Transcript Diapositiva 1 - Royal Institute of Technology

ENTE PER
FPN-FISNUC
/ Bologna
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
EUROTRANS – DM1
Analysis of Protected Accidental
Transients in EFIT with RELAP5 Code
G. Bandini, P. Meloni, M. Polidori
WP 1.5 Progress Meeting
ENEA – Bologna, Italy, May 28-30, 2008
Update of RELAP5 Model
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
22
82
Jun 23
62
Jun 83
Jun 63
branch
branch
branch
175
02
01
176
(177/8/9)

Primary system layout
by D1.26 of ANSALDO
(November 2007)

Primary circuit pressure
drops according to new
ANSALDO data

Gagging at core inlet
according to SIM-ADS

DHR modeling data
according to detailed
ANSALDO analysis
171
02
01
01
01
branch
151
SGs
SGs
SGs
Pb side
water side
Pb side
152
153
154
173
annulus
181
182/3/4
Pth
pipe
281
282/3/4
170
pipe
381
382/3/4
112
DHR
113
Pumps
pumps
plenum
branch
121
branch 160
UPPER PLENUM
branch 120
Jun 106
Jun 104
07
06
05
109
310 311
161
Jun 105
03
04
211 210
08
01
01
02
111 110
Core
102
By pass
&
reflector
108
Target loop
Jun 114
01
06
01
05
Outer Outer Middle Middle Inner Inner
Hot Average Hot Average Hot Average
08
07
06
05
04
03
02
01
01
LOWER PLENUM
branch 100
RELAP5 Nodalization Scheme
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
2
Main EFIT Parameters
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
PRIMARY SYSTEM:

Total power = 395.2 MW

Lead mass flowrate = 33243 kg/s

Lead temperature = 400 / 480 C

Total primary circuit pressure drop = 1.37 bar
(core = 0.7 bar, SG = 0.4 bar, Pump = 0.27 bar )

Total mass of lead = 5880 tons (ANSALDO data = 5954 tons)

Lead free levels = 1.085 / 1.495 / 0.448
(ANSALDO data = 1.085 / 1.473 / 0.406)

SECONDARY SYSTEM:

Feedwater flow rate (4 SGs) = 244.4 kg/s, Temperature = 335 C

Steam pressure = 140 bar

Steam temperature = 452 C (Superheating of 115 C)
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
3
RELAP5 Steady-State Calculation
ENTE PER
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Parameter
Inner
zone
Middle
zone
Outer
zone
Reflector
Target
Total
96
142.3
140.5
5.2
11.2
395.2
7678
11486
11445
1127
1506
33243
Thermal power (MW)
Lead mass flow rate (kg/s)
Maximum
temperature
(°C)
Inner zone
Middle zone
Outer zone
(Fax = 1.14)
(Fax = 1.16)
(Fax = 1.17)
Bypass
outlet
Target
outlet
Hot FA
1/42
Fr = 1.12
Average
FA
41/42
Hot FA
1/66
Fr = 1.13
Average
FA
65/66
Hot FA
1/72
Fr = 1.24
Average
FA
71/72
Central fuel
1251
1151
1329
1214
1284
1093
-
-
Surface fuel
870
818
858
804
816
734
-
-
Internal clad
539
524
535
519
534
508
-
-
External clad
527
513
524
510
525
501
-
-
Lead
494
484
494
483
502
482
431
450
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
4
Transients to be Analyzed by ENEA (1)
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TRANSIENT TO BE ANALYZED FOR PB-COOLED EFIT DESIGN
ENEA
Number
Transient
Description
BOC
EOC
RELAP5 (X-S)
RELAP/PARCS (X-C)
SIMMER
PROTECTED TRANSIENTS
PLOF
Total loss of forced
circulation in primary
system (4 pumps)
x
X-S (reactor trip on
pump speed
threshold)
PLOF-1
Loss of 1 out of 4
primary pumps (pump
rotor seizure)
x
X-S (reactor trip on
core outlet temp.
threshold)
P-4
PLOH
Total loss of secondary
loops (4 loops)
x
x
X-S (reactor trip on
core outlet temp.
threshold)
P-4.1
PLOH-1
loss of 1 out of 4
secondary loops
x
x
X-S (reactor trip on
core outlet temp.
threshold)
P-5
PLOF + PLOH
(station blackout)
Total loss of forced
circulation and
secondary loops
x
x
X-S (reactor trip
at 0 s)
P-10
Spurious beam
trip
beam trip for 1,2,3 …..
10 s intervals
x
x
X-C
P-11
SGTR
Steam generator tube
rupture (1 to 5 tubes)
x
P-1
P-1.1
x
x
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
X (reactor
trip at 0 s)
X (reactor
trip at 0 s)
5
Analysis of Protected Transients
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE

