Overview of CEA Analytical Studies on PWR Nuclear Fuel

Overview of CEA Analytical Studies on PWR
Nuclear Fuel cladding subjected to RIA
Loading Conditions
C. Poussard, X. Averty, O. Duguay, O. Rabouille, M. Le Saux,
J. Pizzanelli, C. Dumas, M. Genisson, M. Le Breton
C. Sainte Catherine and P. Yvon
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
1
Context 1/2
Design safety studies for Reactivity Initiated
Accident)
Ö
Studies underway to raise the average burn-up of fuel
assembly (ex : 1998, EDF, 47 to 52GWd/tU and 62
GWd/tU expected in the future)
Ö
Strong need for investigations of the fuel behavior under
design basis reactivity accidents such as control rod
ejection (failure of the control rod drive mechanism)
Assumption : Accidental ejection of a
control rod
Fuel swelling
Ö
Clad deformations (a few %)
Ö
Potential for crack initiation
and growth (failure criterion
required)
Ö
Fuel dispersal in the coolant,
boiling crisis, etc …
DEN/Saclay/DMN/SEMI
Failed
cladding
Dispersed fuel
1000
900
800
700
cladding ID
clad. midwall
cladding OD
600
500
400
300
200
100
0
0.01
Desquines et al,, 11 TAG, 2004
Ö
Increase of temperature (103
to 104 K.s-1)
movie
REP NA3 SCANAIR computation
Ö
Rapid increase of the local
power (~ 50ms)
Cladding temperature (°C)
Ö
CABRI REP-Na 1, Papin et al., 2003
0.1
1
time (s)
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
10
100
C. Poussard et al.
1000
2
Reactivity Initiated Accident Problematic
Control rod ejection
⇒ Rapid local power increase
Fast fuel temperature rise (104 °C/s)
(~50 ms)
Accumulated fission gas expansion
Fuel thermal expansion
Fuel expansion
Fuel grain decohesion
Pellet-cladding gap closing
Fission gas release
Nakamura et al., 2002
Loss of cladding
ductility due to a
dense hydride
thickness
Papin, 1996
PCMI loading
350<T<600°C, T~103 °C/s, ε~1 s-1
.
.
Crack initiation on outer
diameter
First phase pre DNB failure
Transient PCMI failure
Departure from
Nucleate Boiling (DNB)
Internal pressure increase
Fast cladding
temperature increase
(T<800°C)
Drop of the mechanical
strength
Post-DNB failure by
local ballooning
Last phase post
DNB failure
Fuel fragmentation
Fuel dispersal and coolant
interaction
Mechanical energy
production
Post failure events
REP-Na 8 (Papin et al., 2003)
Waeckel., 1997
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
Nakamura et al., 2002
3
Context 2/2
1992 : IRSN (formerly IPSN) initiated, in partnership with EDF, a
research program, the CABRI REP-Na dedicated to :
Ö Study the behavior of highly irradiated fuel (UO2 and MOX) under RIAs
Ö Verify the adequacy of the present safety criteria with available experimental
database (SPERT, PBF, early NSSR experiments) restricted to fresh or lightly irradiated
Ö Evolution of the criteria and evaluate safety margins
CABRI REP-Na experimental program launched in the sodium loop
reactor in France : fast power transient applied to irradiated rods
Development of the SCANAIR code :
Ö Interpret the test results, perform sensitivity studies
Ö Extrapolate to reactor conditions
Ö Process closely coupled phenomena such as rod thermics and thermal hydraulics, fuel
and clad mechanics, transient behavior of fission gases
1992 : Initiation of a separate effects test program for the study of
transient clad mechanical behavior : PROMETRA
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
4
PROMETRA : transient mechanical testing program
for high burn-up claddings in support to the
interpretation of integral RIA tests
New Hot
Cells at 2005
CEA Saclay
CEA Saclay
ring test
CEA Saclay
axial tensile
test
High
heating
Plane
rates
Stress
Plane
Strain
With
gage
section Without
gage
section
Axial
tensile
Hoop tensile
CEA Saclay PSU
- Plane strain
2000
Cladding
mechanical behavior
during RIA transients
DEN/Saclay/DMN/SEMI
1996
CEA Grenoble
ring test
CEA Saclay
burst test
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
LHA
1992
C. Poussard et al.
5
A Reliable Material Database For Highly
Irradiated Fuel Claddings 1/2
Standard
Zircaloy-4
(43)
(105)
Fresh
(33)
Axial tensile
(8)
Hoop tensile
Irradiated
(2)
Burst
(36)
Axial tensile
(8)
Burst
Hoop tensile
(58)
CEA Saclay
specimen
(8)
CEA Saclay
specimen
(39)
Ductile
High Burnup cladding mechanical (39)
behavior:
Ductile material
→
→
→
→
(3)
(66)
properties
Oxide layer thickness<130 μm,
Burnup: 54 to 64 GWd/tU,
Strain rate: 0.01 to 5 s-1,
[H] content
Cladding temperature: 20 to 900° C.
