Transcript Diapositiva 1 - Royal Institute of Technology

ENTE PER
FPN-FISNUC
/ Bologna
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
EUROTRANS – DM1
Analysis of EFIT Unprotected
Accidental Transients with
PARCS/RELAP5 Coupled Code
G. Bandini, P. Meloni, M. Polidori
WP 1.5 Progress Meeting
ENEA – Bologna, Italy, May 28-30, 2008
OUTLINE
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE

Description of the Codes

The modifications of RELAP5 Model of EFIT

The PARCS Model of EFIT

Analysis of Unprotected Transients


Total Loss of Flow Accident

Beam Power Jump to 100% at HZP
Conclusions
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
2
PARCS/RELAP5 Coupled Code
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
Our State-of-the-Art code to simulate the NeutronicT/H coupled phenomena for safety purpose is:
PARCS v1.01 – 3D Neutronic coarse mesh code that
solves the 2-group diffusion equation in cartesian
geometry, modified to treat subcritical systems.
RELAP5 mod 3.2.2b – Thermal-Hydraulic 1D code
modified to treat HLM (Seban-Shimazaki heat
transfer correlation implemented)
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
3
RELAP5 Model – 6 Rings Active Core Region
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
22
82
Jun23
62
Jun83
Jun63
branch

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

Core Region

Ring 1 – 18 FA (Inner Zone)

Ring 2 – 24 FA (Inner Zone)

Ring 3 – 30 FA (Interm Zone)

Ring 4 – 36 FA (Interm Zone)

Ring 5 – 42 FA (Outer Zone)

Ring 6 – 30 FA (Outer Zone)
branch
branch
175
02
01
176
(177/8/9)
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
Jun114
01
06
01
05
UPPER PLENUM
branch 120
Jun106
Jun104
07
06
05
04
03
02
01
109
311
310
211
210
111
110 108
161
09
Target
Ring_1
Ring_2
Ring_3
Ring_4
Ring_5
102
Ring_6
Bypass & Reflector
Jun105
08
07
06
05
04
03
LOWER PLENUM
branch 100
RELAP5 Noding Scheme
02
01
09
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
4
PARCS Model and Assumptions
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
PARCS Mesh Dimension
EFIT Core Layout
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
Width = 8.27 cm
Height = 9.55 cm
5
PARCS Model and Assumptions
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
Axial Nodal
Correspondance
PARCS
RELAP5
20
18
17
19
16
Vertical View of EFIT Core Layout
15
18
14
17
13
16
12
15
11
14
10
13
9
12
8
11
7
10
6
9
5
8
4
7
3
6
2
5
1
4
3
2
1
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
6
XS Generation
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
XSEC Formalism in PARCS
Tfuel
400°C
Tcoolant
400°C
750°C
1100°C
O
O
O
440°C
O
550°C
O
XSEC Data Set to Find the
Derivative Cross Sections
Omogenized
Collased in 2 groups
(0.079 MeV Cutting Energy)
O
A keff calculation with the Base XSEC Data Set in ERANOS
suggests a value of keff =0.97631
Initial keff  0.958
Normalization of nSf to
achieve the desired keff
keff  0.97515
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
7
Main EFIT Parameters
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE

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
8
R5 SA vs P/R5 Steady-State Calculation
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
Parameter
Code
Inner
zone
Middle
zone
Outer
zone
Reflector
Target
Total
Thermal power
(MW)
R5 SA
P/R5
96
103.3
142.3
153.9
140.5
126.6
5.2
“
11.2
“
395.2
400.2
Lead mass flow
rate (kg/s)
R5 SA
P/R5
7678
7684.5
11486
11496.8
11445
11437.5
1127
1126.9
1506
1505.3
33243
33252
Maximum
temperature
(°C)
Code
Inner zone
Middle zone
Outer zone
(Fax = 1.14)
(Fax = 1.16)
(Fax = 1.17)
Hot FA
Fr =1.12
Fr =1.03
Averag
e FA
41/42
Hot FA
Fr = 1.13
Fr = 1.10
Avera
ge FA
65/66
Hot FA
Fr = 1.24
Fr = 1.20
Avera
ge FA
71/72
Bypass
outlet
Target
outlet
Center fuel
R5 SA
P/R5
1251
1262
1151
1217
1329
1375
1214
1201
1284
1145
1093
788
-
-
Surface fuel
R5 SA
P/R5
870
876
818
853
858
882
804
800
816
758
734
607
-
-
Internal clad
R5 SA
P/R5
539
525
524
519
535
532
519
510
534
512
508
466
-
-
External clad R5 SA
P/R5
527
516
513
511
524
523
510
503
525
506
501
462
-
-
Lead
494
493
484
488
494
499
483
483
502
490
482
453
431
431
450
450
R5 SA
P/R5
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
9
Transients to be Analyzed by ENEA with P/R5
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
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
P-10
Spurious beam
trip
beam trip for 1,2,3 …..
10 s intervals
x
?
X-C
UNPROTECTED TRANSIENTS
U-1
ULOF
Total loss of forced
circulation in primary
system
(4 pumps)
U-2
UTOP
(?) pcm jump in
reactivity at HFP
x
?
X-C
U-4 DEC
ULOH
Total loss of secondary
loops
(4 loops)
x
?
X-C
U-5 DEC
ULOF + ULOH
Total loss of forced
circulation and
secondary loops
x
?
X-C
U-11
Beam Overpower
to (?)% at HFP
x
?
X-C
U-12
Beam Power Jump
to 100% at HZP
x
?
X-C
x
?
X-C
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
X
10
Safety Limits
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE

