Review on Conventional and Innovative Fuel Burning Schema ......2 3 1. Brief introduction on the...
Transcript of Review on Conventional and Innovative Fuel Burning Schema ......2 3 1. Brief introduction on the...
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Review on Conventional and Innovative Fuel Burning Schema
for HTGRsPeng Hong Liem, Ismail, Yasunori Ohoka, Takashi Watanabe and Hiroshi Sekimoto
Research Laboratory for Nuclear Reactors Tokyo Institute of Technology
COE-INES Indonesia SymposiumMarch 2-4, 2005
Bandung, Indonesia
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Contents• Brief introduction on the conventional and
innovative fuel burning schema for HTGRs– Block Fuel Element– Pebble Fuel Element
• Procedures for solving fuel burning problems under core equilibrium condition
• Some examples of analysis results• Impact of fuel burning schema on HTGR safety
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1. Brief introduction on the conventional and innovative fuel
burning schema for HTGRs
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Block-Type Fuel Element (1/2)
Coated Fuel Particle
Fuel Kernel
Fuel Compact
SiC/PyC Coated Layers (4)
1 mm
26 mm
39 mm
8 mmT 580 mm
End Plug
Fuel RodFuel Assembly
(HTTR: Pin-In-Block)
Graphite Sleeve
Fuel Compact
Dowel
Fuel Rod
Burnable Poison Hole
34 mmD
360 mm
Other Block-type (GA): Multihole(Fuel and Coolant Holes)
Coolant flows between fuel compact and graphite sleeve
Source: JAERI-HTTR
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Block-Type Fuel Element (2/2)
• Past Experimental/Demonstration Reactors– Dragon (OECD, Winfrith, UK)– Peach Bottom 1 (GA, Peach Bottom, Pa., US)– Fort St. Vrain (GA, Platteville, Co., US)
• Currently Operating Experimental/Research Reactors– High Temperature Test Reactor, HTTR (JAERI, Oarai, Japan)
• On-going Design (Near/Far Future)– Gas-Turbine Modular Helium Reactor, GT-MHR (US/Russia)– Gas-Turbine High-Temperature Reactor, GTHTR-300 (JAERI,
Japan)– Gas-Turbine HTR Cogeneration, GTHTR-300C (JAERI, Japan)– New Generation Nuclear Power Plant, NGNP (Pebble ? Block ?, US-
DOE)– Very High Temperature Reactor VHTR ANTARES (Framatome ANP
Demo, French)
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HTTR (1/4) Main Data
UO2 (FC 3-10 %)TRISO Fuel
22 GWD/TBurnup (Ave.)
1 Batch (Off-line)Fuel Loading
395/850 (950) ℃Inlet/Outlet Temp
2.5 W/ccPower Density
2.9/2.3 mCore Height/Diam.
-Electric Power
30 MWthThermal Power
Source: JAERI-HTTR
Burning Scheme
Whole core is removed at EOC and replaced by new FE
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HTTR (2/4) Burnup Control
Core Center
BP (B4C-C)
Effe
ctiv
e M
ultip
licat
ion
Fact
or (k
eff)
Burnup (days)
Keff of core without Burnable Poison
Reactivity compensated by BP
Keff of core with Burnable Poison
Excess reactivity (BOL)4.6 %Δk Excess reactivity (EOL)
2.6 %Δk
Yamashita, K et al., NSE 122 (1996)
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HTTR (3/4) Radial Power Control
Core Center
¼ Core1-st Layer
6.7 % 7.9 %
9.4 %
9.9 %U-235 Enrichment
Yamashita, K. et al.,NSE 122 (1996)
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Layer number of fuel blocks
Pow
er D
ensi
ty (W
/cc) U-235
6.7-9.9 %U-235 5.2-7.9 %
U-235 4.3-6.3 %
U-235 3.4-4.8 %
HTTR (4/4) Axial Power Control
Burnup10 days (BOL)
440 days
660 days (EOL)
Yamashita, K. et al.,NSE 122 (1996)
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GTHTR-300 (Japan)
2 Batch/Off-line (Sandwich Reshuffling)
Fuel Loading
120 GWD/TBurnup
UO2 (LEU)Fuel
587/850℃Inlet/Outlet Temp
5.4 W/ccPower Density
8.4/5.1 mCore Height/Diam.
279 MWElectric Power
600 MWthThermal Power
Source: JAERI-HTTR
Burning Scheme
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• Gas-Turbine Modular Helium Reactor
3 Batch/Off-lineFuel Loading
640 GWD/tBurnup
Ex Weapon PuTRISO Fuel
491/850℃Inlet/Outlet Temp
6.6 W/ccPower Density
7.9/4.8 mCore Height/Diam.
