HIGH TEMPERATURE GAS-COOLED REACTOR FOR HEAT SUPPLY AS A NATURALLY SAFE AND INNOVATIVE NUCLEAR SYSTEM

Transcription

1 CIGS 3 rd International Symposium on Global Warming HIGH TEMPERATURE GAS-COOLED REACTOR FOR HEAT SUPPLY AS A NATURALLY SAFE AND INNOVATIVE NUCLEAR SYSTEM December 11, 2013 Masuro OGAWA Nuclear Hydrogen and Heat Application Research Center Japan Atomic Energy Agency (JAEA)

2 CONTENTS 1. Outline of HTGR (High Temperature Gas-cooled Reactor) 2. Reduction CO 2 with Heat Supply from HTGR 3. Solutions for Social Issues 4. Perspective of HTGR 5. Concluding Remarks

3 1. OUTLINE OF HTGR WHAT CAN HTGR DO? ( HTGR: High Temperature Gas-cooled Reactor) 3

4 Theoretical efficiency η HTGR can supply high-temperature heat at 950 o C Heat supply to various industry/transportation fields Temperature ( o C) High thermal efficiency due to high temperature DME /Methanol synthesis Steel production Cement production Direct reduced iron Oil refinery Heavy oil desulfurization Pulp, paper production Urea synthesis Desalination District heating FBR LWR HTGR Glass production Blast furnace High efficient GT power production Thermochemical IS process H 2 production from naphtha H 2 production from steam methane reforming Ethylene production from naphtha Ethylene production from ethane Styrene production from ethyl benzene City gas production T H - T L H 2 production : η = T H - T L 52% 48% 300 o C 31% ~ 23% T H 66% 61% 500 o C LWR Heat Electricity H 2 33% 70-90% T d T d - T L 81% 950 o C 76% 67% Power generation (Carnot cycle) 50% 40% Theoretical efficiency of IS process HTGR Heat H 2 T H - T L T L : Low side temperature (25 o C) T d : Temperature with G = 0 (4436 o C) ~ η = Reactor outlet temperature T H ( ) T H 4

5 WHAT IS HTGR DIFFERENT FROM EXISTING LWR? 5

6 Ceramic fuel-cladding, graphite-moderated and helium gas-cooled HTGR HTGR LWR Coolant Helium gas No phase change Chemically inert No activation Light water Fuel coating Ceramics No melting Metal (Zirconium) Moderator Graphite No evaporation Light water Reactor thermal power Compact (~600MW) Collocation with demand site Large (~4500MW) HTGR Hydrogen production Process heat 950 o C Typical specification Coolant temperature : 950 o C Electricity generation Thermal Output : Max. 600MW Heat utilization ratio : 70-80% Reactor Gas turbine 500 o C Waste heat ~200 o C District heating Seawater desalination Agriculture, Aquatic product industry 6

7 HOW DOES HTGR MAKE PROGRESS IN TECHNOLOGY? 7

8 Previous abundant knowledge and experiences Development of GCR starts from the first days of that of nuclear power, i.e. at the same time as development of LWR. Direction of GCR commercialization with high coolant temperature is summarized to Gen- IV VHTR as shown in the following table (Next generation LWR is classified to Gen-IV) Japan has constructed and been operating VHTR experimental test reactor, HTTR based on extensive technical knowledge obtained in the developments of GCR, AGR, HTGR, and accidents of TMI and Chernobyl. GCR AGR HTGR VHTR Fuel Natural uranium Enriched uranium Fuel coating Metallic material Ceramics Coolant /Temperature CO 2 /400 o C CO 2 /600 o C~ He/700 o C~ He/950 o C~ Pressure vessel Steel, PCRV PCRV PCRV, Steel (Small-size) Steel (Small-size) Progress Commercial operation (UK, France, Italy, Japan, etc.; 37 units) Commercial operation (UK ;14 units) Experimental reactor (UK,US, Germany; 1 unit/country) Prototype reactor (US, Germany; 1 unit/country) Test reactor (China; 1 unit), Demonstration reactor (China; 2 units) Experimental test reactor HTTR (Only exist in Japan) 8