PLOF: Total loss of forced circulation (4 pumps)

PLOF-1: Stop of 1 pump (pump rotor seizure)

PLOH: Total Loss of Heat Sink

PLOH-1: Loss of feedwater to 1 steam Generator

PLOF + PLOH (Station blackout): Total loss of forced
circulation and secondary loops with beam trip

PTOP: Overpower Transient (+10%)
REACTOR TRIP (Proton beam switch-off):

Core outlet temperature > 515 - 525 C (> DTass-max x 1.2 + 400 C)

Pump speed close to 0 (in case of total loss of forced circulation)

Delay in reactor trip = 2 s
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
6
Safety Limits
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
According to PDS-XADS safety analysis:

Lead temperature always below 1500 C

Clad temperature below 550 C during normal
operation

Clad temperature in the range:
 550
– 600 C for less than 600 s,
 600
– 650 C for less than 180 s,
in transient conditions

Vessel wall temperature below 450 C
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
7
Sensitivity Study on Reactor Trip Set-Points (1)
ENTE PER
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Accident
Beam trip set-point
PLOF-0
(4 pumps)
PLOF
(4 pumps)
PLOF-1a
(4 pumps)
PLOF-1
(4 pumps)
PLOF-2
(4 pumps)
PLOF-3
(4 pumps)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead hot-chan > 525 C
(steady = 502 C)
Tlead hot-chan > 525 C
(steady = 502 C)
Tlead hot-chan > 515 C
(steady = 502 C)
PLOF-1p-0
(1 pump)
PLOF-1p
(1 pump)
PLOF-1p-1a
(1 pump)
PLOF-1p-1
(1 pump)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead hot-chan > 525 C
(steady = 502 C)
Tlead hot-chan > 525 C
(steady = 502 C)
Pump speed close to 0
Beam trip
delay (s)
Beam Trip
(s)
Maximum
Tclad (s)
Maximum
Tclad (C)
2
12
12
845
0
10
11.4
821
2
6.8
11.2
742
0
4.8
10.8
683
0
3.4
10.8
645
2
2.8
10.8
630
2
88
88
584
0
86
86
584
2
10
10
566
0
8
8
561
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
8
Sensitivity Study on Reactor Trip Set-Points (2)
ENTE PER
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Accident
Beam trip set-point
PLOH-0
(4 SGs)
PLOH
(4 SGs)
PLOH-1a
(4 SGs)
PLOH-1
(4 SGs)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead hot-chan > 525 C
(steady = 502 C)
Tlead hot-chan > 525 C
(steady = 502 C)
PLOH-1sg-0
(1 SGs)
PLOH-1sg
(1 SGs)
PLOH-1sg-1a
(1 SGs)
PLOH-1sg-1
(1 SGs)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead ave-chan > 525 C
(steady = 482 C)
Tlead hot-chan > 525 C
(steady = 502 C)
PLOHS-0
(St-blackout)
Station-blackout at 0 s
Beam trip
delay (s)
Beam Trip
(s)
Maximum
Tclad (s)
Maximum
Tclad (C)
2
76
76
576
0
74
74
574
2
53
53
556
0
51
51
554
2
340
340
573
0
338
338
573
2
146
146
553
0
144
144
553
0
0
11.4
566
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
9
PLOF + PLOH – Station Blackout (1)
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30000
mflowj
1.6
Pump
1.4
100080000
cntrlvar
50
cntrlvar
51
cntrlvar
56
1.2
20000
Level (m)
Flow rate (kg/s)
Lead Free Levels
Core Mass Flow Rate
40000
10000
Vessel
1.0
0.8
0
0.6
Core
-10000
0.4
-10
0
10
20
30
Time (s)
40
50
-10
0
10
20
Time (s)

