Transcript Les Structures Internes des REP

DEN - Saclay – Nuclear Material departement
DMN / SRMA
Tensile properties and microstructure
of austenitic steels irradiated in
different reactors
Ph. Dubuisson
X. Averty
M. Žamboch
V.K. Shamardin
V.I. Prokhorov
J.P. Massoud
C. Pokor
Y. Bréchet
Influence of Atomic Displacement Rate on
Radiation-induced Aging of Power Reactor
Ulianovsk, Russia - October 2 - 8, 2005
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 1
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Irradiations in Experimental Reactors
Objective : Evaluate the effects of neutron irradiation on
mechanical properties and resistance to SCC
Temperature
370°C
Reach "rapidly" the end-of-life doses  FBR
• Mechanical properties
Tensile specimens
• SCC
• Microstructure
• Modelling
EBR-II/Phénix
360°C
PWR
40 years
320°C
Bor-60
Materials
Representative of Core Internals of the PWRs
 SA 304L
Baffle plates,
Former, Core barrel
 CW 316
Baffle bolts
BORIS
300°C
Dose
 30 dpa
 95 dpa
C
Cr
Ni
Mn
Mo
Si
Cu
SA 304L
0.022
18.6
9.9
1.8
0.06
0.36
0.25
CW 316
0.054
16.6
10.6
1.1
2.25
0.68
0.24
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 2
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Irradiations in Experimental Reactors

Irradiations in FBR
Temperature
370°C
1.E+15
1.E+14
EBR-II/Phénix
Spectrum effect ?
Flux, Gaz
He, H
E.F(E).Flux
(cm-2s-1)
1.E+13
PWR
Osiris
SM
BOR-60
1.E+12
1.E+11
360°C
1.E+10
1.E-04
1.E-01
1.E+02
1.E+05
1.E+08
Energie en eV
PWR
40 years
 BOR-60 / Osiris
Tensile
320°C Osiris
300°C
Bor-60
SM
SAMARA
 30 dpa
2 irradiation areas
10 dpa
Area without shield
Fast & thermal
neutrons
BORIS
 He effect
• Mechanical properties
Dose • SCC tests
 95 dpa
 Modelling
Tensile
Area with Hf shield
Fast neutrons
Steel
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 3
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Tensile properties
Fast Breeder Reactor BOR 60
1200
40
YS0.2% (MPa)
CW 316
1000
Te = 330°C
3 10-4 s-1
U.E. (%)
35
30
800
BOR 60
320°C
1
SA 304L
25
SA 304L
600
20
15
400
10
0
0 20
200
5
CW 316
Dose (dpa)
0
60
20
40
60
80 100 120 140
U.T.S.  YS0.2%
Saturation
0
20
40
140
Dose (dpa)
0
0
100
60
80 100 120
Total Elongation
5 – 10%
140
SA 304L > 5 dpa
CW 316  10 dpa
CW 316 > SA 304L - 125 dpa
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 4
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Tensile properties
BOR 60 - Osiris
5 dpa
SA 304L
Te = 330°C
3 10-4 s-1
10 dpa
Stress (MPa)
Stress (MPa)
800
800
Osiris
Osiris
600
BOR 60
600
BOR 60
400
400
200
200
Elongation (%)
0
Elongation (%)
0
0
2
4
6
8
10
12
0
2
4
6
8
10
12
No difference between Osiris and BOR 60
No effect of neutron spectrum
Saturation of mechanical properties > 5 dpa
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 5
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Tensile properties
BOR 60 - Osiris
1200
YS0.2% (MPa)
40
CW 316
30
800
Osiris
Te = 330°C
3 10-4 s-1
U.E. (%)
35
1000
BOR 60
320°C
1
SA 304L
25
SA 304L
20
600
15
400
10
200
0
CW 316
5
0
10
20
30
Dose (dpa)
Dose (dpa)
0
0
0
10
20
30
0
10
20
30
No difference between Osiris and BOR 60
No effect of neutron spectrum
Saturation of mechanical properties
SA 304L 5 dpa
CW 316 10 dpa
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 6
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Tensile properties
Helium effect SM 2
Same Flux
6 dpa
Te = 330°C
3 10-4 s-1
17 dpa
Stress (MPa)
SA 304L
300°C
Stress (MPa)
800
800
10 appm
He
300 appm
He
600
SM 2
600 appm
He
14 appm
He
600
400
400
200
200
Elongation (%)
0
Elongation (%)
0
0
2
4
6
8
10
0
2
4
6
8
10
No obvious effect of Helium (H2) content
Saturation of mechanical properties < 6 dpa
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 7
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Tensile properties
BOR 60 – Osiris – SM 2
1200
YS0.2% (MPa)
40
CW 316
35
1000
30
BOR 60
800
Osiris
600
SM 2
Te = 330°C
3 10-4 s-1
U.E. (%)
1
SA 304L
25
SA 304L
20
15
400
10
200
0
CW 316
5
Dose (dpa)
0
0
10
20
30
Dose (dpa)
0
0
10
20
30
0
10
20
30
No obvious effect of helium (H2) on tensile characteristics
Tensile characteristics similar to those measured after irradiation
in Bor-60 (FBR) at 320°C both for CW 316 and SA 304L
No flux effect
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 8
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Tensile properties

