increment of plasma ・Continuous improvement can be reflected in blanket change. (Improvement in DEMO phase) ・Multiple paths to meet various needs are possible. ・Flexibility in development of entire fusion program is provided by blanket development. Fast Track