Lead free level fluctuations and stabilization after primary pump stop

Core mass flow rate reduces down to 0 in the initial transient
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
30
40
50
10
PLOF + PLOH – Station Blackout (2)
ENTE PER
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Pump Angular Velocity
Pump Mass Flow Rate
20
9000
pmpvel
910
Flow rate (kg/s)
Velocity (rad/s)
10
mflowj
6000
0
910010000
3000
0
-10
-3000
-20
-6000
-10
0
10
20
Time (s)
30
40
50
-10
0
10
20
Time (s)
30
40
50

Very fast pump coastdown due to low initial pump velocity and low moment of inertia

Pump velocity and mass flow rate reverse in the initial transient following lead free
level stabilization
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
11
PLOF + PLOH – Station Blackout (3)
ENTE PER
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Max Lead Temperature
Max Clad Temperature
600
600
111180000
httemp
111101216
tempf
211180000
httemp
211101216
tempf
311180000
httemp
311101216
550
Temperature (C)
Temperature (C)
550
tempf
500
450
500
450
Inner core
Middle core
Outer core
Inner core
Middle core
Outer core
400
400
-10
0
10
20
Time (s)
30
40
50
-10
0
10
20
Time (s)
30

Maximum lead and clad peak temperature in hot channel of outer core zone

Maximum clad temperature is well below safety limits for transient conditions
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
40
50
12
PLOF + PLOH – Station Blackout (4)
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Core and DHR Power
Core and DHR Mass Flow Rates
3.0E+07
5000
2.5E+07
4000
cntrlvar
116
cntrlvar
131
Core
2.0E+07
Power (W)
Flow rate (kg/s)
DHR
3000
Core
2000
1.5E+07
1.0E+07
1000
mflowj
100080000
mflowj
175010000
DHR
5.0E+06
0.0E+00
0
0
1000
2000
3000
Time (s)
4000
5000
0
1000
2000
3000
Time (s)
4000
5000

Natural circulation in the primary circuit and through the DHR stabilizes in about 500 s

Core decay power is totally removed by the DHR after about 1000 s
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
13
PLOF + PLOH – Station Blackout (5)
ENTE PER
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Lead Temperature
Max Vessel Wall Temperature
500
450
100010000
tempf
120010000
tempf
175010000
tempf
113090000
460
Core out (average)
440
DHR in
420
440
Temperature (C)
Temperature (C)
480
tempf
430
httemp
420
100100401
410
Core in
DHR out
400
400
0
2000
4000
6000
Time (s)
8000
10000
0
2000
4000
6000
Time (s)
8000

Primary hot lead temperature at core outlet stabilizes at about 453 C after 10000 s

Vessel wall temperature reaches a maximum of 435 C after 5000 s
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
10000
14
PLOF – Total Loss of Forced Circulation (1)
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Pump Angular Velocity
20
pmpvel
910
0
10000
-20
0
0
10
20
Time (s)
30
40
50
100080000
20000
-10
-10
mflowj
30000
Flow rate (kg/s)
Velocity (rad/s)
10
Core Mass Flow Rate
40000
-10
0
10
20
Time (s)
30
40

