Super Critical CO 2 Gas Turbine Cycle FBRs

Transcription

1 The First COE-INES International Symposium at Keio Plaza Hotel, November 3, 2004 Super Critical CO 2 Gas Turbine Cycle FBRs Yasuyoshi Kato Research Laboratory for Nuclear Reactors Tokyo Institute of Technology

2 Program Title: Innovative Nuclear Energy Systems for Sustainable Development of the World 1. Advanced nuclear energy systems a) Advanced reactors CO 2 gas turbine reactors Pb-Bi cooling fast reactors b) Advanced partition and transmutation c) Advanced energy utilization Waste heat recovery system Hydrogen production Electricity and heat storage 2. Development of human resources

3 Advantage: Use of Na as Coolant in FBRs - Efficient heat removal of tight fuel pin lattice. Disadvantages: 1) Positive sodium void reactivity. 2) Hazardous (chemical) reaction with water or air in the event of sodium leakage. 3) Higher capital cost mainly ascribed to the need of extra intermediate cooling loops relative to light water reactors.

4 History of Gas Cooled-Reactors Coolant Cycle Steam Indirect (Rankine) UK & France 1956 *1 Magnox reactor ( MWe) 1976 *1 AGR (660 MWe) UK CO 2 He Gas Turbine Direct (Brayton) Steam Indirect (Rankine) Gas Turbine Direct (Brayton) US Germany 1967 *2 Peach Bottom (42 MWe) 1967 * *1 Fort St. Vrain (324 MWe) AVR (15 MWe) 1986 *2 * 1: Start of operation, * 2: Rated full power operation Japan US TIT MIT, ANL, INEEL THTR-300 (308 MWe) PBMR (100 MWe) S. Africa GT-MHR (286 MWe) Russia GTHTR-300 (275 MWe) JAERI

5 Cycle Thermal Efficiency (%) Super Critical CO 2 GT FBR Water/Steam Cycle (Indirect) CO 2 Gas Turbine Cycle (Direct) HTGR Fort St.Vrain (538, 40.6%) LWR (Av.278, about 34%) HTGR Partial Pre-Cooling Cycle (800, 51.4%) Turbine Inlet Temperature ( ) HTGR GT-MHR (850, 47.7%) He Gas Turbine Cycle (Direct) Comparison of Cycle Efficiency with Other Cycles

6 Steam Turbine Reactor Core Primary Na Loop Secondary Na Loop Steam Loop Generator IHX Steam Generator pump Cooling Water pump pump Feedwater Heater Condenser Na-Cooled Steam-Turbine Cycle System (Monju, CRBRP)

7 Reactor Core Na Loop IHX pump Gas Turbine Recuperator Generator Cooling Water Compressor Advantages No secondary Na loop Smaller & simpler turbine system Utilization of Monju Na R&D Smaller core size reference to direct cycle systems Reactor Core a) Indirect Cycle System Gas Turbine Generator Recuperator b) Direct Cycle System Cooling Water Compressor Advantages No primary & secondary Na loops Smaller & simpler turbine system Lower void reactivity Disadvantages Larger core size reference to indirect cycle systems R&D on core cooling and T&H in a reactor vessel CO 2 Gas Turbine FBRs

8 In the Past Elevation of turbine inlet temperature Turbine Work Net Work (=Efficiency) Compressor Work Present Study Reduction through compression around critical temperature (31, 7.4 MPa) Enhancement of Cycle Efficiency

9 Materials CO H e H 2 O Critical Data Temperature T c (ºC) 374 Pressure P c (MPa) 22.1 Pressure MPa 7.4 Solid Liquid Triple Point Gas Super Critical Critical Point 31.1 Temperature ºC Critical State of CO 2

10 Compressibility Factor z Reduced Temperature T r =T/T c = He Compression Condition Higher cycle efficiency could be attained in CO 2 cycles compared with He cycles by utilizing reduced compression work around the critical point Drawn from the data in O.A.Hougen, et al., "Chemical Process Principles,Part, Thermodynamics", John Wiley & Sons Reduced Pressure P r (=P /P c ) Compressibility factor with P r and T r

11 Compression Work of Real Gas Isentropic compression work W: W = V dp = zrt dp/p, where V=volume, P=pressure, R=gas constant, z=compressibility factor=f (T r, P r ), T r =reduced temperature=t/t c, T c =critical temperature, P r =reduced pressure=p/p c, P c =critical pressure. At the critical point, the z value takes an extremely low value as low as about 0.2 or a real gas is five times more compressible than an ideal gas.

