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1CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
TRIPOLI-4A 3D CONTINUOUS-ENERGY MONTE CARLO TRANSPORT CODE
O.Petit, E.Dumonteil, F.X.Hugot, Y.K.Lee, A.Mazzolo, C.Jouanne, C.M. Diop and J.C.Trama.
DEN/DM2S/SERMACEA/Saclay
91191 Gif-sur-Yvette CedexFRANCE
[email protected]@cea.fr
2
2CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
1. A brief history2. Application fields3. General features4. Structure of the code5. Geometry description6. Nuclear data, processing, libraries7. Variance reduction8. Green functions9. Benchmarking10. User interface
TRIPOLI-4 : Outline
TRIPOLI-4 overview
3
3CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
TRIPOLI-1 1976 : J.C. Nimal, S. Katz.
TRIPOLI-2 1982 : J.C. Nimal, T. Vergnaud, L. Bourdet, J. Gonnord, G. Dejonghe.
TRIPOLI-3 1996 : J.C. Nimal, T. Vergnaud, M. Chiron.
TRIPOLI-4 1990 : J.P. Both, Y. Pénéliau, B. Roesslinger,
Y.K. Lee, O. Petit, A. Mazzolo, C. Jouanne, E. Dumonteil, F.X. Hugot.
C.M. Diop : since 1995
J.C. Trama : since 2006.
1. TRIPOLI-4 : A brief history
TRIdimensionnel POLYcinétiqueA Particle Transport Monte Carlo Code in 3D Geometry
Available from the OECD / NEA data bank since 2003
4
4CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Shielding studiesCore and criticality studiesInstrumentation studiesPhysical analysis, numerical experiment Reference and Project Tool
. Power Reactor (PWR, FBR, BWR, ...)
. Dismantling
. Fabrication, Reprocessing, Transport of fuel
. Research reactors
. Nuclear Wastes
. Transmutation, Hybrid System
. Thermonuclear Fusion
. Particle Accelerators
. Medicine
. Industrial plants, …
2. TRIPOLI-4 : Application fields
Neutron and gamma dose ratecalculations inside PWR reactors
OSIRIS : conception of experimentsin OSIRIS research reactor
Dampierre PWRKeff calculation and
ex-core response calculationversus erroneous assembly loading
concrete
Reactor pitHeat insulator
pressure vesselwater
barrel
bafle assembly
water
assemblies
Neutron fluence calculation on PWR vessel
5
5CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
• 3D• Continous energy pointwise cross-sections (20 MeV)• Multigroup self-shielded cross-sections (20 Mev)• Neutron, gamma, coupled (n,γ)• Electron, positron, cascad shower (GeV)• Parallelization
φ = TCφ + TS
• Subcritical problem
• Critical problem
• Time dependent problem
• Perturbations
Specificities for neutrons :
3. TRIPOLI-4 : General features
Physical quantities :
• Flux of particles : φ• Current of particles : J• Reaction rates• Damages• Dose rates• Keff
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6CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Modules Description Languages # of lines
Cplus Memory management library C++ 8kGeom Geometry library C 30kEndl ENDL data management library C++ 4kIpc Parallel computing library C++ 20kNjoy ENDF file management for Njoy F77,F90 100kTripoli4 Monte Carlo core code library C++, yacc, lex 280k
4. TRIPOLI-4 : Stucture of the code
Available platforms :
Linux 32 and 64 bits, Solaris, OSF1, IBM Aix
Parallelism : heterogeneous networks, massively parallel machines.
7
7CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Predefined shapes and combinatorial operators :Reunion, smash, intersection, substractionRotationRepetition of basic pattern
Lattices, Lattices of lattices :
Or definition by surfaces :
Combination of both descriptions is possible.
5. TRIPOLI-4 : 3D Geometry description
User friendly interface
2D cut
8
8CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
→ Evaluated Photon Data Library
Photons :
Electrons, positrons :
→ Evaluated Electron Data Libray
Photoionization, photoexcitation, coherent and incoherent scattering and pair production
Relaxation of ionized atoms back to neutrality
→ Evaluated Atomic Data Library
Transport of electrons. Production of secondary particles :Photons due to Bremsstrahlung and primary electrons due to inelastic scattering
6. TRIPOLI-4 : Nuclear data
Neutrons :All libraries in ENDF-B6 Format : ENDFBVIR8, ENDFBVII, JEF2.2, JEFF3.1, JENDL3.3…
Energy range from 10-5 eV to 20 MeV
9
9CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Nuclear data processing by NJOY99.x1. Reconstruction at 0 K (RECONR, ε = 0.001)2. Doppler Broadening at T K (BROADR, ε = 0.001)3. Treatment of Thermal Neutron scattering data for materials (THERMR)
→ Pointwise cross section library (PENDF)
→ Unresolved Range : Probability Tables by CALENDF code.