9 Japan s Cutting-edge Homegrown Technologies Reactor IHX HTTR (30MW, 950 o C) HTGR test reactor of JAEA at Oarai Japan Ceramic cladding of fuel 0.92 mm UO 2 Isotropic Graphite Heat-resistant Superalloy Quartet coating technology for cladding to have heat resistance Confinement of radioactive materials for about three times longer than of LWR Temperatures up to 1600 o C Hot-pressurizing technology for graphite to have isotropy High strength, thermal conductivity, and radioactive-resistance Temperatures up to 2400 o C Fortifying technology for metal to have heat resistance High-temp. structural technology for components Helium-handling technology for coolant to reduce leakage (Chemical, mechanical and nuclear-physical stability) Utilization of heat at high temperature of 950 o C 9

10 Prismatic HTTR reactor core and fuel Reactor pressure vessel Fuel element Fuel kernel,600μm Low density porous PyC High density inner PyC SiC High density outer PyC 920μm Plug Fuel compact Coated fuel particle Fuel rod 580mm Graphite sleeve 39mm Primary cooling pipe 34mm 26mm Reactor Fuel element Fuel rod Fuel compact 10

11 Remaining development issues in HTGR Establishment of HTGR technologies - Demonstration for performance and reliability of key technologies e.g. fuel, graphite moderator, Heat-resistant alloy, high temperature structural design code, etc., using the HTTR Construction of lead plant and commercial plant (Dec. 2010) - Establishment of regulatory guidance for HTGR Design guideline for high temperature component Design guideline for graphite component Safety design standards - Development of material database including strength test and irradiation test for life extension Consensus-building toward the HTGR deployment in reactor site 11

12 PRESENT STATUS IN THE WORLD? 12

13 National projects in the world HTGR US; NGNP project 2012:Final design started China: HTR-PM 2017:Construction of demonstration plant will be completed Heat supply Power generation 750 o C Cogeneration 750 o C Power generation South Korea:NHDD project Kazakhstan: KHTR project 950 o C H 2 production HTGR H 2 production 2012:Concept study started HTGR 750 o C Power generation H 2 production 発電 District heating Power generation 2013:Feasibility study in preparation 13

14 Industrial Alliances for HTGR in US and Korea US NGNP project <Electric utility> Entergy <Chemical company> Dow(The Dow Chemical Company) <Petrochemical company> ConocoPhillips Petroleum Technology Alliance Canada (PTAC) <Graphite manufacturer> GrafTech International Ltd. SGL Group Mersen Toyo Tanso Co., Ltd. <Reactor vendors> AREVA Ultra Safe Nuclear Westinghouse <Consulting company> Technology Insights SRS Advanced Research Center South Korea NHDD project <Electric utility> KHNP KEPCO <Steel making company> <Petrochemical company> POSCO SK ENERGY GS Caltex <Construction company> <Pump manufacturer> GS construction KNF Hyundai E&C <Automobile company> Hyundai Motors <Heavy Industry> <Electronics> Doosan Heavy Industry SUMSUNG STX Heavy Industry <Research institute> KAERI 14

15 2. REDUCTION OF CO 2 WITH HEAT SUPPLY FROM HTGR 15

16 Concrete solution for reduction of CO 2 emission Issue: Reduction of CO 2 emissions in heat utilization field Natural resources Fossil fuel Nuclear Energy Media Heat 57% Elect ricity 43% Natural energy CO 2 emissions Chemical, petroleum 8% Steelmaking 13% Residential 13% Vehicle 17% Others 23% Power generation 26% 1.19 billion ton CO 2 (2010) 30% One HTGR (600MW) reduces c.a. 0.1% of CO 2 emissions Iron ore H 2 Chemical and petroleum plants Heat demand in plants (MW) 27,000 Number of HTGRs 55 CO 2 emissions reduction (%) 5 Steelmaking High temp. heat Steam (c.a. 540 o C) Crude steel (million t/y) Number of HTGRs CO 2 emissions reduction (%) Heat source Reducing substance Fuel cell vehicle (~950 o C) H 2 Solution: Heat supply from HTGR Thermal power 600 MW Outlet temp. 950 Coolant Cladding of fuel Moderator Fuel H 2 Number of vehicles (million) 75 Helium Ceramics Graphite Number of HTGRs 130 CO 2 emissions reduction(%) 16 16