According to previous PDS-XADS safety analysis:

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
Fuel temperature limited below 1380 C to avoid
MgO inert matrix dissolution problem
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
11
Analysis of Unprotected Transients
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE

ULOF: Total loss of forced circulation in primary pumps

The coupling start from thermal-hydraulic nominal conditions and
external source off.

After 1s the source is switched-on reaching the stationary
conditions after 50s.

At 50s the primary pumps trip with system free evolution.

BEAM TRIP: Beam Power Jump to 100% at HZP

At 50s the external source is switched-off then 100s of free evolution
(decay heat is not considered)

At 150s the external source is switched-on at 100% then free
evolution
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
12
Unprotected Loss of Flow Transients
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
4.50E+08
4.00E+08
3.50E+08
Power [W]
3.00E+08
2.50E+08
2.00E+08
1.50E+08
Reactor Power
Neutronic Power
SG Power
1.00E+08
5.00E+07
0.00E+00
40
Keffective and Reactivity

130 pcm inserted during the LOF transient

3% of Power reduction
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
90
140
190
240
Time [s]
290
340
Reactor and SG power
13
Unprotected Loss of Flow Transients
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
40,000
800
35,000
600
Temperature [°C]
30,000
Mass Flowrate [kg/s]
700
mflowj
100080000
25,000
20,000
15,000
10,000
500
400
300
200
Upper Plenum
5,000
100
0
0
40
90
140
190 240
Time [s]
290
340
Lower Plenum
40
Lead Mass Flowrate
140
240
340
Time [°C]
540
Lead Temperature

Core mass flow rate drop down almost to 0 in the initial transient

Slight overcooling of the Lead in the heat exchanger
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
440
14
Unprotected Loss of Flow Transients
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
1,600
Temperature [°C]
1,400
1,200
Centerline Fuel
External Clad
Lead
1,000
800
600
400
40
140
240
340
440
540
Time [s]
Temperature Ring 3 (Intermediate Zone)

Fuel Peak Temperature 1530°C, 1460°C in long term conditions.

Clad Peak Temperature 810°C approaching the 700°C in long term conditions.
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
15
Beam Trip Transients
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
4.50E+08
4.00E+08
3.50E+08
Power [W]
3.00E+08
2.50E+08
2.00E+08
1.50E+08
Neutronic Power
1.00E+08
SG Power
5.00E+07
0.00E+00
40
Keffective and Reactivity
140
240
340
Time [s]
440
540
Reactor and SG power

100 pcm inserted during the Beam Trip and reinsertion transient

Decay Heat not take into account
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
16
Beam Trip Transients
600
1,500
500
1,300
400
1,100
Temperature [°C]
Temperature [°C]
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
300
200
700
500
Upper Plenum
100
Centerline Fuel
External Clad
Lead
900
Lower Plenum
300
0
40
140
240
340
Time [°C]
440
Lead Temperature

540
40
140
240
340
Time [s]
440
540
Temperature Ring 3
(Intermediate Zone)
The Beat Trip transient seems to be not a safety issue for the system.
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
17
CONCLUSIONS
ENTE PER
LE NUOVE TECNOLOGIE,
L’ENERGIA E L’AMBIENTE
 The results obtained by PARCS/RELAP5 coupled both at
nominal and at ULOF accidental conditions are in good
agreement with that obtained by RELAP5 Stand Alone.
 Some work has to be done to improve the power distribution
among the FA rings.
 It is not foreseen to carry out EOL Unprotected Transients due
to the very small diffence expected.
EUROTRANS DM1 – WP 1.5 Progress Meeting, Bologna, May 28-30, 2008
18