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Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 1
EFIT-Pb Transient AnalysisEFIT-Pb Transient Analysis
M. Schikorr, E. BubelisM. Schikorr, E. Bubelis
EUROTRANS: DM1 WP1.5 : “Safety”
Bologna , 28-29 Mai 2008
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 2
1. Recent EFIT-Pb SA design modifications leading to revised Core and Primary System Pressure Drops (Genova-April, Karlsruhe-April meetings, new Ansaldo document-May).
2. SIM-ADS Transient Results for EFIT-Pb :
a. ULOF results (BOC, EOC)
b. DHRS mode operations
c. PLOHS
Topics:
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 3
1. EFIT Pressure Drops: Historical evolution
1. Initial Pressure drop estimates :
P_core ~ 0.6 bar, P_prim. system ~ 1.0 bar,
2. 1st Iteration based on experimental PDS-XADS SA-inlet and SA-outlet pressure drops(Genova Meeting April 08),
Pressure drop estimates :
P_core ~ 1.2 bar, P_prim. system ~ 1.80 bar,
3. Most current pressure drop estimates after SA redesign by ANSALDO:
P_core ~ 0.75 bar, P_prim. system ~ 1.41 bar,
this will lead to a w_nat ~ 0.31 during ULOF(ss)
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 4
1. EFIT Pressure Drops: as proposed by Ansaldo after SA redesign leading to lower SA inlet and outlet pressure drops.
Ansaldo calculated pressure drops [14], mbar
Corresponding pressure drop coefficients (based on
coolant flowrate of 185 kg/s per SA)
SA Inlet 289 5.50 SA Outlet 86 1.64 Flow along smooth pin section
165
Grid spacers (6) * 94.4 Total core pressure drop 634.4 Total core pressure drop taking into account ~10 % uncertainty
700
Main HX (SG) [15] 400 7.61 Main pump [15] 270 5.16 Total pressure drop of the whole primary system
1370
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 5
2. EFIT Pressure Drops: as proposed to be used in Transient Calcs.Reactor core zone
Inner core zone CZ1
Intermediate core zone CZ2
Outer core zone CZ3
Power, [MW]
94 140 141
Average SA coolant flowrate, [kg/s]
192 182 168
Core flow friction pressure drop, [mbar]
172 156 225
6 Grid spacers pressure drop, [mbar]
101 92 112
Inlet / Outlet pressure drop, [mbar]
408 367 407
Gagging (orificing) pressure drop, [mbar]
63 129 0
Total core pressure drop, [mbar]
744 744 744
Calculated Zeta factor (Ratio of primary system pressure loss / core pressure loss) Zeta = 1.893 (Zeta = pprim syst / pcore = 1420 mbar / 750 mbar = 1.893) Total primary system pressure drop, [mbar]
1409 1409 1409
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 6
EFIT-Pb: Avg and Peak Cladding and Fuel Temperatures at Nominal and ULOF-ss Plant Conditions for BOC and EOC based on new Pressure Drop data (1.42 bar)
Clad Fuel Clad Fuel Clad Fuel Clad Fuel Clad Fuel Clad FuelNominal Conditions BOL 0 µm 505 1162 530 1284 502 1186 519 1262 496 1080 531 1271
EOC 0 µm 506 822 540 1003 503 831 523 938 496 784 525 931
EOC 50 µm 528 863 570 1062 525 871 549 988 513 818 546 978
ULOF Conditions BOL 0 µm 723 1409 700 1379 733 1400
EOC 0 µm 744 1222 709 1129 720 1128
EOC 50 µm 773 1275 732 1176 741 1171
Oxide Layer thickness
EFIT - Pb : Peak Fuel and Cladding Temperatures [°C]
Outer Core Zone CZ3
Avg Pin Peak PinAvg Pin Peak Pin
Inner Core Zone CZ1 Intermediate Core Zone CZ2
Avg Pin Peak Pin
Nominal Conditions BOL 0 µm
EOC 0 µm
EOC 50 µm
ULOF Conditions BOL 0 µm
EOC 0 µm
EOC 50 µm
E8 E8 E9
Oxide Layer thickness
Inner Core Zone CZ1 Intermediate Core Zone CZ2 Outer Core Zone CZ3
EFIT - Pb : Cladding Failure Times [hrs]
Avg Pin Peak Pin Avg Pin Peak Pin Avg Pin Peak Pin
E10
E7
E6
E9
E11 E12
E9
1.8xE3
3.8
1.2
E7
E6
E10E10
E7
E5
E11
E9
3.4XE3
2.8
1.7xE4
23.2
0.6 5.8
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 7
EFIT-Pb: CZ1 Inner Zone
Core averaged Avg. Pin
BOL
MgO-MOX fuel
Static Calculations
Ax_mult 1.000678536B 34.7651 cm Qcore 94.00 MWth Max_T_fuel 1162 3.41 Mpunktcore 8048.22 kg/secCosine-Ax 1 CHI_peak 169.3 W/cm Max_T_f_avg 963 4.48 Pump :Tein 400 grd CHI_peak 168.3 W/cm Max_T_f_surf 765 8.8 Pump_act 0.135 MWDT 80.0 grd Pin/Fuel Properties Data: Max T clad 505 44.6 P_pump_100 0.135 MWTaus 480.0 grd kclad 0.218 [W/cmK] 753.2 P_blower_100 0.135 MW
Chi_ist_dist 148.02 W/cm k_fuel 0.0353 [W/cm*K] T_cool_out 480.0 44.6 NUSSELT-Flag 0 Subbotin(tube)
Chi_ist_cos 148.03 W/cm hgap 0.2700 -21.0 Av_T_cool 439.9 -0.54 Dpgitter 0.10133 barCHI0 148.02 W/cm hs_av 1.5872 [W/cm^2K] Av_T_f_eff 832.9 Dpbeschl 0.47126 bar
