The First COE-INES International Symposiumat Keio Plaza Hotel, November 3, 2004
Super Critical CO2 Gas Turbine Cycle FBRs
Yasuyoshi KatoResearch Laboratory for Nuclear Reactors
Tokyo Institute of Technology
Program Title：Innovative Nuclear Energy Systems forSustainable Development of the World
1. Advanced nuclear energy systemsa) Advanced reactors− CO2 gas turbine reactors− Pb-Bi cooling fast reactors
b) Advanced partition and transmutationc) Advanced energy utilization− Waste heat recovery system− Hydrogen production− Electricity and heat storage
2. Development of human resources
Use of Na as Coolant in FBRs
Advantage: - 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 tolight water reactors.
Coolant Cycle
Steam Indirect(Rankine)
Gas TurbineDirect
(Brayton)
Steam Indirect(Rankine)
Gas TurbineDirect
(Brayton)
CO2
He
1950 1960 1970 1980 1990 2000～
Magnox reactor (60-655 MWe)
AGR (660 MWe)
1967*2 Peach Bottom (42 MWe)Fort St. Vrain (324 MWe)
AVR (15 MWe)
THTR-300 (308 MWe)
1967*2
1986*2
1982*1
PBMR (100 MWe)
GT-MHR (286 MWe)
GTHTR-300 (275 MWe)
TIT
S. Africa
Russia
JAERI*1: Start of operation, *2: Rated full power operation
1956*1
1976*1
History of Gas Cooled-Reactors
MIT,ANL, INEEL
US
UK
Japan
UK &France
Germany
US
Comparison of Cycle Efficiency with Other Cycles
30
35
40
45
50
55
60
200 400 600 800 1000Turbine Inlet Temperature (℃)
Cyc
le T
herm
al E
ffic
ienc
y (%
)
HTGRFort St.Vrain
(538℃, 40.6%)LWR (Av.278℃, about 34%)
HTGRGT-MHR
(850℃, 47.7%)
HTGRPartial Pre-Cooling Cycle
(800℃, 51.4%)
Water/SteamCycle (Indirect)
He Gas TurbineCycle (Direct)
CO2 Gas TurbineCycle (Direct)
Super Critical CO2 GT FBR
Steam TurbineGenerator
Cooling Water
Condenser
pump
Steam Generator
pump pump
IHX
Primary Na LoopReactor
Core
Secondary Na Loop Steam Loop
FeedwaterHeater
Na-Cooled Steam-Turbine Cycle System (Monju, CRBRP)
Gas TurbineGenerator
CoolingWater
RecuperatorCompressor
pump
Na LoopReactorCore
a) Indirect Cycle SystemGas Turbine
Generator
CoolingWater
RecuperatorCompressor
IHX
ReactorCore
b) Direct Cycle System
CO2 Gas Turbine FBRs
Advantages・No secondary Na loop・Smaller & simpler turbine system・Utilization of Monju Na R&D・Smaller core size reference to direct cycle systems
Advantages・No primary & secondary Na loops・Smaller & simpler turbine system・Lower void reactivity
Disadvantages・Larger core size reference to indirectcycle systems・R&D on core cooling and T&H in areactor vessel
In the PastElevation of turbine inlet temperature
Present StudyReduction throughcompression aroundcritical temperature (31℃, 7.4 MPa)
Turbine Work
Net Work (=Efficiency)
Compressor Work
Enhancement of Cycle Efficiency
22.1374H2O0.28-268He
7.431CO2
PressurePc (MPa)
TemperatureTc (ºC)
Critical DataMaterials
Super CriticalSolid
7.4
Pres
sure
MPa
31.1
Liquid
Triple PointGas
CriticalPoint
Temperature ºC
Critical State of CO2
Compressibility factor with Pr and Tr
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0 2 4 6 8 10 12 14 16 18 20 22 24Reduced Pressure P r (=P /P c)
Com
pres
sibi
lity
Fact
or
z15
108
64
321.6
1.41.21.1
Reduced Temperature T r =T/Tc=1.0
1.0
1.1
1.2
1.41.6
2
Higher cycle efficiency could be attained inCO2 cycles compared with He cycles byutilizing reduced compression work aroundthe critical point.
