Transcript Заголовок слайда отсутствует

Influence of neutron irradiation
parameters on swelling and mechanical
properties of stainless steels - materials
of BN-350 fuel assembly ducts
O.P.Maksimkin, M.N.Gusev, K.V.Tsai, O.G.Romanenko, L.G.Turubarova,
N.S.Silnyagina, O.V.Tivanova
Laboratory of the materials physical-mechanical
properties investigations, [email protected]
Almaty, Kazakhstan Republic, 2005
Report contents
• Mechanical properties of investigated steels
• Influence of damage dose rate on microstructure
and swelling of investigated steels.
• Peculiarities of plastic deformation of highly
irradiated materials.
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Investigated materials
поток
Neutron flux
нейтроно
в
Т, оС
280
•08Cr16Ni11Mo3
•12Cr18Ni10Ti
450
Object of investigation – hexagonal
shroud of fuel assemblies
Sample’s sizes:
2020.3mm.
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Irradiation condition for investigated steels
Assembly, mark.
08Cr16Ni11Mo3
08Cr16Ni11Mo3
08Cr16Ni11Mo3
N-214(2)
V-300
V-337
12Cr18Ni10Ti,
N-214(1)
Dose, dpa [T,C]
15.6 [337°]
17.1 [354°]
Damage rate, dpa/s
4.810-8
1.610-7
Dose, dpa [T,C]
-
0
11.0 [346°]
12.1 [354°]
7.1 [309°]
2.010-7
2.610-7
2.210-7
+500
Damage rate, dpa/s
Dose, dpa [T,C]
7.08 [309°]
10.8 [302°]
11.9 [305°]
Damage rate, dpa/s
2.210-8
1.910-7
2.610-7
Dose, dpa [T,C]
1.27 [281°]
Damage rate, dpa/s
410-9
Dose, dpa [T,C]
0.25 [280°]
Damage rate, dpa/s
810-10
-500
-900
1200
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Experimental equipment and
investigation techniques
 Uniaxial tensile mechanical test.
(definition of 02 В, full).
Transmission and scanning electron
microscopy (concentration and
morphology of radiation defects,
swelling value).
Metallography and microhardness
measurement.
Magnitometry and optical
extensometry.
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Influence of irradiation on mechanical
properties of 08Cr16Ni11Mo3 steel
18
B
1200
1000
16
elongation, %
yield and ultimate stress, MPa
1400
02
800
600
14
12
10
8
6
400
4
200
2
0
0
0
5
10
dose, dpa.
15
20
0
5
10
15
20
dose, dpa
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Correlation between yield stress
and microhardness
1200
Yield stress, MPa
1000
800
600
400
200
ini
Busby et. All
(JNM, v.336,2005)
0
0
100
200
300
400
500
Micrihardness, kg/mm^2
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Changes in density of irradiated
08Cr16Ni11Mo3 steel
7,98
density, g/cm3
V-337
-500
N-214(2)
7,96
7,94
7,92
V-337
+500
V-300
-500
7,9
7,88
7,86
0,25%
V-300
+500
7,84
7,82
0
2
4
6
8
10
12
14
16
18
fluence, dpa
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Swelling of irradiated 08Cr16Ni11Mo3 steel
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Voids in irradiated 08Cr16Ni11Mo3 steel
N-214, «-900», 1.27 dpa., 410-9dpa/s
N-214(2), «-500», 7.08 dpa. 2.210-8
0.15 мкм
N-214(2), «0», 15.6 dpa. 2.210-8dpa/s
ТВС «V-337», 11.9 dpa, 2.610-7dpa/s
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Voids in irradiated 12Cr18Ni10Ti,
assembly N-214(1)
Dose 0.67 dpa,
Dose rate 0,1210-8 dpa/s,
Tirr = 281°С
50 nm
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Influence of dose rate on yield stress of
08Cr16Ni11Mo3
20
low dose rate
920
15
dose, dpa
high dose rate
960
10
1010
871
5
0
914
711
550
0,0E+00
5,0E-08
1,0E-07
1,5E-07
2,0E-07
2,5E-07
3,0E-07
3,5E-07
dose rate, dpa/s
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Peculiarities of plastic deformation and
fracture of high irradiated samples
The deformation relief develops
in zone of localized deformation
SEM image of fracture surface
for specimen from «-1200mm»
mark (08Cr16Ni11Mo3 steel).
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Method of mark extensometry for miniature
irradiated samples
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Distribution of strains and stresses on on deformed
sample of 08Cr16Ni11Mo3 steel
σист,кг/мм2
170
ε, %
60
160
150
50
140
40
130
30
120
20
110
10
100
0
6
5 4
3
Рабочая
длина образца
2
1
6
5
4
3
2
Рабочая
длина образца
1
V-337, -500.
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Engineering curves and
dependences “true stress – conditional strain”
180
Irradiated (V-337, -500)
true stress, kg/mm^2
160
140
«true» curves
120
100
80
60
Unirradiated steel
40
20
0
0
20
40
60
80
100
120
140
deformation, %
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Relationship between true stress and true strain
for irradiated 08Cr16Ni11Mo3 steel
1800
true stress, MPa
1600
Irr., V-300, 10,8dpa
Irr, V-337, 11,9dpa
1400
1200
1000
N-214, -900mm (1.27dpa)
800
unirradiated
600
400
200
0
0
0,2
0,4
0,6
true strain
0,8
1
1,2

Laboratory of the materials physical-mechanical properties investigations, INP NNC RK
Conclusion
The changes in structure and mechanical properties of 08Cr16Ni11Mo3 and
12Cr18Ni10Ti steels – as materials of spent fuel assemblies of BN-350 reactor –
irradiated up to damage doses 0.25 – 15.6 dpa at dose rate from 810-10 to 2.6107dpa/s were investigated.
•It was found that the dose rate is one of important factors influencing on void
formation and development as well as on formation of mechanical properties of
investigated materials.
•The void formation at low dose rates and low damage doses (1.27 dpa for
08Cr16Ni11Mo3 steel and 0.67 dpa for 12Cr18Ni10Ti steel) was observed.
•The method of mark extensometry was proposed and applied for investigation of
peculiarities of plastic deformation of miniature specimens irradiated at various dose
rates.
•It was shown that relation between true stresses and true strains at localized
deformation of high irradiated steel samples can be described by equation =k0.5+0.
Laboratory of the materials physical-mechanical properties investigations, INP NNC RK