CORPUS : A MULTIPHYSICS SALOME
APPLICATION FOR REACTOR
MULTIPHYSICS ANALYSIS
COUPLING BETWEEN THE NEUTRONICS (APOLLO3®) THE
THERMAL-HYDRAULICS (FLICA4) AND THE FUEL
PERFORMANCE (ALCYONE/PLEIADES) FOR THE
MODELING OF A PWR ROD EJECTION ACCIDENT (REA)
| PAGE 1
Jean-Charles LE PALLEC1 ,K. Mer-Nkonga2, N. Crouzet1
1CEA France, DEN/DANS2CEA France, DEN/CAD
JUS 2016 – EDF LAB, Saclay, December 09
7 DÉCEMBRE 2016
| PAGE 2
OUTLINE
Context
CORPUS multi physics platform
REA Exercice
Conclusion and Prospects
REA PHENOMENOLOGY
7 DÉCEMBRE 2016 | PAGE 4JUS 2016 - EDF Lab, Saclay, December 09
1. Core power ↑↑↑↑ especially around the ejected control rod assembly2. Core power ↓↓↓↓ due to the Doppler (1st order) + moderator (2nd order) feedbacks 3. Core power ↓↓↓↓ due to the control rods emergency shutdown (‘scram’)
coreΓ
maxcoreP
maxt Fhot spot < 100 ms 10 Pnom 200 ms 20
Control rods ejection (0.1s) ����fast reactivity core transient (1s)
SAFETY CRITERIA: fuel temperature, fuel enthalpy, clad temperature
⇒⇒⇒⇒ Integrity of the first containment barrier (cladding)
����
REA CHALLENGES
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Access to safety criteria = local responses (fuel)
MODELING FOR SAFETY ANALYSIS : methodological evolution
� 3D modeling
� multiphysics approach
ThermalhydraulicsModerator feedback
Fuel performanceDoppler feedback
NeutronicsCore power
Safety criteria
From conservatism to best-estimate (BE) approach2D static/1D kinetic 3D cinétique
BE modeling = CORPUS development frameworkJUS 2016 - EDF Lab, Saclay, December 09
CORPUS PRESENTATION
7 DÉCEMBRE 2016
| PAGE 6
CEA | 10 AVRIL 2012
� Motivation
� Perimeter
� Architecture
� Current modeling development
Coooorpus
7 DÉCEMBRE 2016 | PAGE 7
⇒⇒⇒⇒ Core design : LWR (900MWe,1300MWe, N4, EPR, GEN3+)⇒⇒⇒⇒ Accident scenarios : steady state and transient : RIA (MSLB, REA)
CORPUS: OVERVIEW (1/2)
A SALOME application for reactor multphysics analysis
JUS 2016 - EDF Lab, Saclay, December 09
CORPUS: OVERVIEW (2/2)
7 DÉCEMBRE 2016 | PAGE 8
CRONOS2(Access)
FLICA4(Access)
CATHARE2(ICoCo)
Th. limit conditions
Core analysis(REA)
Integral plant analysis(MSLB)
Mixing grid application(MELANGE)
Interpolation process(INTERP2_5D)
APOLLO2Cross-sections
Library
CALCULATION SCHEMES
Coooorpus
JUS 2016 - EDF Lab, Saclay, December 09
CORPUS: ARCHITECTURE (1/2)
7 DÉCEMBRE 2016 | PAGE 9
« Russian doll » structure based on SALOME environment
Coooorpus
CODESPrerequisisites (C, C++
Fortran libraries)
Codes C++ wrapper libraries(API). Generation of SALOME components with YACSGEN
Supervision of distributedcomponents (implementation
of multiphysics schemes).
…
JUS 2016 - EDF Lab, Saclay, December 09
CORPUS: ARCHITECTURE (2/2)
7 DÉCEMBRE 2016 | PAGE 10
Coooorpus
Typical API used for CODE supervision
Method definition
initialize(), terminate() Initilize/finalize the problem
solve(), interate() Resolution of steady problems
computeTimeStep () Time step value estimation
initTimeStep (dt) Initialise all the variables for the time step
solveTimeStep () Start the calculation on the time step
validateTimeStep ()/abortTimeStep () Validate/Abort the time step calculation
save()/restore() Save the internal state, and restore it
setInputField(), getInputField() Field Exchange at MED format
ICOCO : standard API for code coupling shared by a large range of SALOME codes (neutronics, thermalhydraulics, fuel, from core to system description) adopted notably by the EU NURESIM platform
JUS 2016 - EDF Lab, Saclay, December 09
CORPUS : CURRENT MODELING DEVELOPMENT (1/4)
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Existing modeling : internal fuel treatment in CRONOS2(C2) and FLICA4 (F4)Limitations = modeling limited to the thermal response calculation (heat conduction eq.)
