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Understanding on the Mechanisms of Irradiation Embrittlement of RPV Steels
andDevelopment of Embrittlement Correlation
Method
30/9/20141
IAEA Training Workshop onAssessment of Degradation Mechanisms of Primary Components in Water Cooled Nuclear Reactors: Current Issues and Future Challenges
Akiyoshi NomotoCentral Research Institute of Electric Power Industry (CRIEPI)
Embrittlement Mechanism : General Consensus
Formation of Cu-enriched clusters (CEC, CRP) in Cu-containing materials Cu core associated with Ni, Mn and Si 2~3 nm in diameter obstacle to dislocation motion dose rate effect exists
Formation of matrix damage (MD) point defect clusters such as dislocation loops or vacancy
clusters, or point defect – solute atom complexes. main contributor to the embrittlement of low Cu materials
Phosphorus segregation on grain boundary P segregation weakens grain boundaries.
P
MD
CECG.B.
Dislocation
Cu
30/9/2014 2
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
330/9/2014
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
430/9/2014
5
APT characterization of irradiated RPV steel
EW-P2 R7-00561: 30x29x232 nm3, 6.4M atoms
30nm
232nmCu P Si
Clusters consist of Cu, Ni, Mn, Si and P. Cu atoms are at the center. Ni, Mn and Si atoms are around the Cu core, and P atoms are at
the periphery.
High impurity (Cu) weld metal irradiated to high fluence
30/9/2014
High Cu steel0.12Cu, 4x1019n/cm2, E>1MeV
Medium Cu steel0.07Cu, 6x1019n/cm2, E>1MeV
Low Cu steel0.03Cu, 6x1019n/cm2, E>1MeV
Nature of Cu-enriched clusters
Cu-Ni-Si-Mn cluster
Ni-Si-Mn cluster
High Cu steel0.12Cu, 4x1019n/cm2, E>1MeV
35 x 41 x 491 nm3 :13.7M atoms
33 x 38 x 284 nm3 : 8.1M atoms
41 x 49 x 264 nm3 : 11.2M atoms
30/9/2014 6
Cu P Si
Contribution of SC to embrittlement
0
20
40
60
80
100
0 0.02 0.04 0.06 0.08
Vf1/2
T 4
1J
0
50
100
150
200
0.00 0.05 0.10 0.15
RT N
DT
(o C)
Vf1/2
Surveillance data(N. Soneda et al. CRIEPI Q06019, 2007)
MTR irradiated data(JNES PRE Project, N. Soneda et al. JAI 102128, 2009.)
RT N
DT
(oC
)
RT N
DT
(oC
)
Vf1/2 Vf
1/2
Transition temperature shift is almost proportional to Vf1/2 of
solute atom clusters. This relationship between RTNDT and Vf
1/2 is independent of chemical compositions of the clusters.
Slight difference in the slopes is observed between the surveillance data and MTR data.
30/9/2014 7
TEM Observation : Surveillance Materials
Dislocation loops are observed in the RPV materials irradiated in commercial reactors.
Number densities of the loops are relatively low.
50nm50nmB=[011], 3g (g=21-1) B=[133], 3g (g=-110)
0.12Cu : 4x1019n/cm2 0.07Cu : 6x1019n/cm2
Mean size: 2.6 nmNumber density: 1.8x1022 m-3
Mean size: 2.3 nmNumber density: 1.9x1022 m-3
30/9/2014 8
TEM Observation : MTR irradiated materials
Dislocation loop are observed.• Number density is 1021~1022 m-3, and the diameter is 4~5 nm.
Some of the loops are formed near one side of the line dislocations.
930/9/2014
g g
B9-2 (0.04Cu, 6x1019n/cm2) B9-3 (0.04Cu, 12x1019n/cm2)
Dislocation loop formation near line dislocations Clusters are preferentially formed near one
side of dislocation. Some clusters are the rings that lie on the
same plane, suggesting dislocation loops. Some of the other clusters may be small
dislocation loops with solute atom segregation.
