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MCNP-4C2 and TRIM 98.01 based calculations of radiation damage
in copper
V. Slugeň, G. Farkas, P. DomonkošSlovak University of Technology Bratislava, Ilkovicova 3, 812 19 Bratislava, Slovakia,
e-mail:slugen@elf.stuba.sk
Aims•Simulation of the defects movement based on the Embedded Atom Method (EAM) potentials
and ab initio method in combination with Monte Carlo technique.
•Irradiation of specimens with neutrons and protons.
•Measurement of microstructure changes in materials using Positron annihilation techniques
compared with TEM.
•Heat treatment, measurements and evaluations of results from microstructutal point of view.
GB
[210]
<110>
The interatomic potential used in the simulation is based on the Embedded Atom Method (EAM).For additional simulations we usedAb initio method in combination withthe usual copper pseudopotential.
0 5 10 15 20 25 30 35 40 45-0.01
0.00
0.01
0.02
0.03
Relative graindisplacement (CLS cell%)
∆EGB
(J/m2 )
0 5 10 15 20 25 30 35 40 45-0.01
0.00
0.01
0.02
0.03
Relative graindisplacement (CLS cell%)
∆EGB
(J/m2 )
0 5 10 15 20 25 30 35 40 45-0.01
0.00
0.01
0.02
0.03
Relative graindisplacement (CLS cell%)
∆EGB
(J/m2 )
0 5 10 15 20 25 30 35 40 45-0.01
0.00
0.01
0.02
0.03
Relative graindisplacement (CLS cell%)
∆EGB
(J/m2 )
V acuum vessel
F irs t wall
Distribution of neutron fluency, atomic displacement, nuclear heating and nuclear reactions in copper alloys
foreseen for ITER first wall were calculated using Monte Carlo N-Particle Transport code MCNP-4C2.
Geometrical model consists of the slab with dimensions 12 x 12 x 0.5 mm, divided into 50 layers which create elementary cells with thickness 10 µm to provide detailed spatial distribution of the nuclear parameters. The shape of the modeled specimen correlates with the shape of samples used in the foreseen experiment - PAS measurements.
Arealneutron source
0.5 mm
12 mm
12 mmAlloy specimen
Vacuum
Specimens chemical composition and implantation dose.
Specimen Material Implantation dose[C/cm2]
SS CuCrZr – 98.95w.%Cu; 0.6-0.9w.%Cr; 0.07-0.15w.%Zr NoneSA CuCrZr 0.4SM CuCrZr 1.1TT CuAl25 – 99.5w.%Cu; 0.25w.%Al as Al2O3; 0.22w.%O as Al2O3;
0.025w.%B as B2O3
None
TA CuAl25 0.4TM CuAl25 1.1
MATERIAL CHARACTERISTICS OF THE SPECIMEN.
Material Mass density(g/cm3)
Isotope fraction (%)
Cu 8.93 63Cu 67.1765Cu 30.83
Distribution of primary knock-out atoms in the specimen
PARTICLE PRODUCTION IN THE SPECIMEN
8,3E-02
8,4E-02
8,5E-02
8,6E-02
8,7E-02
8,8E-02
8,9E-02
1 4 7 10 13 16 19 22 25 28 31 34 37 40
layer
nu
mb
er o
f P
KA
[at
om
s/(s
ou
rce
neu
tro
n.c
m3 )
]
Particle Total normalized production in the specimen
[1/(source neutron⋅cm3)]
Total unnormalized production in the specimen
(1/cm3)Photon 2.539E-01 7.842E11
Proton 1.324E-02 4.090E10
Deuterium 5.578E-04 1.723E09
3He 2.002E-07 6.184E05
The decreasing of the specimen activity in the time dependence
NUCLEAR REACTION IN THE SPECIMEN. Target isotope
Reaction Product Number of reactions[1/(source neutron⋅cm3)]
63Cu
(n,2n) 62Cu → 62Ni stable (st.) 1.82378E-02
(n,n´p) 62Ni st. 1.06331E-02
(n,n´α) 59Co st. 5.10850E-04
(n,p) 63Ni → 63Cu st. 1.86386E-03
(n,d) 62Ni st. 3.84324E-04
(n,3He) 61Co → 61Ni st. 1.55531E-07
(n, α) 60Co → 60Ni st. 1.70658E-03
(n,γ) 64Cu → 64Ni st. (61%)→ 64Zn st. (39%)
1.28033E-04
65Cu
(n,2n) 64Cu → 64Ni st. (61%)→ 64Zn st. (39%)
1.62292E-02
(n,n´p) 64Ni st. 3.02890E-04
(n,n´α) 61Co → 61Ni st. 1.39880E-05
(n,p) 65Ni → 65Cu st. 4.37881E-04
(n,d) 64Ni st. 1.73503E-04
(n,3He) 63Co→ 63Ni → 63Cu st. 4.66784E-08
(n, α) 62Co → 62Ni st. 1.82165E-04
(n,γ) 66Cu → 66Zn st. 1.47605E-05
1 MeV cascade accelerator at STU Bratislava
1 MeV cascade accelerator at STU Bratislava
Technical specificationTotal accelerating voltage: 0 - 1 MVRipple factor: < 1%Energy rangefor singly charged particles: 5 keV to 1 MeV Energy spread: 70 keV – 1 MeV: ≈ 2 keV
< 70 keV: < 0,1%Beam current: 1 - 100 µA
Ion implantation and measurements using PLEPS
• For the simulation of radiation stress of neutron flux, the ion implantation of protons has been applied.
