Role of Nuclear Energy and University Research

Transcription

1 Special panel session celebrating the 75 th anniversary of the discovery of fission, November 13, 2013, American Nuclear Society, Winter Meeting. Washington DC, USA Role of Nuclear Energy and University Research Yoshiaki Oka Professor, Waseda University Shinjuku ku, Tokyo, Japan Emeritus professor, University of Tokyo 1

2 Outline Energy sources, Global warming, Nuclear energy Role of University Research Super LWR and Super FR studies, High breeding by light water cooling, R&D of Thermal hydraulics and materials New textbooks of nuclear engineering 2

3 Energy sources 3

4 Fossil fuels are major primary energy source since industrial revolution for 250 years Source; 4

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7 Many countries depend on imported energy sources US energy (basic) policy : Less than 25% of import dependence for national security Source; 7

8 Global warming 8

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10 Temperature rise in Compared to average temperatures recorded between 1951 and 1980 The most extreme warming, shown in red, was in the Arctic Source: Wikipedia;Global warming 10

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12 Nuclear energy 12

13 US electricity production cost Nuclear is the cheapest after depreciation of the construction cost Source: nuclear.org/info/inf02.html 13

14 Natural gas prices ( ) not stable Japan Germany UK USA Germany (Russian boarder) UK (ICE) USA(NYMEX) Japan(imported LNG) Source:JOGMEC,

15 Combined cycle gas turbine power plants Innovation of power plant technology Source: Wikipedia

16 What necessary for future nuclear power? Improve NPP operation& maintenance; Safe operation, decrease in outages etc. Improvement of LWR technologies New construction: keeping work force and skills Decrease in capital cost of LWR; Compete with CCGT in construction Innovation of nuclear power plant technologies Large plants Small plants? Seek innovation? Raising human resources for the future

17 Types of researches Industries: Work for commercial products Unknowns should not remain and be avoided. Research institutes : Work for projects Universities: Explore unknown area and raise human resources: Information exchange among the parties is important

18 SCWR, Supercritical pressure water cooled reactors Not constructed before, nor similar plants Reactor concept itself needs to be explored through design study (by numerical simulation) Good subject for students to learn methods and fundamentals of LWR design and safety Difference is small, but need to develop methods/concepts and ideas for SCWR

19 What is supercritical water? 19 No boiling phenomenon High specific enthalpy Pressure Solid Liquid Supercritical Critical point (22.1MPa, 374 ) Gas Temperature Phase diagram of water Density [kg/m 3 ] Specific heat [kj/kg/k] MPa 24 MPa Temperature [ ] 7 MPa 24 MPa Temperature[ ]

20 Water level Circular Boiler LWR Water level Water tube boiler Once-through boiler Super LWR, Super FR (SCWR) Evolution of boilers 20

21 Super LWR and Super FR Super LWR: reactor developed at Univ. of Tokyo and Waseda university Super FR: Fast reactor version of Super LWR (MOX fuel) Once through direct coolant cycle Control rods Pressure: 25 MPa Inlet: 280 Outlet (average): 500 Flow rate: 1/8 of BWR Supercritical water 500 Turbine Generator 280 Core Condenser Reactor Heat sink Pump 21

22 Super LWR: a thermal reactor concept

23 3 D N T Coupled Core Calculation T H calculation based on single channel model Neutronic calculation; SRAC Core consists of homogenized fuel elements 3-D core calculation Homogenized Fuel element Single channel T-H model Coolant q c (i) q w (i) Water rod wall pellet Cladding Moderator 1/4 core Fuel assembly Single channel T-H analyses 23

24 Coolant flow scheme (two pass core) Flow directions Coolant Moderator Inner FA Upward Downward Outer FA Downward Downward To keep high average coolant outlet temperature CR guide tube Outlet: Inlet: Mix Kamei, et al., ICAPP 05, Paper 5527 Inner FA Outer 24 FA

