Influence of Thermo-mechanical Cycling on Pre-hydrogenated Zircaloy-4 … · 2019-06-26 ·...
Transcript of Influence of Thermo-mechanical Cycling on Pre-hydrogenated Zircaloy-4 … · 2019-06-26 ·...
IRS
N/F
RM
-29
6 in
d 5
Influence of
Thermo-mechanical Cycling
on
Pre-hydrogenated Zircaloy-4 Embrittlement
by
Radial hydrides
Jean Desquines*, Manfred Puls**, Stéphane Charbaut*
and Marc Philippe*
*IRSN
**MPP Consulting
2 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
Context & Objectives▌ Situations where thermo-mechanical cycling of fuel rods is expected:
- Dry cask storage,
- Spent fuel transportation from one spent fuel pool to another one
▌ Expected influence of cycling based on literature data
o No clear trend (Kearns, Mishima, Chu, Sakamoto, Billone,...)
o Possibly more radial hydrides and rather stronger embrittlement
▌ Main Goals of the study: clarify the expected influence of cycling on radial
hydride precipitation:
- Relying on a large data set on single cycle test results using « C »-shaped samples,
- Then cycle samples and evaluate the radial hydride precipitation and cladding
embrittlement.
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1- Experimental protocol
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“C”-Shaped Compression Tests in the Elastic Range
0
1
2
3
4
5
6
7
8
0 0.1 0.2 0.3 0.4 0.5 0.6
fqq= 0.0
X: location within the cladding thickness
(0: Outer Diameter, 1: Inner diameter)
fqq= 0.0
s:
cu
rvil
ine
ar
dis
tan
ce
to
A(m
m)
𝜎𝑡 𝑥, 𝑠 = 𝜎𝑡 𝐴 . 𝑓𝜃𝜃 𝑥, 𝑠
𝜎𝑡 𝐴 =𝐹 𝑁
0.013 𝐿 𝑚𝑚
Stress free area
Stress free area
A q
r
CCT sample
Load
Load
x
1s
0
A
F
𝐿
Equator
5 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
Radial Hydride Heat Treatments (RHT) considered
0
100
200
300
350
0 4 8 12 16 20
Com
pre
ssio
n load
Tem
pera
ture
(°C
)
Time (h)
5 N
315°C
FRHT
20°C/h
2h1h
Tem
pera
ture
(°C
)Time (h)
5 N
365°C
FRHT
20°C/h
0
100
200
300
400
0 4 8 12 16 20
2h1h
Com
pre
ssio
n load
350°C Max temperature RHT 400°C Max temperature RHT
• The load is applied as late as possible to limit the sample creep but
significantly before hydride precipitation
• The creep is expected to increase linearly with cycle number
F[H] contents – 50 to 236 wppm
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Equator
Post-test metallography
Using CCT to study radial hydride precipitation
Hydrided sampleF
RHT, 1 to 30 cycles
(Constant Load)
F.d
at RT
Failure test: CCT
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Experimental device
500 N load cellFan cooling
the load cell
FurnaceElectromechanical tension-
compression machine
L1
L2
F.d
2.Re
Furnace
Simple model of the test
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𝑊𝑒𝑙𝑙 𝑘𝑛𝑜𝑤𝑛𝑚𝑎𝑡𝑒𝑟𝑖𝑎𝑙 𝑝𝑟𝑜𝑝𝑒𝑟𝑡𝑦𝐹𝐸 𝑐𝑎𝑙𝑐𝑢𝑙𝑎𝑡𝑖𝑜𝑛
Interpretation of the RHT load displacement record
F.d
Furnace
𝛿 = 𝛿𝑜𝑓𝑓𝑠𝑒𝑡 + 𝛿𝑠𝑎𝑚𝑝𝑙𝑒𝑒𝑙 + 𝛿𝑠𝑎𝑚𝑝𝑙𝑒
𝑡ℎ𝑒𝑟𝑚𝑎𝑙 + 𝛿𝑠𝑎𝑚𝑝𝑙𝑒𝑐𝑟𝑒𝑒𝑝
+ 𝛿𝑟𝑜𝑑𝑠𝑡ℎ𝑒𝑟𝑚𝑎𝑙
Reasonably good agreement is obtained between calculations and
measurement assuming 0 creep
RE
OR
-103 –
firs
t cycle
𝑎𝑑𝑗𝑢𝑠𝑡𝑒𝑑
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Interpretation of the RHT load displacement record
𝛿𝑠𝑎𝑚𝑝𝑙𝑒𝑐𝑟𝑒𝑒𝑝
= 𝛿 − 𝛿𝑚𝑜𝑑𝑒𝑙
Creep deformation remains below ~1% diameter change after 30 cycles
F.d
Furnace
time (h)-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
0 100 200 300 400 500
𝛿 − 𝛿𝑚𝑜𝑑𝑒𝑙(𝑚𝑚)
REOR-103 –30 RHT cycles
Creep displacement (temperature stabilized)
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RHT & CCT Test matrix
350 & 400°C Max temperature – 1 to 30 cycles – [H] content below 240 wppm
Maximum stress at equatorial location: between 190 and 220 MPa
RHT
parameters
REOR-XXX ([H](wppm)) – Test ID and associated hydrogen content
Italic: the hydrogen content of tested conditions in past programs.