flow_fr 1.000 flow fraction Av_T_fuel_center 1067.2 -23.5 Dpcore 0.17185 barPein 10 bar kfuel_fact 1.000 [factor] Av_T_f_avg 899.9 -22.41 Dptotal 0.74444 barP_fr 1.000 power fraction hgap_fact 1.000 28.1 Av_T_f_surf 732.5 -19.9 Dpsystem 1.40922 barPump_fr 1.0000 pump fraction hs_fact 1.000 [factor] Av_T_clad_surf 474.2 -5.6 (rho*vel^2)/2 5651 pascal
w 8048.22 kg/sec temp_drops: DP_core 0.17185 0.040w 8048.23 kg/sec delT_fuel_av 336.1 C DP_core_100 0.172 barMpunkt 1.14E+00 kg/sec/Pin delT_gap_av 244.0 C DP_system 1.40922 barMpunkt_100 1.14E+00 kg/sec/Pin delT_clad_av 15.2 C DP_boyancy 3468 pascal
Vpunktcore 7.65E+05 cm^3/sec Clad_failure inf hrs @ 100 bar delT_cl_cool_av 34.4 C 3468 3468
Design Pb -cooled Reactor : EFIT BOL Inner Core Zone 1
EFIT-Pb CZ1 BOL Axial Temperature Profile, Average Pin 148 W/cm
474
440480
505
1067
900963
733765
1162
400
500
600
700
800
900
1000
1100
1200
-45 -35 -25 -15 -5 5 15 25 35 45
Axial Core Position [cm]
Tem
per
atu
res
[°C
]
Clad surf
Coolant
Center Fuel
Surf Fuel
Avg Fuel
Fission Gas Model X_He 0.980 frX_Kr 0.001 frX_Xe 0.019 frk_He 2.64E-03 W/mK
k_Kr 8.25E-05 W/mK
k_Xe 4.35E-05 W/mKgap_eps 4.0.E-06 m
T_gas 611 °CP_pin_gas 2.7Gap fraction 0.702 EFIT-Pb
MWd/kg BOL avg
Burn_avg_pin 1 1.0Burn 1.0 0.1
Rel_gas_fr 1.00 EOL peak-burnMA_fr MOX_fract
0.543 0.43
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 8
EFIT-Pb: CZ2 Intermediate Zone
Core averaged Avg. Pin
BOL
MgO-MOX fuel
Static Calculations
Ax_mult 0.956701641B 28.2385 cm Qcore 140.00 MWth Max_T_fuel 1186 2.69 Mpunktcore 11986.72 kg/secCosine-Ax 1 CHI_peak 164.7 W/cm Max_T_f_avg 973 3.76 Pump :Tein 400 grd CHI_peak 163.7 W/cm Max_T_f_surf 761 7.7 Pump_act 0.201 MWDT 80.0 grd Pin/Fuel Properties Data: Max T clad 502 41.4 P_pump_100 0.201 MWTaus 480.0 grd kclad 0.218 [W/cmK] 753.2 P_blower_100 0.201 MW
Chi_ist_dist 140.29 W/cm k_fuel 0.0322 [W/cm*K] T_cool_out 480.0 44.6 NUSSELT-Flag 0 Subbotin(tube)
Chi_ist_cos 140.30 W/cm hgap 0.2635 -21.3 Av_T_cool 439.9 -0.54 Dpgitter 0.09170 barCHI0 140.29 W/cm hs_av 1.5470 [W/cm^2K] Av_T_f_eff 828.0 Dpbeschl 0.49626 bar
flow_fr 1.000 flow fraction Av_T_fuel_center 1072.3 -23.8 Dpcore 0.15646 barPein 10 bar kfuel_fact 1.000 [factor] Av_T_f_avg 897.8 -23.13 Dptotal 0.74442 barP_fr 1.000 power fraction hgap_fact 1.000 27.4 Av_T_f_surf 723.3 -21.0 Dpsystem 1.40919 barPump_fr 1.0000 pump fraction hs_fact 1.000 [factor] Av_T_clad_surf 473.3 -5.9 (rho*vel^2)/2 5076 pascal
w 11986.72 kg/sec temp_drops: DP_core 0.15646 0.040w 11986.72 kg/sec delT_fuel_av 350.4 C DP_core_100 0.156 barMpunkt 1.08E+00 kg/sec/Pin delT_gap_av 236.5 C DP_system 1.40919 barMpunkt_100 1.08E+00 kg/sec/Pin delT_clad_av 14.5 C DP_boyancy 3468 pascal
Vpunktcore 1.14E+06 cm^3/sec Clad_failure inf hrs @ 100 bar delT_cl_cool_av 33.5 C 3468 3468
Design Pb -cooled Reactor : EFIT BOL Inter Core Zone 2
EFIT-Pb CZ2 BOL Axial Temperature Profile, Average Pin 148 W/cm
473
440480
502
1072
898973
723761
1186
400
500
600
700
800
900
1000
1100
1200
1300
-45 -35 -25 -15 -5 5 15 25 35 45
Axial Core Position [cm]
Tem
per
atu
res
[°C
]
Clad surf
Coolant
Center Fuel
Surf Fuel
Avg Fuel
Fission Gas Model X_He 0.976 frX_Kr 0.001 frX_Xe 0.022 frk_He 2.64E-03 W/mK
k_Kr 8.25E-05 W/mK
k_Xe 4.35E-05 W/mKgap_eps 4.0.E-06 m
T_gas 606 °CP_pin_gas 2.7Gap fraction 0.710 EFIT-Pb
MWd/kg BOL avg
Burn_avg_pin 1 1.0Burn 1.0 0.1
Rel_gas_fr 1.00 EOL peak-burnMA_fr MOX_fract
0.543 0.50
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 9
EFIT-Pb: CZ3 Outer Zone
Core averaged Avg. Pin
BOL
MgO-MOX fuel
Static Calculations
Ax_mult 1.000678536B 28.6180 cm Qcore 141.00 MWth Max_T_fuel 1080 3.41 Mpunktcore 12072.34 kg/secCosine-Ax 1 CHI_peak 151.8 W/cm Max_T_f_avg 893 4.48 Pump :Tein 400 grd CHI_peak 150.9 W/cm Max_T_f_surf 707 9.5 Pump_act 0.202 MWDT 80.0 grd Pin/Fuel Properties Data: Max T clad 496 44.6 P_pump_100 0.202 MWTaus 480.0 grd kclad 0.218 [W/cmK] 753.2 P_blower_100 0.202 MW
Chi_ist_dist 132.69 W/cm k_fuel 0.0340 [W/cm*K] T_cool_out 480.0 44.6 NUSSELT-Flag 0 Subbotin(tube)
Chi_ist_cos 129.52 W/cm hgap 0.2565 -21.0 Av_T_cool 439.9 -0.54 Dpgitter 0.11234 barCHI0 129.52 W/cm hs_av 1.7832 [W/cm^2K] Av_T_f_eff 765.9 Dpbeschl 0.40671 bar
flow_fr 1.000 flow fraction Av_T_fuel_center 979.6 -23.1 Dpcore 0.22537 barPein 10 bar kfuel_fact 1.000 [factor] Av_T_f_avg 827.0 -22.41 Dptotal 0.74441 barP_fr 1.000 power fraction hgap_fact 1.000 28.1 Av_T_f_surf 674.4 -19.5 Dpsystem 1.40917 barPump_fr 1.0000 pump fraction hs_fact 1.000 [factor] Av_T_clad_surf 464.1 -4.5 (rho*vel^2)/2 5629 pascal