12 Specific Heat Cp kj/kmol K Large P & T dependency in CO 2 Temperature, (K) Cp Pressure & Temperature Dependency

13 Low Pressure Compressor High Pressure Compressor Bypass Compressor Turbine Reactor Pre-Cooler Intercooler Generator Recuperator Partial Pre-Cooling Cycle

14 65 60 Pre-Cooler Temperature : 35 Compressor Efficiency : 90% Turbine Efficiency : 90% Recuperator Effectiveness: 95% Cycle Efficiency (%) He(827 ) He(527 ) CO 2 (827 ) Reactor Outlet Pressure 20.0MPa 15.0MPa 10.0MPa 5.0MPa CO 2 (527 ) Pre-Cooler Outlet Temperature : 35 Compressor & Turbine Efficiency : 90% Effectiveness of Recuperator : 95% Bypass Flow Ratio (-) Bypass Flow Fraction Dependency Cycle Efficiency (%) CO 2 Partial Pre-cooling He Reactor Pressure 20.0MPa 15.0MPa 10.0MPa 5.0MPa Reactor Outlet Temp. ( ) Temperature & Pressure Dependency Cycle Efficiency in Partial Pre-Cooling Cycle

15 Direct Cycle Core Parameters Materials Coolant Fuel Absorber ( 10 B = 90%) Structural Pu Enrichment (atomic %) Inner Core/Outer Core Core Geometry (mm) Effective Core Height Equivalent Diameter Blanket Thickness (mm) Axial/Radial Subassembly Geometry (mm) Pitch/Duct Thickness Core Fuel Pin Number per Subassembly Outer Diameter (mm) Cladding Thickness (mm) Spacing Pitch (mm) Core Fuel Volume Ratio (%) Fuel Structural Material Coolant Gap CO 2 UO 2 -PuO 2 -NpO 2 B 4 C 316 SS 14.0 / / / Grid Spacer

16 (n, ) 87 y (n, ) 237 Np 238 Pu 239 Pu (n, ) 234 U 235 U Absorber Fertile Fissile 237 Np- 239 Pu, 235 U Conversion Chain

17 (BOC) Breeding Ratio 1.11 (EOC) k eff Np= 0.0% Np= 4.5% Np=10.0% Burnup Reactivity Loss: 0.17% k Time (Year) Burnup Performance with 237 Np Content

18 Control Requirement and Reactivity Worth Items Number of Control Rods Control Requirement (% k/kk ) Cold to Full Power Reactivity Burnup Reactivity Uncertainty Allowance for Operation Total Reactivity Worth Available (% k/kk ) Shutdown Margin (% k/kk ) Present GCFR (243.8 MWe) Primary * 0.5 Backup Demonstration FBR (660 MWe) Primary Backup * Worth of one stuck rod.

19 Direct Cycle Core Design Equivalent Core Diameter 2776 mm Reflector M B M M B Reflector Blanket Outer Core Blanket : 200 mm Inner Core Outer Core Blanket : 200 mm Gas Plenum Reflector Blanket Reflector Core Height 1500 mm 3500 mm B M Inner Core : 114 Outer Core : 90 M B Primary Control Rod : 4 Backup Control Rod : 3 Radial Blanket : 114 Reflector : 216 Core Configuration

20 Np ton Produced in 20 LWRs Am ton Pu ton U -2.7 ton HM Inventory Change with Burnup Time

21 Void Reactivity 0.61% k/kk Reactivity in the case of depressurization from 12.5 MPa to atmospheric pressure.

22 Hot Spot Temperature of Cladding > 700ºC (Maximum permissible temperature of 316SS) Items Coolant Hot Spot Factors Film Cladding Direct Power measurement Power distribution Inlet temperature Subchannel flow Total Statistical Flow distribution Coolant property Manufacturing Pellet eccentricity Total Grand Total

23 Gas Turbine Volume ( Weight or Cost 5 : m 0.81 m 1.94 m 1.80 m 2.01 m 1.10 m 1.25 m 1.00 m 1.33 m He Gas Turbine CO 2 Gas Turbine Comparison of Gas Turbine Size

24 Basic Plant Design Conditions Power Output Core Cooling System CO 2 Gas Turbine Inlet Design parameters Thermal (MW) Efficiency (%) Coolant Core Inlet/Outlet Temperature (ºC) Pressure (MPa) Turbine Inlet Temperature (ºC) Pressure (MPa) Direct Cycle 40 CO 2 388/ Indirect Cycle 40/42 Na 425/ /20

25 Direct Cycle Plant Design - designed by Fuji Electric for TIT Auxiliary Core Cooling System Generator Turbine Recuperator BC Core HPC Reactor Vessel Core Catcher Cooling System LPC Intercoole r Pre-Cooler BC=Bypass Compressor HPC=High Pressure Compressor LPC= Low Pressure Compressor

26 Direct Cycle Plant Design - designed by Fuji Electric for TIT Auxiliary Core Cooling System Generator Turbine Recuperator BC Core HPC Reactor Vessel Core Catcher Cooling System LPC Intercoole r Pre-Cooler BC=Bypass Compressor HPC=High Pressure Compressor LPC= Low Pressure Compressor

27 Indirect Cycle Plant Design- Loop Type (IHX-Pump Combined) - designed by ARTECH for TIT

28 Indirect Cycle Reactor Structure Design - designed by ARTECH for TIT

29 Compact Heat Exchangers Development History

30 What is the PCHE? Fluid flow channels are etched chemically on metal plates. - Typical plate: thickness = 1.6mm, width = 600mm, length = 1200mm, - Channels have semi-circular profile with 1-2 mm diameter. Etched plates are stacked and diffusion bonded together to fabricate a block The blocks are then welded together to form the complete heat exchanger core

31 Construction of PCHEs Plate stacking Diffusion bonding

32 Advantages of PCHE Photo-etching technology: Micro channels with smaller hydraulic diameter D h : Pressure capability > 50 MPa. Compact size (L) or higher efficiency (98%). j=(d h /4L) Pr 2/3 N, where N=NTU (Number of Thermal Units)=(T out -T in )/ T LMTD. No plate-fin brazing: Manufacturing cost reduction. Diffusion bonding technology: Maintain parent material strength: Temperature capability up to 700 o C. No braze, flux or filler: Corrosion resistant.