Pump speed = 0 after 0.8 s  Reactor trip with 2 s delay at 2.8 s

Initial core mass flow rate undershoot and fluctuations after primary pump stop
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
50
15
PLOF – Total Loss of Forced Circulation (2)
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Max Lead Temperature
Max Clad Temperature
650
650
111180000
tempf
211180000
tempf
311180000
600
Temperature (C)
Temperature (C)
600
tempf
550
500
450
400
-10
0
20
Time (s)
30
40
50
httemp
211101216
httemp
311101216
500
Inner core
Middle core
Outer core
400
10
111101216
550
450
Inner core
Middle core
Outer core
httemp
-10
0
10
20
Time (s)
30
40

Enhanced lead and clad temperature peaks after reactor trip at 2.8 s

Maximum clad temperature (hot channel of outer core) is below safety limits for
transient conditions (less then 180 s in the range 600 – 650 C)
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
50
16
PLOF-1 – Stop of 1 Primary Pump (1)
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Pump Angular Velocity
Lead Free Levels
1.6
25
Running pumps
1.4
1.2
15
10
pmpvel
910
pmpvel
920
Level (m)
Velocity (rad/s)
20
Running pumps
Vessel
cntrlvar
50
cntrlvar
51
cntrlvar
52
cntrlvar
56
1.0
Stopped pump
0.8
5
0.6
Core
Stopped pump
0
0.4
-10
0
10
20
Time (s)
30
40
50
-10
0
10
20
Time (s)
30
40

No reverse pump velocity is allowed after pump stop

Lead free level above stopped pump lies between vessel and core free levels
after pump stop (reverse flow from vessel to core zone)
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
50
17
PLOF-1 – Stop of 1 Primary Pump (2)
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Pump Mass Flow Rate
Core Mass Flow Rate
40000
12000
Running pumps
8000
mflowj
4000
mflowj
910010000
mflowj
920010000
Flow rate (kg/s)
Flow rate (kg/s)
30000
0
-4000
Stopped pump
100080000
20000
10000
-8000
-12000
0
-10
0
10
20
30
Time (s)
40
50
-10
0
10
20
Time (s)
30
40

Slight increase in running pump mass flow rate and reverse flow through stopped
pump

Core mass flow rate reduces by about 30%
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
50
18
PLOF-1 – Stop of 1 Primary Pump (3)
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Core and SGs Extracted Power
Core In-Out Lead Temperature
5.E+08
575
Temperature (C)
525
475
tempf
tempf
tempf
tempf
tempf
tempf
tempf
111180000
211180000
311180000
110180000
210180000
310180000
100010000
Core
4.E+08
Power (W)
Trip set-point
425
cntrlvar
280
cntrlvar
116
SGs
3.E+08
2.E+08
1.E+08
375
Reactor trip on
Hot–average T-channel
0.E+00
325
-50
0
50
100 150
Time (s)
200
250
300
-50
0
50
100 150
Time (s)
200

Reactor trip at 10 s (on hot channels T > trip set-point) or 86 s (on average
channels T > trip set-point)

SG removal power decreases by about 12% after pump stop due to primary
circuit mass flow rate reduction
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
250
300
19
PLOF-1 – Stop of 1 Primary Pump (4)
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Max Clad Temperature
Max Fuel Temperature
600
1400
111101216
httemp
211101216
httemp
1200
311101216
Temperature (C)
Temperature (C)
550
httemp
500
450
400
350
-50
0
50
200
250
300
httemp
211100701
httemp
311100701
800
Inner core
Middle core
Outer core
400
100 150
Time (s)
111100701
1000
600
Inner core
Middle core
Outer core
httemp
-50
0
50
100 150
Time (s)
200

Clad temperature is kept below safety limits for transient conditions (less than
600 s in the range 550 – 600 C)

Maximum fuel temperature is below acceptable value
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
250
300
20
PLOH – Total Loss of Heat Sink (1)
ENTE PER
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Core In-Out Lead Temperature
Max Clad Temperature
575
600
Trip set-point
550
Reactor trip on
Hot–average T-channel
Temperature (C)
Temperature (C)
525
475
tempf
tempf
tempf
tempf
tempf
tempf
tempf
425
375
111180000
211180000
311180000
110180000
210180000
310180000
100010000
0
50
100 150
Time (s)
200
250
300
httemp
211101216
httemp
311101216
450
350
-50
111101216
500
400
325
httemp
Inner core
Middle core
Outer core
-50
0
50
100 150
Time (s)
200

