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1EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
XT-ADS DHR Conceptual DesignXT-ADS DHR Conceptual Design
L. Mansani
2EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
1. PHX (2X2) 2. Safety Vessel3. Reactor Vessel 4. Inner Vessel5. Core Barrel 6. Support7. Reactor Cover 8. Primary Pumps
(2X1)9. Spallation loop
XT-ADS Reactor Assembly
3EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
XT-ADSSecondary and Tertiary Systems
DHR System
4EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
0.1
1
10
1 10 100 1000 10000 100000 1000000
Time [s]
Dec
ay H
eat
[%]
XT-ADS Decay Heat
5EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Mid PointFuel
Mid PointPHX
2000
900
el + 814
el -1186
el 0
el + 2000
el +308
el +8 94
el +1390
el +2610
el +3490
el +4390
el +5098
el +2000
el +2700
el +1300
el +2520
el +1480
el -3100
el -4596
Pump (2)mass flow rate/pump: 3500 kg/sΔPpump: 47000 PaΔppump=0.5 ξ ρ v2
ξ = 2.5 pump in operationξ = 3.3 pump not locked ξ = 4.8 pump locked
PHX (4)mass flow rate/PHX: 1750 kg/sΔPSG = 25000 Pa
Core mass flow rate:Fuel A: 4518 kg/sBy Pass: 296 kg/sDummy A: 1258 kg/sTarget: 206 kg/sStorage fuel: 90 kg/sOthers: 631 kg/s
ΔPFA = 90900 Pamfr = 4518 kg/s
LBE volume inside the inner vessel till elevation + 3490: 66 m3
LBE volume inside the vessel till elevation 4390: 149 m3(inner vessel excluded
Total Pressure drop at 7000 Kg/s: 162900 Pa
Total LBE volume: 215 m3
XT-ADSPrimary System
Main Characteristics
6EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
XT-ADSSecondary System
Main Characteristics
El 7520
El 12000
El 14000
El 12500
El 31500
Separator
Air Condenser
PHX-2PHX-1
El 8395
El 25800
El 16500
RiserLength: ~18 mOD: 406.4 mmID: 363 mmSch: 80Ω: 0.104 m2
DowncomerLength: ~12 mOD: 273 mmID: 242.82 mmSch: 80Ω: 0.046 m2
AnnulusLength: ~4740 mmΩ: 0.249 m2
Inner feed pipeLength: ~7175 mmID: 164 mmΩ: 0.021 m2
Steam lineLength: ~80 mOD: 558.8 mmID: 511.6 mmSch: 80Ω: 0.205 m2
Condensate lineLength: ~80 mOD: 114.3 mmID: 97.18 mmSch: 80Ω: 0.0074 m2
7EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Spurious Trip
After reactor trip the following events are postulated
Primary Pumps continue to operateAir Fans stop Louvers remain in their actual position Large condenser isolated in 60 secondsSmall condenser remains in operation
8EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30 35
Time [min]
Po
we
r [M
W]
Core Power
ACs Power
PHXs Power
Spurious Trip
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0 5 10 15 20 25 30 35
Time [min]
Mas
s F
low
Rat
e [k
g/s
]
Fuel Assemblies mfr
Dummy Assemblies mfr
By-Pass mfr
Others mfr
Power
LBE Flowrates
9EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
180
200
220
240
260
280
300
320
340
360
380
0 5 10 15 20 25 30 35
Time [min]
Tem
pera
ture
[°C
]
Core LBE outlet temperature
Core LBE inlet temperature
PHX LBE outlet temperature
PHX LBE inlet temperature
PHX WATER inlet temperature
Spurious Trip
0
5
10
15
20
25
30
35
40
45
50
0 5 10 15 20 25 30 35
Time [min]
Pre
ssu
re [
Ba
r(a
)]
Steam Pressure in the Separator
Temperatures
Secondary SystemPressure
10EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 1
Primary Pumps Inertia 20 kg m2
After reactor trip the following events are postulated
Primary Pumps stopAir Fans stop Louvers remain in their actual position Large condenser isolated in 60 secondsSmall condenser remains in operation
11EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30 35
Time [min]
Po
wer
[M
W]
Core Power
Acs Power
PHXs Power
Protected Loss of Flow 1
0
5
10
15
20
25
30
35
40
45
50 55 60 65 70 75 80
Time [sec]
Pu
mp
ve
loci
ty [
rad
/s] Pump velocity
Power
Primary Pump Velocity
12EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 1
3.000
3.200
3.400
3.600
3.800
4.000
4.200
4.400
50 55 60 65 70 75 80
Time [sec]
Lev
el [
m]
Hot Level: LBE level inside inner vessel
Cold Level: LBE level outside inner vessel
-8000
-6000
-4000
-2000
0
2000
4000
6000
8000
50 55 60 65 70 75 80
Time [sec]