Cycles Number 1 2 5 10 30
Max R
HT t
em
pera
ture
(°C
)
350
53 ; 63 ;
69 ; 74 ;
REOR-117 (109)
127 ; 141 ;
177 ; 217 ;
309 ; 322 ;
525 ; 540
REOR-114 (176)
REOR-118 (95)
REOR-115 (101)
REOR-110 (139)
REOR-106 (203)
REOR-119 (86)
REOR-116 (94)
REOR-111 (138)
REOR-112 (209)
REOR-113 (210)
400
REOR-131 (61)
REOR-133 (141)
REOR-134 (187)
217 ; 218 ;
398 ; 478
REOR-126 (62)
REOR-120 (78)
REOR-125 (147)
REOR-123 (236)
REOR-121 (75)
REOR-124 (148)
REOR-135 (177)
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2- Analysis of Metallographic data
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RHT at 350°C max temperature
• When cycling: higher density but comparable fraction of radial hydrides
• Saturated influence of cycling over 5 cycles
1 5 10 30
130
200
REOR-17 [11]
REOR-14 [11] REOR-110
REOR-106
REOR-111
REOR-112 REOR-113
Cycles
[H]
(wppm)
Meta
llogra
phs
at equ
ato
rial lo
cation
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RHT at 400°C max temperatureM
eta
llogra
phs
at equato
rial lo
cation
1 5 10
150
200
REOR-134
REOR-125
REOR-123
REOR-124
Cycles[H]
(wppm)
75
REOR-120
REOR-133
REOR-135
REOR-131 REOR-121
At H~200 wppm: higher density but comparable fraction of radial hydrides
Below H~150 wppm: no influence of cycling
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Influence of cycling and stress on incipient radial
hydride precipitation
Slight influence of cycling at 350°C maximum temperature
No clear influence at 400°C
Ta
nge
ntialstr
ess (
MP
a)
[H] (wppm)
Mixed radial & circumferential hydrides
Circumferential hydrides
0
20
40
60
80
100
120
0 100 200 300 400 500 600
Temp.
12
35
0 5
10
30
RHT cycles
400°C RHT350°C RHT
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Influence of cycling and stress on radial hydride
precipitation
Limited influence of cycling on radial hydride precipitation stress thresholds
Circumferential hydrides
Ta
ng
en
tia
lstr
ess (
MP
a)
[H] (wppm)
Mixed radial & circumferentialhydrides
Radial hydrides
(Eq.10)
0
20
40
60
80
100
120
140
160
180
200
0 100 200 300 400 500 600R
HT
max
imu
m t
emp
erat
ure
(°C
) 12
35
04
00
45
0
5
10
30
5
10
1
RHT cycles0%
10
0%
1
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3- Radial hydride
Embrittlement
F, d
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Load displacement records – an illustration
Crack nucleation is associated with the first significant load-drop and
deviation to the elastic-plastic trend
0
2
4
6
8
10
12
14
16
18
20
0 0.5 1 1.5 2 2.5Displacement (mm)
CCT-112 (209wppm)Elasticity
Plasticity
CCT-115 (101wppm)
Cra
ck n
ucle
ation
Brittle
cra
ck p
ropagation
Cra
ck n
ucle
ation
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Load displacement records
Surprisingly ductile nucleation was associated with brittle crack
propagation and brittle crack nucleation with ductile crack propagation
Rather high [H] contents
&low fracture toughness
Rather low [H] contents
&high fracture toughness
Elasticity
Plasticity
ducti
le
bri
tlle
bri
tle
ducti
le
Cra
ck
nucle
ati
on
Cra
ck
pro
pagati
on
F/L
(N/m
m)
Displacement (mm)
0
2
4
6
8
10
12
14
16
18
20
0 0.5 1 1.5 2
REO
R-1
10
REO
R-1
06
REO
R-1
11
REO
R-1
12
REO
R-1
13
REO
R-1
14
REO
R-1
15 REOR-116
REO
R-1
17
REO
R-1
18
REO
R-1
19
REOR-120
REOR-121 REO
R-1
23
REO
R-1
24
REO
R-1
25
RC
T-1
26
REOR-131
REO
R 1
33
REO
R-1
34
REO
R-1
35
2.5
19 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
Crack nucleation displacement – 1 cycle
Maximum sensitivity to crack nucleation at about [H]= 100 wppm,
No obvious influence of maximum RHT temperature
Cra
ck n
ucle
atio
nd
isp
lace
me
nt
(mm
)
[H] (wppm)
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0 100 200 300 400 500 600
350°C
400°C
450°C
Maximum RHT temperature
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Crack nucleation displacement – several cycles
[H] (wppm)
0.5
1.0
1.5
2.0
0 100 200 300 400 500 600
Protective influence of RHT cycling
Detrimental influence of RHT cycling
2
350
400
5
10
30
5
10
RHT cyclesTemp.
