Abstract

The present work deals with two essential degradation mechanisms of zirconium alloys: Hydrogen behavior and microstructural transformations due to neutron irradiation. The studies were carried out by using samples taken from Zircaloy-4 components, which remained for 14 years in the Atucha I pressurized heavy water reactor, accumulating neutron fluences of up to 1022neutrons/cm2. A hydrogen/deuterium solubility increase was observed in both dissolution and precipitation processes. With the aim to follow this evolution with radiation damage recovery, the irradiated samples were annealed for different periods at 350 and 400°C in a differential scanning calorimeter (DSC). These temperatures were chosen to reproduce those reached by spent fuels in the early stages of the dry storage (DS). Between intervals, the terminal solid solubility temperatures in dissolution (TTSSd) and in precipitation (TTSSp) were determined. They were also determined after additional annealing at 500 and 600°C, trying to simulate long periods at DS. The hydride morphology and the metallurgical state of the Zr(Fe,Cr)2 second-phase particles (SPPs) were followed between annealing by optical microscopy, analytical electron microscopy, synchrotron light X-ray diffraction

X-ray diffraction diagrams were obtained at the Brazilian Synchrotron (LNLS), Campinas, S. P., Brazil.

(SXRD), and DSC. As a brief summary, we found from the first to the last run of the annealing sequence an increase of 55°C in TTSSd and 40°C in TTSSp on average. The optical and transmission electron microscopies (TEM) indicate that in the material in the irradiated condition, exists a hydride size distribution of four orders of magnitude, from 10 nm to 100μm, but biased to sizes smaller than 5μm. A complete amorphisation of the SPPs was observed in high fluence samples by TEM and SXRD. Similar TEM observations made in irradiated samples annealed above 400°C show a re-precipitation process of nano-SPPs forming clusters. The re-precipitation is affected by kinetics: The SPPs crystallization temperature, Tc, rises from 450 to 500°C as the heating rate increases from 5 to 20°C/min. The measured heat of crystallization was 27.3±2.1kJ/mol(Fe+Cr).