●Cu, ●Si, ●P
B9-3: R7_02571, 35.7x41.6x235nm, 8.05M
B9-3: R7_02618, 42.9x49.4x265nm, 12.0M
gB9-3
Presented at ASTM Symposium in 2008.30/9/2014 10
TEM Observation
1130/9/2014
0.0E+00
2.5E+21
5.0E+21
7.5E+21
1.0E+22
0.0E+00 5.0E+19 1.0E+20 1.5E+20
Num
ber d
ensit
y (m
-3)
Fluence (n/cm2, E>1MeV)
0
2
4
6
8
0.0E+00 5.0E+19 1.0E+20 1.5E+20
Mea
n di
amet
er (n
m)
Fluence (n/cm2, E>1MeV)
B1
S1
B9
P1B
Both number density and mean diameter increases with increasing fluence.
Number density can be larger because of resolution limit of our TEM measurement.
Num
ber d
ensi
ty (m
-3)
Mea
n di
amet
er (n
m)
Fluence (n/cm2, E>1MeV) Fluence (n/cm2, E>1MeV)
Estimates of T due to dislocation loops
1230/9/2014
0
50
100
150
200
0 50 100 150 200
Estim
ated
T
due
to d
isl lo
op (
o C)
RTNDT (oC)
B1
S1
B9
P1B
dNbM
65.0NDTRT
: 0.4M : 2
Orowan model:
Embrittlement mechanism: revised
Copper-enriched cluster Matrix damage Phosphorus segregation on
grain boundary
P
MD
CRP G.B
Disl.
Cu
Solute atom cluster Dislocation loop
MD
SC G.B.
Disl.
Solute atom
30/9/2014 13
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
1430/9/2014
Effect of solute element
Copper is the most harmful element.
Synergetic effect of copper and nickel has been well recognized since the work by Hawthorne (1982).
Phosphorus?
Manganese?
30/9/2014 15
Effect of Ni : IVAR Materials
1630/9/2014
ID TypeComposition / wt%
Cu Ni Mn Cr Mo P C Si S Fe
CM15A533BPlate
0.22 0.02 1.59 0.02 0.58 0.002 0.14 0.15 0.003 Bal.
CM16A533BPlate
0.22 0.82 1.58 0.00 0.51 0.004 0.16 0.25 0.000 Bal.
CM17A533BPlate
0.22 1.59 1.54 0.00 0.50 0.004 0.16 0.25 0.000 Bal.
ID Flux(x1012n/cm2/s, E>1MeV)
Fluence(x1019n/cm2, E>1MeV)
Temperature(℃)
T16 0.3 1.6 290
Chemical composition
Irradiation Condition
1730/9/2014
Ni Effect of Ni on 0.22Cu-xNi-1.6Mn alloys
20nm
Dislocation
1.59wt%Ni(CM17)(78x80x220nm, 31M atoms)
0.82wt%Ni(CM16)(89x88x230nm, 41M atoms)0.02wt%Ni(CM15)
(85x85x260nm, 41M atoms)
φt=1.6x1019 n/cm2, φ=3x1011 n/cm2/s, T=290oC
●Cu●Si●P
1830/9/2014
0.E+00
1.E+23
2.E+23
3.E+23
4.E+23
5.E+23
0.0 0.5 1.0 1.5 2.0Ni content (wt%)
Clu
ster
Num
ber D
ensi
ty (m
-3)
3.0
3.2
3.4
3.6
3.8
0.0 0.5 1.0 1.5 2.0Ni content (wt%)
Clu
ster
Dia
met
er
(nm
)
0.0E+00
2.0E-03
4.0E-03
6.0E-03
8.0E-03
1.0E-02
1.2E-02
0.0 0.5 1.0 1.5 2.0Ni content (wt%)
Clu
ster
Vol
ume
Frac
tion
0%
20%
40%
60%
80%
100%
0.02 0.82 1.59Ni content (wt%)
Clu
ster
Com
posi
tion
(at.%
)
CPSiCuNiCrMnFe
Effect of Ni on 0.22Cu-xNi-1.6Mn alloysN
umbe
r den
sity
(m-3
)
Gui
nier
diam
eter
(nm
)
Volu
me
frac
tion
Ni content (wt.%) Ni content (wt.%)
Ni content (wt.%) Ni content (wt.%)
Com
posi
tion
(at.%
)
Effect of Ni on Hardening
G.R. Odette, G.E. Lucas, ASTM STP 1046 (1990) 323. H. Shibamoto, et al., ASTM STP 1405
(2001) 722.