Cra
ck n
ucle
atio
nd
isp
lace
me
nt
(mm
)
350°C RHT cycling trend
• Regions associated with higher density of radial hydrides have a lower
sensitivity to crack nucleation
• Protective influence of RHT cycling on crack nucleation
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Conclusion▌ The thermo-mechanical cycling was studied relying on CCT tests
▌ Analysis of metallographs
- At 350°C for H contents between 75 and 230 wppm, and at 400°C for H contents
close to 200 wppm: shorter and denser hydrides observed,
- A 400°C below 200 wppm, no influence of cycling is observed
- The denser and short hydrides were associated with slightly easier radial hydride
precipitation
▌ A protective influence of cycling was observed on radial hydride
embrittlement.
▌ Extrapolation of these results to irradiated claddings:
If there is any location containing 100 wppm, then no influence of cycling is
expected
22 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
23 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
Stress at crack nucleation– several cycles
Brittle crack nucleation region remains at [H] contents of about 100 wppm
and no influence of cycling is observed in this region
Cra
ck n
ucle
atio
nta
ng
en
tia
lstr
ess
(MP
a)
[H] (wppm)
Plasticity
Elasticity
500
700
900
1 100
1 300
1 500
0 100 200 300 400 500 600
2
350
400
5
10
30
5
10
RHT cyclesTemp.
350°C RHT cycling trend
24 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
-3.0
-2.0
-1.0
0.0
0.5
0 2 4 6 8 10 12 14 16 18
ModelRecord
d(mm)
50 N loading
Cooling @ 20°C/h
2h dwell @ 350°C
heating
Time (h)
25 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
𝛿𝑠𝑎𝑚𝑝𝑙𝑒𝑒𝑙 =
𝐹 1 − 𝜈2
2.6410−3𝐸. 𝐿𝑒
𝑅𝑒 − 𝑒
2.7644
Interpretation of the RHT load displacement record
L1
L2
F.d
2.Re
Furnace
𝛿 = 𝛿𝑜𝑓𝑓𝑠𝑒𝑡 + 𝛿𝑠𝑎𝑚𝑝𝑙𝑒𝑒𝑙 + 𝛿𝑠𝑎𝑚𝑝𝑙𝑒
𝑡ℎ𝑒𝑟𝑚𝑎𝑙 + 𝛿𝑠𝑎𝑚𝑝𝑙𝑒𝑐𝑟𝑒𝑒𝑝
+ 𝛿𝑟𝑜𝑑𝑠𝑡ℎ𝑒𝑟𝑚𝑎𝑙
𝛿𝑟𝑜𝑑𝑠𝑡ℎ𝑒𝑟𝑚𝑎𝑙
= −15.510−6 𝑇 − 𝑇0 . 𝐿1 + 𝐿2
𝛿𝑠𝑎𝑚𝑝𝑙𝑒𝑡ℎ𝑒𝑟𝑚𝑎𝑙
= −5.610−6 𝑇 − 𝑇0 · 2𝑅𝑒
Reasonably good agreement is obtained between calculations and
measurement assuming 0 creep
RE
OR
-103 –
firs
t cycle
26 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
Load displacement records
Surprisingly ductile nucleation was associated with brittle crack
propagation and brittle crack nucleation with ductile crack propagation
0
2
4
6
8
10
12
14
16
18
20
0 0.5 1 1.5 2 2.5Displacement (mm)
CCT-112 (209wppm)
𝐹 𝐿𝑁/𝑚
𝑚
Elasticity
Plasticity
CCT-115 (101wppm)
Cra
ck n
ucle
ation
Brittle
cra
ck p
ropagation
Cra
ck n
ucle
ation
27 19TH INTERNATIONAL SYMPOSIUM ON ZIRCONIUM IN THE NUCLEAR INDUSTRY
Elasticity
Plasticity
ducti
le
bri
ttle
bri
ttle
ducti
le
Cra
ck
nucle
ati
on
Cra
ck
pro
pagati
on
F/L
(N/m
m)
Displacement (mm)
0
2
4
6
8
10
12
14
16
18
20
0 0.5 1 1.5 2
REO
R-1
10
REO
R-1
06
REO
R-1
11
REO
R-1
12
REO
R-1
13
REO
R-1
14
REO
R-1
15 REOR-116
REO
R-1
17
REO
R-1
18
REO
R-1
19
REOR-120
REOR-121 REO
R-1
23
REO
R-1
24
REO
R-1
25
RC
T-1
26
REOR-131
REO
R 1
33
REO
R-1
34
REO
R-1
35
2.5