� Dynamic fuel/clad gap: NO (� simplified Hgap model)� Fuel irradiation state (rim effect): NO
Target modeling : go beyond those limitations
BE fuel description challenges
Fuel performance
neutronic
thermohydraulique
Doppler Feedback Moderator Feedback
Heat exchange
Power1 – fgamma fgamma
Coooorpus
use of a dedicated code = ALCYONE
CRONOS2 ���� APOLLO3® switch+ JUS 2016 - EDF Lab, Saclay, December 09
7 DÉCEMBRE 2016 | PAGE 12
CORPUS : CURRENT MODELING DEVELOPMENT (2/4)
Development strategy
Neutronics
Thermalhydraulics
Fuel performance
Coooorpus
Sta
rtin
gpo
int
Intermediate modeling: APOLLO3®/ALCYONE coupling
Final target: APOLLO3®/FLICA4/ALCYONE coupling
AL
AP3
F4
AL
AP3
F4
C2
STEP by STEP …
JUS 2016 - EDF Lab, Saclay, December 09
7 DÉCEMBRE 2016 | PAGE 13
PWR1300MWe –GEMMES managment(193 UOx assemblies - 24 with Gd)
� Ejection of the Control rods situated in H2 ass.� Hot spot in the H1 ass.
modeling steps(APOLLO3®/ALCYONE coupling)
REA scenario target
Coooorpus
STEP2Control Rod specification
APOLLO3®
STEP3REA transient
APOLLO3®/ALCYONE coupling
APOLLO3®/ALCYONE coupling
STEP1Irradiation state calculation (depletion)
Internal simplified fuel/fluid description
0: Fresh fuel assembly1: Assemblies batch 12: Assemblies batch 23: Assemblies batch 3
JUS 2016 - EDF Lab, Saclay, December 09
CORPUS : CURRENT MODELING DEVELOPMENT (3/4)
7 DÉCEMBRE 2016 | PAGE 14
Coooorpus
⇒⇒⇒⇒ APOLLO3®/FLICA4/ALCYONE coupling on a mini-core desig n
Principle : to make the developments on a small core (mini-core denomination)submitted to a REA scenario accident and update them progressively in the fullcore design� Simplification of the coupling scheme analysis and the simulation in terms ofcomputation time + data analysis
Design simplification for calculation schemes develop ment
JUS 2016 - EDF Lab, Saclay, December 09
CORPUS : CURRENT MODELING DEVELOPMENT (4/4)
REA EXERCICE
7 DÉCEMBRE 2016
| PAGE 15
CEA | 10 AVRIL 2012
� Mini core presentation
� REA scenario
� Modeling
� First results
MINI-CORE PRESENTATION (ACCADEMIC CASE)
7 DÉCEMBRE 2016 | PAGE 16
Geometric data Assembly pitch 0.21504 m
Fuel pins per assembly 264 Fuel Cell dimension 1.26 10-2 m
Active height 4.2672 m Reflector height 2×0.21 m (bottom/top)
Clad external radius 4,75 10-3 m Clad internal radius 4,1785 10-3 m Fuel pellet radius 4,096 10-3 m
isotopic data (fresh fuel) U235 enrichment 4%
MiniCore design
3D 3*3 fuel core with a reflector envelope Standard fuel assembly design
Control Rod to be ejected JUS 2016 - EDF Lab, Saclay, December 09
Coooorpus
RIA SCENARIO
7 DÉCEMBRE 2016 | PAGE 17
STEP1
Core Power (Pcore) NOC * 110.0 10+06 W/ HS ** 10000 W
Average linear fuel power (Plin)
NOC 10849.46 W.m-1 HS 1W.m-1
Initial core Burn-up 0 MWd/t (fresh core) Depletion duration STEP1 result HS to NOC transition 1 day
STEP3 Initial Pcore/Plin HS level Initial core Burn-up STEP1 result Rod ejection duration 0.1s Transient duration 0.3 s
STEP1/STEP3 (common data) Fast neutron Flux *** 3.8 1012 n.J-1. m-1 × Plin Fuel cell mass flow 0.3307 kg.s-1 Outlet Pressure 1.55 107 Pa Inlet fluid temp. 563 K (*) NOC: Nominal Operating Condition (**) HS: Hot Shutdown (***) Eneutron>1Mev
Fuel/cladaccomodation
���� STEP 1: cycle length calculation � BU(x,y,z) at the beginning of the transient (EoC config.)���� STEP 2: characterization of the Control Rod to be ejected (CR worth)���� STEP 3: REA transient calculation