17 3. SOLUTIONS FOR SOCIAL ISSUES WHAT WILL HAPPEN IN HTGR AT THE FUKUSHIMA ACCIDENT? 17

18 - HTTR Can Intrinsically Shutdown with the Case Equivalent to TEPCO Fukushima Accident- Natural convection Flow rate (%) Power (%) Temp. ( o C) Control rod Thermal radiation HTTR Circulators trip Coolant flow rate in the core : Experiment : Analysis Reactor power Temp. limit; 1600 o C Water Gas circulator Helium HTTR test result Fuel temperature Time (hr) Dissipated to air Vessel cooling system HTTR test condition (On December 12, 2010) Initial reactor power 30%(9MW) Stop all circulators Without scram Operation of vessel cooling system maintained Reactor inherently shut down without control rod insertion Decay heat removal occurs naturally even if normal heat transport systems are not available HTTR can intrinsically shutdown reactor TEPCO Fukushima NPP accident Earthquake Control rod insertion Reactor scram Tsunami Loss of offsite power Loss of function for decay heat removal, core heat up, core melt H 2 explosion Release of radioactive material 18

19 (1) Safety Issue: Obtain consent of risk concept from public who concerns the following - Even a small probability of occurrence such as once in 1 million reactor years, there is no guarantee that it will not occur tomorrow. - For events that lead to very large consequence, the event shall be evaluated only the impact of the consequence instead of evaluation in risk (Risk) = (Occurrence probability) x (Consequence of the event) Safety objective Protect people and the environment from harmful effects of ionizing radiation must be met in the layer of consequence mitigation. The degree of attainment would be evaluated by risk assessment (in review). Probability of occurrence for the accident which results in Cs-137 release of 100 TBq or larger should be reduced to the value lower than 10-6 /reactor year Defense in depth: Having provisions responding to the event progression based on the assumption of the failure in the former layer. 1. Prevention of accident (occurrence, progression), if failed, 2. Mitigation of consequences, 3. Emergency planning (Evacuation, etc.) If mitigation of consequence failed, evacuation is required. What if evacuation failed? For that reasons, mitigation of consequence must accomplished successfully 19

20 Solution: Consequence Mitigation by Natural Phenomena Confinement Reactor Core Reactor Pressure Vessel Physical events to lose confinement function Diffusion Fission product Uranium Cladding Sublimation Containment Vessel Corrosion Rupture Cause events Core Heat-up Cladding oxidation by air CO explosion Counter physical phenomena Doppler effect Thermal radiation, Natural convection and so on Oxide layer formation CO oxidation Attain stable state Retain fission products within cladding Reactor can intrinsically secure safety by mitigating physical events to lose confinement function only with physical phenomena without reliance on backup systems Issues accompanied by risk concept and evacuation can be solved 20

21 Radiotoxicity [Sv] (per 1ton of fuel) 1.E E+08 1.E E+06 1.E E+04 1.E (2) Radioactive Waste Reduction Issue:Reduction of Radiotoxicity in Radioactive Waste Solution:Utilization of Thorium U 235 : 10% Th 232 : 90% HTGR Spent Fuel High Level Waste U 235 : 4.5% U 238 : 95.5% LWR Spent Fuel High Level Waste After Transmutation 1.E+02 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E Elapsed Years Partitioning of U and Pu Partitioning of MA Fuel composition LWR U-235 : 4.5% U-238 : 95.5% HTGR U-235 : 10% Th-232 : 90% Remarks Enrichment of uranium and reprocessing of Th are needed. LWR can also use Th. 21

22 GBq/yr Worker dose (man Sv/y) GBq/yr Less spent fuel per unit power generation rate (Depends on enrichment, efficiency) Unit:[t-U(Enriched)/GWe] Cooled by natural circulation of air Spent fuel 348 LWR GTHTR300 Easy management of spent fuel Operation and Maintenance 被 10 ばく線量 5 ( 人 Sv/ 年 ) 0 Low worker dose 1~15.5 LWR BWR(2005) PWR(2005) 1~6.4 Shallow ground disposal for spent graphite Spent graphite quantity: ~3000m 3 /unit, 60 years (1/500 of baseball dome volume (1.58M m 3 )) 軽水炉の 1/600 of 1/600 LWR HTTR Less Low-level radioactive waste LWR 175 LWR Gaseous 0 HTTR Liquid 0 HTTR ( 22

23 Power generation cost (Yen/kWh) (3) Economy Issue: In general, as the power density becomes lower the plant economic get worse Power generation cost LWR : 5.3 Yen/kWh HTGR : 4.2 Yen/kWh (HTGR 1 unit ( =4 modules) ) For 100MW electric power, LWR : 9.7 Yen/kWh HTGR : 5.3 Yen/kWh In spite of High fuel enrichment, Multi-layer coating of fuel, Heat resistant alloy utilization, compelling economics can be achieved because of High electricity generation efficiency Simplified safety system Easy maintenance and operation Shop fabrication and preassembly Ref: M. Takei, et al., Economical Evaluation on Gas Turbine High Temperature Reactor 300 (GTHTR300), Trans. At. Energy Soc. Japan, 5(2), pp (2006) HTGR LWR GTHTR300 Recuperator Precooler HX vessel Electric power (MWe) Reactor Thermal/Electric Power :600/275MW Reactor outlet temp. :850 o C Core Turbine PCS vessel Generator Compressor 23

