opal reactor full 3-d calculations using the montecarlo ...€¦ · opal reactor full 3-d...
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OPAL Reactor Full 3-D Calculations using the
MonteCarlo Code Serpent 2
By Diego Ferraro & Eduardo Villarino Nuclear Engineering Department – INVAP S.E. - Argentina
16th IGORR 2014/IAEA Technical Meeting
17th-21th November 2014 – Bariloche - Argentina
Presentation Overview
1- Introduction – Why using Serpent?
2- Previous Experiences & Motivation
3- Full Core 3-D model for the OPAL Research
Reactor
4- Results & Comparisons with experimental values
and other codes
5- Future works
6-Conclusions
2
16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
1- Introduction – Why Serpent?
• MonteCarlo (MC) Codes are used mainly :
Criticality Calculations (Reactors, Fuel Storages)
Shielding Calculations (Coupled N,P)
Ex-Core Facilities design & performance evaluation in RR
Code to Code comparisons
Detailed flux profile calculations
•Several MC codes extensive validated are available (MCNP, KENO, etc).
•Usually demand high computational resources applications such as full
core burnup and cell calculations have been prohibitive in the past decades.
•Serpent Code is a brand-new Neutron/photon transport code developed
since 2004 at VTT Technical Research Centre of Finland specifically
oriented for such tasks, including burnup capabilities.
•Serpent 2 enhances geometrical capabilities. Allows burnup calculations, few-
group constant generation, kinetic parameters, flux distributions, etc.
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16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
2- Previous experiences & Motivation
• The OPAL Research Reactor.
State of art 20MWth multi-purpose open-pool type Research Reactor located
at Lucas Heights, Australia.
It was designed and built by INVAP between 2000 and 2006 and it is owned
and operated by ANSTO.
The reactor consists of a compact core of 16 LEU MTR-type fuels, cooled and
moderated by light water and reflected by heavy water contained in a
Reflector Vessel.
Several irradiation facilities in the Reflector Vessel: Cold Neutron Source with
two beams, a thermal neutron source with two beams, 17 vertical irradiation
tubes, 19 pneumatic RIGs , 6 NTDs facilities, space for a HNS.
It was designed, commissioned and performance tested using INVAP´s
calculation line (CONDOR + CITVAP) + MCNP4C.
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16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
2- Previous experiences & Motivation
• Previous works: Serpent 1 used as a cell-level code to model FA to obtain
few group constants to be used in core calculations (CITVAP) for the OPAL
Research Reactor, showing a good performance [1].
• Nowadays:
Increase in Serpent Capabilities + Parallelization Complex core models
may be developed, including burnup for Research Reactors.
Encouraged by the past results, a full 3-D Serpent 2 model for the OPAL
Research Reactor is developed in the present work.
Comparisons with experimental results from Commissioning & results
from INVAP´s neutronic calculation line & MCNP.
[1] D. Ferraro, E. Villarino, "OPAL Reactor Calculations using the Monte Carlo Code
Serpent", Proceedings of the 4th International Symposium on Material Testing Reactors
December 5-9, 2011, Oarai, Japan.
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16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
6
Objective:
Develop a full 3D
core model in
Serpent 2 &
compare results
with other codes &
experimental data
from Reactor
Commissioning
16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
2- Previous experiences & Motivation
Full 3-D Serpent
Results
INVAP Neutronic Calculation Line:
7
• A 3-D full core model for OPAL Research Reactor was developed for
Serpent 2 v1.21.
• Automatic Input generation through and spreadsheet.
• First Core configuration is modeled:
3 Fuel types (MTR)
5 CR, Chimney, Reflector Vessel.
• Simplified models for most relevant experimental facilities are included:
17 vertical irradiation tubes.
A simplified model for the Cold Neutron Source (CNS)
2 Cold neutron beams.
2 Thermal neutron beams.
Hot neutron beam.
• Results for these models are compared with experimental data from
Reactor Commissioning & Other codes:
Critical positions (from Reactor Commissioning).
Kinetic parameters.
In-core thermal flux profiles.
Full core burnup (1st cycle). 16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
3- Full Core 3-D model for OPAL RR
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16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
Full model x-y cut – 4 cm below core centre
Full model x-y cut – 4 cm below core centre
3- Full Core 3-D model for OPAL RR
Full model y-z cut – CR and CNS details
Developed model characteristics:
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16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
Full model x-y cut core detail
3- Full Core 3-D model for OPAL RR
For burn cases, 10 axial subdivisions.
Plates and BP (Cd wires) evolved independent.
Unionized grid optimization to face RAM requirements.
Parallel calculations are compulsory (OMP).
Statistical error (1) <1% (flux) and 10/20 pcm (keff).