30/9/2014 19
Increase in nickel content causes hardening even in very low or no copper materials.
Number density of dislocation loops increases and loop size decreases in nickel containing materials.
Effect of Phosphorus
Effect of P has been widely accepted, but the mechanism has not been identified yet.
Non hardening embrittlement due to P segregation on grain boundaries is a possibility, but it seems that this is not the mechanism of P effect in western-type RPV materials.
There is a data indicating that P plays a role in low Cu materials but not in high Cu materials. P contributes to hardening by forming precipitates. Recent US correlation method
P atoms are found mostly on dislocation lines and solute atom clusters (APT). They agglomerate to such features very quickly.
30/9/2014 20
Effect of P in low and high Cu materials
P effect is evident only in low Cu materials.
Very little data are available in the surveillance database for low Cu & high P materials. It is not easy to separate the
effect of P from that of Cu.
Hawthorne, 1986.30/9/2014 21
Effect of Mn on Hardening
Mn effect may exist in RPV materials.
Fe-Mn model alloy also shows larger embrittlement than pure Fe. (A. Kimura, et al.) Mn clusters are also observed in
Fe-Mn model alloy. (Y. Nagai, et al.) Fe-ion irradiation of Fe-Mn alloy
shows similar results.
Fe-ion irradiationRT, 0.3dpa, 3.8x10-5dpa/s
30/9/2014 22
Nominal Mn vs LEAP Mn
The Mn contents measured by APT is far less than the nominal bulk Mn contents, and there is non trivial scatter.
Carbides detected by LEAP contain a lot of Mn atoms.
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.30 1.40 1.50 1.60
Mn
Con
tent
by
LEA
P (w
t.%)
Bulk Mn Content (wt.%)
Mn1:1 line
xy
z
Carbide includeing Mn
Direction of composition profile
0
4
8
0 10 20 30 40 50Distance (nm)
Mn Cr NiCu Si P
0
50
100
Fe C
Com
posi
tion
(at.%
)
30/9/2014 23
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
2430/9/2014
Effect of temperature
Low temperature irradiation causes larger shifts in both high and low Cu materials.
Empirical linear correlation has been proposed by Jones and Williams for low Cu materials.
A533BShift at Charpy 41JFluence : 1.7x1019n/cm2, E>1MeV
Weld:0.25wt.%Cu
Weld: 0.15wt.%Cu
Base metal: 0.04wt.%Cu
Irradiation Temp. (oC)
D
BTT
(oC
)
J. Ahlf, F.J. Schmitt, IAEA Specialists’ Meeting on “Irradiation Embrittlement and Surveillance of Reactor Pressure Vessels,” IAEA, Vienna, 19-21, Oct. 1981.
30/9/2014 25
Effect of temperature : IVAR materials
2630/9/2014
ID Flux(x1012n/cm2/s, E>1MeV)
Fluence(x1019n/cm2, E>1MeV)
Temperature(℃)
T18 0.36 1.7 270
T16 0.3 1.6 290
T20 0.34 1.6 310
Chemical composition
Irradiation Condition
ID TypeComposition / wt%
Cu Ni Mn Cr Mo P C Si S Fe
LIA533BPlate
0.20 0.74 1.37 - 0.55 0.005 0.16 0.24 0.015 Bal.
