ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 1
Analysis of the heat exchanger tube rupture accident in the XT-ADS reactor with the SIMMER-III code
Abstract
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
2 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Introduction
XT-ADS design and operating conditions
Figure 1: HX design and its arrangement in the primary system of XT-ADS reactor
2 m
1 m
ISOLATION
VALVES
INLET
INLET
OUTLET
2 m
1 m
ISOLATION
VALVES
INLET
INLET
OUTLET
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 3
Table 1: Main XT-ADS operating parameters
Parameter Unit Value
Core power at BOL MW 70
LBE cold temperature C 300
LBE hot temperature C 369
Core mass flow rate kg/s 4 772
Core bypass mass flow rate kg/s 2 228
LBE mass flow rate in one HX kg/s 1 750
Feedwater pressure bar 30.03
Feedwater temperature C 233
Secondary pressure at HX outlet bar 29.67
Equilibrium quality at HX outlet – 0.408
SIMMER-III simulation of postulated accidents
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
4 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Figure 2: XT-ADS model used in the SIMMER-III transient analysis
a) Primary system b) Safety valves and lines
c) HX and pump compartment
HX
Cover gas
Safety valves
Hot
plenum
Cold plenum
CoreBy-pass
Pump
Cold zone
Reactor
cover
SV lines
HX
Cover gas
Safety valves
Hot
plenum
Cold plenum
CoreBy-pass
Pump
Cold zone
Reactor
cover
SV lines
Tube BreakTube Break
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 5
HX water inventory by RELAP5 code
Table 2: HX water inventory
Component Volume
[m3] Mean void
fraction Liquid
mass [kg] Steam
mass [kg] Total H2O mass [kg]
Inlet pipe 0.162 1.00 133 00 133
Cold collector 0.086 1.00 071 00 071
Tube bundle 0.084 0.54 032 01 033
Hot collector + tube outlet 1.348 0.77 255 15 270
Total 1.680 – 491 16 507
Cover gas circuit and safety valve simulation
Table 3: Main cover gas circuit and safety valve parameters
Parameter Unit Value
Safety valves number – 2
Opening pressure set-point bar 6
Valve cross-flow area m2 0.39
Valve capacity (saturated steam) kg/s 6
Inner diameter of line to SV M 0.154
Length of line to SV above reactor cover M 1
In-vessel cover gas volume m3 36
Cover gas pressure bar 1
Out-of-vessel cover gas circuit volume – Neglected
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
6 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Analysis of accident scenarios
Table 4: Break characteristics in the analysed HX tube rupture events
Event Break type Diameter
[m] Flow area
[m2] Initial leakage flow rate
[kg/s]
Single tube rupture
Guillotine break of 1 tube at the inlet
0.0137 0.000295 2.3
(by RELAP5 [1])
Multiple tube rupture
Guillotine break of 5 tubes at the inlet
0.0137 0.001475 11.5
(by RELAP5 [1])
Single tube rupture
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 7
Figure 3: Material fractions and gas velocity field during the transient phase
a) t = 2 s (1 s after break opening) b) t = 30 s (1 s after SV opening)
Figure 4: Main results of the single tube rupture simulation
a) Break flowrate and cumulated value b) Cover gas pressure
0
1
2
3
4
5
0 7 14 21 28 35 42
Time (s)
Flo
wra
te (
kg/s
)
0
20
40
60
80
100
Ma
ss (
kg
)
H2O flowrate
Cumulated value
0
2
4
6
8
0 7 14 21 28 35 42
Time (s)
Pre
ssu
re (
ba
r)
SV1 inlet
SV2 inlet
In-vessel
c) HX secondary pressure d) HX – Pump compartment pressure
28.4
28.8
29.2
29.6
30.0
0 7 14 21 28 35 42
Time (s)
Pre
ssu
re (
ba
r)
Tube inlet
Tube bundle
0
2
4
6
8
10
1.0 1.2 1.4 1.6 1.8 2.0
Time (s)
Pre
ssu
re (
ba
r)
pump comp.