25 Improvement flow scheme of Super LWR one pass core Two pass core (previous) One pass core (improved)

26 Fuel loading pattern of the core

27 Inner and peripheral core assemblies of high temperature core

28 Characteristics of high and low temperature cores of Super LWR Cores High T. core Low T. core Thermal power/electric power[mw] 3492/ /1200 Thermal efficiency[%] Operating pressure[mpa] 25 Temperature inlet/outlet[⁰c] 280/ / 465 Max. Cladding Surface Temp.[⁰C] Number of fuel assembly Average fuel enrichment Fuel/cladding UO 2 /SS Average power density[mw/m 3 ] Core effective height/diameter 4.20/ /3.23 Discharge burnup[gwd/t] Max. Linear Heat Gene. Rate[kW/m] To be presented tomorrow at 1pm

29 Safety principle of Super LWR Keeping coolant inventory is not suitable due to no water level and large density change. Coolant inventory is not important due to no circulation. No natural circulation Safety principle is keeping core coolant flow rate. Coolant supply (main coolant flow rate) Coolant outlet (pressure) BWR PWR Super LWR Requirement RPV inventory PCS inventory Core flow rate Monitoring RPV water level Pressurizer water level Main coolant flow rate, 29 Pressure

30 Plant and safety system SLCS RPV Control rods Containment SRV/ADS Turbine bypass valves Turbine control valves LPCI line MSIV Turbine Condenser AFS LPCI LPCI Condensate pumps Suppression chamber LPCI AFS AFS LP FW heaters Condensate water storage tank HP FW heaters Booster pumps Reactor coolant pump (Main feedwater pump) Deaerator 30

31 Analysis code for supercritical pressure Mass conservation Energy conservation Momentum conservation -downcomer / water rod -average / hot channels Radial heat transfer -Oka-Koshizuka correlaiton Point kinetics 31 31

32 Summary of safety analysis results Increase of temperature from initial value [ ] Transients Criterion for accident and ATWS Accidents ATWS without alternative action ATWS with alternative action (ADS) Criterion for transient Event number Peak pressure [MPa] Criterion for transient Transients Accidents ATWS without alternative action ATWS with alternative action (ADS) Criterion for accident and ATWS 3 4 Event number Peak power [%] Criterion for power rising rate of ovre 10% Criterion for power rising rate of 1-10% Criterion for power rising rate of 0.1-1% Transient number Transients 1. Partial loss of reactor coolant flow 2. Loss of offsite power 3. Loss of turbine load 4. Isolation of main steam line 5. Pressure control system failure 6. Loss of feedwater heating 7. Inadvertent startup of AFS 8. Reactor coolant flow control system failure 9. Uncontrolled CR withdrawal at normal operation 10. Uncontrolled CR withdrawal at startup Accidents 1. Total loss of reactor coolant flow 2. Reactor coolant pump seizure 3. CR ejection at full power 4. CR ejection at hot standby 5. Large LOCA 6. Small LOCA 32

33 Super FR a fast reactor concept

34 Advantages of Super Fast Reactor 34 Same plant system as Super LWR High power density of Super FR is an advantage in capital cost over Super LWR and LWR Capital cost; Super FR< Super LWR< LWR Low reactor coolant flow rate (due to high enthalpy rise) High head pumps Suitable for tight fuel lattice core of Super FR No pumping power increase and instability problems of high conversion LWR

35 Coolant flow schemes of Super FR

36 Fuel assemblies and core of Super FR seed fuel assembly blanket assembly Loading pattern of one path core

37 Super FR (one pass core) characteristics Power MWt/MWe 2337/1006 Coolant pressure (MPa) 25.0 Inlet/outlet temperature ( o C) 280/501 Active/overall power density (kw/l) 206/149 Number of seed assembly 78 Number of blanket assembly 37 Active core height (m) 2.4 Eq. active core diameter (m) 2.47 Pu enrichment in seed assembly (wt%) 32(bottom)/25(top) Pu enrichment in bottom blanket (wt%) 10(bottom) Cycle length (EFPD)/fuel batch 200/3 Average/max discharge burn-up (GWd/t) 53.8/72.7