w 12072.34 kg/sec temp_drops: DP_core 0.22537 0.040w 12072.34 kg/sec delT_fuel_av 306.4 C DP_core_100 0.225 barMpunkt 9.98E-01 kg/sec/Pin delT_gap_av 199.2 C DP_system 1.40917 barMpunkt_100 9.98E-01 kg/sec/Pin delT_clad_av 11.9 C DP_boyancy 3468 pascal
Vpunktcore 1.15E+06 cm^3/sec Clad_failure inf hrs @ 100 bar delT_cl_cool_av 24.3 C 3468 3468
Design Pb -cooled Reactor : EFIT BOL Outer Core Zone 3
EFIT-Pb CZ3 BOL Axial Temperature Profile, Average Pin 130 W/cm
464
440480
496
980
827893
674707
1080
400
500
600
700
800
900
1000
1100
1200
-45 -35 -25 -15 -5 5 15 25 35 45
Axial Core Position [cm]
Tem
per
atu
res
[°C
]
Clad surf
Coolant
Center Fuel
Surf Fuel
Avg Fuel
Fission Gas ModelX_He 0.976 frX_Kr 0.001 frX_Xe 0.022 frk_He 2.64E-03 W/mK
k_Kr 8.25E-05 W/mK
k_Xe 4.35E-05 W/mKgap_eps 4.0.E-06 m
T_gas 575 °CP_pin_gas 2.7Gap fraction 0.710 EFIT-Pb
MWd/kg BOL avg
Burn_avg_pin 1 1.0Burn 1.0 0.1
Rel_gas_fr 1.00 EOL peak-burnMA_fr MOX_fract
0.543 0.50
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 10
EFIT-Pb: CZ1 Inner Zone
Core averaged Avg. Pin
EOC
MgO-MOX fuel
Static Calculations
Ax_mult 1.01307632 1.) push "init", reset flow_fr E11 to 1.0, push "init" again. Repeat procedure until convergence is achieved in flow rate wB 38.5828 cm Qcore 94.00 MWth Max_T_fuel 863 7.35 Mpunktcore 8048.22 kg/secCosine-Ax 1 CHI_peak 167.3 W/cm Max_T_f_avg 708 10.58 Pump :Tein 400 grd CHI_peak 166.3 W/cm Max_T_f_surf 558 24.6 Pump_act 0.135 MWDT 80.0 grd Pin/Fuel Properties Data: Max T clad 528 34.6 P_pump_100 0.135 MWTaus 480.0 grd kclad 0.218 [W/cmK] 753.2 P_blower_100 0.135 MW
Chi_ist_dist 148.02 W/cm k_fuel 0.0442 [W/cm*K] T_cool_out 480.0 44.6 NUSSELT-Flag 0 Subbotin(tube)Chi_ist_cos 148.03 W/cm hgap 3.9148 -13.1 Av_T_cool 439.9 -0.54 Dpgitter 0.10133 barCHI0 148.02 W/cm hs_av 0.8849 [W/cm 2̂K] Av_T_f_eff 613.5 Dpbeschl 0.47126 bar
flow_fr 1.000 flow fraction Av_T_fuel_center 800.2 -19.5 Dpcore 0.17185 barPein 10 bar kfuel_fact 1.000 [factor] Av_T_f_avg 666.8 -17.39 Dptotal 0.74444 barP_fr 1.000 power fractionhgap_fact 1.000 44.6 Av_T_f_surf 533.4 -10.9 Dpsystem 1.40922 barPump_fr 1.0000 pump fraction hs_fact 1.000 [factor] Av_T_clad_surf 501.5 -8.1 (rho*vel 2̂)/2 5651 pascal
w 8048.22 kg/sec temp_drops: DP_core 0.17185 0.040w 8048.22 kg/sec delT_fuel_av 267.9 C DP_core_100 0.172 barMpunkt 1.14E+00 kg/sec/Pin delT_gap_av 16.9 C DP_system 1.40921 bar
kg/s per SA 191.6 Mpunkt_100 1.14E+00 kg/sec/Pin delT_clad_av 15.2 C DP_boyancy 3468 pascal
Vpunktcore 7.65E+05 cm 3̂/sec Clad_failure inf hrs @ 100 bardelT_cl_cool_av 61.8 C 3468 3468
Design Pb -cooled Reactor : EFIT EOC Inner Core Zone 1
EFIT-Pb CZ1 EOC Axial Temperature Profile, Average Pin 148 W/cm, 50mm Oxide
501
440480
528
800
667708
533558
863
400
450
500
550
600
650
700
750
800
850
900
-45 -35 -25 -15 -5 5 15 25 35 45
Axial Core Position [cm]
Tem
per
atu
res
[°C
]
Clad surf
Coolant
Center Fuel
Surf Fuel
Avg Fuel
Fission Gas Model X_He 0.784 frX_Kr 0.017 frX_Xe 0.198 frk_He 2.64E-03 W/mK
k_Kr 8.25E-05 W/mK
k_Xe 4.35E-05 W/mKgap_eps 4.0.E-06 m
T_gas 498 °CP_pin_gas 57.8Gap fraction 0.027 EFIT-Pb
MWd/kg EOC avg
Burn_avg_pin 66.5 66.5Burn 66.5 7.1
Rel_gas_fr 1.00 EOL peak-burnMA_fr MOX_fract
0.543 0.43
dL 3.70 m
grav 9.81 m/s 2̂Zeta 1.893P_min 0.3 barP_mult1 1N_Rey_trans 1187.4N_Rey_up 5000
alph_turb 0.0791 Blasiusbeta_turb 0.25 Blasiusalph_lam 16beta_lam 1 TurbulentN_Rey_aver 71286 Forced conv.f_weight 0.0048 70828w_nat 1262.68 kg/sw_nat_fr 0.157(w - w_nat) 6785.55K_orf 1.101 1.418K_inlet 5.50 core inlet friction coefficient
K_outlet 1.64 core outlet friction coeff
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 11
EFIT-Pb: CZ2 Intermediate Zone
Core averaged Avg. Pin
EOC
MgO-MOX fuel
Static Calculations
Fission Gas Model X_He 0.782 frX_Kr 0.017 frX_Xe 0.200 frk_He 2.64E-03 W/mK
k_Kr 8.25E-05 W/mK
k_Xe 4.35E-05 W/mKgap_eps 4.0.E-06 m
T_gas 496 °CP_pin_gas 72.1Gap fraction 0.027 EFIT-Pb
MWd/kg EOC avg
Burn_avg_pin 72 72.0Burn 72.0 7.7
Rel_gas_fr 1.00 EOL peak-burnMA_fr MOX_fract
0.543 0.50
EFIT-Pb CZ2 EOC Axial Temperature Profile, Average Pin 140 W/cm, 50mm Oxide
499
440480
525
797
663711
530555
871
400
450
500
550
600
650
700
750
800
850
900
-45 -35 -25 -15 -5 5 15 25 35 45
Axial Core Position [cm]
Tem
per
atu
res
[°C
]
Clad surf