Saturation dose at

No evolution between 10 and 125 dpa for both SA 304L - CW 316

CW 316 > SA 304L

No neutron spectrum effect on tensile characterictics
5 dpa for SA 304L
10 dpa for CW 316
hardness – residual ductility
Gaz content and flux
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 9
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Hardening Model
Evolution of the Yield Stress after irradiation
Temperature, fluence, neutron spectrum
TEM
Model of the population
of point defects clusters
(dislocation loops)
Yield Strength of
neutron irradiated materials
Model of hardening
by a cluster population
Microstructural data of
neutron irradiated materials
Tensile tests
Ds proportional a, L
EBR II, Osiris, BOR 60
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
PWR Internals
Ph. Dubuisson - 10
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Microstructure
Frank Loops
Voids
EBR II
375°C - 10 dpa
Black dots
SA 304L
20
1.E+24
diameter
nm
density
-3
m
375°C
330°C
1.E+23
SA 304L
10
330°C
375°C
dose dpa
dose dpa
EBR II
Osiris
BOR 60
CW 316
No precipitation
No more dislocation lines
0
1.E+22
0
10
20
30
40
50
0
10
20
30
40
50
Saturation for dose about 5 - 10 dpa
size
SA 304L  316
density
SA 304L > CW 316
Main feature
Frank loops formation
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 11
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Microstructure Modelling
Frank loop
Loops
Chemical kinetic Model
"Cluster Dynamics"
External source
of irradiation
defects
Neutrons
Evolution of the concentration of point defects
dC v,i
Interstitial
or vacancy
Interstitial
Interstitial
or .
vacancy
vacancy
cluster
sinks : clusters
dislocation lines
grain boundaries /
free surfaces
Homogeneous medium
dt
 Production
- Recombination (v-i)
- Loss of v and i at sinks
- Agglomeration
Neutron spectrum
Flux - EPKA
Evolution of the concentration of interstitial
or vacancy cluster containing n defects
dC n ( t )
 an 1Cn 1 ( t )  bn Cn ( t )  cn 1Cn 1 ( t )
dt
Dislocation network evolution
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 12
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Microstructure Modelling
Frank loop
Chemical kinetic Model
"Cluster Dynamics"
Loops
2,5 10
21
21
2 10
External source
of irradiation
defects
1,5 10
Density
-3
m
50 dpa
30 dpa
21
10 dpa
21
1 10
Neutrons
Interstitial
or vacancy
Interstitial
Interstitial
or .
vacancy
vacancy
cluster
sinks : clusters
dislocations
grain boundaries /
free surfaces
1 dpa
20
5 10
Diameter
nm
0,1 dpa
0
0
5
10
15
25
23
50
10
Density
-3
m
Diameter
40
nm
22
10
30
21
20
20
Dose 10
dpa
10
0
10
Homogeneous medium
20
0
20
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
40
60
Ph. Dubuisson - 13
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Microstructure Modelling
Frank loops
Chemical kinetic Model
"Cluster Dynamic"
30
1,E+24
diameter
nm
density
m-3
SA 304L
1,E+23
20
375°C
1,E+22
10
Emv
1.35 eV
Emi
0.45 eV
Eb2i
0.6 eV
r0
1,E+21
1010 cm-2
330°C
dose dpa
0
0
1.
2.
3.
4.
dose dpa
1,E+20
10
20
30
40
50
0
10
20
30
40
50
Adjust material parameters of the model on low dose data
EBR II - Osiris
Predict the behavior at higher doses
EBR II – Osiris – BOR 60
Comparison with experimental data – BOR 60
Comparison with future results
high doses BOR 60 (90 dpa) and Osiris (10 dpa)
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 14
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Microstructure of expertised components
Temperature dose
Material
(°C)
(dpa) f (nm)
i
CW 316
SA 304
Experimental
Simulation
ri (m-3)
fv (nm)
rv (m-3)
fi (nm)
ri (m-3)
320
10
11,5
25 10 21
/
/
11,2
27 10 21
320
19
7
92 10 21
2
< 10 20
12,8
32 10 21
333
24
10
12 10 21
/
/
18,7
18 10 21
310
35
10
15 10 21
1
1 10 21
