Transcript Kein Folientitel - Royal Institute of Technology

Forschungszentrum Karlsruhe
Technik und Umwelt
EFIT Design and Transient
Analysis
M. Schikorr, E. Bubelis
EUROTRANS: DM1 WP1.5 : “Safety”
Madrid , 13-14 November 2007
EUROTRANS WP1.5 Safety Meeting :
Madrid, Nov 13-14. 2007
IRS /FzK
W.M.Schikorr
1
Forschungszentrum Karlsruhe
Technik und Umwelt
Topics:
1. Design Criteria for EFIT-Pb
2. EFIT design data for Transient Analysis
3. Some EFIT-Pb results to the ULOF transient
EUROTRANS WP1.5 Safety Meeting :
Madrid, Nov 13-14. 2007
IRS /FzK
W.M.Schikorr
2
Forschungszentrum Karlsruhe
Technik und Umwelt
1.
Some important EFIT Design Criteria:
1. Use of MgO-based MA-MOX Fuel Mixture
2. Operate EFIT at k_eff ~ 0.95 - 0.97 with flat k_eff burnup characterisitics
3. Adopted 3-Core region design to obtain flat radial power profile
(designed by ENEA and ANSALDO)
4. Design core and primary system in such a manner to allow sufficient
natural convection flow rate to sustain a ULOF transient for at least 30
minutes without „large number“ of pin failures (via gas blowdown)
5. Account for burn-up and protective oxide layer formation during
operation of plant
EUROTRANS WP1.5 Safety Meeting :
Madrid, Nov 13-14. 2007
IRS /FzK
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Technik und Umwelt
EFIT ULOF Design Criteria requires :
Assure a sufficiently large natural convection flow rate ( > 25 % nominal
flow) under ULOF-ss conditions.
This implies :
1.
keep pressure drop across the core „low“ (~< 0.75 bar) by
selecting an appropriate fuel pin / subassembly design
2.
minimize pressure losses throughout the primary / DHR
system such that total system pressure loss <~ 1.0 – 1.1 bar
3.
assure a height differential between the core midplane and the
heat sink midplane of at least > 2.00 m
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IRS /FzK
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Keeping DP_core in the XT-ADS Design low:
1. Select an appropriate pin / sub-assembly design by optimizing the pin
diameter, pin pitch, wrapper dimensions etc.
2. Minimize the number of grid-spacers and optimise design
3. Keep the length of the fuel pin low
4. Optimize inlet and outlet support structures to keep pressure drops
small
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Madrid, Nov 13-14. 2007
IRS /FzK
W.M.Schikorr
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Forschungszentrum Karlsruhe
Technik und Umwelt
Most current EFIT Design Data: Inner Core Region, Core Zone 1
EUROTRANS WP1.5 Safety Meeting :
Madrid, Nov 13-14. 2007
IRS /FzK
W.M.Schikorr
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Forschungszentrum Karlsruhe
Technik und Umwelt
Most current EFIT Design Data: Intermediate Core Region, Core Zone 2
EUROTRANS WP1.5 Safety Meeting :
Madrid, Nov 13-14. 2007
IRS /FzK
W.M.Schikorr
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Technik und Umwelt
Most current EFIT Design Data: Outer Core Region, Core Zone 3
EUROTRANS WP1.5 Safety Meeting :
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IRS /FzK
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Height difference Core and HX
Other EFIT Data Inputs:
T_in
T_out
Flow Rate
854mm lower gas plenum
3.7
m
400
480
32101
°C
°C
kg/s
Calc. Prim. System Pressure Drops:
274mm upper gas plenum
6 Spacers @ 0.50mm thickness
Core Inlet/Outlet
Flow Friction
Total Core
Total Prim. System
Assumed Zeta Factor (Ratio of
Prim.System/Core Pressure Drop)
0.181
0.24
0.124
0.544
0.751
bar
bar
bar
bar
bar
1.38
Calc. Prim. System Pressure Drops:
EFIT-PB
XT-ADS
EUROTRANS WP1.5 Safety Meeting :
P/D
1.581
1.40
6 Spacers @ 0.25mm thickness
Core Inlet/Outlet
Flow Friction
Total Core
Total Prim. System
Assumed Zeta Factor (Ratio of
Prim.System/Core Pressure Drop)
Madrid, Nov 13-14. 2007
IRS /FzK
0.05
0.24
0.124
0.413
0.569
bar
bar
bar
bar
bar
1.38
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EFIT - Pb : Peak Fuel and Cladding Temperatures [°C]
Inner Core Zone CZ1
Nominal
Conditions
ULOF
Conditions
Intermediate Core Zone CZ2
Outer Core Zone CZ3
Oxide
Layer
thickness
Clad
Fuel
Clad
Fuel
Clad
Fuel
Clad
Fuel
Clad
Fuel
Clad
Fuel
BOC
0 µm
505
1220
530
1399
503
1242
519
1365
497
1133
531
1394
EOC
0 µm
505
824
539
1006
503
842
523
953
497
786
526
933
100 µm
600
1126
580
1058
571
1025
200 µm
677
1241
650
1160
631
1117
300 µm
758
1347
722
1258
695
1206
BOC
0 µm
675
1475
652
1436
692
1473
EOC
0 µm
689
1149
660
1086
685
1083
EOC
100 µm
743
1259
705
1185
726
1170
EOC
200 µm
797
1361
758
1279
767
1255
EOC
300 µm
868
1457
832
1367
816
1336
Avg Pin
Peak Pin
Avg Pin
Peak Pin
Avg Pin
Peak Pin
EFIT - Pb : Cladding Failure Times [hrs]
EFIT-Pb: Avg and Peak Cladding and Fuel
Temperatures at Nominal and ULOF-ss Plant
Conditions for BOC and EOC
EOC state is defined to be max burnup ~ 100
MWd/kg of MOX-MA fuel
EUROTRANS WP1.5 Safety Meeting :
Oxide
Layer
thickness
Nominal
Conditions
ULOF
Conditions
Madrid, Nov 13-14. 2007
Inner Core Zone CZ1
Intermediate Core
Zone CZ2
Outer Core Zone CZ3
Avg Pin
Peak Pin
Avg Pin
Peak Pin
Avg Pin
Peak Pin
BOC
0 µm
E11
E10
E11
7.0XE10
E11
E10
EOC
0 µm
E9
E6
6.8XE8
2.5xE7
6.9xE8
5.2xE6
EOC
100 µm
7.0XE4
1.90E+05
1.1xE5
EOC
200 µm
4.5xE4
1.0xE3
1.2xE3
EOC
300 µm
1.44
9.8
17.4
2XE10
5.5xE5
3.0xE4
BOC
EOC
0 µm
66.7
371
23.9
EOC
100 µm
2.57
208
2.02
EOC
200 µm
0.14
0.97
0.21
EOC
300 µm
0.3 min
2.0 min
1.0 min
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EFIT ULOF Transient Cases Analysed:
1.