He Compression Condition
Drawn from the data in O.A.Hougen, et al.,"Chemical Process Principles,PartⅡ,Thermodynamics", John Wiley & Sons
Compression Work of Real GasIsentropic compression work W:
W = − V dP = − zRT dP/P,
where V=volume, P=pressure, R=gas constant, z=compressibility factor=f (Tr, Pr),
Tr=reduced temperature=T/Tc, Tc=critical temperature,
Pr=reduced pressure=P/Pc, Pc=critical pressure.
At the critical point, the z value takes an extremelylow value as low as about 0.2 or a real gas is five times more compressible than an ideal gas.
∫ ∫
Cp Pressure & Temperature Dependency
Temperature, (K)
Spec
ific
Hea
t C
pkJ
/km
olK
Large P & T dependency in CO2
Partial Pre-Cooling Cycle
Turbine
High Pressure Compressor
Low Pressure Compressor
Bypass Compressor
Reactor
Pre-
Coo
ler
Inte
rcoo
ler
Recuperator
Generator
Cycle Efficiency in Partial Pre-Cooling Cycle
Bypass Flow Fraction DependencyTemperature & Pressure Dependency
20
30
40
50
60
0 0.1 0.2 0.3 0.4Bypass Flow Ratio (-)
Cyc
le E
ffic
ienc
y (%
)
20.0MPa15.0MPa10.0MPa 5.0MPa
・Pre-Cooler Outlet Temperature : 35℃・Compressor & Turbine Efficiency : 90%・Effectiveness of Recuperator : 95%
He(527℃)
He(827℃)
CO2(827℃)
CO2(527℃)
Reactor Outlet Pressure
30
35
40
45
50
55
60
65
500 600 700 800 900 1000 1100
R eactor O u tlet T em p . (℃ )C
ycle
Eff
icie
ncy
(%)
20 .0M P a 15 .0M P a 10 .0M P a 5 .0M P a
R eactor Pressu re
C O 2 P artia lP re-coolin g
・P re-C ooler T em peratu re : 35℃・C om pressor E ffic iency : 90%・T u rb in e E ffic ien cy : 90%・R ecu p erator E ffectiven ess: 95%
H e
34.0517.2546.741.96
Core Fuel Volume Ratio (%)FuelStructural MaterialCoolantGap
3916.5
0.35Grid Spacer
8.45
Core Fuel PinNumber per SubassemblyOuter Diameter (mm)Cladding Thickness (mm)SpacingPitch (mm)
182/3.5Subassembly Geometry (mm)
Pitch/Duct Thickness
200 / 334.6Blanket Thickness (mm)
Axial/Radial
1502776
Core Geometry (mm)Effective Core HeightEquivalent Diameter
14.0 / 19.0Pu Enrichment (atomic %)
Inner Core/Outer Core
CO2UO2-PuO2-NpO2
B4C 316 SS
MaterialsCoolantFuelAbsorber (10B = 90%)Structural
Direct Cycle Core Parameters
(n, γ)
α 87 y
(n, γ)
(n, γ)237Np 238Pu 239Pu
234U 235U
Fertile FissileAbsorber
237Np-239Pu, 235U Conversion Chain
Burnup Performance with 237Np Content
0.99
1.00
1.01
1.02
1.03
0 2 4 6 8 10Time (Year)
k eff
Np= 0.0%
Np= 4.5%
Np=10.0%Burnup Reactivity
Loss: 0.17% ∆k
1.28 (BOC) Breeding Ratio 1.11 (EOC)
Control Requirement and Reactivity Worth
0.72.02.60.5Shutdown Margin (%∆k/kk’)2.48.03.22.7*Reactivity Worth Available (%∆k/kk’)
1.3
-
0.4
-
1.7
1.3
3.1
1.4
0.2
6.0
0.6
-
-
-
0.6
0.6
0.3
1.0
0.3
2.2
Control Requirement (%∆k/kk’)
Cold to Full Power Reactivity
Burnup Reactivity
Uncertainty
Allowance for Operation
Total
61834Number of Control RodsBackupPrimaryBackupPrimary
Demonstration FBR(660 MWe)
Present GCFR(243.8 MWe)Items
* Worth of one stuck rod.