Coolant
Center Fuel
Surf Fuel
Avg Fuel
dL 3.70 m
Ax_mult 0.98687607 1.) push "init", reset flow_fr E11 to 1.0, push "init" again. Repeat procedure until convergence is achieved in flow rate w grav 9.81 m/s 2̂B 31.0480 cm Qcore 140.00 MWth Max_T_fuel 871 5.92 Mpunktcore 11986.72 kg/sec Zeta 1.893Cosine-Ax 1 CHI_peak 162.7 W/cm Max_T_f_avg 711 8.78 Pump : P_min 0.3 barTein 400 grd CHI_peak 161.8 W/cm Max_T_f_surf 555 21.3 Pump_act 0.201 MW P_mult1 1DT 80.0 grd Pin/Fuel Properties Data: Max T clad 525 29.9 P_pump_100 0.201 MW N_Rey_trans 1187.4Taus 480.0 grd kclad 0.218 [W/cmK] 753.2 P_blower_100 0.201 MW N_Rey_up 5000
Chi_ist_dist 140.29 W/cm k_fuel 0.0419 [W/cm*K] T_cool_out 480.0 44.6 NUSSELT-Flag 0 Subbotin(tube)alph_turb 0.0791 BlasiusChi_ist_cos 140.30 W/cm hgap 3.8800 -13.8 Av_T_cool 439.9 -0.54 Dpgitter 0.09170 bar beta_turb 0.25 BlasiusCHI0 140.29 W/cm hs_av 0.8723 [W/cm 2̂K] Av_T_f_eff 609.7 Dpbeschl 0.49626 bar alph_lam 16
flow_fr 1.000 flow fraction Av_T_fuel_center 797.0 -20.3 Dpcore 0.15646 bar beta_lam 1 TurbulentPein 10 bar kfuel_fact 1.000 [factor] Av_T_f_avg 663.2 -18.47 Dptotal 0.74442 bar N_Rey_aver 67564 Forced conv.P_fr 1.000 power fractionhgap_fact 1.000 44.6 Av_T_f_surf 529.5 -12.0 Dpsystem 1.40919 bar f_weight 0.0049 67129Pump_fr 1.0000 pump fractionhs_fact 1.000 [factor] Av_T_clad_surf 499.1 -9.1 (rho*vel 2̂)/2 5076 pascal w_nat 1880.60 kg/s
w 11986.72 kg/sec temp_drops: DP_core 0.15646 0.040 w_nat_fr 0.157w 11986.72 kg/sec delT_fuel_av 268.5 C DP_core_100 0.156 bar (w - w_nat) 10106.12Mpunkt 1.08E+00 kg/sec/Pin delT_gap_av 16.1 C DP_system 1.40919 bar K_orf 2.521 1.418
kg/s per SA 181.6 Mpunkt_100 1.08E+00 kg/sec/Pin delT_clad_av 14.4 C DP_boyancy 3468 pascal K_inlet 5.50 core inlet friction coefficient
Vpunktcore 1.14E+06 cm 3̂/sec Clad_failure inf hrs @ 100 bardelT_cl_cool_av 59.4 C 3468 3468 K_outlet 1.64 core outlet friction coeff
Design Pb -cooled Reactor : EFIT EOC Inter Core Zone 2init_cos
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 12
EFIT-Pb: CZ3 Outer Zone
Core averaged Avg. Pin
EOC
MgO-MOX fuel
Static Calculations
Fission Gas ModelX_He 0.783 frX_Kr 0.017 frX_Xe 0.200 frk_He 2.64E-03 W/mK
k_Kr 8.25E-05 W/mK
k_Xe 4.35E-05 W/mKgap_eps 4.0.E-06 m
T_gas 483 °CP_pin_gas 66.8Gap fraction 0.027 EFIT-Pb
MWd/kg EOC avg
Burn_avg_pin 66 66.0Burn 66.0 7.1
Rel_gas_fr 1.00 EOC peak-burnMA_fr MOX_fract
0.543 0.50
dL 3.70 m
Ax_mult 0.97844124 1.) push "init", reset flow_fr E11 to 1.0, push "init" again. Repeat procedure until convergence is achieved in flow rate w grav 9.81 m/s 2̂B 29.0019 cm Qcore 141.00 MWth Max_T_fuel 818 6.63 Mpunktcore 12072.47 kg/sec Zeta 1.893Cosine-Ax 1 CHI_peak 151.5 W/cm Max_T_f_avg 674 9.86 Pump : P_min 0.3 barTein 400 grd CHI_peak 150.6 W/cm Max_T_f_surf 536 24.9 Pump_act 0.202 MW P_mult1 1DT 80.0 grd Pin/Fuel Properties Data: Max T clad 513 34.6 P_pump_100 0.202 MW N_Rey_trans 1187.4Taus 480.0 grd kclad 0.218 [W/cmK] 753.1 P_blower_100 0.202 MW N_Rey_up 5000
Chi_ist_dist 129.52 W/cm k_fuel 0.0433 [W/cm*K] T_cool_out 480.0 44.6 NUSSELT-Flag 0 Subbotin(tube)alph_turb 0.0791 BlasiusChi_ist_cos 129.52 W/cm hgap 3.8234 -12.7 Av_T_cool 439.9 -0.54 Dpgitter 0.11234 bar beta_turb 0.25 BlasiusCHI0 129.52 W/cm hs_av 0.9427 [W/cm 2̂K] Av_T_f_eff 582.5 Dpbeschl 0.40671 bar alph_lam 16
flow_fr 1.000 flow fraction Av_T_fuel_center 749.5 -19.9 Dpcore 0.22537 bar beta_lam 1 TurbulentPein 10 bar kfuel_fact 1.000 [factor] Av_T_f_avg 630.2 -17.75 Dptotal 0.74441 bar N_Rey_aver 57120 Forced conv.P_fr 1.000 power fractionhgap_fact 1.000 44.6 Av_T_f_surf 510.8 -10.6 Dpsystem 1.40917 bar f_weight 0.0051 56753Pump_fr 1.0000 pump fraction hs_fact 1.000 [factor] Av_T_clad_surf 485.7 -7.7 (rho*vel 2̂)/2 5629 pascal w_nat 1894.08 kg/s
w 12072.47 kg/sec temp_drops: DP_core 0.22537 0.040 w_nat_fr 0.157w 12072.34 kg/sec delT_fuel_av 239.7 C DP_core_100 0.225 bar (w - w_nat) 10178.40Mpunkt 9.98E-01 kg/sec/Pin delT_gap_av 13.4 C DP_system 1.40917 bar K_orf 0.000 1.418
kg/s per SA 167.7 Mpunkt_100 9.98E-01 kg/sec/Pin delT_clad_av 11.8 C DP_boyancy 3468 pascal K_inlet 5.50 core inlet friction coefficient
Vpunktcore 1.15E+06 cm 3̂/sec Clad_failure inf hrs @ 100 bardelT_cl_cool_av 45.9 C 3468 3468 K_outlet 1.64 core outlet friction coeff
Design Pb -cooled Reactor : EFIT EOC Outer Core Zone 3init_cos
EFIT-Pb CZ3 EOC Axial Temperature Profile, Average Pin 130 W/cm, 50mm Oxide
486
440480
