Satoshi Konishi Institute for Advanced Energy, Kyoto University May.25, 2005

1. 7th International Symposium on Fusion Nuclear Technology A critical review and comparison of power reactor blankets from nuclear technology and socio-economic aspects Satoshi Konishi Institute for Advanced Energy, Kyoto University May.25, 2005 Contents - Broader “Externality” aspect - Tritium release to the environment - Waste strategy - Fuel supply - Deployment to hydrogen market Special Thanks to Kunihiko Okano, Yusuke Ichimasa and Kenji Tobita

2. Socio-Economic Aspect of Fusion Outcome/benefit Institute of Advanced Energy, Kyoto University ・Future energy will be evaluated by social preference. ・Such evaluation will consider all the possible impacts and effects to future society and environment. Government Public Damage/cost/ ”Externality” Industry funding Future Social Demand Energy Supply Fusion Other Energy Different outcome are expected for sponsors.

3. Generation Plant How fusion affects? Environment,Society Facility Blanket Wastes (Solid nuclides, T,C-14) Plasma Heat Transfer Exhausts (T,heat) Fuel, Material (D,Li-6,..) Energy (Electricity) (Recycle) Economy Fusion will be evaluated - what it consumes - what it exhausts - what it generates , and - what it leaves Blanket is the key For Socio-economic Feature of fusion

4. How fusion will benefit public? Energy － Energy sales is not the only outcome of the research. →”Externality” ; economical effect out of the market 　・Impact by various pathways -outside of energy market - estimated with economical value (monetary term) environmental negative：pollution, global warming environmental positive：recycling, cleaning, reduced emission social negative：nuclear proliferation, terrorism, fear of risk social positive ：security, backstop, technology positive negative risk ・All the risks and benefits ・evaluated from the viewpoint of sponsor ・market sales is only a part ・cost is not a good measure but cost affects the market share benefit cost social security Environ. recycle pollution cleaning warming

5. ６．２％ For R&D Investment for nuclear technology ・various sponsors provide funding ・different purpose, different phase of development ・investment for research is a certain fraction of total sales →investment must yield benefit to sponsors sales Fission reactor case 1960 industry Basic research transfer Research institute utility Further competitiveness Research institutes improvements commercialization

6. Thermal Efficiency Temperature coolant CO2 CalderHall 1956 Shippingport V B W R N P D 300 Obninsk(RBMK) 30% P W R 1 9 5 7 1954 1 9 5 7 1 9 6 2 Light water SGHWR Heavy water 、 E B R 1 1968 EL-4 1 9 5 1 1966 Molten salt F E R M I 4 0 % 1 9 6 3 （ 商 用 ） 5 0 0 Liquid metal A G R 1 9 7 6 8 0 0 Helium 5 0 % Variety of fission reactors developed

7. Strategies for blankets Generations of blankets fit different phases - Fusion has multiple generations with single plasma Learn from the history of fission. 1) Technically possible. (liquid metal) 2) Governments policy and social preferences. (graphite, heavy water) 3) Market selection. (light water reactor) Each generations has different purpose. -expected functions of blanket differs.

8. Fusion development strategy Design Concept Const. Test Drawn from Fast track working group in Japan, 2002,Dec. 2000 2010 2020 2030 Power Demo Generation ITER BPP Const. EPP TBM module1 module2 Tokamak High beta, long pulse Test Evolution required In a same facility IFMIF KEP Const. EVEDA New line 10dpa/y 20dpa/y RAF In pile irradiation 1/2 irrad. Full irrad. The 1st Blanket will aim at “earliest power generation”. Next target will be “deployment into the future society.

9. Technology temperature efficiency use of heat Fossil fire Supercritical 600 ℃47% + Combined 1200℃>60% + Fission LWRs 300 ℃ 33% - FBR 500 ℃ 40%+- Fusion Supercritical 500 ℃39-41% +- High T gas900℃ 50%+ Renewables rt - - Energy Conversion Issue Blanket heat transfer media will have to fit advanced energy. Steam ~ 500 ℃ or high temperature He~900℃

10. Introduction into the market resource renewable price technology year Possible introduction price of Fusion : increases with time as fossil price increases. 150 mill/kWh 145 125 125 109 100 92 Current target of the development 75 65 Possible Introduction price 50 25 0 2050 2060 2070 2080 2090 2100 year Target cost of electricity varies as a function of Introduction time.