ULOF:
BOC, Peak Pin, 6 Spacer @ 0.50mm thickness
2.
ULOF:
EOC, Peak Pin, 6 Spacer @ 0.50mm thickness, 100 um oxide
EUROTRANS WP1.5 Safety Meeting :
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IRS /FzK
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ULOF FzK (SIM-ADS) : Clad Failure and Fission Gas Pressure
Power_th
Power
Flow_Cool
Flow
0
50
100
150
200
Time [sec]
1.E+12
1.E+11
1.E+10
5
5
1.E+09
1.E+08
1.E+07
1.E+06
1.E+05
1.E+04
5
Clad Failure Time [sec]
Fission Gas Pressure [bar]
5
30 min
limit
1.E+03
1.E+02
1.E+01
1.E+00
Temperature [°C]
5
5
0
1500
Min. Pin Clad Failure Time = 17 hrs
5
ULOF FzK (SIM-ADS) : Temperatures
1700
5
Fission Gas Pressure [bar]
ULOF FzK (SIM-ADS) : Power and Flow Rate
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Clad Failure Time [sec]
rel. Units [fr]
EFIT-Pb : ULOF, BOC, Peak Pin, 6 Spacer @ 0.50mm thickness, no oxide
50
100
Time [sec]
150
200
Conclusion:
Fuel
Fuel_c_peak
1300
For current design EFIT peak pin clad will
NOT fail under BOC conditions even though
of flow undershoot that is ~ 22 % nom. flow.
Clad_peak
1100
Cool_out
T_clad_max = 810 °C
Cool_in
900
Cladding
700
Coolant
500
Min Clad Failure Time ~ 17 hours
300
0
50
100
150
200
Time [sec]
EUROTRANS WP1.5 Safety Meeting :
Madrid, Nov 13-14. 2007
IRS /FzK
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Forschungszentrum Karlsruhe
Technik und Umwelt
EFIT-Pb : ULOF, EOC, Peak Pin, 6 Spacer @ 0.50mm thickness, 100um oxide
ULOF FzK (SIM-ADS) : Clad Failure and Fission Gas Pressure
Power_th
Flow_Cool
Power
Flow
0
50
100
150
1.E+10
1.E+09
1.E+08
1.E+07
1.E+06
1.E+05
1.E+04
1.E+03
1.E+02
1.E+01
1.E+00
200
98
96
Clad Failure Time [sec]
94
Fission Gas Pressure [bar]
92
30 min
Min. Pin Clad Failure Time = 1000
sec
90
88
0
Time [sec]
50
100
Time [sec]
150
86
200
ULOF FzK (SIM-ADS) : Temperatures
1500
1300
Temperature [°C]
100
Fission Gas Pressure
[bar]
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Clad Failure Time [sec]
rel. Units [fr]
ULOF FzK (SIM-ADS) : Power and Flow Rate
Fuel
Conclusion:
Fuel_c_peak
Clad_peak
1100
Cool_out
T_clad_max = 820 °C
900
Cool_in
Cladding
700
500
300
0
50
100
150
200
For current design EFIT peak pin clad will
most likely NOT fail under EOC conditions
even though of flow undershoot ~ 22% (min.
clad failure time ~ 1000 sec). Peak pin fission
gas pressure will be </~ 100 bar.
Time [sec]
EUROTRANS WP1.5 Safety Meeting :
Madrid, Nov 13-14. 2007
IRS /FzK
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Conclusions on EFIT ULOF Transient :
1.) The ULOF transient is less sensitive in the Pb-cooled EFIT design than
to the XT-ADS design because of its better natural convection
characterisitcs:
(38% of nominal flow for EFIT-Pb compared to ~ 25% nominal flow for
the XT-ADS under ULOF-steady state conditions).
2.) The current design of the Pb-cooled EFIT system achieves the design
goal of sustaining a ULOF transient for at least 0.5 hours without pin
failures.
EUROTRANS WP1.5 Safety Meeting :
Madrid, Nov 13-14. 2007
IRS /FzK
W.M.Schikorr
14