513
750
630674
536
818
511
400
450
500
550
600
650
700
750
800
850
-45 -35 -25 -15 -5 5 15 25 35 45
Axial Core Position [cm]
Tem
per
atu
res
[°C
]
Clad surf
Coolant
Center Fuel
Surf Fuel
Avg Fuel
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 13
Grid spacer calculation for EFIT-Pb
Grid spacers pressure drop is calculated as follows:
,2
22 v
cNP vspacers
where: N – number of grid spacers, N = 6 ;
cv – modified loss coefficient of spacer, for CZ1/CZ2/CZ3 correspondingly equal to 7.33/7.38/7.56 ;
ε – flow section blockage factor by the spacer, for CZ1/CZ2/CZ3 correspondingly equal to 0.201/0.201/0.209 (for open dimple design).
Hexagonal box o outer width: wb = 13.63 mm o thickness: 0.3 mm o outer perimeter of the box: pb = ( 13.63 / (2 * cos 30) ) * 6 = 47.217mm o total section occupied of 168 box wall: Sb = 47.217 * 0.3 * 168 = 2380mm2 Dimples (open type) o outer radius of the dimples: rd = 2.205 mm o thickness th = 0.3 mm o numbet of dimples in one box : 3 o section occupied by the dimples in one box: Sd1 = π * 2.205 * 0.3 * 3 = 6.2312 mm2 o section occupied by the dimples in 168 box: Sd = 6.2312 * 168 = 1046.8 mm2 External hexagonal layer o outer width of the layer: wl = 178 mm o thickness of the layer: th = 0.3 mm o outer perimeter of the layer: p1 = ( 178 / (2 * cos 30) ) * 6 = 616.628 mm o section occupied by the layer: Sl = 616.628 * 0.3 = 185 mm2 • Total transversal area occupied by the spacer:
Av=Sb + Sd + Sl = 2380 + 1046.8 + 185 = 3611.8 mm2 • Relative plugging of the flow area by the spacer grid:
ε = Av / Ab = 3611.8 / 17527 = 0.206 • Pressure loss through the grids according to [16]: Number of grids: Ng = 6 Grid loss coefficient Cv = 6 ÷7; The value Cv = 7 is assumed Relative plugging: ε = 0.206 ΔPg = Ng * Cv * ε2 * ( mfr2 / (2 * ρ *Ab2) ) = 6 * 7 * 0.2062 * (1852 / (2 * 10516 * 0.0175272) ) = 9441 Pa
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 14
1. EFIT-Pb ULOF Transient Cases Analysed using SIM-ADS
Comparison to RELAP BOC calculations performed by ENEA and Ansaldo(ENEA: G. Bandini, P. Meloni, M. Polidori, ANSALDO: L. Mansini):
1a. ULOF: BOL, Avg Pin, Peak Pin
1b. ULOF: EOC, Avg Pin, Peak Pin
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.Schikorr EUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008
15
The EFIT Reactor Design:
4
EFIT is a pool-type reactor of about 400 MW power
Sub-critical reactor (Keff = 0.97) sustained by a spallation neutron source (beam proton energy 800 MeV and beam current 20 mA)
Reactor core with 3 U-free fuel zone with (Pu,MA)O2 in MgO matrix to improve the burning efficiency
Pure melt lead as primary coolant (lower cost and less activation products such as Polonium than LBE)
Core power is removed by forced circulation (4 pumps placed in the hot collector) through 8 steam generators with helical-coil tube bundle
4 DHR heat exchangers are immersed in the annular cold pool between the inner vessel and the reactor vessel
DHR
Steam generator
DHR
Steam generator
Pump
Core
Target
Reactor vessel
Inner vessel
heat exchanger
EFIT Reactor Block
Proton Beam
Figure Source: G. Bandini, P. Meloni, M. Polidori (ENEA - Bologna)
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 16
SIMMER-III ANSALDOResults at after 1 hourt = 3600 s: (P = 16 MW)
mC = 2740 kg/s
mD = 2983 kg/s 2985 Kg/s
TCi = 410.5 C
TCo = 449.1 C
TDi = 444.6 C 444 C
TDo = 407.0 C 407 C
y = mC(TDi - TDo)
(TCi - TDo)
x = y + mD - mC
y = 255 kg/s
Recirculation ratio at DHR outlet:x = 498 kg/s (17% of mD)
Simplified scheme of RELAP5 model
xy
mC
mD
TCi
TCo
TDo
TDi
TDi
TCi
TCo
TCi
TCo
SIMMER-III ANSALDOResults at after 1 hourt = 3600 s: (P = 16 MW)
mC = 2740 kg/s
mD = 2983 kg/s 2985 Kg/s
TCi = 410.5 C
TCo = 449.1 C
TDi = 444.6 C 444 C
TDo = 407.0 C 407 C
y = mC(TDi - TDo)
(TCi - TDo)
x = y + mD - mC
y = 255 kg/s
Recirculation ratio at DHR outlet:x = 498 kg/s (17% of mD)
Simplified scheme of RELAP5 model
xy
mC
mD
TCi
TCo
TDo
TDi
TDi
TCi
TCo
TCi
TCo
xy
mC
mD
TCi
TCo
TDo
TDi
TDi
TCi
TCo
TCi
TCo
Figure Source: G. Bandini, P. Meloni, M. Polidori (ENEA - Bologna)
The In-vessel Flow Paths during normal Heat Removal mode:
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 17
EFIT-Pb : ULOF, BOC, RELAP results May 2008 Source:(G. Bandini)3 DHRS in operation, Power level remains at ~100% during transient
Core Flow Rate
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0 50 100 150 200
Time [°C]
rel.