• The proton mass is approximately identical as the neutron mass
• The energy of protons of about 95 keV was found out with the help of program TRIM 98.01
• Two implantation doses 1,1 and 0,4 C/cm2 were chosen
• Pulsed Low Energy Positron System PLEPS seems to be optimal technique for the evaluation of defects structure and concentration in Cu-alloys
• This system enables to study the micro structural changes in the region from 20 to 500 nm
Reasons for application of PAS• Mechanical tests give not enough information about changes in
material microstructure. Therefore, additional methods should be applied.
• PAS technique is a well-established method for studying open-volume type atomic defects and defect’s interactions in metals
• Ability of PAS to detect very small defects as well as very low defects concentration
• PAS can give additional information about • radiation induced defects,• thermal annealing of these defects.
SLUGEŇ, V. et. al.: Positron annihilation investigations of defects incopper alloys selected for nuclear fusion technology. In: Fusion Engineering and Design, 70/2, 2004, p.141-153
Non-destructive techniques for defects investigation
General overview of applicability range for some spectroscopy techniques [Howell, R., Physics Space Technology, 1987].
(OM – optical microscopy, TEM - transmission electron microscopy, nS – neutron scattering, STM/AFM – scanning tunnelling microscopy/atom probe ion microscopy).
PAS Theory
Scheme of positron experiments (A),
Quantitative illustration of positron annihilation γ-rays from different environments (B)
PAS Theory (PAS LT)
Lifetime spectra (PAS LT).Scheme of Lifetime measurement system
Three detector set-up of PALSrealization
BaF2 detectors and samples with 22Na source
PALS – electronic part
Start detector
Stop detector
2nd Stop detector(Energy)
Samples withpositron source
Distribution of vacancies in Cu-alloys after irradiation (calculated by TRIM)
0,00
0,20
0,40
0,60
0,80
1,00
0 100 200 300 400 500 600 700 800
Target depth [nm]
Vaca
ncie
s [v
ac/im
plan
ted
ion]
PLEPS
• Schematic view of the latest version of the pulsed low energy positron system.