3 calculation steps
JUS 2016 - EDF Lab, Saclay, December 09
Coooorpus
APOLLO3-ALCYONE MODELINGCALCULATION SCHEME (1/3)
7 DÉCEMBRE 2016 | PAGE 18
Models and data exchanges
INT
ER
PO
LAT
ION
JUS 2016 - EDF Lab, Saclay, December 09
Coooorpus
(+ simplified thermal hydraulics)
ρρρρfluid /Tfuel
Pfuel
Multi-threaded calculation
CODE SAMPLE
import Queue, threading
class ThreadOneAlcyoneStep(threading.Thread):
def __init__(self, queue_in, queue_out):
threading.Thread.__init__(self)
self.queue = queue_in # resources
self.queue_out = queue_out # results
def run(self):
while True:
ressources = self.queue.get()
pinId=ressource[0]
alcyone_compo=ressource[1]
# ETC
alcyone_compo.initTimeStep(currentTimeStep)
alcyone_compo.setInputField(“linpower", power)
if alcyone_compo.iterateTimeStep() : # send results in output queue
fuel_temperature=alcyone_compo.getOutputField("TEMPERATURE")
fcoolant_density=alcyone_compo.getOutputField("RHOK")
output=[pinId, fuel_temperature, coolant_density]
self.queue_out.put(output)
else:
# Stop computation
self.queue.task_done() # signals to queue that the job is done
7 DÉCEMBRE 2016 | PAGE 19CEA | 26 SEPTEMBRE 2012
Get results and Put them in out queue
Compute oneTime-step
Get theresources
Initialization
APOLLO3-ALCYONE MODELINGCALCULATION SCHEME (2/3)
Code sample
Coooorpus
APOLLO3-ALCYONE MODELINGCALCULATION SCHEME (3/3)
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time marching management
���� Depletion (STEP1) ���� REA transient (STEP3)
- Synchronous explicit scheme
- Time step (∆ti,i+1) determined by APOLLO3® � constant value during the transient (∆ti = 1.e-3s)
- Synchronous implicit Block Gauss-Seidel (BGS) coupling scheme with a relaxation method to improve efficiency
- Time step (∆ti,i+1) determined by ALCYONE (stability of the thermo-mechanical/thermal-hydraulics resolution) � If the current time step does not converged (due to a code or to the BGS coupling scheme), the time step is divided by two and the BGS computation is restarted
7 DÉCEMBRE 2016
AP3
ALC
ti ti+1Kinetic calculation
Kinetic calculation3
2
4
1
7 DÉCEMBRE 2016
AP3
ALC
ti ti+1
51
Depletion calculation
Depletion calculation3
BGS(CV criteria)
= Stationary calculation1
2
4JUS 2016 - EDF Lab, Saclay, December 09
Coooorpus
7 DÉCEMBRE 2016 | PAGE 21
Depletion calculation (STEP 1)
CBoron BoD*
[ppm] BUEoD**
[MWd/t] APOLLO3® 1521 11046 APOLLO®/ ALCYONE
1499 (-22) 11025 (-21)
(*) Boron concentration at the Begin of Depletion (**) Core Burn-up at the End of Depletion
Limitation : each code runs its own depletion model that potentially lead to a drift in terms of BUcomparison of the burn-up evolution obtained by APOLLO3® and ALCYONE: close behavior of the 2 models � coherence between the two codes in terms of depletion
� effect of a fine fuel description on a depletion calculation without invalidating the simplified fuel/fluid modeling currently used for cycle length calculations
Coupling effects
Global effects
Local effects
APOLLO3-ALCYONE MODELINGFIRST RESULTS (1/2)
JUS 2016 - EDF Lab, Saclay, December 09
Coooorpus
Fraction of delayed neutron [pcm] 568 Control rod worth [pcm | $] 879 | 1.55 Adiabatic model ALCYONE Max. linear fuel Power (Pmax) [W.m-1] 775.103 954.103 linear fuel energy at t = 0.3s [J] 19075 23138 Pulse width at Pmax/2 [ms] 21 20 Max. Fxyz 4.17 4.15
7 DÉCEMBRE 2016 | PAGE 22
REA transient (STEP 3)