Inner Core
Outer C
ore
Blanket : 200 mm
Reflector
Equivalent Core Diameter2776 mm
Core H
eight1500 m
m
3500 mm
Blanket
Blanket
Blanket : 200 mm Outer C
ore
Gas Plenum
Reflector
Reflector
Reflector
M
M
M
B
B
B
M
Inner Core : 114
Outer Core : 90
Primary Control Rod : 4
Backup Control Rod : 3
Radial Blanket : 114
Reflector : 216
MB
Core Configuration
Direct Cycle Core Design
40
45
50
55
60
0 2 4 6 8 10
Time (Year)
Inventory (ton)
HM Inventory Change with Burnup Time
U：-2.7 ton
Pu：+0.83 ton
Np：-0.50 ton ≈ Produced in 20 LWRs
Am：+0.11 ton Cm：+0.01 ton
Void Reactivity
・ 0.61% ∆k/kk’
・ Reactivity in the case of depressurization from 12.5 MPa to atmospheric pressure.
Hot Spot Temperature of Cladding> 700ºC (Maximum permissible temperature of 316SS)
1.341.491.16Grand Total
-1.031.061.201.21
-1.301.041.161.34
1.021.021.03
-1.04
StatisticalFlow distributionCoolant propertyManufacturingPellet eccentricityTotal
1.031.08
--
1.11
1.031.08
--
1.11
-1.081.021.021.12
DirectPower measurementPower distributionInlet temperatureSubchannel flowTotal
CladdingFilmCoolantHot Spot Factors
Items
1.33 m1.00 m1.10 m1.25 m
0.81 m
He Gas Turbine CO2 Gas Turbine
Comparison of Gas Turbine Size
Gas Turbine Volume ( ≈ Weight or Cost）5 : 1
1.84 m
1.94 m 1.80 m 2.01 m
Basic Plant Design Conditions
12.5/2012.5Pressure (MPa)
Turbine Inlet Temperature (ºC)
CO2 GasTurbine
Inlet
-12.5Pressure (MPa)
425/550388/527Core Inlet/Outlet Temperature (ºC)
NaCO2CoolantCore
CoolingSystem
40/4240Efficiency (%)600Thermal (MW)Power
Output
Indirect Cycle
Direct Cycle
Design parameters
527
Direct Cycle Plant Design - designed by Fuji Electric for TIT
ReactorVessel
Core CatcherCooling System
Auxiliary Core Cooling System
Generator
Recuperator
Intercooler
BC
BC=Bypass CompressorHPC=High Pressure CompressorLPC= Low Pressure Compressor
Pre-Cooler
Turbine
HPC
LPC
Core
Direct Cycle Plant Design - designed by Fuji Electric for TIT
ReactorVessel
Core CatcherCooling System
Auxiliary Core Cooling System
Generator
Recuperator
Intercooler
BC
BC=Bypass CompressorHPC=High Pressure CompressorLPC= Low Pressure Compressor
Pre-Cooler
Turbine
HPC
LPC
Core
［熱交換器・ポンプ合体方式］
図7.3-2 超臨界二酸化炭素ガスタービンＦＢＲプラント系統図
600MWt
(*)
N L
(*)
A/C A/C
Indirect Cycle Plant Design- Loop Type (IHX-Pump Combined)- designed by ARTECH for TIT
4500
4000
19000
Indirect Cycle Reactor Structure Design- designed by ARTECH for TIT
Compact Heat Exchangers Development HistoryCompact Heat Exchangers Development History
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 with1-2 mm diameter.
Etched plates are stacked and diffusion bondedtogether to fabricate a blockThe blocks are then welded together to form the complete heat exchanger core
Construction of PCHEs
Plate stacking Diffusion bonding
Photo-etching technology:Micro channels with smaller hydraulic diameter Dh:
Pressure capability > 50 MPa.
Compact size (L) or higher efficiency (98%).j=(Dh/4L) Pr2/3N,
where N=NTU (Number of Thermal Units)=(Tout-Tin)/∆TLMTD.No plate-fin brazing:
Manufacturing cost reduction.
Diffusion bonding technology:Maintain parent material strength:
Temperature capability up to 700oC.No braze, flux or filler:
Corrosion resistant.
Advantages of PCHE
PCHE T-H Test Loop for CO2 Cycle GCRs
Cooler
Compressor
Oil Separator
Heater
PCHE (3 kW)
* 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.