286 MWElectric Power
600 MWthThermal Power
GT-MHR(US/Russia)
Burning Scheme
Level of Pu-239 burning 90 % (Deep Burn)
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CANDLE Burning Scheme (1/3)Applied to Block-type HTGRs
• Constant Axial Shape of Neutron Flux, Nuclide Densities and Power Shape During Life of Energy Producing Reactor (Sekimoto, H. et. al., Nucl. Sci. Eng. 139, 2001)
• Features:– No need for burnup reactivity control mechanism– Constant reactor characteristics (simple reactor
operation)– Reactor height is proportional to core lifetime– kinf of fresh fuel < 1 (optimal use of BP); small risk of
criticality accident
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CANDLE Burning Scheme (2/3)
BurningDirection
(Axial)
Spent Fuel
Discharge
Loading
Fresh Fuel
Loading
Fresh Fuel
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CANDLE Burning Scheme (3/3)
• Fresh Fuel Region (k<1)– BP is burnt slowly by
neutrons leaked from the burning region
• Burning Region (k>1)– BP is almost completely
burnt– Fissile material is depleted
for producing energy and neutrons
– Fertile material is converted to fissile material
• Spent Fuel Region (k<1)– Fission products are
accumulated– Depleted fuel
BurningDirection
BP Fissile
FP
Flux
BP:Burnable PoisonFP:Fission Products
Steady-State(Equilibrium)
Burning Region
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Pebble-Type Fuel Element (1/2)
SiC/PyC Coated Layers (4)
Fuel Kernel
1mm
6 cm
Coolant flows between pebbles
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Pebble-Type Fuel Element (2/2)• Past Exp/Proto Reactors
– Arbeitsgemeinschaft Versuchsreaktor, AVR (BBC/HRB, Hamm-Uentrop, FRG)
– Thorium High-Temperature Reactor, THTR-300 (BBC/HRB, Hamm-Uentrop, FRG)
– High-Temperature Reactor Modul, HTR-M (Siemens/Interatom, Design Only, FRG)
• Currently Operating Res Reactors– HTR-10 (Tsinghua Univ.-INET, China)
• On-going Design Proto/Demo/Commercial Reactors– Pebble Bed Modular Reactor, PBMR (Escom, South Africa)– HTR-PM (INET, Beijing, China)
• Near/Far Future Design– Peu-A-Peu, PAP-80, PAP-20, PAP-20-H (KFA-Julich, FRG)– Advanced Atomic Cogenerator for Industrial Application, Acacia/Incogen
(ECN, Petten, Netherland)– Modular Pebble Bed Reactor, MPBR (MIT, US)– New Generation Nuclear Power Plant, NGNP (Pebble ? Block ?, US-DOE)
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HTR-M Main Data
76He Gas Flow (kg/s)
6He Pressure (Mpa)
250/700He Temp (℃)
1020Fuel Residence Time (day)
80Fuel Burnup (GWD/t)
MultipassFuel Burning Scheme
UraniumFuel Cycle
TRISOCoated Fuel Particle
8Fissile Enrichment (%)
7HM loading/ball (g)
9.6Core Height (m)
3Core Diameter (m)
3Ave. Pow. Dens. (W/cc)
200Thermal Power (MWth)
Reutler, H. and Lohnert, G.H., Nucl. Technol. 62, 22 (1983), 78, 129 (1984)
Burningscheme
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OTTO Burning Scheme
• Once-Through-Then-Out (OTTO)
• Features:– No recycling of FE (Simpler
than Multipass )– No burnup measurement
devices and recycle mechanism
– Good axial power density profile for steady-state condition (power density is strongly tilted towards the top)
Spent
Fresh
Depleted CoreRegion
Reactive Core Region
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Multipass Burning Scheme (1/3)
• HTR-M• Features:
– Better neutron economy– Higher fuel burnup– Low max. power density– Low max. fuel temp.
during depressurization accident
Spent
Fresh
Small BU
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Multipass (2/3) - Inner Refl.