measurement
CEA Grenoble
specimen
(19)
Brittle
(2)
(6)
Ductile
Brittle
(8)
Ductile-Brittle
Transition
(58)
(3)
(18)
(3)
Metallography or
fractography
( ): number of valid tests
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
6
A Reliable Material Database For Highly
Irradiated Fuel Claddings 2/2
54 -64
64 GWd /tU
Plane Strain test
Hoop tensile
Burst
(58)
(planned)
(3)
1.5% Sn Zircaloy
(61)
PROMETRA hoop tests
on irradiated alloys
(13)
ZIRLO
Plane Strain test
Hoop tensile
~75 GWd /tU
( ):
DEN/Saclay/DMN/SEMI
TM
(11)
(planned)
(34)
M5
(2)
Burst
(planned)
Plane Strain test
TM
(2)
(32)
Hoop tensile
Burst
60 -75 GWd /tU
number of valid tests
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
7
CEA testing technique for high temperature rings :
(induction heating, T > 480°C up to 900°C)
5
LOAD Ö Conventional and
true stress
R=1.5
TEMPERATURE
3±0,0
2±0.05
UTS
0.2YS
D
TC : welded to
specimen
JACK DISPLACEMENT Ö
Conventional and true strain
UE
Test
Temperature
-1
t=
0
20
Load
control
°C
.s
Co
Load control Ö
Displacement
control
/d
T
d
Room
temperature
TE
10 to 20s
oli
ng
:c
on
con du ct
ve ion
cti
on + n at
u
r al
Displacement
control
TIME
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
8
x2 times faster than real life
PROMETRA hoop tensile test at high temperature
movie
Test specifications : 800°C, 1s-1 Test duration : 20s including induction heating @ 100°C/s
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
9
On going research : towards a better interpretation
of the PROMETRA test data
Conventional and true stress-strain interpretation of the PROMETRA
data is made :
Ö To derive validated mechanical transient mechanical properties usable in SCANAIR
Ö To develop failure criteria
1000
1000
Zry-4 strd - 5 cycles - 5/s
M5 - 5 cycles - 5/s
M5 - 6 cycles - 1/s
ZIRLO - 75 GWj/tU - 1/s
900
800
800
UTS (MPa)
YS (MPa)
700
600
500
700
600
500
400
400
300
300
200
200
100
100
0
0
100
200
300
400
500
600
700
Test temperature (°C)
800
Zry-4 strd - 5 cycles - 5/s
M5 - 5 cycles - 5/s
M5 - 6 cycles - 1/s
ZIRLO - 75 GWj/tU - 1/s
900
900
0
0
100
200
300
400
500
600
700
Test temperature (°C)
800
900
YS and UTS for irradiated Zy4, M5 and Zirlo, Cazalis et al., SMIRT 18, 2005
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
10
On going research : towards a better interpretation
of the PROMETRA test data
Conventional and true stress-strain interpretation of the PROMETRA
data is made :
Ö To derive validated mechanical transient mechanical properties usable in SCANAIR
Ö To develop failure criteria
60
TotalElongation(%)
50
40
30
20
M5TM- 5 cycles- 5/s
M5TM- 6 cycles- 1/s
ZIRLOTM- 75 GWj/tU - 1/s
10
0
0
100
200
300
400
500
600
Test temperature (°C)
DEN/Saclay/DMN/SEMI
700
800
900
TE for irradiated M5 and Zirlo, visual view
of M5TM broken leg, tested 816°C
Cazalis et al., SMIRT18, 2005
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
11
On going research : towards a better interpretation
of the PROMETRA test data
FE modeling is achieved to deeply understand the tests data and
insure that experimental artifacts, geometry (strain and stress
gradients), boundary conditions (contacts and friction) do not
invalidate the data
1500
1450
Force (kN)
1400
1350
mu = 0,0
1300
mu = 0,10
mu = 0,15
1250
mu = 0,20
mu = 0,30
1200
mu = 0,40
Essai 2640, M5 5 cycles
étage 6, 5 s-1, 280°C
1150
mu = 0,50
Expérience
1100
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
Déplacement plastique (mm)
movie
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
12
On going research : towards a better interpretation
of the PROMETRA test data
GPL constitutive law (Goguel Poussard Limon) (Goguel et al., 2005) :
Ö
For a better use of the PROMETRA data, a validated constitutive equation applicable to the whole
temperature, strain rate and loading conditions RIA domain, compatible with structural mechanics
computations codes (CAST3M, SCANAIR, …) has been identified
with
Ε
vp
= Ε
Σ =
and
70 tests
available, 20 to
800°C
Ö
0
⎡
⎢
⎢⎣ V (T ). Ε
(
3
s :M : s =
2
Σ
vp
+ Ε
H
vp
Ε
Jean Lemaitre formalism :
r
)(
n T
0
(Σ θ
)
3 Ε
2
=
vp
⎤
⎥
+ ϕ (T , φ t ) ⎥⎦
− Σ
z
)2
+ H
θ
M :
m (T
(Σ
z
s
Σ
C. Poussard et
al., FSRM 2006
)
− Σ
80 tests
available, 20 to
900°C
r
)2
+ H
z
(Σ r
− Σθ
)2
5 tests
available, 20 to
350°C
Domain of application :
