Post on 12-Sep-2018
Fissuration des culasses des moteurs diesel de
secours du parc 900 MWe
Cylinder heads cracking of 900 MWe reactors back-
up diesel generators
Salome-Meca 2018 users day – March 20th – EDF Lab Paris-Saclay
Robin Degeilh, Dominique Geoffroy, Samuel Géniaut, David
Haboussa (R&D/ERMES), François Curtit (R&D/MMC)
Client : Fréderic Gaudeaux (DPN/UNIE/GMAP)
| 2Cylinder heads cracking of 900 MWe reactors back-up diesel generators
INTRODUCTIONCONTEXT
30 x start / shut down per year
| 3Cylinder heads cracking of 900 MWe reactors back-up diesel generators
INTRODUCTIONCONTEXT
| 4Cylinder heads cracking of 900 MWe reactors back-up diesel generators
INTRODUCTIONCONTEXT
Valves bridge cracking
Crack
Water cooling
Combustion chamber
| 5Cylinder heads cracking of 900 MWe reactors back-up diesel generators
INTRODUCTIONCONTEXT
Can bridge cracks propagate up to motor failure ?
UNIE: Need to define (and justify to ASN) the maintenance program
| 6Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Thermal simulation of a start / shut
down motor cycle
Determination of crack growth rate
SUMMARY
Conclusion
Mechanical simulation of a start /
shut down motor cycle
Realisation of the CAD model and
mesh
1
6
5
4
3
2
Ma
teria
l Th
erm
o-m
ec
ha
nic
al
pro
pe
rties
| 7Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Thermal simulation of a start / shut
down motor cycle
Determination of crack growth rate
SUMMARY
Conclusion
Mechanical simulation of a start /
shut down motor cycle
Realisation of the CAD model and
mesh
1
6
5
4
3
2
Ma
teria
l Th
erm
o-m
ec
ha
nic
al
pro
pe
rties
| 8Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Tests
at
20,
220
and 4
20°C
Monotonous tensile test
Cyclic compression/tensil test
Fatigue propagation test
IDENTIFICATION OF THERMO-MECHANICAL PROPERTIESEXPERIMENTAL CHARACTERIZATION
Cast iron GJL300 from
rejected cylinder heads
Elastic-plastic behaviour
| 9Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Tests
at
20,
220
and 4
20°C
Monotonous tensile test
Cyclic compression/tensil test
Fatigue propagation test
IDENTIFICATION OF THERMO-MECHANICAL PROPERTIESEXPERIMENTAL CHARACTERIZATION
Tension/compression
dissymmetry
Growing symmetrical strain controlled test
Applie
d s
train
0
| 10Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Tests
at
20,
220
and 4
20°C
Monotonous tensile test
Cyclic compression/tensil test
Fatigue propagation test
IDENTIFICATION OF THERMO-MECHANICAL PROPERTIESEXPERIMENTAL CHARACTERIZATION
Température Cmoyen mmoyen
20°C 1,77E-12 6,65
220°C 3,98E-12 6,55
420°C 1,83E-11 6,50
| 11Cylinder heads cracking of 900 MWe reactors back-up diesel generators
IDENTIFICATION OF THERMO-MECHANICAL PROPERTIESCONSTITUTIVE MODEL DEVELOPMENT
code_aster
Identification at 20, 220 and
420°C
Implementation MFront
Development
non-linear kinematic
hardening function of
sign of trace(σ)
| 12Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Thermal simulation of a start / shut
down motor cycle
Determination of crack growth rate
SUMMARY
Conclusion
Mechanical simulation of a start /
shut down motor cycle
Realisation of the CAD model and
mesh
1
6
5
4
3
2
Ma
teria
l Th
erm
o-m
ec
ha
nic
al
pro
pe
rties
| 13Cylinder heads cracking of 900 MWe reactors back-up diesel generators
NUMERICAL MODEL3D CAD
| 14Cylinder heads cracking of 900 MWe reactors back-up diesel generators
NUMERICAL MODEL3D SANE MESH
640 000 nodes
Element size ~2mm
| 15Cylinder heads cracking of 900 MWe reactors back-up diesel generators
NUMERICAL MODEL3D CRACKED MESHES
One crack per bridge 3 meshes
28mm
20mm
Maximal measured length according to UNIE
Zcracks
| 16Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Thermal simulation of a start / shut
down motor cycle
Determination of crack growth rate
SUMMARY
Conclusion
Mechanical simulation of a start /
shut down motor cycle
Realisation of the CAD model and
mesh
1
6
5
4
3
2
Ma
teria
l Th
erm
o-m
ec
ha
nic
al
pro
pe