24 Solution; HTGR can be economically competitive because of the superior characteristics and the low ratio of reactor cost to plant cost Bird s eye view of PWR (2 modules) PWR 1 unit Reactor and primary system 100% Reactor cost (ca.2%) 118% x 10 0 LWR HTGR Construction cost Ref: *1 Private communication, *2 JAIF report, 1992;. *3ORNL_sub_ _7 Energy economic data base(eebd) program phase VIII update(1986) BWR supplement 20% Construction cost *1 [Unit %] Building (Reactor & turbine buildings, others)(25.6) Reactor & station auxiliary system (13.0) Primary system (9.2) Reactor (1.8) Condensate, feed water, Others turbine auxiliary systems, Others (1.5) (13.1) Reactor protection system (4.0) Rad waste Turbine, generator (11.5) I&C, electric equipment(10.7) Reactor control system (3.9) system, Fuel handling (5.7) HTGR with low power density core can achieve compelling economics due to the following reasons Reactor cost only responsible for 2% of plant cost Core power density of HTGR is 1/10 of that of LWR Increase in portion of reactor cost from 2% to 20% (x10) results in increase in plant cost only by 18%. The 18% cost increase can be canceled out by advantages in HTGR. 24

25 The Foot Print of HTGR HTGR ( 1100MWe ) Equivalent power output LWR (1100MWe ) GTHTR300 (275MWe x 4 modules ) ) BWR-5 Reactor building Turbine building A 68.5 m m 45 m 84.0 m 53 m 80 m 76 m A 22 m Turbine building A-A cross section 47 m 93.7 m 24 m Total building inventory:533,000 m m 11 m 80% of LWR s building inventory Ref: X. Yan, et al., Nuclear Eng. Design., 226, p (2003) Total building inventory: 674,000 m 3 Ref: Figure cited from application for establishment permit of Kasiwazakikariwa nuclear power plant unit No.3 of TEPCO 25

26 4. PERSPECTIVE OF HTGR 26

27 Naturally Safe and Innovative HTGR Commercial plant Lead plant 水素製造プラント熱化学法 IS プロセス 高温ガス炉 ガスタービン HTTR Establishment of most of the HTGR technologies Heat supply for industrial demand No core melt Economically competitive 原子炉 中間熱交換器 Reduce radio toxicity in radioactive waste on the order of hundred years by utilizing Thorium (Separation of spent fuel is required. Residual fuel after separation will be recycled) Maintain sustainability using uranium from seawater (Recycling for nuclear fuel supply is unnecessary) Achievement of natural-safety Green fuel;h 2 production Corresponding to temporal storage by inert matrix fuel. Reduce the amount of spent fuel per produced electricity by 1/3 due to high burnup. Incinerate surplus plutonium. 27

28 Present Status on National Activities Mitsubishi Heavy Industry Conduct conceptual study for a commercial HTGR plant MHR. Propose construction of lead plant. Make a contribution to promoting commercial deployment of HTGR by own technology. NFI Developed coated fuel particle fuel for higher burn-up condition Fuel compacts are currently under irradiation (100GWd/t) Fuel compacts for irradiation test M. Toyama (MHI), et al.,, Expectations to HTGR, HTR2012, Tokyo Japan. JAEA Typical HTGR designs (GTHTR300, GTHTR300H, and so on.) Power : 600MW Hydrogen : 51t/day Electricity : 200MW Temperature : 950 o C Burnup : 120GWd/t GTHTR300H Receive a contract for core components of HTR-PM in China Toyo Tanso IG μm 28

29 5. CONCLUDING REMARKS HTGR is a Gen-IV and a small-sized reactor up to 600MW for heat supply such as hydrogen, process heat, and steam. HTGR technologies have been almost confirmed in HTTR and lifetime verification remains. Technologies of hydrogen production should be demonstrated. HTGR can solve issues such as safety, reduction of CO 2 and radioactive waste in environmental protection, economy and so on. 29

30 THANK YOU FOR YOUR ATTENTION! HTTR 30