Reactor trip at 53 s (on hot channels T > trip set-point) or 76 s (on average
channels T > trip set-point)

Clad temperature is kept well below safety limits for transient conditions
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
250
300
21
PLOH – Total Loss of Heat Sink (2)
DHR Mass Flow Rate
Core and DHR Power
6000
3.0E+07
5000
2.5E+07
4000
2.0E+07
Power (W)
Flow rate (kg/s)
ENTE PER
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3000
mflowj
2000
175020000
Core
1.5E+07
1.0E+07
1000
5.0E+06
0
0.0E+00
0
2000
4000
6000
Time (s)
8000
DHR
10000
0
2000
cntrlvar
116
cntrlvar
131
4000
6000
Time (s)
8000

DHR mass flow rate stabilizes at approximately 3500 kg/s after about 3 hours

DHR system reaches maximum performances (about 20 MW for 3 units) after
about 400 s
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
10000
22
PLOH – Total Loss of Heat Sink (3)
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Lead Temperature
Max Vessel Wall Temperature
500
450
Temperature (C)
480
tempf
100010000
tempf
120010000
tempf
175010000
tempf
113090000
460
440
440
Temperature (C)
Core in
Core out
DHR in
DHR out
430
420
410
400
400
0
2000
4000
6000
Time (s)
8000
10000
httemp
420
0
2000
100100401
4000
6000
Time (s)
8000

Primary lead temperature stabilizes at about 435 C after 10000 s

Maximum vessel wall temperature around 3000 s is below safety limit (450 C)
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
10000
23
PLOH-1 – Loss of Feedwater to 1 SG (1)
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Core In-Out Lead Temperature
Core and SGs Extracted Power
575
5.E+08
Temperature (C)
525
475
tempf
tempf
tempf
tempf
tempf
tempf
tempf
111180000
211180000
311180000
110180000
210180000
310180000
100010000
425
Core
4.E+08
Power (W)
Trip set-point
3.E+08
cntrlvar
280
cntrlvar
116
SGs
2.E+08
1.E+08
375
Reactor trip on
Hot–average T-channel
325
-200
0
200
400 600
Time (s)
800
1000 1200
0.E+00
-200
0
200
400 600
Time (s)
800 1000 1200

Reactor trip at 146 s (on hot channels T > trip set-point) or 340 s (on average
channels T > trip set-point)

SGs removal power reduces down to 75% at transient initiation
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
24
PLOH-1 – Loss of Feedwater to 1 SG (2)
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
Max Fuel Temperature
Max Clad Temperature
1400
600
111101216
httemp
211101216
httemp
311101216
500
450
400
1200
Temperature (C)
Temperature (C)
550
httemp
350
-200
0
200
400 600
Time (s)
800
1000 1200
111100701
httemp
211100701
httemp
311100701
1000
800
600
Inner core
Middle core
Outer core
httemp
Inner core
Middle core
Outer core
400
-200
0
200
400 600
Time (s)
800
1000 1200

Clad temperature is kept below safety limits for transient conditions (less than
600 s in the range 550 – 600 C)

Maximum fuel temperature is below acceptable value
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
25
PTOP – Overpower Transient (+10%)
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
Core and SGs Power
Max Lead Temperature
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
Max Clad Temperature
Max Fuel Temperature
26
CONCLUSIONS
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE

Core decay heat removal by natural circulation
through the DHR system is efficient in all investigated
scenarios with total loss of heat removal by the
secondary loops

Core and vessel structures temperatures are kept well
below safety limits in all investigated protected
scenarios even under the most conservative
assumptions on reactor trip occurrence based on core
outlet temperature measurements and trip set-point

Reactor trip on low pump rotational speed signal is
needed in case of total loss of forced circulation in the
primary circuit to keep clad temperature peak within
acceptable values
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
27