Forschungszentrum Karlsruhe Technik und Umwelt IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting :...
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Transcript of Forschungszentrum Karlsruhe Technik und Umwelt IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting :...
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 1
EFIT Design and Transient EFIT Design and Transient AnalysisAnalysis
M. Schikorr, E. BubelisM. Schikorr, E. Bubelis
EUROTRANS: DM1 WP1.5 : “Safety”
Madrid , 13-14 November 2007
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 2
1. Design Criteria for EFIT-Pb
2. EFIT design data for Transient Analysis
3. Some EFIT-Pb results to the ULOF transient
Topics:
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 3
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
1. Some important EFIT Design Criteria:
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 4
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
EFIT ULOF Design Criteria requires :
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 5
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
Keeping P_core in the XT-ADS Design low:
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 6
Most current EFIT Design Data: Inner Core Region, Core Zone 1
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 7
Most current EFIT Design Data: Intermediate Core Region, Core Zone 2
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 8
Most current EFIT Design Data: Outer Core Region, Core Zone 3
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 9
Other EFIT Data Inputs:
854mm lower gas plenum
274mm upper gas plenum
Height difference Core and HX 3.7 m
T_in 400 °CT_out 480 °CFlow Rate 32101 kg/s
P/DEFIT-PB 1.581XT-ADS 1.40
Calc. Prim. System Pressure Drops: 6 Spacers @ 0.50mm thickness 0.181 barCore Inlet/Outlet 0.24 barFlow Friction 0.124 barTotal Core 0.544 barTotal Prim. System 0.751 bar
Assumed Zeta Factor (Ratio of Prim.System/Core Pressure Drop)
1.38
Calc. Prim. System Pressure Drops: 6 Spacers @ 0.25mm thickness 0.05 barCore Inlet/Outlet 0.24 barFlow Friction 0.124 barTotal Core 0.413 barTotal Prim. System 0.569 barAssumed Zeta Factor (Ratio of Prim.System/Core Pressure Drop)
1.38
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 10
EFIT-Pb: Avg and Peak Cladding and Fuel Temperatures at Nominal and ULOF-ss Plant Conditions for BOC and EOC
Clad Fuel Clad Fuel Clad Fuel Clad Fuel Clad Fuel Clad FuelNominal Conditions 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 1206ULOF Conditions 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
Inner Core Zone CZ1 Intermediate Core Zone CZ2
Avg Pin Peak PinOxide Layer thickness
EFIT - Pb : Peak Fuel and Cladding Temperatures [°C]
Outer Core Zone CZ3
Avg Pin Peak Pin
Avg Pin Peak Pin Avg Pin Peak Pin Avg Pin Peak Pin
Nominal Conditions 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 17.4ULOF Conditions BOC 2XE10 5.5xE5 3.0xE4
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
Oxide Layer thickness
Inner Core Zone CZ1Intermediate Core
Zone CZ2Outer Core Zone CZ3
EFIT - Pb : Cladding Failure Times [hrs]
EOC state is defined to be max burnup ~ 100 MWd/kg of MOX-MA fuel
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 11
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
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 12
EFIT-Pb : ULOF, BOC, Peak Pin, 6 Spacer @ 0.50mm thickness, no oxide
Conclusion:
For current design EFIT peak pin clad will NOT fail under BOC conditions even though of flow undershoot that is ~ 22 % nom. flow.
Min Clad Failure Time ~ 17 hours
ULOF FzK (SIM-ADS) : Power and Flow Rate
0.00.10.20.30.40.50.60.70.80.91.01.1
0 50 100 150 200Time [sec]
rel.
Un
its
[fr
]
Power_th
Flow_CoolPower
Flow
ULOF FzK (SIM-ADS) : Temperatures
300
500
700
900
1100
1300
1500
1700
0 50 100 150 200
Time [sec]
Te
mp
era
ture
[°C
] Fuel_c_peak
Clad_peak
Cool_out
Cool_in
Fuel
T_clad_max = 810 °C
Coolant
Cladding
ULOF FzK (SIM-ADS) : Clad Failure and Fission Gas Pressure
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E+10
1.E+11
1.E+12
0 50 100 150 200Time [sec]
Cla
d F
ailu
re T
ime
[s
ec
]
5
5
5
5
5
5
5
5
Fis
sio
n G
as
Pre
ss
ure
[b
ar]
Clad Failure Time [sec]
Fission Gas Pressure [bar]
30 min limit
Min. Pin Clad Failure Time = 17 hrs
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 13
EFIT-Pb : ULOF, EOC, Peak Pin, 6 Spacer @ 0.50mm thickness, 100um oxide
Conclusion:
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.
ULOF FzK (SIM-ADS) : Power and Flow Rate
0.00.10.20.30.40.50.60.70.80.91.01.1
0 50 100 150 200Time [sec]
rel.
Un
its
[fr
]
Power_th
Flow_CoolPower
Flow
ULOF FzK (SIM-ADS) : Temperatures
300
500
700
900
1100
1300
1500
0 50 100 150 200
Time [sec]
Te
mp
era
ture
[°C
] Fuel_c_peak
Clad_peak
Cool_out
Cool_in
Fuel
T_clad_max = 820 °C
Cladding
ULOF FzK (SIM-ADS) : Clad Failure and Fission Gas Pressure
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
1.E+10
0 50 100 150 200Time [sec]
Cla
d F
ailu
re T
ime
[s
ec
]
86
88
90
92
94
96
98
100
Fis
sio
n G
as
Pre
ss
ure
[b
ar]
Clad Failure Time [sec]
Fission Gas Pressure [bar]
30 min Min. Pin Clad Failure Time = 1000
sec
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Madrid, Nov 13-14. 2007 14
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.