HX bundle
e) Steam release through safety valves f) Active core voiding
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 7 14 21 28 35 42
Time (s)
Flo
wra
te (
kg
/s)
SV1 flowrate
SV2 flowrate
0.00
0.10
0.20
0.30
0.40
0 7 14 21 28 35 42
Time (s)
Vo
id f
raction
(%
)
Active core
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
8 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Figure 4: Main results of the single tube rupture simulation (cont.)
a) Break flowrate and cumulated value b) Cover gas pressure
0
1
2
3
4
5
0 7 14 21 28 35 42
Time (s)
Flo
wra
te (
kg/s
)
0
20
40
60
80
100
Ma
ss (
kg
)
H2O flowrate
Cumulated value
0
2
4
6
8
0 7 14 21 28 35 42
Time (s)
Pre
ssu
re (
ba
r)
SV1 inlet
SV2 inlet
In-vessel
c) HX secondary pressure d) HX – Pump compartment pressure
28.4
28.8
29.2
29.6
30.0
0 7 14 21 28 35 42
Time (s)
Pre
ssu
re (
ba
r)
Tube inlet
Tube bundle
0
2
4
6
8
10
1.0 1.2 1.4 1.6 1.8 2.0
Time (s)
Pre
ssu
re (
ba
r)
pump comp.
HX bundle
e) Steam release through safety valves f) Active core voiding
0.0
0.2
0.4
0.6
0.8
1.0
1.2
0 7 14 21 28 35 42
Time (s)
Flo
wra
te (
kg/s
)
SV1 flowrate
SV2 flowrate
0.00
0.10
0.20
0.30
0.40
0 7 14 21 28 35 42
Time (s)
Vo
id f
ractio
n (
%)
Active core
Multiple tube rupture
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 9
Figure 5: Material fractions and gas velocity field during the transient phase
a) t = 2 s (1 s after break opening) b) t = 20 s (13 s after SV opening)
Figure 6: Main results of the multiple tube rupture simulation
a) HX – Pump compartment pressure b) Break flowrate and cumulated value
0
4
8
12
16
20
1.0 1.1 1.2 1.3 1.4 1.5
Time (s)
Pre
ssu
re (
ba
r)
pump comp.
HX bundle
0
3
6
9
12
15
0 10 20 30 40 50 60
Time (s)
Flo
wra
te (
kg/s
)
0
100
200
300
400
500
Ma
ss (
kg
)
H2O flowrate
Cumulated value
c) HX secondary pressure d) Cover gas pressure
0
5
10
15
20
25
30
0 10 20 30 40 50 60
Time (s)
Pre
ssu
re (
ba
r)
Tube inlet
Tube bundle
0
2
4
6
8
0 10 20 30 40 50 60
Time (s)
Pre
ssu
re (
ba
r)
SV1 inlet
SV2 inlet
In-vessel
e) Steam release through safety valves f) Active core voiding
0
1
2
3
4
5
6
0 10 20 30 40 50 60
Time (s)
Flo
wra
te (
kg
/s)
SV1 flowrate
SV2 flowrate
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 10 20 30 40 50 60
Time (s)
Vo
id f
ractio
n (
%)
Active core
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
10 ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012
Figure 6: Main results of the multiple tube rupture simulation (cont.)
a) HX – Pump compartment pressure b) Break flowrate and cumulated value
0
4
8
12
16
20
1.0 1.1 1.2 1.3 1.4 1.5
Time (s)
Pre
ssu
re (
ba
r)
pump comp.
HX bundle
0
3
6
9
12
15
0 10 20 30 40 50 60
Time (s)
Flo
wra
te (
kg/s
)
0
100
200
300
400
500
Ma
ss (
kg
)
H2O flowrate
Cumulated value
c) HX secondary pressure d) Cover gas pressure
0
5
10
15
20
25
30
0 10 20 30 40 50 60
Time (s)
Pre
ssu
re (
ba
r)
Tube inlet
Tube bundle
0
2
4
6
8
0 10 20 30 40 50 60
Time (s)
Pre
ssu
re (
ba
r)
SV1 inlet
SV2 inlet
In-vessel
e) Steam release through safety valves f) Active core voiding
0
1
2
3
4
5
6
0 10 20 30 40 50 60
Time (s)
Flo
wra
te (
kg/s
)
SV1 flowrate
SV2 flowrate
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 10 20 30 40 50 60
Time (s)
Vo
id f
ractio
n (
%)
Active core
Conclusions
ANALYSIS OF THE HEAT EXCHANGER TUBE RUPTURE ACCIDENT IN THE XT-ADS REACTOR WITH THE SIMMER-III CODE
ACTINIDE AND FISSION PRODUCT PARTITIONING AND TRANSMUTATION, ISBN 978-92-64-99174-3, © OECD 2012 11
References