Burnup up to 64 GWd/tU),
Temperature (200 up to 800°C),
Strain rate (3.10-4 up to 5 s-1)
Material anisotropy (temperature and neutron flux dependant … the anisotropy
decreases when the irradiation increase)
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
Ö The GPL law, available in À and CAST3M can now be used to model structures
13
On going research : towards a better interpretation
of the PROMETRA test data
International collaboration with ANL and Penn State University (USA),
JAEA (Japan) and Studsvik (Sweden) underway since 2001:
Ö Experimental and analytical Round Robin to exchange and validate experimental
practice and test interpretation
with Teflon tape
1 Gage ring
tensile specimen
2 gauges and dog
bone ring tensile
specimen
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
2 gauges ring
tensile specimen
C. Poussard et al.
14
On going research : towards a better interpretation
of the PROMETRA test data
International collaboration with ANL and Penn State University (USA),
JAEA (Japan) and Studsvik (Sweden) underway since 2001:
Ö Experimental and analytical Round Robin to exchange and validate experimental
practice and test interpretation
900
45
YS 700ppm
40
UTS 700ppm
YS as received
850
35
UTS as received
800
UE, TE (%)
YS, UTS (MPa)
30
750
700
YS 700ppm
UTS 700ppm
25
YS as received
UTS as received
20
15
650
10
600
5
550
0
IK
IK
DEN/Saclay/DMN/SEMI
SV
D
U
ST
L
AN
EA
C
EA
JA
SV
D
U
ST
L
AN
EA
C
EA
JA
Lab
Lab
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
15
On going research : measurement of local strains
Ö Measurement of local strain at failure from Penn State University specimens
with a zero strain biaxiality between the notches
Room
temperature tests
Speckle
Painting
+
Image analysis
V direction
U direction
U Cast3m (mm)
U Image analysis (mm)
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
16
On going research : measurement of local strains
Ö Example of local strain measurements for a ring specimen @350°C through the
window of the furnace available in M04 hot cell :
movie
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
17
Towards a representative RIA analytical test...
CABRI REP Na tests,
IRSN
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
Assumption : isotropic plasticity
Actual available experiments do not fully represent the biaxiality
expected during an RIA :
A. Motta et al., ASTM 2004
C. Poussard et al.
18
Towards a representative RIA analytical test...
PhD thesis (Matthieu Le Saux) underway to develop further
an EDC test with a controlled biaxility
Mechanical properties : - Media : inverse identification
- Cladding : GPL law
Inverse identification of friction coefficients (media vs. jack and media vs. cladding)
Computation vs. experiment
Modeling
Biaxiality
εθθp
0
0.41
Aluminium, T = 300°C, μPM = 0, μTM = 0.2
movie
EDC ~ pure circumferential loading :
DEN/Saclay/DMN/SEMI
⇒ It is necessary to control the axial deformation
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
19
Summary and closing points
PROMETRA represents an extensive material database with :
Ö over 250 validated tests results for fresh and high burnup Zircaloys, M5 and Zirlo
subjected to thermomechanical transients
Ö various geometries tested with high heating rates systems and dynamic testing
machines
Ö supported by full 3D modeling , indispensable for a correct interpretation of the data
Ö over 15 publications worldwide with our colleagues of EDF and IRSN
On-going research within PROMETRA :
Ö new measuring techniques developed in hot cells (image analysis, acoustic emission, …)
Ö new mechanical tests prototypical of reactor biaxial loading
Ö constituve equations for a better representation of the material database
Ö development of constituve equation coupled with damage
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
20
x2 times faster than real life
PROMETRA axial tensile test at high temperature
Thank you for your attention !
movie
Any questions ?
Test specifications : 800°C, 5s-1 Test duration : 18s including Joule effect heating @ 100°C/s
DEN/Saclay/DMN/SEMI
Experimental Tools & Modelling for Nuclear Safety Studiesof Irradiation in Materials, 10/2007, Saclay, France
C. Poussard et al.
21

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