33 Oil Separator Cooler Heater Compressor PCHE (3 kw) PCHE T-H Test Loop for CO 2 Cycle GCRs

34 New PCHE Model in TIT Parameters HEATRIC Model TIT Model Flow Channel Fluid PCHE Size (mm) Width/Length Metal Plate Material/ Thickness (mm) Fin Geometry Angle (degree)/ Width (mm) Channel Geometry (mm) Width/Depth Flow Rate (kg/s) Hot/Cold Side Coolant Inlet Temp. ( ) Hot/Cold Side Coolant Outlet Temp. ( ) Hot/Cold Side Overall Heat Transfer Coefficient * (w/m 2 K) Pressure Drop * (kp/m) Hot/Cold Side Zigzag CO / SS/1.6 38/ / x10-4 /1.3x / / / (0.96) 1187 (1) 336/312 (5.8/6.5) 58/48(1/1) ** * Values in brackets are normalized to unity in the case of the TIT model. ** Now applying for a patent. To be presented at HEAT-SET 2005, April 5-7, 2005, Grenoble, France.

35 CO 2 Gas Turbine Cycle Mockup Test Verification of - Compression work reduction around critical point - PCHE T&H performance - Operability of bypass flow configuration

36 4.7 MPa, 300, 646 kg/h Heater 30 kw Expander 4.6 MPa kg/h 4.6 MPa kg/h LPC 6.8 MPa kg/h 6.8 MPa kg/h Pre- Cooler Inter- Cooler 12.9 MPa, kg/h HPC Bypass Compressor 12.9 MPa kg/h 4.6 MPa kg/h 12.9 MPa kg/h 12.8 MPa, 281, 646 kg/h Recuperator-1 (22kW) 4.7 MPa, kg/h Recuperator-1 (19 kw) Flow Diagram of Mockup Test Facility LPC= Low Pressure Compressor, HPC= High Pressure Compressor

37 Material Corrosion Test - Corrosion rate & mechanism (break away corrosion?) - Material selection & corrosion control Impurity Sensor O 2 H 2 O CO CO 2 Pump 100 ml/min Safety Valve Temperature Sensor Heater Filter Temperature Sensor Filter Test Section - SUS316, 12%Cr alloy - 10 pipes with 1/8inch diameter - 10 MPa (Temperature gradient in pipes) F F F F F F F F F F Pressure & Flow Rate Sensor Impurity Sensor O 2 H 2 O CO Flow Diagram of Material Corrosion Test Facility

38 Na CO 2 Reaction Test - Heat of reaction - Chemical kinetics - Rupture propagation

39 CO 2 gas Target Pipe Ar cover gas Na CO 2 gas Reactor Vessel (0.5 m Dx3.3 m H) CO 2 gas pipe CO 2 gas ejection Pipe attacked Na-CO 2 reaction products Pipe Rupture Propagation Test using SWAT for MONJU

40 Mile stone for Super Critical CO 2 FBR Construction Phase First Step (MEXT Program) Verification of Fundamental Performance, System Design & Evaluation Second Step Turbomachinery & IHX Mockup Tests Third Step Engineering Mockup Tests R&D 1. Cycle Mockup Test - Compressor work reduction around critical point - PCHE T&H performance - Operability 2. Material Corrosion Test - Corrosion Mechanism - Corrosion control 3. Na-CO 2 Reaction Test - Reaction mechanism - Rupture propagation 4. Design Study - Direct/indirect system design - Comparison with conventional systems - Selection of next generation FBR system 1. Turbomachinery Test - Turbine - Compressor 2. Na-CO 2 IHX Test - T&H performance -CO 2 leak protection 1. Engineering Test - Core - Components - Materials - Safety et al 2. Prototype Plant Construction Information Exchange as I-NERI * International Collaboration International Project * Japan US France England Korea

41 Super Critical CO 2 Gas Turbine Cycle FBRs 1 Carbon dioxide gas turbine cycles are achievable 4 to 11% higher cycle efficiency than He cycles due to compressor work reduction around the critical points. 2 Cycle efficiency of the CO 2 cycles are about 41% at 527 ºC and 12.5MPa,which is comparable with those of LMFRs at the same core outlet temperature. 3. The CO 2 cycles might exclude the problems related to safety, cost and maintenance. 4. Fast reactors with the CO 2 cycles are expected to be a potential alternative option to LMFRs.