Ma
ss
Flo
w R
ate
[k
g/s
]
Primary Pump mfr
From upper to lower cold plenum mfr
Core inlet mfr
LBE Levels
LBE Flowrates
13EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 1
180
200
220
240
260
280
300
320
340
360
380
0 5 10 15 20 25 30 35
Time [min]
Te
mp
era
ture
[°C
]
Core LBE outlet temperature
Core LBE inlet temperature
PHX LBE outlet temperature
PHX LBE inlet temperature
PHX WATER inlet temperature
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35
Time [min]
Pre
ss
ure
[B
ar(
a)]
Steam Pressure in the Separator
Secondary SystemPressure
Temperatures
14EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 2
Primary Pumps Inertia 100 kg m2
After reactor trip the following events are postulated
Primary Pumps stopAir Fans stop Louvers remain in their actual position Large condenser isolated in 60 secondsSmall condenser remains in operation
15EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 2
0
5
10
15
20
25
30
35
40
45
50 55 60 65 70 75 80 85 90 95 100
Time [sec]
Pu
mp
ve
loci
ty [
rad
/s] Pump velocity (I=100 kg-m2)
Pump velocity (I=20 kg-m2)
3.400
3.600
3.800
4.000
4.200
4.400
50 55 60 65 70 75 80
Time [s]
Le
ve
l [m
]
LBE level inside inner vessel
LBE level outside inner vessel (I=100)
LBE level outside inner vessel (I=20)
Primary Pump Velocity
LBE Levels
16EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 2
-6000
-4000
-2000
0
2000
4000
6000
8000
50 55 60 65 70 75 80
Time [s]
Mas
s F
low
Rat
e [k
g/s
]
Primary pumps mfr (I=100)
From upper to lower cold plenum mfr (I=100)
Inlet core mfr (I=100)
180
200
220
240
260
280
300
320
340
360
380
0 5 10 15 20 25 30 35
Time [min]
Te
mp
era
ture
[°C
]
Core LBE outlet temperature
Core LBE inlet temperature
PHX LBE outlet temperature
PHX LBE inlet temperature
PXH WATER inlet temperature
Temperatures
LBE Flowrates
17EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 2
-3000
-2000
-1000
0
1000
2000
3000
4000
5000
6000
7000
8000
50 55 60 65 70 75 80
Time [s]
Ma
ss
Flo
w R
ate
[k
g/s
]
Primary Pumps mfr (I=100)
Primary Pumps mfr (I=20)
18EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 3
Only 1 out of 2 DHR LOOP CreditedPrimary Pumps Inertia 100 kg m2
After reactor trip the following events are postulated
Primary Pumps stopAir Fans stop Louvers remain in their actual position Large condenser isolated in 60 secondsSmall condenser remains in operation
19EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30 35
Time [min]
Po
wer
[M
W]
Core Power
One AC Power
One couple PHX Power
Protected Loss of Flow 3
-6000
-4000
-2000
0
2000
4000
6000
8000
50 55 60 65 70 75 80
Time [s]
Ma
ss
Flo
w R
ate
[k
g/s
]
Primary Pump 1 mfr
Primary Pump 2 mfr
From upper to lower cold plenum mfr
Core inlet mfr
Power
LBE Flowrates
20EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Protected Loss of Flow 3
180
200
220
240
260
280
300
320
340
360
380
0 5 10 15 20 25 30 35
Time [min]
Te
mp
era
ture
[°C
]
Core LBE outlet temperature
Core LBE inlet temperature
PHX LBE outlet temperature
PHX LBE inlet temperature
PHX WATER inlet temperature
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35
Time [min]
Pre
ssu
re [
Ba
r(a
)]
Steam Pressure in the separator
Secondary SystemPressure
Temperatures
21EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Spurious Trip with No Isolation of the Large Condenser
After reactor trip the following events are postulated
Primary Pumps continue to operateAir Fans stop Louvers remain in their actual position Large condenser remains in operationSmall condenser remains in operation
22EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Spurious Trip with No Isolation of the Large Condenser
0
10
20
30
40
50
60
70
80
0 5 10 15 20 25 30 35
Time [min]
Po
we
r [M
W]
Core Power
Acs Power
PHXs Power
180
200
220
240
260
280
300
320
340
360
380
0 5 10 15 20 25 30 35
Time [min]
Te
mp
era
ture
[°C
]
Core LBE outlet temperature
Core LBE inlet temperature
PHX LBE outlet temperature
PHX LBE inlet temperature
PHX WATER inlet temperature
Power
Temperatures
23EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
XT-ADS RVACS Evacuated Power Vs Reactor Vessel Temperature
138
252
415
517
634
914
1252
93
169
279
348
428
619
852
46
85
139
174
214
310
428
0
200
400
600
800
1000
1200
1400
200 300 400 500 600 700 800 900
Vessel Inner Wall Temperature
Po
wer
[K
W]
Exchanging height: 6 m
Exchanging height: 4 m
Exchanging height: 2 m
161
296
487
606
741
1058
1431
108
199
329
410
502
720
980
54
99
164
205
251
361
494
0
200
400
600
800
1000
1200
1400
1600
200 300 400 500 600 700 800 900
Vessel Inner Wall Temperature [°C]
Po
wer
[K
W]
Exchanging height: 6 m
Exchanging height: 4 m
Exchanging height: 2 m
Emissivity 0.5 Emissivity 0.6
24EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
300
350
400
450
500
550
600
650
700
0 10 20 30 40 50 60
Time [hours]
Tem
per
atu
re [
°C]
Exchanging height: 4 m
Exchanging height: 6 m
550°C12.4 h
550°C33.7 h
Vessel Inner Wall Temperature - Surface Emissivity 0.6
300
350
400
450
500
550
600
650
700
0 10 20 30 40 50 60
Time [hours ]
Tem
per
atu
re [
°C]
Exchanging height: 6 m
Exchanging Height: 4 m550°C13.8 h
XT-ADS RVACS Performances
Emissivity 0.5 Emissivity 0.6
25EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
XT-ADS 3D Model and Temperature Field at Nominal Power
26EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
XT-ADS Velocity Field at Nominal Power
27EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
XT-ADS Temperature
and Velocity Field
with RVACS Operation
After 50 seconds
After 5.54 hours
After 5.54 hours
28EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
LBE max Temperature and Vessel Inner Wall Temperature Vs Time
300
320
340
360
380
400
420
440
460
480
500
0,00 1,00 2,00 3,00 4,00 5,00 6,00
Time [hours]
Te
mp
era
ture
[°C
]
Vessel Inner Wall Temperature -1D calculation
LBE max Temperature - 3D calculation
XT-ADS RVACSReactor Vessel Temperature
3D and Simplified Calculation Comparison
29EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
XT-ADS RVACS Performance with Primary Forced Circulation Restored
300
350
400
450
500
550
600
650
700
0 10 20 30 40 50 60
Time [hours]
Tem
per
atu
re [
°C]
Exchanging height: 4 mExchanging height: 6 mRestart of the Pumps
550°C12.4 h
550°C33.7 h
300
350
400
450
500
550
600
650
700
0 10 20 30 40 50 60
Time [hours]
Tem
per
atu
re [
°C]
Exchanging heigth: 4m
Exchanging height: 6m
Restart of the pumps
526 °C
10.7 h
Emissivity 0.5 Emissivity 0.6
30EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Conclusions 1/2
Normal Decay Heat Removal Function is performed by forced/natural convection through the Primary Heat Exchanger cooled by the secondary system water/steam in natural circulation and by the tertiary system air in forced circulation (the normal path to evacuate the reactor power)
Emergency Decay Heat Removal Function is performed by: Natural convection through the Primary Heat Exchanger cooled
by the secondary system water/steam in natural circulation and by the tertiary system air in natural circulation (DHR number 1)
Reactor Vessel Air Cooling systems by irradiation from the Reactor Vessel wall to the Safety Vessel wall and to the wall of dedicate pipes and by air in natural convection inside the pipes (DHR number 2)
31EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
Conclusions 2/2
No actuation is required to start to operate both DHR systems DHR Systems are already in operation during normal operating
conditions DHR number 1 needs:
after the reactor trip an automatic shutdown of the tertiary system fan and the automatic isolation of a portion of the air cooler to prevent LBE freezing
In the medium term an operator action (not required within the first 30 minutes from the accident) to reduce the system capability to prevent LBE freezing
DHR number 2 needs: an operator action, within the first 12 hours from the accident,
to restart at least one primary pump to avoid exceeding the temperature limit on the Reactor Vessel wall
32EUROTRANS: WP1.5 Technical meeting, Karlsruhe, November 27 – 28, 2008