LHA533BPlate
0.11 0.74 1.39 - 0.55 0.005 0.16 0.24 0.015 Bal.
Atom Maps : LI (high Cu) materials
2730/9/2014
LI-T1870x70x270nm, 26M atoms
270oC
LI-T2090x93x210nm, 39M atoms
LI-T1679x79x220nm, 29M atoms
290oC 310oC
20nm
●Cu●Si●P
Atom Maps : LH (low Cu) materials
2830/9/2014
LH-T1891x91x210nm, 39M atoms
LH-T2091x95x310nm, 58M atoms
LH-T1679x79x220nm, 29M atoms
20nm
●Cu●Si●P
270oC 290oC 310oC
0.E+00
2.E-03
4.E-03
6.E-03
8.E-03
1.E-02
260 270 280 290 300 310 320Irradiation Temperature (℃)
Clu
ster
Vol
ume
Frac
tion LI
LH
Temperature Effect
2930/9/2014
0.E+00
2.E-02
4.E-02
6.E-02
8.E-02
1.E-01
260 270 280 290 300 310 320Irradiation Temperature (℃)
Squa
re ro
ot o
f clu
ster
Vol
ume
Frac
tion
LILH
0.E+00
1.E+23
2.E+23
3.E+23
4.E+23
5.E+23
6.E+23
7.E+23
8.E+23
260 270 280 290 300 310 320Irradiation Temperature (℃)
Clu
ster
Num
ber D
ensi
ty (m
-3)
LILH
2.5
3.0
3.5
4.0
260 270 280 290 300 310 320Irradiation Temperature (℃)
Clu
ster
Dia
met
er
(nm
) LILH
Num
ber d
ensi
ty (m
-3)
Gui
nier
diam
eter
(nm
)
Volu
me
frac
tion
Squa
re ro
ot o
f Vf
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
3030/9/2014
Effect of fluence
The amount of embrittlement is predicted as a power function of fluece with the exponent of 0.15~0.35 for the fluences up to 1x1020 n/cm2, E>1MeV. RG1.99 : 0.28-0.10logf JEAC4201 : 0.29-0.04logf (base metal), 0.25-0.10logf (weld) FIS : 0.35 VVER : 0.29-0.04logf (VVER-440), 0.33 (VVER-1100)
Recent mechanism-guided correlation equations predict that different fluencefunctions for CRP and MD. TMD = A (f)0.5
TCRP = B (1+tanh((log f - C)/D Late Blooming Phase
High Ni and high fluence log f
T
CRP
MD
30/9/2014 31
Fluence effect on the volume fraction of SC
0.0000
0.0025
0.0050
0.0075
0.0100
0.0125
0.0150
0 5 10 15
Volu
me
fract
ion
Fluence (x1019 n/cm2, E>1MeV)
0.0000
0.0025
0.0050
0.0075
0.0100
0.0125
0.0150
0 5 10 15Vo
lum
e fra
ctio
nFluence (x1019 n/cm2, E>1MeV)
B1 (0.21/0.63)
B4 (0.17/0.62)
B5 (0.10/0.59)
B9 (0.04/0.62)
B6 (B5+0.92Ni)
B7 (B5+0.017P)
B8 (B5+0.32Si)
S1 (0.09/0.62)
S1s (0.09/0.62)
S2s
P1B (0.06/0.58)
P2B (0.25/0.59)
P3B (P1B+0.018P)
P4B (P1B+1.78Ni)
W1 (0.20/0.88)
W2 (0.13/0.86)
W3 (0.10/0.88)
W4 (0.02/0.84)
N. Soneda et at., J. of ASTM International, Vol. 6, No. 7, Paper ID JAI102128
JNES PRE Project
30/9/2014 32
Volume fractions of solute atom clusters keep increasing with fluence. This is primarily due to the growth of clusters. Number density does not increase very much with fluence.