38 High breeding by light water cooling

39 Tightly packed-rods fuel assembly

40 breeding core

41 Characteristics of high breeding core and comparison with RMWR (reduced moderation BWR)

42 Scope of studies and Computer codes 1.Fuel and core Single channel thermal hydraulics (SPROD), 3D coupled core neutronic/thermal-hydraulic (SRAC-SPROD), Coupled subchannel analysis, Statistical thermal design method, Fuel rod behavior (FEMAXI-6), Data base of heat transfer coefficients of supercritical water 2. Plant system; Plant heat balance and thermal efficiency 3. Plant control 4. Safety; Transient and accident analysis at supercritical-and subcritical pressure, ATWS analysis, LOCA analysis (SCRELA) 5. Start-up (sliding-pressure and constant-pressure) 6. Stability (TH and core stabilities at supercritical and subcritical-pressure) 7. Probabilistic safety assessment 42

43 Super Fast Reactor R&D 43 1 st Phase ( ), 2 nd phase ( ) 1 st phase: University of Tokyo, JAEA, Kyushu Univ. and TEPCO 2 nd phase: Waseda University, Univ. of Tokyo, JAEA, Kyushu Univ. Tohoku univ. TEPCO systems entrusted by MEXT Development of the Super FR concept Thermal hydraulic experiments Materials experiments

44 Thermal hydraulic experiment with surrogate fluid Supercritical thermal hydraulic loop of Kyushu University 44

45 Thermal hydraulics R&D Surrogate Fluid (Freon) at Kyushu University 1. Single tube/rod bundle experiments 2. Critical heat flux experiment at subctriticalpressure 3. Critical flow measurement 4. Condensation experiment 5. Cross flow measurement Supercritical water at JAEA 1. Single rod/rod bundle experiment 2. Single tube experiment at high temperature 45

46 Materials R&D Developed 15Cr 20Ni SS cladding material based on cladding material for LMFBR Developed thermal insulating material, Yttriastabilized zirconia (YSZ) Measurement of Corrosion and elusion characteristics of cladding materials

47 Mass transfer experiments Elusion and deposition characteristics from 20C to 550C and to 20C Auto crave Diagram of mass transfer experiment loop Control system 47

48 Super LWR design study started in Results of the design study (until 2009) are summarized. Also a textbook of reactor design and anlysis: Core & fuel design, plant control, start up, plant heat balance, stability, safety design and analysis of Super LWR and Super FR as well as the comutational methods Publidhed in July 2010 from Springer 2 nd book supercritical pressure light water cooled reactors is Source: under preparation. 48 energy+technology/book/

49 Contents: PSA in design and maintenance of ABWR, Passive ECCS of APWR, Severe accident mitigation features of APR1400, EPR core catcher, Severe accident research in China, Full MOX core design of ABWR, CFD applications, Digital I&C system, 3D-CAD application to construction, Progress in seisimic design Available from Springer, 295 pages Based on the lectures of International summer school of NPP and young generation work shop ; Bridgeing fundamental research and practical applications in 2009 in Tokai-mura Japan

50 Modern textbooks 最新の原子力教科書 of nuclear engineering including advancement in 30years English versions are under preparation at U.Tokyo 日本の優れた原子力発電技術と30 年間の実用の進展を反映英語版も作成中 (Springerより出版) 第 1 号第 2 号第 3 号第 4 号第 5 号第 6 号 英語版出版 英語原稿作成 英語原稿作成 第 7 号 第 8 号 第 9 号 第 10 号 第 11 号 第 12 号 英語原稿作成 英語原稿作成 英語原稿作成 5050 Source: engineering/energy+technology/b ook/

51 Thank you 51