10,2
80 10 21
In agreement with results
from experimental reactors
In terms of interstitial loops size and density,
the results of the model are in relatively good agreement
with the results obtained from field experience in PWRs.
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 15
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Hardening - Orowan Model
Ds  Mmb a loops r loopsfloops + al (
Cluster Dynamics
Model
1200
Ds
?
800
Data / Model
)
Dislocations network
evolution
SA 304L
Mpa
Good agreement at
low dose
rdi - rdo
330°C
aloops  0,4
BOR 60
400
Osiris
dose dpa
0
0
Model of defect clusters
Orowan hardening
20
40
60
80
100
Same for
CW 316
no diameter and density saturation
no hardening saturation
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 16
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Modified Orowan Model
 Hardening due to Frank Loops
Ds  M mb a
 Defaulting of the Frank loops
loops
r loops f loops
r
 Transformation in perfect loop under a applied stress
Critical shear stress for defaulting
a Frank loop of diameter f
One relation between r and f
 r and f increase with dose
 Perfect loop glide and annihilate
 Saturation at the critical stress
 Critical dose for the mechanism of hardening
Defaulting
No Defaulting
f
Ds
No
Defaulting
Defaulting
dose
Main parameters
g : Stacking Fault Energy, rd
dc
One adjustable parameter
Number of dislocations in the pile-up
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 17
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Modified "Orowan" model
Hardening model permitting defaulting of Frank Loops
 Saturation of Hardening
800
800
Ds
Ds
CW 316
CW
316
MPa
330°C
330°C
MPa
600
600
330°C
330°C
375°C375°C
Voids
400
400
375°C
375°C
SA 304L
304L
SA
200
200
r0
g
1010 cm-2
26 Jm-2
dose dpa
r0
g
dose dpa
1014 cm-2
42 Jm-2
0
0
0
20
40
330°C
375°C
60
80
100
0
20
40
60
80
100
Good description of experimental data
Need data at high dose to verify
Voids
 data / Model in SA 304
Well description of experimental data by the model
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
 2 steels : r0 g
Ph. Dubuisson - 18
DEN - Saclay – Nuclear Material departement
Slow Strain Rate Tests (SSRT)
PWR environment
13 MPa
DMN / SRMA
O2 ~ 0 ppb
<10 ppb
H2 29 – 30 ml/kg
s (MPa)
1000
CW 316
s MPa
800
B71
700
700
B70
600
Air
500
Air
600
B65
PWR
A53
500
B68
400
PWR
400
A54
300
300
200
0
0
0,02
0,04
0,06
 (%)
0,08
A59
A60
200
B65: 5,2 dpa, 10 appm He, Tensile test in air
B71: 5.0 dpa, 298 appm He, Tensile test in air
B68: 5.6 dpa, 15 appm He, SSRT in PWR
B70: 5.4 dpa, 297 appm He, SSRT in PWR
100
SA 304L
CW 316
Te = 320°C
5 10-8 s-1
SA 304L
900
800
5 dpa
(MPa)
1000
s MPa
900
300°C
s
Flow rate
2 autoclave vol./h
A53: 4.5 dpa, 9 appm He, Tensile test in air
A59: 4.3 dpa, 294 appm He, Tensile test in air
A60: 4.6 dpa, 9 appm He, SSRT in PWR
A54: 4.5 dpa, 294 appm He, SSRT in PWR
100
0
0,1
0
0,02
0,04
0,06
0,08
0,1
 (%)
T.E. of SSRT specimens
strongly reduced (compared to tensile tests in air)
Slight effect
lower for the specimens with “low helium”
of He content
Hardening lower for SA 304 after tests in PWR
No significant difference in susceptibility between SA304L and CW 316
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 19
DEN - Saclay – Nuclear Material departement
DMN / SRMA
TG / IG
fracture
Fracture surfaces
ductile
fracture
ductile
fracture
5 facets
SA 304L
IG
fracture
CW 316
He (appm)
294
9
297
15
% brittle fracture
33,3
71,1
38,0
50,8
facet initiation
TG
IG
TG»IG
IG
fracture in facets
TG»IG
IG>TG
TG=IG
IG>TG
3 facets
Low He
high He
Transgranular
Intergranular
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 20
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Conclusions - Perspectives