Composition change in high-Cu material
3330/9/2014
0
50
100
150
200
250
0 1000 2000 3000 4000 5000 6000
Num
ber o
f Cu atom
s in a cluster
Cluster size
G1
G3
0
20
40
60
80
100
120
140
160
0 1000 2000 3000 4000 5000 6000
Num
ber o
f Si atoms in a cluster
Cluster size
G1
G3
0
20
40
60
80
100
120
140
160
0 1000 2000 3000 4000 5000 6000
Num
ber o
f Ni atoms in a cluster
Cluster size
G1
G3
0
50
100
150
200
250
300
350
0 1000 2000 3000 4000 5000 6000
Num
ber o
f Mn atom
s in a cluster
Cluster size
G1
G3
Cu Si
Ni Mn
φt=1.6(G3), 13(G1) x1019 n/cm2, φ=1x1014 n/cm2/s, T=290oC
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
3430/9/2014
Dose Rate Effect in Low Cu Material
3530/9/2014
60
50
40
30
20
10
0
硬化量(MPa)
5 6 7 8 9
10112 3 4 5 6 7 8 9
1012
中性子照射速度(n/cm 2 -s)
中性子照射量 低(~1018n/cm2)
高(~1019n/cm2)
高照射量
低照射量
Incr
ease
in y
ield
stre
ss (
MP
a)Dose rate (n/cm2-s)
Tran
sitio
n te
mpe
ratu
re s
hift
(oC
)
Fluence (x1019n/cm2)
Comparison of French surveillance data and test reactor irradiation data
Comparison of test reactor data irradiated at different fluxes
No clear dose rate effect is observed in low Cu materials.
P. Petrequin, ASMES:1996. Report Number 6 EUR 16455 EN 1996.
CRIEPI/UCSB Joint Program
FluenceLowHigh
Low flux irradiation data in Japan
Very low flux irradiation causes larger shifts.
0
10
20
30
40
50
60
70
80
0.0E+00 5.0E+17 1.0E+18 1.5E+18 2.0E+18 2.5E+18 3.0E+18
Fluence (n/cm2)
Del
ta T
r30
(o C)
Surveillance (A)Surveillance (W)
MTR
SPT1
SPT2
SP1
~109 n/cm2-s~1010 n/cm2-s~1012 n/cm2-s
Cu: 0.24 wt.%
Neutron fluence (n/cm2, E>1MeV)
R
T ND
T(o
C)
30/9/2014 36
0
10
20
30
40
50
60
70
80
0.0E+00 5.0E+17 1.0E+18 1.5E+18 2.0E+18 2.5E+18 3.0E+18
Fluence (n/cm2)
Del
ta T
r30
(o C)
Surveillance (A)Surveillance (W)MTR
SPT1
SPT2
SP1
~109 n/cm2-s~1010 n/cm2-s~1012 n/cm2-s
Surveillance materials study (2)
0
10
20
30
40
50
60
70
80
0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.2 5.6 6.0
Cluster diameter (nm)
Counts
Cou
nts
Guinier diamter (nm)
SP1Cu 0.24 wt.%t 9x1017 n/cm2
Nd 4.32 x 1023 m-3
Vf 4.39 x 10-3
dG 2.58 nm
Low flux Irradiation (BWR)
0
5
10
15
20
25
30
0.0 0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.4 4.8 5.2 5.6 6.0
Cluster diameter (nm)
Cou
nts
Guinier diameter (nm)
Cou
nt
SPT1Cu 0.24 wt.%t 1.3x1019 n/cm2
Nd 2.94 x 1023 m-3
Vf 1.25 x 10-3
dG 1.96 nm
High flux Irradiation (MTR)
R
T ND
T(o
C)
Neutron fluence (oC)
Very low flux irradiation causes larger shifts.