Flo
w R
ate
Flow RELAP
FLOW SIM-ADS
Flow_i SIM-ADS
Flow RELAP
FLOW SIM-ADS
Flow_i SIM-ADS
Avg Core Temperatures
300
400
500
600
700
800
900
0 50 100 150 200
Time [sec]
Te
mp
era
ture
[°C
]
Tcore_in RELAP
Tcore_out RELAP
Tcore_in SIM-ADS
Tcore_out SIM-ADS
T_clad_RELAP
T_clad SIM-ADS
T_upper RELAP
T_upper SIM-ADS
Peak Core Temperatures
300
400
500
600
700
800
900
0 50 100 150 200
Time [sec]
Tem
per
atu
re [
°C]
Tcore_in RELAP
Tcore_out_peak RELAP
Tcore_in SIM-ADS
Tcore_out SIM-ADS
T_clad_peak RELAP
T_clad SIM-ADS
T_upper RELAP
T_upper SIM-ADS
Slide 1
What has changed since Madrid meeting:
w_nat has decreased to ~ 30% from ~ 38% during ULOF(ss) due to revised prim. system pressure drops
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 18
EFIT-Pb : ULOF, BOC, RELAP results May 2008 Source:(G. Bandini)3 DHRS in operation, Power level remains at ~100% during transient
Transferred MHX Power
0
50
100
150
200
250
300
350
400
450
0 50 100 150 200Time [sec]H
X P
ow
er t
ran
sfer
red
[M
W]
PHX RELAP
PHX tube SIM-ADS
PHX shell SIM-ADS
PHX water SIM-ADS
Slide 2
HX Temperatures
300
350
400
450
500
550
600
650
0 50 100 150 200Time [sec]
Tem
per
atu
re [
°C]
T_HX_out RELAP
T_HX_in RELAP
T_HX_out SIM-ADS
T_HX_in SIM-ADS
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 19
EFIT-Pb : ULOF, BOC, SIM-ADS results compared to RELAP May 2008 3 DHRS in operation, Power level remains at ~100% during transient
Core Flow Rate
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0 50 100 150 200Time [°C]
rel.
Flo
w R
ate Flow RELAP
FLOW SIM-ADS
Avg Core Temperatures
300
400
500
600
700
800
900
0 50 100 150 200Time [sec]
Tem
pe
ratu
re [
°C]
Tcore_in RELAP
Tcore_out RELAP
Tcore_in SIM-ADS
Tcore_out SIM-ADS
T_clad_RELAP
T_clad SIM-ADS
T_upper RELAP
T_upper SIM-ADS
Peak Core Temperatures
300
400
500
600
700
800
900
0 50 100 150 200Time [sec]
Te
mp
era
ture
[°C
]
Tcore_in RELAP
Tcore_out_peak RELAP
Tcore_in SIM-ADS
Tcore_out SIM-ADS
T_clad_peak RELAP
T_clad SIM-ADS
T_upper RELAP
T_upper SIM-ADS
Slide 1
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 20
EFIT-Pb : ULOF, BOC, SIM-ADS results compared to RELAP 3 DHRS in operation, Power level remains at ~100% during transient
HX Temperatures
300
350
400
450
500
550
600
650
0 50 100 150 200Time [sec]
Te
mp
era
ture
[°C
]
T_HX_out RELAP
T_HX_in RELAP
T_HX_out SIM-ADS
T_HX_in SIM-ADS
Transferred MHX Power
0
50
100
150
200
250
300
350
400
450
0 50 100 150 200Time [sec]
HX
Po
wer
tra
nsf
erre
d [
MW
]
PHX RELAP
PHX tube SIM-ADS
PHX shell SIM-ADS
Slide 2
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 21
EFIT-Pb : ULOF, BOC, SIM-ADS results 3 DHRS in operation, Power level remains at ~100% during transient
Slide 3ULOF FzK (SIM-ADS) : Power and Flow Rate
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
0 50 100 150 200
Time [sec]
rel.
