Cosires 2004 C.S. Becquart RPV steels microstructure evolution under irradiation: a multiscale approach Charlotte Becquart and... EDF Electricité de France A. Barbu: CEA, C. Domain: EDF, S. Jumel: EDF, M. Hou: U.L.B, A. Legris: LMPGM, L. Malerba: SCK-CEN,J-M. Raulot, J-C. Van Duysen: EDF, A. Souidi: U. Saida, D. Bacon: U. Liverpool, M. Perlado: Polytech., M. Hernández-mayoral, CIEMAT, R. Stoller: ORNL, B. Wirth: LLNL, B. Odette: UCSB... PhD and Master of Science students : P. Renuit, E. Vincent, S. Jumel, A. Marteel, P. Herrier, J-C. Turbatte, J-M Raulot, S. Pourchet, A. Tigeras, Z. Zhao
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RPV steels microstructure evolution under irradiation: a multiscale approach
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Cosires 2004 C.S. Becquart
RPV steels microstructure evolution under irradiation: a multiscale approach
Charlotte Becquart and...
EDFElectricitéde France
A. Barbu: CEA, C. Domain: EDF, S. Jumel: EDF, M. Hou: U.L.B, A. Legris: LMPGM, L. Malerba: SCK-CEN,J-M. Raulot, J-C. Van Duysen: EDF, A. Souidi: U. Saida, D. Bacon: U. Liverpool, M. Perlado: Polytech., M. Hernández-mayoral, CIEMAT, R. Stoller: ORNL, B. Wirth: LLNL, B. Odette: UCSB...
PhD and Master of Science students : P. Renuit, E. Vincent, S. Jumel, A. Marteel, P. Herrier, J-C. Turbatte, J-M Raulot, S. Pourchet, A. Tigeras, Z. Zhao
Cosires 2004 C.S. Becquart
Vessel
12 m
4.4 m
22 cm
Cosires 2004 C.S. Becquart
0
50
100
150
200
250
-200 -100 0 100 200 300
Temperature (°C)
En
erg
y (J
) baselineirradiated
DBTT shift (41 J level)
USE drop
Displacement
Lo
ad
Baseline
Irradiated
04 Oct 2001 29 Nov 2001
yield increase
DD
00
ll
00
Displacement
------ Baseline
------ Irradiated
Under irradiation: modification of the mechanical properties
===> hardening and embrittlementTDoseFluxComposition
54 atoms (555 k points) – 128 atoms (333 k points)
all atomic positions for defects calculation are relaxed
Methods and cohesive models
Ab initio
Semi-empirical potentials (FeCu)
M. Ludwig, D. Farkas, D. Pedraza and S. Schmauder, Modelling Simul. Mater. Sci. Eng, 6 (1998) 19
G.J. Ackland, D.J. Bacon, A.F. Calder and T. Harry Phil. Mag. A, vol.75 (1997) 713
VASP:
G. Kresse and J. Hafner, Phys. Rev. B 47, 558 (1993); ibid. 49, 14 251 (1994)G. Kresse and J. Furthmüller, Comput. Mat. Sci. 6, 15 (1996)G. Kresse and J. Furthmüller, Phys. Rev. B 55, 11 169 (1996)
Static calculations, molecular dynamics, atomic Kinetic Monte Carlo
Cosires 2004 C.S. Becquart
The primary damage : MD simulations
Cosires 2004 C.S. Becquart
The primary damage
MD simulations 2i
2
ii t
rmf
Large systems ===> empirical potentials
Embedded Atom Method
Finnis Sinclair...