rties
| 17Cylinder heads cracking of 900 MWe reactors back-up diesel generators
T=20°C
Start
Temperature stabilisation
Shut down
THERMAL SIMULATION OF A MOTOR CYCLEBOUNDARY CONDITIONS - START
Exchange
condition
Exchange condition
Exchange
condition
Exchange condition = h(r)
0
50
100
150
200
250
300
350
400
0 50 100 150 200 250 300
Te
mpé
ratu
re (
°C)
Temps (s)
PAA
PAE1
PAE2
PEE
r
| 18Cylinder heads cracking of 900 MWe reactors back-up diesel generators
T=20°C
Start
Temperature stabilisation
Shut down
THERMAL SIMULATION OF A MOTOR CYCLEBOUNDARY CONDITIONS - STABILISATION
Exchange
condition
Exchange condition
Exchange
condition
Exchange condition = h(r)
r
0
50
100
150
200
250
300
350
400
450
500
0 20 40 60 80 100 120 140
Te
mp
era
ture
(°C
)
Radius (mm)
Mesure
Calcul
| 19Cylinder heads cracking of 900 MWe reactors back-up diesel generators
0
50
100
150
200
250
300
350
400
300 2 300 4 300 6 300 8 300 10 300 12 300 14 300 16 300
Te
mpe
ratu
re (
°C)
Time (s)
PAA
PAE1
PAE2
PEE
T=20°C
Start
Temperature stabilisation
Shut down
THERMAL SIMULATION OF A MOTOR CYCLEBOUNDARY CONDITIONS – SHUT DOWN
Exchange condition(water flow /50)
| 20Cylinder heads cracking of 900 MWe reactors back-up diesel generators
THERMAL SIMULATION OF A MOTOR CYCLERESULT
| 21Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Thermal simulation of a start / shut
down motor cycle
Determination of crack growth rate
SUMMARY
Conclusion
Mechanical simulation of a start /
shut down motor cycle
Realisation of the CAD model and
mesh
1
6
5
4
3
2
Ma
teria
l Th
erm
o-m
ec
ha
nic
al
pro
pe
rties
| 22Cylinder heads cracking of 900 MWe reactors back-up diesel generators
MECHANICAL SIMULATION OF A MOTOR CYCLEBOUNDARY CONDITIONS
normal displacement=0
r
| 23Cylinder heads cracking of 900 MWe reactors back-up diesel generators
MECHANICAL SIMULATION OF A MOTOR CYCLERESULT ON SANE MESH
End of start End of shut down
| 24Cylinder heads cracking of 900 MWe reactors back-up diesel generators
MECHANICAL SIMULATION OF A MOTOR CYCLERESULT ON SANE MESH
End of start
End of shut down
End of start End of shut down
Linear mesh
Quadraticmesh
Depth (mm)
| 25Cylinder heads cracking of 900 MWe reactors back-up diesel generators
MECHANICAL SIMULATION OF A MOTOR CYCLERESULT ON CRACKED MESH
| 26Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Thermal simulation of a start / shut
down motor cycle
Determination of crack growth rate
SUMMARY
Conclusion
Mechanical simulation of a start /
shut down motor cycle
Realisation of the CAD model and
mesh
1
6
5
4
3
2
Ma
teria
l Th
erm
o-m
ec
ha
nic
al
pro
pe
rties
| 27Cylinder heads cracking of 900 MWe reactors back-up diesel generators
DETERMINATION OF CRACK GROWTH RATERESULTS IN ΔK
Post-treatment with POST_K1_K2_K3 (elastic)
Cracking rateParis law
Curvilinear abscise (mm)
Bridge C
Bridge A
Bridge D
| 28Cylinder heads cracking of 900 MWe reactors back-up diesel generators
DETERMINATION OF CRACK GROWTH RATERESULTS IN CRACK GROWTH
Bridge A Bridge C Bridge D
1500 start / shut down
Margin=7,10mm Margin=7,01mmMargin=7,75mm
| 29Cylinder heads cracking of 900 MWe reactors back-up diesel generators
Thermal simulation of a start / shut
down motor cycle
Determination of crack growth rate
SUMMARY
Conclusion
Mechanical simulation of a start /
shut down motor cycle
Realisation of the CAD model and
mesh
1
6
5
4
3
2
Ma
teria
l Th
erm
o-m
ec
ha
nic
al
pro
pe
rties
| 30Cylinder heads cracking of 900 MWe reactors back-up diesel generators
CONCLUSION
Note EDF R&D 6125-1716-2017-00547-FR « Projet MODERN - Justification de la tenue des culasses des moteurs diesels des tranches 900 MWe (LP 3.6) »
Can bridge cracks propagate up to motor failure ?
Bridge cracks cannot propagate up to motor break down over 1500 start / shut down
• Experimental mechanical characterisation
• New cyclic inelastic behaviour model in MFront
• 3D complex shape CAD from plans
• Thermo-mechanical study in code_aster
Questions ?