Un
its
[fr]
Power_th
Flow_CoolPower
Flow
ULOF FzK (SIM-ADS) : Clad Failure and Fission Gas Pressure
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E+10
1E+11
1E+12
1E+13
1E+14
1E+15
0 20 40 60 80 100 120 140 160 180 200Time [sec]
Cla
d F
ailu
re T
ime
[sec
]3.0
3.0
3.1
3.1
3.2
3.2
3.3
3.3
3.4
3.4
3.5
Fis
sio
n G
as P
ress
ure
[b
ar]
Clad Failure Time [sec]
Fission Gas Pressure [bar]
30 min
Min. Pin Clad Failure Time = 3 hrsMin. Pin Clad Failure Time at ULOF(ss) ~
1E8 sec
1. Acceptable agreement between SIM-ADS and RELAP by assuming P_core ~ 100% during ULOF transient, and by making appropriate assumptions as regards inertial masses in the various primary system flow path volumes are made
2. Max clad temperatures of peak pin ~ 850 °C 18 seconds into ULOF due to flow undershoot down to ~ 10%,
3. For BOC conditions, minimum pin clad failure time > 30 minutes (acceptable !)
4. Need reactivity coefficients for EFIT-Pb to assess more realistic power response during ULOF transient
Conclusions:
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 22
EFIT-Pb Reactivity Coefficient Data:
Source : G.Glinatsis, „EFIT-MgO/Pb Core Design Reactivity Coefficients” Genova, April Meeting 2008
Coolant density Effect: 1% dens
whole Active Core zones: (DK/K )/ 1% dens = 0.00058 0.00002
Fuel Temperature Effect: T nom_fuel/zone 1800 K,
BoL: Keff = 0.96147 0.00025; ( 0.96123 0.00027)
BoC: Keff = 0.96207 0.00025; (0.96183 0.00025 )
EoC: Keff = 0.96227 0.00026; (0.96227 0.00026 ).
This translates to:
Coolant temp. coeff ~ + 0.65 pcm/°C
Fuel temp. coeff ~ - 0.014 pcm/°C,
or A_dopp ~ - 20 pcm
Please somebody else verify above data calculations in term of [pcm/°C] !
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 23
EFIT-Pb : ULOF, EOC, SIM-ADS calcs. compared to RELAP May 2008 (BOC),
3 DHRS in operation, realistic reactivity coefficients, power level >100%
Slide 1
Core Flow Rate
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
0 50 100 150 200Time [°C]
rel.
Flo
w R
ate
Flow RELAP
FLOW SIM-ADS
Peak Core Temperatures
300
400
500
600
700
800
900
0 50 100 150 200Time [sec]
Te
mp
era
ture
[°C
]
Tcore_in RELAP
Tcore_out_peak RELAP
Tcore_in SIM-ADS
Tcore_out SIM-ADS
T_clad_peak RELAP
T_clad SIM-ADS
T_upper RELAP
T_upper SIM-ADS
Avg Core Temperatures
300
400
500
600
700
800
900
0 50 100 150 200Time [sec]
Te
mp
era
ture
[°C
]
Tcore_in RELAP
Tcore_out RELAP
Tcore_in SIM-ADS
Tcore_out SIM-ADS
T_clad_RELAP
T_clad SIM-ADS
T_upper RELAP
T_upper SIM-ADS
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 24
EFIT-Pb : ULOF, EOC, SIM-ADS calcs. compared to RELAP 3 DHRS in operation, realistic reactivity coefficients, power level >100%
Slide 2
ULOF Conclusions:
1. Power level > 100% during above ULOF transient due to ~ 0 Doppler coefficient and positive coolant coef.
2. Peak Fuel temperatures always remain < 1500 °C (not explicitly shown in above transparencies, thus no concern as regards possible MgO-MOX fuel evaporation expected )
3. Max clad temperatures of peak pin ~ 870 °C 18 seconds into transient,
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 200Time [sec]
Tem
per
atu
re
[°C
]
Fuel_c_peakClad_peakCool_outCool_in
Fuel
T_clad_max = 880 °C
Coolant
Cladding
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 25
EFIT-Pb : ULOF, EOC, SIM-ADS calcs. compared to RELAP 3 DHRS in operation, realistic reactivity coefficients, power level >100%
Slide 3
ULOF Conclusions cont:
4. For EOC conditions, minimum pin clad failure time ~ 80 sec because of flow undershoot down ~ 10% flow (acceptable ?????). Could expect peak pin clad leakages during this transient. Note: assumed 100% fission gas release in above calculations (very conservative !!, more realistic is probably ~ 70-80%)
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) : Clad Failure and Fission Gas Pressure
1E+00
1E+01
1E+02
1E+03
1E+04
1E+05
1E+06
1E+07
1E+08
1E+09
1E+10
1E+11
0 50 100 150 200Time [sec]
Cla
d F
ailu
re T
ime
[sec
]
88
90
92
94
96
98
100
102
104
Fis
sio
n G
as P
ress
ure
[b
ar]
Clad Failure Time [sec]
Fission Gas Pressure [bar]
30 min
Min. Pin Clad Failure Time = 80sec Min. Pin Clad Failure Time at ULOF(ss) =
1E5 sec
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 26
2. EFIT-Pb PLOH Transient using SIM-ADS
Comparison to RELAP BOC calculations performed by ENEA and Ansaldo(ENEA: G. Bandini, P. Meloni, M. Polidori, ANSALDO: L. Mansini):
DHRS operational mode (such as PLOHS): BOL
Sequence of events:
1. Total Loss of primary heat sink (loss of all MHX)
2. Source shutdown; decay heat as heat source
3. 3 out of 4 DHRS systems function as heat sink
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.Schikorr EUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008
27
The Decay Heat Removal (DHR) System of EFIT-Pb
The DHR system is conceived for inherently safe decay heat removal and passive mode actuation
4 independent loops partially filled with organic oil, that dissipate the decay heat to the atmosphere by natural convection circulation
Each loop consists of a dip cooler immersed in the cold pool where the oil partially vaporize and an air-vapor condenser with stack chimney and interconnecting piping
Oil boiling point is determined by superimposed pressure of an inert gas
In normal operation the oil is below its boiling point and the DHR removes only heat losses from SGs and inner vessel (few 100 kW) to keep cold the upper part of the reactor vessel
Condensed Oil
Boiling Oil
Cooling air Chimney
Air Vapour Condenser
Nitrogen Header
Oil VapourSeparator
Condensed Oil Drum
EFIT ReactorSafety-Related DHR Loop
DHRDip Cooler
Inner vessel
Reactor vessel
Figure Source: G. Bandini, P. Meloni, M. Polidori (ENEA - Bologna)
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 28
SIMMER-III ANSALDOResults at after 1 hourt = 3600 s: (P = 16 MW)
mC = 2740 kg/s
mD = 2983 kg/s 2985 Kg/s
TCi = 410.5 C
TCo = 449.1 C
TDi = 444.6 C 444 C
TDo = 407.0 C 407 C
y = mC(TDi - TDo)
(TCi - TDo)
x = y + mD - mC
y = 255 kg/s
Recirculation ratio at DHR outlet:x = 498 kg/s (17% of mD)
Simplified scheme of RELAP5 model
xy
mC
mD
TCi
TCo
TDo
TDi
TDi
TCi
TCo
TCi
TCo
SIMMER-III ANSALDOResults at after 1 hourt = 3600 s: (P = 16 MW)
mC = 2740 kg/s
mD = 2983 kg/s 2985 Kg/s
TCi = 410.5 C
TCo = 449.1 C
TDi = 444.6 C 444 C
TDo = 407.0 C 407 C
y = mC(TDi - TDo)
(TCi - TDo)
x = y + mD - mC
y = 255 kg/s
Recirculation ratio at DHR outlet:x = 498 kg/s (17% of mD)
Simplified scheme of RELAP5 model
xy
mC
mD
TCi
TCo
TDo
TDi
TDi
TCi
TCo
TCi
TCo
xy
mC
mD
TCi
TCo
TDo
TDi
TDi
TCi
TCo
TCi
TCo
Figure Source: G. Bandini, P. Meloni, M. Polidori (ENEA - Bologna)
The In-vessel Flow Paths during the Decay Heat Removal mode:
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 29
DHRS Mode Issues:
1. How long does it take until the complicated natural convection flow pattern in EFIT-Pb is established ?
2. ENEA / ANSALDO have performed SIMMER III and RELAP calculations trying to obtain a first estimate of the time it will take until heat removal via natural circulation through the DHRS dip coolers is established.
See presentation by G. Bandini, P. Meloni, M. Polidori, „Assessment of Decay Heat Removal by Natural Circulation in the EFIT Reactor” during THIRS meeting in Karlsruhe April 14-16 2008.
3. RELAP needed some modifications in pressure drop coefficients to simulate the time delay effect. SIM-ADS needs similar adjustments.
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.Schikorr EUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008
30
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000Time (s)
Flo
w r
ate
(kg
/s)
Core flow (simmer)
DHR flow (simmer)
Core flow (relap5)
DHR flow (relap5)
0
5
10
15
20
25
30
0 1000 2000 3000 4000 5000
Time (s)
Po
we
r (M
W)
DHR power (simmer)
DHR power (relap5)
Decay power
Core and DHR Mass Flow RateCore Decay and DHR Power
Core Decay Heat Removal in Natural Circulation
RELAP and SIMMER III Code Result Comparison to PLOHS
Both codes (SIMMER and RELAP) predict efficient removal of decay power after about 2000 s
Mass flow rates through the core and DHR well compare in the medium term
Code results differ in the initial transient owing to the different modelingFigure Source: G. Bandini, P. Meloni, M. Polidori (ENEA - Bologna)
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.Schikorr EUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008
31
0
1000
2000
3000
4000
5000
0 1000 2000 3000 4000 5000Time (s)
Flo
w r
ate
(kg
/s)
Core flow (simmer)
DHR flow (simmer)
Core flow (relap5)
DHR flow (relap5)
0
5
10
15
20
25
30
0 1000 2000 3000 4000 5000
Time (s)
Po
we
r (M
W)
DHR power (simmer)
DHR power (relap5)
Decay power
Core Decay Heat Removal in Natural CirculationSIM-ADS, RELAP and SIMMER III Code Result Comparison to PLOHS
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0 1000 2000 3000 4000 5000Time [sec]
Flo
w R
ate
fr
Core Flow SIMMER
Core Flow RELAP
DHRS Flow Rate SIMMER
DHRS Flow Rate RELAP
SIM-ADS
0
5
10
15
20
25
30
0 1000 2000 3000 4000 5000Time [sec]
Pow
er [M
W]
Decay Heat
DHRS RELAP
DHRS SIMMER
Decay Heat SIM-ADS
DHRS SIM-ADS
1. w_nat ~ 9% during DHRS mode
2. ~ 2000 sec full nat. convection flow established
1. SIM-ADS predicts overshoot in heat removal of DHRS HX compared to RELAP and SIMMER
2. ~ 4000 sec removal of heat in balance with decay heat
3. What limits heat removal in DHRS HX to ~ 20 MW ???
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008 32
Conclusion:To continue and fianlize our EFIT-PB transient anlysis:
1. We need to decide if the thermal inertia of the nominal heat flow path as encountered during ULOF transient (i.e natural convection response after primary pump shutdown) with a flow undershoot down to ~ 10% nominal flow (or even less) shall be accepted as reference and then be used during all the transients with similiar primary system plant response.
2. We need to decide if the thermal inertia of the DHRS heat flow paths as encountered during a PLOH or ULOH as predicted by SIMMER III (and adjusted to in RELAP and in SIM-ADS) shall be accepted as the reference response of the primary system (i.e., it takes about 2000 sec until full DHRS nat. convection flow is establihed).
3. The response of the DHRS and MHX heat exchanger to various transients needs to be checked by the various codes as SIM-ADS predicts an overshoot in the DHRS HX heat removal during the PLOHS transient.
4. Definition of the secondary side conditions of the DHRS HX : T_inlet = 392 °C ??T_inlet = 404 °C ??, T_sat = ???, what are pressure conditions P= 11.5 bar ???, consistency with oil property tables ??, what tables ??
Forschungszentrum KarlsruheTechnik und Umwelt
IRS /FzK W.M.Schikorr EUROTRANS WP1.5 Safety Meeting : Bologna, May 28-29, 2008
33
18
Core and DHR Mass Flow Rate Core Decay and DHR Power
PHLOS Transient: RELAP5 Results (1)
Reactor trip is calculated by RELAP5 at 46 s
After some initial oscillations (free level movements) core and DHR mass flow rates becomes stable and the DHR attains maximum performance (20 MW for 3 loops in operation) after about 700 s
0
5
10
15
20
25
30
0 2000 4000 6000 8000 10000Time (s)
Po
we
r (M
W)
DHR power (relap5)
Decay power
0
5000
10000
15000
20000
25000
30000
35000
0 100 200 300 400 500
Time (s)
Flo
w r
ate
(kg
/s)
Core flow (relap5)
DHR flow (relap5)
Reactor trip
THIRS Workshop, Forschungszentrum Karlsruhe, Germany, April 14-16, 2008