i
ii r
rf
V
M.W. Finnis and J.E. Sinclair, Phil. Mag. A 50 (1984) 45
R.J. Harrison, A.F. Voter and S.P. Chen, "Embedded Atom Potential for BCC Iron", Atomistic simulation
of Materials- Beyond Pair Potentials, V. Vitek and D.J. Srolovitz (editors), 219, Plenum New York (1989)
M.I. Haftel, T.D. Andreadis, J.V. Lill and J.M. Heridon, Phys. Rev. B 42 (1990) 11540
G. Simonelli, R. Pasianot and E.J. Savino, Mat. Res. Soc. Symp. Proc. 291 (1993) 567
R.A. Johnson and D.J. Oh. J. Mater. Res. 4 (1989)1195
Yu. N Osetsky and A. Serra, Phys. Rev. B 57 (1998) 755
Cosires 2004 C.S. Becquart
Fe I
•Not a T effect
•role of short range interaction of the potential
F
Fe II
RCS
Role of the cohesive model (interatomic potential)
Cosires 2004 C.S. Becquart
Use BCA adjusted on MD results
121212
62.13.022
1.055.035.0 a
r
a
r
a
r
eeer
eZrV 12a
r
eArV
Molière potential Born Mayer potential
range = distance between atoms for which V(r ) = 30 eV
)(rVh rstifness
Statistics needed:
Role of the cohesive model (interatomic potential)
Cosires 2004 C.S. Becquart
0
50
100
150
200
0.1 0.6 1.1 1.6
Molière IIIBorn Mayer III
Distance (Å)
Pot
entia
l Ene
r gy
(eV
)
0-200 eV : formation range of RCS
Role of the cohesive model (interatomic potential)
0 200 400 600 800 1000 1200 1400 16000
100
200
300
400
500
Effet du potentiel sur les LCSComparaison entre Molière et Born-Mayerajustés aux FeIII (Farkas)Sans DBND
Sans DBNDE=20 keV
Molière (a12
=0.0781) Born-Mayer (a
12=0.2180)
Mean n
um
ber
of
LC
S
Temperature (K)
No
mb
re m
oye
n d
e R
CS
Température (K)
Molière III
BM III
Mea
n nu
mbe
r of
RC
S
Temperature (K)
Cosires 2004 C.S. Becquart
Kin
etic
ene
rgy
(eV
)Role of the cohesive model
(interatomic potential)
0
10
20
30
40
50
0 1000 2000 3000 4000 5000 6000
Time (s)
Kin
eti
c e
ne
rgy
(e
V)
Time (x10-16s)
0
5
10
15
20
25
30
35
40
45
50
0 500 1000 1500 2000 2500 3000 3500
Time (s)
Kin
eti
c e
ne
rgy
(e
V)
Time (x10-16s)
Kin
etic
ene
rgy
(eV
)
MD Fe III potential. The sequence is defocusing, then focusing
MD Fe I potential. The sequence is defocusing
50 eV PKA initiated at 0.3 deg. from <111>
Influence of potential on focusing
Cosires 2004 C.S. Becquart
The stiffer the BCA potential (the shorter ranged)
•the lower the focalisation threshold•the less kinetic energy losses between successive collisions•the more numerous the RCS and the longer.
Role of the cohesive model (interatomic potential)
Cosires 2004 C.S. Becquart
Fuel. Usually pellets of uranium oxide (UO2) arranged in tubes to form fuel rods. The rods are arranged into fuel assemblies in the reactor core.
Moderator. This is material which slows down the neutrons released from fission so that they cause more fission. It may be water, heavy water, or graphite.
Control rods. These are made with neutron-absorbing material such as cadmium, hafnium or boron, and are inserted or withdrawn from the core to control the rate of reaction, or to halt it. (Secondary shutdown systems involve adding other neutron absorbers, usually as a fluid, to the system.)
Coolant. A liquid or gas circulating through the core so as to transfer the heat from it.
Pressure vessel or pressure tubes. Either a robust steel vessel containing the reactor core and moderator, or a series of tubes holding the fuel and conveying the coolant through the moderator.
Steam generator. Part of the cooling system where the heat from the reactor is used to make steam for the turbine.
Containment. The structure around the reactor core which is designed to protect it from outside intrusion and to protect those outside from the effects of radiation or any malfunction inside.Ý It is typically a metre-thick concrete and steel structure.
There are several different types of reactors as indicated in the following table.
Cosires 2004 C.S. Becquart
guide design and analysis of experimental irradiation programs
explore conditions outside existing databases (very long time and high fluences), important to lifetime extension
systematically evaluate individual and combined influence of multitude of material variables (composition and microstructure) and the irradiation service conditions (T, flux, spectrum, ...)
help design advanced materials for future fission and fusion reactors.
Virtual Test Reactors (VTRs)
Cosires 2004 C.S. Becquart
Reconstruction 3D acier VVER 440 irradié neutrons (20 ans)