New PCHE Model in TIT
58/48(1/1)336/312 (5.8/6.5)Hot/Cold SidePressure Drop* (kP/m)1187 (1)1134 (0.96)Overall Heat Transfer Coefficient* (w/m2K)438/496439/494Hot/Cold SideCoolant Outlet Temp. (℃)
553/382Hot/Cold SideCoolant Inlet Temp. (℃)6.9x10-4/1.3x10-3Hot/Cold SideFlow Rate (kg/s)
1.9/0.94Width/DepthChannel Geometry (mm)38/0.8Angle (degree)/ Width (mm)Fin Geometry
316 SS/1.6Material/ Thickness (mm)Metal Plate10.3/121Width/LengthPCHE Size (mm)
CO2Fluid
**ZigzagFlow Channel
TIT ModelHEATRIC ModelParameters
CO2 Gas Turbine Cycle Mockup Test
Verification of
- Compression work reduction around critical point
- PCHE T&H performance
- Operability of bypass flow configuration
Flow Diagram of Mockup Test FacilityLPC= Low Pressure Compressor, HPC= High Pressure Compressor
低圧圧縮機
加熱器(50kW)
前置き冷却器
再生熱交換器
膨張器
高圧圧縮機
中間冷却器
バイパス圧縮機
Heater30 kW
Expander
Pre-Cooler
LPC HPC
BypassCompressor
Inter-Cooler
Recuperator-1 (22kW)
Recuperator-1 (19 kW)
4.7 MPa, 300℃, 646 kg/h
12.8 MPa, 281℃, 646 kg/h
12.9 MPa192.1℃161 kg/h
4.6 MPa91.4℃485 kg/h
12.9 MPa, 85.7℃485 kg/h
4.6 MPa35℃
485 kg/h
6.8 MPa69.4℃
485 kg/h
6.8 MPa35℃485
kg/h
4.6 MPa91.4℃
161kg/h
4.7 MPa, 203.5℃646 kg/h
12.9 MPa192.1℃646 kg/h
Material Corrosion Test- Corrosion rate & mechanism (break away corrosion?)- Material selection & corrosion control
CO2
F
FF
F
FF
F
FF
F
Pump100 ml/min
Safety Valve
Temperature Sensor
Filter
Test Section- SUS316, 12%Cr alloy- 10 pipes with 1/8inch diameter- 10 MPa- 200-600℃ (Temperature gradient in pipes)
Heater
Filter
Pressure & Flow Rate Sensor
Impurity Sensor
O2H2O CO
Temperature Sensor
Impurity Sensor
O2H2O CO
Flow Diagram of Material Corrosion Test Facility
Na−CO2 Reaction Test- Heat of reaction - Chemical kinetics- Rupture propagation
CO2ガス
Arカバーガス収納容器へ
ターゲット伝熱管
伝熱管の損耗
反応容器(0.5mDx3.3mH)
CO2ガス注入管
CO2ガスの噴出
Na-CO2反応により発生する反応生成物
Target Pipe
Na-CO2 reaction products
Ar cover gas
Pipe attacked
Na Reactor Vessel(0.5 m Dx3.3 m H)
CO2 gas
CO2 gas ejection
CO2gas CO2 gas pipe
Pipe Rupture Propagation Testusing SWAT for MONJU
* Japan，US，France，England，Korea
1. Cycle Mockup Test- Compressor work reduction
around critical point- PCHE T&H performance- Operability
3. Na-CO2 Reaction Test- Reaction mechanism- Rupture propagation
4. Design Study- Direct/indirect system
design- Comparison with conventional systems
- Selection of next generation FBR system
2. Na-CO2 IHX Test- T&H performance- CO2 leak protection
1. Engineering Test- Core- Components- Materials- Safety et al
2. Prototype Plant Construction
2. Material Corrosion Test- Corrosion Mechanism- Corrosion control
R&D
International Project
International Collaboration
Information Exchange as I-NERI *
Engineering Mockup Tests
Turbomachinery & IHX Mockup Tests
Verification of Fundamental Performance, System Design & Evaluation
Third Step（2011-2015）
Second Step（2007-2010）
First Step (MEXT Program)（2003-2006）Phase
1. Turbomachinery Test- Turbine- Compressor
Mile stone for Super Critical CO2 FBR Construction
Super Critical CO2 Gas Turbine Cycle FBRs
1．Carbon dioxide gas turbine cycles are achievable 4 to 11% highercycle efficiency than He cycles due to compressor work reductionaround the critical points.
2．Cycle efficiency of the CO2 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 CO2 cycles might exclude the problems related to safety, cost and maintenance.
4. Fast reactors with the CO2 cycles are expected to be a potentialalternative option to LMFRs.