Lower flux irradiation makes Cu-enriched clusters much larger.
Cu: 0.24 wt.%
30/9/2014 37
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
3830/9/2014
Understanding on the Mechanisms of Irradiation Embrittlement of RPV Steels
andDevelopment of Embrittlement Correlation
Method
30/9/201440
IAEA Training Workshop onAssessment of Degradation Mechanisms of Primary Components in Water Cooled Nuclear Reactors: Current Issues and Future Challenges
Akiyoshi NomotoCentral Research Institute of Electric Power Industry (CRIEPI)
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
4130/9/2014
Embrittlement correlations
4230/9/2014
FFCFT J 41US NRC RG1.99r1 (1977)
1980 1990 2000
FIS/FIM (1987)
KTA 3203 (6/01) (2001)
Williams et al. (1988)
EWO (1996)
E900-02 (2002)
Statistics based
Mechanism based
WWER-1000 (2002)
CRPMDJ TTT 41
WR-C(5)Rev.1 (2010)
2010JEAC4201-2013 (2013)
KTA 3203 (3/84) (1984)
WWER-440 (1993)
US NRC RG1.99r2 (1988)JEAC4201-1991 (1991)
Revised EWO (2000)
Fisher et al. (1983, 1985, 1987)Odette, Lucas (1983, 1985)
Williams et al. (2001,2002)
Williams et al. (2010)EDF (2010)
EONY (2007)JEAC4201-2007 (2007)
Debarberis et al. (2005, 2006)
Margolin et al. (2012)Ahlstrand et al. (2012)
Statistics based correlations
4330/9/2014
5.041 08.01000008.0500040
95 fCuPT J
US NRC RG1.99r1 (1977)
US NRC RG1.99r2 (1988)
fJ fNiCuCFT log1.028.0
41 ),(95
FIS (1987)
JEAC4201-1991 (1991)
35.0219108.0238008.01537248 CuNiCuPTT
fJ fCuNiCuPT log04.029.05.0
41 77215121016
fJ fCuNiNiSiT log1.025.05.0
41 301612426
FFCFT J 41
Mechanism based correlation(USA)
4430/9/2014
CRPSMD41 JT
f
c
fPT
ASMD log0597.04449.04
7.571460
10906.1exp95
plates ,10x24.1forgings ,10x98.8
welds,10x10.1
7
8
7
A fGCuFNiBCRP 358.156.2195
plates ,172forgings ,135
welds,209B
wt%0.300 Cu 0.367,
%wt072.0Cu,)072.0(Cu%wt072.0Cu,0
678.0CuF
600.0290.181048.5log
tanh21
21 12
ftffG
EWO (1996)CRPMDJ TTT 41
Mechanism of embrittlement(EWO)
4530/9/2014
0
20
40
60
80
100
120
0 2E+19 4E+19 6E+19 8E+19 1E+20
∆R
TND
T (°
C)
Fluence (n/cm², E>1MeV)
TotalMDCEC/CRP
∆R
T ND
T(°
C)
Fluence (n/cm2, E>1MeV)
燐
SMD
CRP 粒界
転位
銅
CRPSMD
: Copper Rich Precipitate: Stable Matrix Damage
(2~3 nanometers)
Cupper enriched clusters and matrix damage cause embrittlement
CRP formation is a function of Copper content, Nickel content and irradiation time and will be saturated.