Tensile properties
 Saturation dose at
5 dpa for SA 304L
No evolution between
10 dpa for CW 316
10 and 125 dpa
 CW 316 > SA 304L
hardness – residual ductility
 No neutron spectrum effect on tensile characterictics
Gaz content and flux

Microstructure





High density of small Frank loops
+ Voids at high temperature in SA 304L
Disappearance of the initial dislocations network
No precipitation
Reproduce Microstructure observed on PWR components
Hardening Model
 Cluster Dynamic Model
Good agreement with TEM quantification – Frank loops
No real saturation of loop number density and diameter
 Hardening Model
● Orowan Model
No saturation of hardening
● Modified Orowan Model permitting the defaulting of Frank loops
Saturation of Hardening
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 21
DEN - Saclay – Nuclear Material departement
DMN / SRMA
Conclusions - Perspectives

In simulated PWR water
 Total Elongation of the SSRT specimens strongly reduced
 Fracture surface partly intergranular
 T.E. lower - Fracture surfaces more intergranular “low helium” content

Further examinations and SCC tests will be performed on more
highly irradiated materials
 Mechanical properties saturate
 He content increases

Intergranular fracture
SM 2 > BOR 60
Flux effect ? Medium ?
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 22
DEN - Saclay – Nuclear Material departement
DMN / SRMA
This work was performed through a collaboration between
EDF, CEA and RIAR partly sponsored by EPRI
Authors are grateful to:
HT Tang (EPRI),
V. Golovanov and G. Shimansky (RIAR),
P. Brabec and A. Brožova (NRI)
F. Rozenblum, J.C. Brachet and A. Barbu (CEA).
"Influence of atomic displacement rate… " Workshop - Ulyanovsk - October 5, 2005
Ph. Dubuisson - 23