Full model x-y cut –centre of core – FA detail NE corner
4 – Results & Comparisons
10
Critical points: Measurement from Reactor Commissioning (CR calibrations):
16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
-700
-600
-500
-400
-300
-200
-100
0
0 5 10 15 20 25 30
Cal
cula
ted
rea
ctiv
ity [
pcm
]
Case Number
Calibration CR 1&4
Calibration CR 5
Calibration CR 2&3
Cases Serpent
2 [pcm] MCNP [pcm]
CONDOR-
CITVAP [pcm]
CR 1 & 4 -400 -360 -300
CR 5 -340 -370 -130
CR 2 & 3 -500 Not Calculated -240
All 74 cases -420 -390 -220
Calculations
Cold w/o Xe,
1st Core Fresh.
Comparison with Other codes (from Commissioning):
Fairly good
agreement!
4 – Results & Comparisons
11
Kinetic Parameters: Measurements from Reactor Commissioning:
Due to detector efficiency requirements, during Commissioning of the OPAL
Reactor, the neutron decay constant was measured for a 15FA core
configuration using the Feynman-α method.
This configuration was modeled with Serpent. IFP method was used.
16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
Kinetic Parameters for 16 FA configuration: The final 16FA was
calculated and compared with calculations: In good
agreement with
Calculated values
(<4%).
Kinetic
Parameter
CONDOR-
CITVAP MCNP
Serpent 2
(IFP)
βeff [pcm] 768 770 766
Λ [μs] 171 172 177
α [1/s] 45 45 44
Kinetic
Parameter Measurement
Serpent 2
(IFP) MCNP
α [1/s] 38.1 38.8 37.2
In good agreement with calculated and
measured values (<3%).
4 – Results & Comparisons
12
In-Core Thermal Flux:
Measurements from commissioning at low power (36kW±6)
Modeled in Serpent considering CR positions
Mesh detectors included
Overall power set to 36kW
Relevant positions considered
Axial profiles included
16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
Fairly good agreement
0.E+00
5.E+10
1.E+11
2.E+11
2.E+11
3.E+11
3.E+11
4.E+11
4.E+11
5.E+11
5.E+11
-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30
Ther
mal
Flu
x (
E<
0.6
25eV
) [
n/c
m2s]
Axial position [cm]
A2 - measured
A2 - Calculated Serpent 2
A2 - CONDOR-CITVAP
0.E+00
5.E+10
1.E+11
2.E+11
2.E+11
3.E+11
3.E+11
4.E+11
4.E+11
5.E+11
-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30
Th
erm
al F
lux
(E
<0
.62
5eV
) [
n/c
m2
s]
Axial position [cm]
D2 - measuredD2 - Calculated Serpent 2 D2 - CONDOR-CITVAP
Positions in FA in D2 and A2
4 – Results & Comparisons
13
In-Core Thermal Flux:
Measurements from commissioning for at low power
(36kW±6):
16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
Differences with experimental data are below 5/8% in
average and inside the Power Uncertainty.
0.E+00
1.E+11
2.E+11
3.E+11
4.E+11
5.E+11
6.E+11
7.E+11
8.E+11
-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30
Th
erm
al F
lux
(E
<0.6
25eV
) [
n/c
m2
s]
Axial position [cm]
B1 - MeasuredB1-Calculated Serpent 2 B1 - CONDOR-CITVAP
0.E+00
1.E+11
2.E+11
3.E+11
4.E+11
5.E+11
6.E+11
7.E+11
-30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30
Ther
mal
Flu
x (
E<
0.6
25eV
) [
n/c
m2s]
Axial position [cm]
C1 - measuredC1 - Calculated Serpent 2C1 - CONDOR-CITVAP
Channels B1 and C1
4 – Results & Comparisons
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16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
Fairly good agreement with experimental values (Differences
800/400 pcm)
Full Core Burnup Calculations:
Critical positions for First Cycle burnup.
Real days converted to FPD.
ARO burn at Hot Full Power, saving a restart case. Then Critical CR
positions are modeled using compositions from restart.
-1000
-800
-600
-400
-200
0
200
400
600
800
1000
16 17 18 19 20 21 22 23 24 25 26
Cal
cula
ted
Rea
ctiv
ity [pcm
]
FPD
Serpent 2 Calculated values for Critical positions at Full Power
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5- Conclusions
• A full 3-D core model was developed in Serpent 2 v1.21 for the
state of art - 20MWth OPAL Research Reactor.
• All main parameters measured during reactor commissioning
were calculated, Good agreement was encountered compared
with experimental data and with results from INVAP
deterministic Calculation line and independent MCNP models.
• Full core calculations including burnup are feasible in MTR
reactors considering:
High memory resources requirements are expected.
Fuel management capabilities are to be required.
16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
6 – Future Works
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16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina
Encouraged by the results from last sections, it is intended to extend the
burnup calculations to other cycles material management scheme is
compulsory.
Comparisons to experimental data to be extended to the reported
Neutron fluxes in bulk irradiation facilities, placed in the Reflector Vessel.
Questions?
Thanks for your attention!!
16th IGORR 2014/IAEA Technical Meeting - 17th-21th November 2014 – Bariloche – Argentina