Effect of temperature and P on MD
Mechanism based correlation(USA)
4630/9/2014
EONY (2007)termCRPtermMFTTS
ei tMnPTAtermMF 47.213.61001718.01
for welds10417.1platesfor 10561.1
forgingsfor 10.1401
7
7
7
A
1010
10
1039.4 1039.41039.4
fort
fortte
eee tNiCugPCufNiBtermC ,,,77.031 RP 191.1
plates SRMfor 128.2for welds 155.0
vesselsmfg. CEin platesfor 35.21 vesselsmfg. CE-nonin platesfor 02.51
forgingsfor 02.31
B
.% 072.0for ,min
.% 072.0for 0wtCuCuMaxCu
wtCuCu
ee
materialsother allfor .3010
welds80 Linde 0.5) (Ni lfor typica 243.0eCuMax
668.0008.0359.1072.0, PCuPCuf ee
629.0
120.18448.0139.1logtanh21
21,, 10 NiCuttNiCug ee
ee
Based on EWOEffective fluence teEffect of Mn
Russia/VVER
4730/9/2014
WWER-1000 (2002)
Debarberis et al. (2005, 2006)
3107.0800 Rk FCuPT
WWER-440 (1993)
3120 Rk FT
dcebaDBTT startn
shiftsat tanh5.05.01
Matrix damage CEC P segregation
France
4830/9/2014
FIS/FIM (1987)
EDF (2010)
35.0219108.0238008.015373.17 CuNiCuPTT
35.0219108.0238008.01537248 CuNiCuPTT
59.028.508.06.6008.07.351 CuNiCuPATT
FIMFIS
Low copper content in French RPV steels
USA
4930/9/2014
BM
CuT
0
052.031.0,MINMAX30
WR-C(5)Rev.1 (2010)
105.058.078.122.4
17
012.01.0
63.0433.0
550
0,3.613,0.13810151.1lnlnMINMAX675.0989.0073.1
PNiT
MMM
M
F
P
W
173.042.035.1105.041.4
5503.010
36.163.055.0
012.01.0
550
10335.9167.1315.1
2.1
MnNiPT
BBB
B
F
P
W
WR-C(5) Rev-1
Statistics based correlation
Not only US surveillance data but also non-US data and MTR data are used for the development ~2400 data
The formula is similar to EONY as a result
Developed by Dr. Mark Kirk (NRC)
30/9/2014 50
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
5130/9/2014
Previous Japanese correlation
5230/9/2014
JEAC4201-1991
fJ fCuNiCuPT log04.029.05.0
41 77215121016
fJ fCuNiNiSiT log1.025.05.0
41 301612426
ΔT41J, ΔTTCu, Ni, P, Sif,
:DBTT shift(℃):Content of Cu, Ni, P and Si (wt.%):Neutron fluence(x1019 n/cm2, E>1MeV)
Statistics based correlations
Prediction by JEAC4201-1991
5330/9/2014
TBD
D s
hift
Neutron fluence (n/cm2, E>1MeV)
6x1019n/cm2
(40years)1x1020n/cm2
(60years)
Hi Cu steelsHigh Cu steels irradiated at low flux
Low Cu steels
Low Cu steels irradiated up to high fluences
JEAC4201-1991Surveillance data
fJ fCuNiCuPT log04.029.05.0
41 77215121016
fJ fCuNiNiSiT log1.025.05.0
41 301612426
Development new Japanese correlation
Larger embrittlement in high Cu steels than expected at lower flux conditions.
Trend of embrittlement of low Cu steels irradiated up to high fluences is different from predicted.
New results/knowledge of mechanism of irradiation embrittlement
Development of new correlation based on understanding of mechanism
30/9/2014 54
Embrittlement mechanism
MD
SC G.B.
Disl.
Solute atom
55
Solute atom cluster Dislocation loop
30/9/2014
Dislocation loop formation near line dislocations Clusters are preferentially formed near one
side of dislocation. Some clusters are the rings that lie on the
same plane, suggesting dislocation loops. Some of the other clusters may be small
dislocation loops with solute atom segregation.