• PBMR (Nominal) Design• Features:
– Two pebble types (fuel and graphite)
– Central and peripheral loading tubes
– Higher max. power density at the graphite-fuel interfaces
– Better neutron economy (FC 8%) than alternative design
Fresh
Spent
Small BU
Graphite Ball
Graphite Ball
Inner ReflectorRegion
Core Region
H. D. GOUGAR, W. K. TERRY, and A. M. OUGOUAG(INEEL)
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Multipass (3/3) Out-In
• PBMR alternative design• Features:
– Central and peripheral loading tubes
– Control on the radial distribution of fuel burnup
– Radial power distribution flattening
– Worse neutron economy (FC 10%) than the nominal design
Fresh
Spent
Small BU
High BU
Depleted CoreRegion
Reactive Core Region
H. D. GOUGAR, W. K. TERRY, and A. M. OUGOUAG(INEEL)
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Peu-a-Peu Burning Scheme (1/3)
• PAP-80, PAP-20, PAP-20H
• Acacia (Incogen)• Features:
– Simplest fuel loading scheme
– Axial power density is similar to OTTO and CANDLE
– Large difference of core pressure drops between BOC and EOC
Reactive Core Region
Fresh
BOL(Critical)Depleted Region
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Peu-a-Peu Burning Scheme (2/3)Acacia/Incogen
18.0 MWthHeat Cogen
494/800℃Inlet/Outlet Temp
16.5 MWElectric Power
40 MWthThermal Power
Source: NRG-Petten
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Peu-a-Peu Burning Scheme (3/3)Example: Small-Size HTGR
1.6Fissile Loading (kg/GWD)
250 / 700He Inlet/Outlet Temp. (C)
4.8 / 1.5Max. Pow. Dens. BOL/EOL (W/cc)
871 / 750Max. Fuel Temp. BOL/EOL (C)
28 / 17Neut Leakage BOL/EOL (%)
49.8 / 69.2Ave. and Max. BU (GWD/t)
8.0Uranium Cycle FC(%)
10Core Life Time (year)
1.2 / 6.9Core Height BOL/EOL (m)
3.0Core Diameter (m)
25Power (MWth)
Liem, P.H., Ann. Nucl. Energy 23(3), 1996
Max. Pow. Dens.
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2. Procedures for solving fuel burning problems under core
equilibrium condition
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Criticality
Φ=Φ ),(1),( σσ NFNMk
NTN ),,( σλΦ=∂∂
t
Non-Moving FE(Off-line, Batch refueling)
Moving FE, Burning Region(On-line, Cont. refueling)
NTNN ),,( σλΦ+∂∂
−=∂∂
sv
t sEquilibrium Core Conditions
0=∂∂
tN
Batan-EQUIL
PREC, PREC2 (OTTO)Batan-MPASS (Multipass)SRAC-CD (CANDLE)
Problem Statement
EOCBOC ),(),( )()1( ≤≤=+ ttt jj rNrN
jjj all )()1( SS =+
jjj all BOC),(BOC),( )(Fresh
)1(Fresh rNrN =+
j is core cycle, S is reshuffling and refueling matrix. Example:
)(EOC),(BOC),( 1Fresh
)()1( rNrSNrN ++ += jjj
NTN ),,(1 σλΦ=∂∂
svs
vs is pebble flow velocity or burning region velocity
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Φ=Φ ),(1),( σσ NFNMk
NTN ),,(1 σλΦ=∂∂
svs
SOR-Newton Method
Φ∂Φ∂Φ
−Φ=Φ Φ+
),(),()()1(
NfNfωll
NNgNgNN
∂Φ∂Φ
−=+
),(),()()1(
Nll ω
Good guesses for
Given
)0(N )0(Φ
sv
Sekimoto, H., et. al., J. Nucl. Sci. Tech. 24(10), 1987Obara, T. and Sekimoto, H., J. Nucl.Sci. Tech. 28(10), 1991
PREC Algorithm
0Nf =Φ),(
0Ng =Φ),(
Acceleration parameter similar to SOR method
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Φ=Φ ),(1),( σσ NFNMk
NTN ),,(1 σλΦ=∂∂
svs
Liem, P.H., Ann. Nucl. Energy 21(5), 1994Liem, P.H., Ann. Nucl. Energy 23(3), 1996
Given sv
)0()0(
)0( ),(1),( Φ=Φ σσ FreshFresh
kNFNM
)()()1(
),,(1 ll
s
l
vsNTN σλΦ=
∂∂ +
),(1),( )1()1()1(
)1()1( +++
++ Φ=Φ lll
ll
kNFNM
Batan-MPASS Algorithm (1/2)
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Annals of Nuclear Energy 29 (2002) 1345–1364Direct deterministic method for neutronicsanalysis andcomputation of asymptotic burnupdistribution in a recirculating pebble-bed reactorW.K. Terry*, H.D. Gougar, A.M. OugouagIdaho National Engineering and Environmental Laboratory
Asymptotic=Equilibrium
Recirculating=Multipass