PAS results10
0
300
500
457 37
8 305 238 178 124 78 41
140
160
180
200
220
240
260
280
300
MLT [ps]
Temperature [°C]
Depth [nm]
SS non-irradiated sample
•Non-irradiated CuCrZr sample (0 C/cm0 C/cm22)•There have not been observed any defects
100
250
400
550
457 34
1 238 15
0 78
26
140160180200220240260280300320
MLT [ps]
Temperature [°C]
Depth [nm]
SM proton irradiated sample (1,1 C/cm2)
•Irradiated CuCrZr sample (1,1 C/cm1,1 C/cm22)the shape of voids is spherical with diameter from 2 to 15nm
PLEPS Results for ITER
370
380
390
400
410
420
430
440
450
460
470
480
Ta u 2 [ p s ]
Te m p e r a t u re [ °C ]
En e rg y [ k e V] . Fo r C u 18 k e V~ 4 5 7 n m
S M s a mp le
470-480
460-470
450-460
440-450
430-440
420-430
410-420
400-410
390-400
380-390
370-3800
10
20
30
40
50
60
I2 [ %]
Te m p e r a t u re [ °C ]
En e r g y [ k e V] . Fo r C u 18 k e V~ 4 5 7 n m
S M s amp le
50-60
40-50
30-40
20-30
10-20
0-10
130
140
150
160
170
180
190
200
210
220
Ta u 1 [ p s ]
Te m p e ra t u re [ °C ]
En e rg y [ k e V] . Fo r Cu 18 k e V~ 4 5 7 n m
S M s a m ple
210-220
200-210
190-200
180-190
170-180
160-170
150-160
140-150
130-140
Decomposition of PASLT spectrum in two components
PAS and TEM results are useble for microstructural evalution of new materials
100120140160180200220240260280300320
MLT [ps]
Te m pe ra ture [°C ]
Ene rg y [ke V] . F o r C u 18 ke V~ 4 5 7 nm
SM sample
300-320280-300260-280240-260220-240200-220180-200160-180140-160120-140100-120
SLUGEŇ, V. – KURIPLACH, J. - BALLO, P. – DOMONKOŠ, P.: Hydrogen Implantation Effect in Copper Alloys Selected for ITER Investigated by Positron Annihilation Spectroscopy. Nuclear Fusion 44, 2004, p.93-97.
The calculated dependence of the positron lifetime on the size of the vacancy cluster in Cu.
PLEPS Results for ITER
Annealing behaviour of irradiated CuAl25-sample (TM)
18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3100120140160180200220240260280300320
MLT [ps]
Te m pe ra ture [ °C ] Ene rg y [ke V] . F o r C u 18 ke V~ 4 5 7 nm
TM sample
300-320280-300260-280240-260220-240200-220180-200160-180140-160120-140100-120
Conclusions I• The distinction between the two studied materials consists –
in accordance with TEM observations – in the fact that the microstructure of CuAl25 material is almost intact to irradiation contrary to CuCrZr.
• In CuCrZr material positron annihilation characteristics are apparently changed due to irradiation.
• Annealing up to 600 °C seem to result to a state similar to annealed non-irradiated sample.
• It is important to be very precise by sample preparationand by excluding of contributions from oxides, source, back-diffusion, etc.
Neutron irradiation at BR2 reactor
Nominal power 60-120 MWMaximum neutron flux (at 600 W/cm2)thermal neutrons 1.2×1015 n.cm-2.s-1
fast neutrons (E>0.1 MeV) 8.4×1014
n.cm-2.s-1
Days of operation per year 168 to 240Irradiation positions up to 100Cannel diameter up to 200 mm
Dose dependence, measured on PA samples irradiated to different dose levels at Tirr=50°C. Experimental values are compared with the
trapping model value τcalc, using trapping rate κ values.
PA sample Tirr=50ºC
141 ps
112,3 ps
93 ps 91ps ± 34ps
206,4 ps
192,08 ps
168,7 ps
178,5 ps
0
50
100
150
200
250
0 0,001 0,01 0,1
Dose [dpa]
Life
time c
ompo
nent
s [ps
]
tau1tau2MLTtau1calc
The intensity I2 of the long-lived component in dose dependence for neutron irradiated prime aged CuCrZr
(Outokumpu) alloy.
PA sample Tirr=50ºC
79,9%
54,3%
64,6%
96,0%
0
10
20
30
40
50
60
70
80
90
100
110
0 0,001 0,01 0,1Dose [dpa]
Inte
nsity
I 2 [%
]
Trapping rate κ into the defect (trapping site) in neutron irradiated PA sample at Tirr=50°C for three different
irradiation doses.
PA sampleTirr=50ºC
3,58
16,8
9,43
83,7
0
10
20
30
40
50
60
70
80
90
0 0,001 0,01 0,1Irradiation dose [dpa]
Tra
ppin
g ra
te
[ns-1
]
• In all neutron irradiated samples from dose 1×10-1 dpaup to 3×10-1 dpa the values for the positron mean lifetime increased and the defect lifetime of 175±5 pswas observed. Thus, compared to the non-irradiated state an additional trapping site was observed, probably in the form of Stacking Fault Tetrahedra.
• In all the positron lifetime measurements on neutron irradiated samples no lifetime component longer than 206 ps was observed, implying that no voids are created in the neutron irradiated CuCrZr (Outokumpu) alloy.
Results from PAS experiment at neutron irradiated samples (collaboration with Risoe N.L. and SCK.CEN Mol)
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