IMPACT CAPE-B: Critical Power Analysis Code for BWR Fuel Bundle - Evaluation Method - Analytical Step Calculation Method 4. Detection of D ryout 2. Spacer Effect 1. Fuel Bundle 3. Each Subchan nel 3-D Subchannel Anal ysis with Drift-flux Mod el 3-D Liquid Droplet Transport Analysis In Turbulent Steam Flow Liquid Film Flow Rate = 0 Liquid Film Flow Analysis
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IMPACT CAPE-B: Critical Power Analysis Code for BWR Fuel Bundle - Evaluation Method - Analytical Step Calculation Method 4. Detection of Dryout 2. Spacer.
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IMPACT
CAPE-B: Critical Power Analysis Code for BWR Fuel Bundle- Evaluation Method -
Analytical Step Calculation Method
4. Detection of Dryout
2. Spacer Effect
1. Fuel Bundle
3. Each Subchannel
3-D Subchannel Analysis with Drift-flux Model
3-D Liquid Droplet Transport AnalysisIn Turbulent Steam Flow
Liquid Film Flow Rate = 0
Liquid Film Flow Analysis
(a) Comparison of mass flux
Pressure : 6.9 Mpa Number of axial subchannel division : 50
Un-heated test (4 test runs)
Average mass flux : 651-2671 kg/m2sInlet subcooling : 1174 kJ/kg
Heated test (13 test runs)
Average mass flux : 719-1464 kg/m2sInlet subcooling : 68-603 kJ/kg Heated length : 1.83 mPower distribution : UniformHeat flux : 710-2130 W/m2
IMPACT
CAPE-B: Verification of Subchannel Analysis Model (1. Analysis of the test conducted by Lahey, et al.)
0
1000
2000
3000
4000
1000 2000 3000Measured mass flux (kg/m2s)
Cal
cula
ted
mas
s flu
x (
kg/m
2s)
4000
(Standard deviation)=7%
:Inner:Side:Corner
(b) Comparison of steam quality
0.1
0.2
0.3
0.4
0.5
0.1 0.2 0.3 0.4 0.5Measured quality
Cal
cula
ted
qual
ity
+e -e(Measurement error)e=0.024
:Inner:Side:Corner
0
PERI IN-3IN-1 IN-2
: 1.30: 1.15: 0.90: 0.45
Radial power distribution
0.6
0.2
0.4
PERI IN-1 IN-2 IN-3Region in bundle
Reg
iona
l ave
rage
voi
d fr
actio
n
0.8
Pressure : 7.2 Mpa
Mass flow rate : 1562 kg/m2s
Inlet subcooling : 50.2 kJ/kgAxial power distribution : UniformNumber of axial subchannel division : 48
IMPACT
CAPE-B: Verification of Subchannel Analysis Model (2. Analysis of NUPEC full scale bundle test)
: Present calculation: COBRA-BWR
Test data
IMPACT
CAPE-B: Concept of Liquid Film Flow Analysis
dGfdz
( Gf + dz
)
= dGfdz
(D - E - B)peA
Fuel rod
Dryout
Heat transfer to liquid film
Entrainment rate: E
Evaporation rate: B
Deposition rate: D
Liquid droplet
Inflow to the mesh: Gf
Mesh height
Outflow from the mesh(=Inflow to the next mesh)
Liquid film
dz
IMPACT
CAPE-B: Verification of Spacer Effect Analysis Model (Analysis of the test conducted by Nagayoshi, et al.)
(a) Test section
Hot wire probe
Rectangular duct
Plate spacer(Thickness: 0.5, 1.0 mm)
Flow
30 mm
10 mm
40 mm
Flow
(b) 2-dimensional analysis region
Rectangular duct
Plate spacer (Thickness: 0.5, 1.0 mm)
10 mm 42 meshes
70 meshes80 mm30 mm50 mm
Z
Z=0
Distance from the edge of the spacer (mm)
Incr
emen
t ra
tio
of t
urbu
lent
flu
ctua
tion
u'/u
' ∞
1
2
3
4
0 10 20 30 40 50
Thickness Exp. Cal.
0.5 mm
1.0 mm
IMPACT
CAPE-B: Turbulent Enhancewment due to the Spacer (Analysis of the test conducted by Nagayoshi, et al.)
IMPACT
CAPE-B: Test analysis condition for model validation