consistence between the 2 models that gives a good level of confidence of the coupling APOLLO3®/ALCYONE
ρρρρ = 1,55$
APOLLO3-ALCYONE MODELINGFIRST RESULTS (2/2)
JUS 2016 - EDF Lab, Saclay, December 09
Coooorpus
| PAGE 23
APOLLO3® - FLICA4- ALCYONE MODELING
JUS 2016 - EDF Lab, Saclay, December 09
Coooorpus
Fuel:
Fluid:
REA transient (STEP 3)
“proof of concept” � coupling effect to be analysed
CONCLUSION AND PROSPECTS (1/2)
7 DÉCEMBRE 2016 | PAGE 25
promising opening: first demonstration of the CORPU S capability to integrate a BE fuel description (ALCYONE) in a PWR core model f or depletion and transient
analysis
Prospects���� in terms of calculation schemes� Numerical aspect : calculation time optimisation and robustness improvement� Data exchanges : extension to the fast neutron flux from APOLLO3® to ALCYONE� Feedback models : Fuel effective temperature formula from TRowland to TAlcyone
Conclusion
���� in terms of scenario calculationaccademic case � realistic REA bias analysis (typically simplified fuel description versus BE modeling)
JUS 2016 - EDF Lab, Saclay, December 09
Coooorpus
7 DÉCEMBRE 2016 | PAGE 27
Standardized environment …Exchanged codes format (MED)Code running interface (ICoCo)
… adapted to CORPUS applications …Supervision of complex modeling � multi physics couplingYACS graphical interface � « User friendly » calculation management (interactivity tools like stop and go)
Why to use the SALOME plateform ?
… and CORPUS capabilities extension– Modeling coupling extension – Uncertainties analysis management
CORPUS: ARCHITECTURE (3/3) Coooorpus
JUS 2016 - EDF Lab, Saclay, December 09
7 DÉCEMBRE 2016 | PAGE 28
Simulation tools to understand and predict fuel behavior under irradiation
Dev. framework: the PLEIADES software env.
C++ software architecture based on the SALOME norm for exchanges with other platforms (thermo-hydraulic and neutronic)
Modeling perimeter� Multidimensional approach (1D, 2D, 3D)
� Multiphysics modelling
Thermal/mechanical behaviourMaterial modifications under irradiationFission products inventorySimplified model for the fluid (coolant) flowSimplified model for the neutronic behavior
Focus on 1D scheme� 1 fuel pin/1 sub-chanel flow description
Several axial slices (usually 30 slices)1D radial calculation on every fuelslice 1D scheme for fuel rod modeling
T, P coolant
cladpellet
Slice n
Slice n+1 rpellet clad
Mechanical and thermal interactions
r
CoooorpusCURRENT MODELING DEVELOPMENT
ALCYONE for fuel performance
JUS 2016 - EDF Lab, Saclay, December 09
OverviewNew generation code, shared project with industry (EDF and AREVA)
3D deterministic multi-purpose code for any kind of reactor concepts
Neutronics at fuel pin to core scales
High Performance Computing (different levels of parallelization)
Focus on the Neutronic core calculationApproximate models of Boltzmann equation :
� Multigroup diffusion or SPN solver MINOS
Finite Elements for 3D extruded hexahedral and hexagonal structured meshes
� Multigroup SN or SPN solver MINARET
Finite Elements for 3D extruded unstructured meshes
Bateman equations for isotopic evolution (depletion)
| PAGE 29
CURRENT MODELING DEVELOPMENT
APOLLO3 * for neutronic modeling
Coooorpus
PWR
(*) D. Schneider et al., “APOLLO3®: CEA/DEN Deterministic Multi Purpose Code for Reactor Physics Analysis”, PHYSOR2016
JUS 2016 - EDF Lab, Saclay, December 09