11. P L A S M A P R I M A R Y L O O P C O O L A N T P R O C E S S T R I T I U M I N V E N T O R Y ( k g ) 1 0 . 5 T R I T I U M T H R O U G H P U T ( k g / d a y ) 3 0 0 . 5 6 0 5 0 0 0 0 0 T O T A L T H R O U G H P U T ( k g / d a y ) Tritium processing systems t r i t i u m l e a k / p e r m e a t i o n b u i l d i n g c o n f i n e m e n t s e c o n d a r y c o n f i n e m e n t T R I T I U M R E C O V E R Y B L A N K E T P R I M A R Y G E N E R A T I O N L O O P S Y S T E M r e a c t o r b o u n d a r y C O O L A N T P R O C E S S - I N G S E C O N D A R Y L O O P S A I R D E T R I T I A T I O N Emission dominated by normal detritiation Water based heat transfer requires isotope separation.

12. Impact pathway of tritium Tritium is detectable far below the level that affects health.

13. Dose caused by normal tritium release of 1g And total “detriment” 1E6 1E-6 1E-2 1E4 Collective dose( personSv) Effective dose equivalent (Sv/g) population 1E-8 1E-4 1E2 1E-10 1E-6 1E2 1E3 1E4 1E5 Distance from the source(m) Impact of radioactive emission Tritium released from the facility diffuses but not disappear. According to the LNT hypothesis by ICRP, detriment increases with distance. Normal release accumulates in the environment. Dose is negligible compared with natural radiation, but detectable in environment, foods and drinking water. Same thing happens with C-14 and worse.

14. D I S P O S A L B L A N K E T R E L E A S E R E P R O C E S S I N G E X H A U S T S O L I D W A S T E D E C O N T A M I N A T I O N D E T R I T I A T I O N B L A N K E T O F S O L I D W A S T E S E X H A U S T S R E P L A C E M E N T E F F L U E N T S T R I T I U M B L A N K E T P R I M A R Y L O O P S E X T R A C T I O N P L A S M A E V A C U A T I O N P U R I F I C A T I O N T U R B I N E H X G E N E R A T O R F U E L I N G I S O T O P E S T O R A G E W A T E R S E P A R A T I O N D E T R I T I A T I O N L O A D I N G I N / O U T R E L E A S E S E C O N D A R Y L O O P S : 1 0 0 g t r i t i u m P R I M A R Y L O O P S : K g t r i t i u m H i g h t e m p e r a t u r e , p r e s s u r e m o d e r a t e c o n d i t i o n L a r g e p r o c e s s r o b u s t c o n t a i n m e n t O u t o f p r i m a r y e n c l o s u r e E n v i r o n m e n t a l r e l e a s e Waste Disposal Issue

15. VACUUM VESSEL DETRITIATION SYSTEM Against accidental release, Pressurized Helium requies Huge vacuum volume to Keep sound confinment. HX TURBINE GENERATOR FUEL LOOP PIPING Tritium confinement in acceident TRITIUM containing medium will be confined : expansion volume : He expansion pool : water (easy) : other liquids IN CASE OF SPILL, TRITIUM IS RECOVERED BEFORE GOING OUT TO THE NEXT BARRIER BUILDING DETRITIATION SYSTEM DETRITIATION SYSTEM volume Accidental spill can be recovered with normal detritiation. Heat transfer media and pressure requires different confinement.

16. 3 TBR large 2 1 Li-6 burnout Tritium Inventory TBR control 0 1 10 100 1000 TBR insufficient -1 -2 Operation days Fuel Supply Issue Availability and stability of fuel resource will be important. TBR and plant inventory Deuterium:its own detritiation Initial tritium : other power plant or its own Lithium : cooling sea water Lithium6 : lithium metal production Carbon : liquified natural gas - reduction of carbon-14, i.e. removal of nitrogen and carbon-13 Synergetic isotope separation systems must be considered for fuel and material supply.

17. 100 80 2050 2060 2070 2080 60 40 20 0 Possible share of fusion energy Maximum Construction Speed Case Initial Tritium Constraint Limit Share of fusion in 2100 (%) Fusion introduction year Early introduction is essential for fusion. (Market will be occupied) Construction speed may limit possible fusion share. Avoiding initial tritium constraints increases capability of fusion.

18. Conclusion ○Deployment of fusion requires socio-economic consideration. ・economy 　 ・passive safety in accidental scenarios 　 ・normal tritium emission ・solid waste issues ・fuel and material supply and control ○Socio-economic features are strongly dependent on blanket ・economy – high temperature, high efficiency, hydrogen ・environment - low activation, short life of rad-waste ○Strategic consideration ・generations of blanket concepts have different purposes. 　・Evolution of blanket in ITER and DEMO is essential.