●Cu, ●Si, ●P
B9-3: R7_02571, 35.7x41.6x235nm, 8.05M
B9-3: R7_02618, 42.9x49.4x265nm, 12.0M
gB9-3
Presented at ASTM Symposium in 2008.30/9/2014 56
Modeling of microstructural change
59
Irradiation induced clustersIrradiation enhanced clusters
Matrix damage Matrix damage
Irradiation induced clusters
30/9/2014
Contribution of clusters to embrittlement
監視試験データ(N. Soneda et al. CRIEPI Q06019, 2007)
試験炉照射データ(JNES PRE Project, N. Soneda et al. JAI 102128, 2009.)
0
20
40
60
80
100
0 0.02 0.04 0.06 0.08
Vf1/2
T41
J
0
50
100
150
200
0.00 0.05 0.10 0.15
RT N
DT
(o C)
Vf1/2
RT N
DT
(oC
)
RT N
DT
(oC
)Vf
1/2 Vf1/2
DBTT shift is proportional to sqrt of volume fraction of solute atom clusters Independent of chemical composition
6030/9/2014
Embrittlement due to microstructure
Microstructural change
Japanese correlation (JEAC4201-2007/-2013)
6130/9/2014
2089214 1 NiCu
availCuMDCu
matCu
SC CDCCDCt
C
t
CCFt
C SCNiT
MD
276
25
SCSC
enhSc
SC
matCu Cv
tC
vt
C
21
thermalCu
irradCu
thermalCuCu DDDD
MDMD CT 18
22MDSC TTT
,17 fSC VT SCCuNiSCmatCuf CtDCCCfV
1110
20
1416 11, 15
Japanese correlation
Based on revised embrittlement mechanism Solute atom clusters
Effect of neutron flux
Independent of product form (base metal, weld)
Prediction of "trend" of embrittlement
Offset correction
6230/9/2014
照射量
脆化量
照射量
脆化量 T
tOffset
T
tOffset
脆化量
照射量Fluence
T
Fluence
T
Fluence
T
Surveillance data vs prediction
6330/9/2014
-20
0
20
40
60
80
100
120
140
160
180
200
-20 0 20 40 60 80 100 120 140 160 180 200
Cal
cula
ted
ΔR
T ND
T(°
C)
Measured ΔRTNDT (°C)
Base and weld metalsSRM materialsMTR materials1:1 line±22°C
-20
0
20
40
60
80
100
120
140
160
180
200
-20 0 20 40 60 80 100 120 140 160 180 200C
alcu
late
d Δ
RT N
DT
(°C
)
Measured ΔRTNDT (°C)
Base and weld metalsSRM materialsMTR materials1:1 line±18°C
Outline
Part I Irradiation-induced features that cause embrittlement Effect of solute element Effect of temperature Effect of neutron fluence Effect of neutron flux
Part II Embrittlement correlation methods Development of Japanese embrittlement correlation Known unknows and unknown unknows
6430/9/2014
Known unknows
Unstable matrix feature (UMF) Does high flux irradiation cause larger shifts at high fluences? Is UMF a new phase (MD, CEC + UMF) or anything else?
Late Blooming Phase Ni-Mn-Si phase are formed in low Cu and medium Ni materials
irradiated in both power reactors and MTRs. Does LB phase appear at high fluences in high Ni (and maybe
high Cu) materials? Material effect (?)
CE effect, Linde80 effect, … Product form effect Initial strength effect
Decoration of dislocations by dislocation loops What is the effect of decoration?
30/9/2014 65
Dislocation loop formation near line dislocations Clusters are preferentially formed near one
side of dislocation. Some clusters are the rings that lie on the
same plane, suggesting dislocation loops. Some of the other clusters may be small
dislocation loops with solute atom segregation.
●Cu, ●Si, ●P
B9-3: R7_02571, 35.7x41.6x235nm, 8.05M
B9-3: R7_02618, 42.9x49.4x265nm, 12.0M
gB9-3
Presented at ASTM Symposium in 2008.30/9/2014 66
Unkown unknows
Embrittlement only from micro- and macro-scopic(mechanical property) points of view has been discussed.
30/9/2014 67
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