TRIPOLI-4 : Nuclear data processing
10
10CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
TRIPOLI-4 generates XDR portable binary and angular distributionfiles the first time it reads a PENDF and an ENDF file
TRIPOLI-4 : Nuclear data libraries
TRIPOLI-4
Evaluation
RECONRBROADRTHERMR
PENDF
Deterministic code libraries(e.g. from APOLLO-2)
CALENDF PT
11
11CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
The biasing scheme in TRIPOLI-4 :
• An importance map I(P) is automatically pre-computed on a (r,E) grid; the adjoint flux form is used as a hint (INIPOND module).
• Importance definition :
• Biasing parameters K and directions of interest are calculated
(related to importance by : ).
• In each cell and each group is computed by :
- a shortest path algorithm (for discrete « attractors »)
- or an analytical form, e.g. cylindrical (for a surface « attractor »)
),,()(),(),,( Ω××=Ωrrrrr ErIEIErIErI des
IIK ∇
=Ωr
r0
0Ωr
),( ErIsr
7. TRIPOLI-4 : Variance Reduction
12
12CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Examples of iso-importances produced :
TRIPOLI-4 : Biasing
Iron
Water
Neutron source
Detector
Discrete detectors for « passing-round » problems
Detector surfacefor uniform FOM on a surface
Detector surface
13
13CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Exponential transform is used for the transport sampling :
Biased cross-sections are :
Russian roulette and splitting are played
Biasing of the source
The beginning of the simulation is used to adjust Iref
from group to group (using weight discrepancies).
0* Ω⋅Ω−Σ=Σ
rrKtt
TRIPOLI-4 : Biasing
Ω0
ΩSource Resultregion
∫ ΩΩ+Σ−ΩΣ=Ω→ dsEsrErErrT tt )',',''(exp)',',()',','( ***
wrt. the Iref map.
14
14CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Example of β values (biasing’s strength adjustment) :PONDERATION
NEUTRONDECOUPAGE 6
20. 8. 4.5 2. 1. 1.E-11
DETECT_RHO 1 220.5 [β]MAILLAGE 69 1 21
4.68 1.5715 5.65 3REPERE CYLINDER
-0.001 -0.001 -50.1 β = 0 β = 0.1 β = 1100 -0.02 0
β FOM Efficiency0. 0. 1 0. 0.05 1
FIN_MAILLAGE 0.1 0.15 3INIPOND AUTO 0.5 3.66 70OMEGA SET_OMEGA CYLINDER 0 0 1 0 0 0 1.0 5.33 100FIN_INIPOND 1.4 16.00 300
FIN_PONDERATION 2.0 12.50 240
TRIPOLI-4 : Biasing
15
15CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Directsource Detector
Adjointsource
Adjointdetector D
= S(P) (P) dP+χ∫I
D= h(P) (P) dPχ∫I
8. TRIPOLI-4 : Green functions
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16CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Large storageEasy and fast re-use of Green functions
Small storageEasy and fast re-use
of adjoint flux
Large storage
BiasingBiasingBiasing
One transport calculation for several source distributions
Two steps scheme (first step requires time to compute Green functions)
One transport calculation for several source distributions
One transport calculation for eachsource distribution
multi-detectorsmulti-scorings
one detectormulti-detectorsmulti-scorings
continous energymultigroupcontinous energy
« Green functions pseudo-adjoint»« Classical »adjoint
Direct biased
D= h(P) (P) dPχ∫I
D= S(P) (P) dP+χ∫I
0' '
( ) ( , , ' , ') ( ', ') ' '( ) k
r Z E E
N r G r E r Z E s r E dr dE dEN r∈
= ∈∫ ∫ ∫I
TRIPOLI-4 : Green functions
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17CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
« initial » data :
• position r• energy E• source intensity S(r,E)• weight W
« final » data :
• energy E’• contribution χ• weight W’
assembliesbafle assemblywater
concrete
pressure vessel
barrel
reactor pit
heat insulator
capsules
Example : neutron fluence calculation :
Exploitation : Simulation M.C :264 s > 2 days
2.7693E+10 (1.05%) 2.7695E+10 (0.51%)
TRIPOLI-4 : Green functions
18
18CEA/DEN/DM2S/SERMATRIPOLI-4 Monte Carlo code overview
ICRM meeting, November 27-28, 2006
Ben
chm
ark
IAEA
(LL
NL
-Cul
len,
200
4) “How accurately can we calculate
thermal systems ?”
- K-inf and S(α,β) : s +/-0.0001- U-235 : 0.98%, 3.5% and 70%
- Monte Carlo codes :TRIPOLI-4.3 MVP MCNP-4C MCNP-5KENO-5 COGMCU MONK-8TART04 VIM RCP RACER
Publication: IAEA-INDC(USA) – 107, May, 2004
9. TRIPOLI-4 : Benchmarking