Batan-MPASS Algorithm (2/2)Comparison with Other Codes
PREC
PREC2
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Φ=Φ ),(1),( σσ NFNMk
)()()(
)1(
),,(1 lll
z
l
vzNTN σλΦ=
∂∂ + )()(
)(
)1(
),,(1 lll
z
l
vzNTN σλΦ=
∂∂ +
)0(zvGood guesses for )0(Φ
Ohoka, Y. and Sekimoto, H., Nucl. Eng. Design 229(1), 2004
),(1),( )1()1()1(
)1()1( +++
++ Φ=Φ lll
ll
kNFNM
∫∫Φ
Φ=+
dV
dVzz
l
ll
C )(
)()1(
)1( +lzvCorrect )()1( l
Cl
C zz −+based on
SRAC-CD Algorithm
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3. Examples of Analysis Results
• Case Study: Small-Size HTGRs (25 MWth)• Burning Schema:
– Multipass– OTTO– Peu A Peu– CANDLE
• Fuel Cycle (Fissile Content 8 %)– Uranium– Thorium
Pebble Fuel Element
Block Fuel Element
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Burning Schema Comparison for Small-Sized HTGRs
BURNING SCHEME Multipass OTTO Peu-a-Peu CANDLE HTTRFuel Element Type Block Block
Fuel Loading Method - Off-line, Batch
Calculation Code Batan-Peu SRAC-CD NDCSThermal Power (MWth) 30Core Diameter (m) 2.3Fissile Content (%) 3-10Active Core Height (m) 4.5 4.5 6.9 4.0+2.0 2.9
4.5 4.5 4.0 3.0+2.0Core Life Time (year)/ 11.0 9.4 10.0 10.0 1.8Residence Time (year) 16.5 14.0 10.0 10.0Velocity (cm/day)/ 1.8 0.14 1774.0 0.108Fueling Rate (ball/month) 1.2 0.09 703.0 0.080Ave. Burnup (GWD/t) 78.5 67.2 49.8 48.3 22.0
117.0 99.4 71.1 76.4Max. Power Density (W/cc) 0.99 1.53 4.78 3.30 4.50
1.02 2.10 7.33 4.96
8.0
Batan-MPASS
Pebble
On-line, Continuous
25.03.0
Uranium Thorium Just for reference
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4. Impact of Burning Schema on the HTGR Safety
• Case Study: HTR-M (200 MWth)• Burning Schema
– OTTO– Multipass
• Fuel Cycle (Fissile Content 8 %)– Uranium– Thorium
• Accident Analysis: Depressurization Accident
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Burning Scheme Impact on Steady-State Power Dist.(Uranium Fuel)
200
300
400
500
600
700
800
0 200 400 600 800 1000 1200
Distance from top (cm)
Temperature (℃)
0
2
4
6
8
10
12
14
Power Density (W/cc)
OTTO
Multipass
HePebble
He Flow
Pow Dens
Top
Ref
l
Bot
tom
Ref
l
Upp
er V
oid
Liem, P.H., Ann. Nucl. Energy 21(5), 1994Liem, P.H., Ann. Nucl. Energy 23(3), 1996
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0
2
4
6
8
10
12
14
16
0 200 400 600 800 1000 1200
Distance from top (cm)
Power Density (W/cc)
Fuel Cycle Impact on Power Distribution
He Flow
Top
Ref
l
Bot
tom
Ref
l
Upp
er V
oid
OTTO
Thorium
Uranium
MultipassThorium
Uranium
Liem, P.H., Ann. Nucl. Energy 21(5), 1994Liem, P.H., Ann. Nucl. Energy 23(3), 1996
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HTR-M (OTTO)Max. Fuel Temp. During Depressurization Accident
He Flow
Top
Ref
l
Bot
tom
Ref
l
Distance from top of the core
Fuel Limit Temperature
Hiroshe, Y, Liem, P.H., Suetomi, E., Obara, T., Sekimoto, H, Journ. Of Nucl. Sci. Tech. 26 (1989)
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HTR-M (Multipass) Max. Fuel Temp. During Depressurization Accident
He Flow
Top
Ref
l
Bot
tom
Ref
l
Distance from top of the core
Fuel Limit Temperature
Hiroshe, Y, Liem, P.H., Suetomi, E., Obara, T., Sekimoto, H, Journ. Of Nucl. Sci. Tech. 26 (1989)
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Keywords to Memorize
• HTGR• Coated Fuel Particle• Block, Pebble-type FE• On-line, Off-line Refueling• Batch, Continuous Refueling• Multipass, OTTO, Peu-A-Peu• CANDLE• Uranium, Thorium, Ex Weapon Pu
Fuel• Fissile Content (enrichment)• Burnable Poison• Fuel Burnup• Max. Power Density• Max. Fuel Temperature• Depressurization Accident
• CANDLE– Large-Size CANDLE
Reactor Design– Radial Optimization– Thermal-Hydraulic
Design– Accident Analyses– Etc.
• Analysis Code Development
Future Works
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Terima kasih !