References

1.
Charit
,
I.
and
Murty
,
K. L.
, “
Creep Behavior of Niobium-Modified Zirconium Alloys
,”
J. Nucl. Mater.
 0022-3115, Vol.
374
,
2008
, pp.
354
363
. https://doi.org/10.1016/j.jnucmat.2007.08.019
2.
Duriez
,
C.
,
Dupont
,
T.
,
Schmet
,
B.
, and
Enoch
,
F.
, “
Zircaloy-4 and M5 High Temperature Oxidation and Nitriding in Air
,”
J. Nucl. Mater.
 0022-3115, Vol.
380
,
2008
, pp.
30
45
. https://doi.org/10.1016/j.jnucmat.2008.07.002
3.
Anand
,
M. S.
,
Mansel
,
W.
,
Wallner
,
G.
, and
Weck
,
W.
, “
Effect of Alloying Elements on Recovery and Damage Rates in Zirconium
,”
J. Nucl. Mater.
 0022-3115, Vol.
126
,
1984
, pp.
144
151
. https://doi.org/10.1016/0022-3115(84)90084-9
4.
Toffolon-Masclet
,
C.
,
Guilbert
,
T.
, and
Brachet
,
J. C.
, “
Study of Secondary Intermetallic Phase Precipitation/Dissolution in Zr Alloys by High Temperature–High Sensitivity Calorimetry
,”
J. Nucl. Mater.
 0022-3115, Vol.
372
(
2–3
),
2008
, pp.
367
378
. https://doi.org/10.1016/j.jnucmat.2007.04.042
5.
Vizcaíno
,
P.
,
Banchik
,
A. D.
, and
Abriata
,
J. P.
, “
Synchrotron X-Ray Diffraction Evidences of the Amorphization/Dissolution of the Second Phase Particles (SPPs) in Neutron Irradiated Zircaloy-4
,”
Mater. Lett.
 0167-577X, Vol.
62
,
2008
, pp.
491
493
. https://doi.org/10.1016/j.matlet.2007.05.062
6.
Vizcaíno
,
P.
,
Banchik
,
A. D.
, and
Abriata
,
J. P.
, “
Hydrogen in Zircaloy-4: Effects of the Neutron Irradiation on the Hydride Formation
,”
J. Mater. Sci.
 0022-2461, Vol.
42
,
2007
, pp.
6633
6637
. https://doi.org/10.1007/s10853-007-1525-x
7.
Vizcaíno
,
P.
,
Banchik
,
A. D.
, and
Abriata
,
J. P.
, “
Hydride Phase Dissolution Enthalpy in Neutron Irradiated Zircaloy-4
,”
J. Nucl. Mater.
 0022-3115, Vol.
336
(
1
),
2005
, pp.
54
64
. https://doi.org/10.1016/j.jnucmat.2004.08.013
8.
Vizcaíno
,
P.
,
Banchik
,
A. D.
, and
Abriata
,
J. P.
, “
Solubility of Hydrogen in Zircaloy-4: Irradiation Induced Increase and Thermal Recovery
,”
J. Nucl. Mater.
 0022-3115, Vol.
304
(
2–3
),
2002
, pp.
96
106
. https://doi.org/10.1016/S0022-3115(02)00883-8
9.
McMinn
,
A.
,
Darby
,
E. C.
, and
Schofield
,
J. S.
Terminal Solid Solubility of Hydrogen in Zirconium Alloys
,”
Zirconium in the Nuclear Industry: 12th International Symposium, ASTM STP 1354
,
G. P.
Sabol
,
G. D.
Moan
, eds.,
ASTM International
,
West Conshohocken, PA
,
2000
, pp.
173
195
.
10.
Pan
,
Z. L.
and
Puls
,
M. P.
, “
Precipitation and Dissolution Peaks of Hydride in Zr-2.5Nb During Quasistatic Thermal Cycles
,”
J. Alloys Compd.
 0925-8388, Vol.
310
,
2000
, pp.
214
218
. https://doi.org/10.1016/S0925-8388(00)01028-8
11.
Khatamian
,
D.
and
Root
,
J. H.
, “
Comparison of TSSD Results Obtained by Differential Scanning Calorimetry and Neutron Diffraction
,”
J. Nucl. Mater.
 0022-3115, Vol.
372
(
1
),
2008
, pp.
106
113
. https://doi.org/10.1016/j.jnucmat.2007.02.010
12.
Goll
,
W.
,
Spilker
,
H.
, and
Toscano
,
E. H.
, “
Short Time Creep and Rupture Test on High Burn up Fuel Rod Cladding
,”
J. Nucl. Mater.
 0022-3115, Vol.
289
,
2001
, pp.
247
253
. https://doi.org/10.1016/S0022-3115(01)00438-X
13.
Carpenter
,
J. C.
and
Watters
,
J. F.
, “
Irradiation Damage Recovery in Some Zirconium Alloys
’’,
Zirconium in Nuclear Applications ASTM STP 551
,
American Society for Testing and Materials
,
1974
, pp.
400
415
.
14.
Peeks
,
M.
,
Garzarolli
,
F.
, and
Goll
,
W.
, “
Assessment of Dry Storage Performance of Spent LWR Fuel Assemblies with Increasing Burnup
,”
International Symposium on Storage of Spent Fuel From Power Reactors, IAEA-SM-352/39
, Nov. 9–13,
1998
, IAEA and OECD Nuclear Agency, pp.
313
324
.
15.
Erwin
,
K. T.
,
Delaire
,
O.
,
Motta
,
A. T.
,
Chu
,
Y. S.
,
Mancini
,
D. C.
, and
Birtcher
,
R. C.
, “
Observation of Second-Phase Particles in Bulk Zirconium Alloys Using Synchrotron Radiation
,”
J. Nucl. Mater.
 0022-3115, Vol.
294
,
2001
, pp.
299
304
. https://doi.org/10.1016/S0022-3115(01)00436-6
16.
Tenckhoff
,
E.
Review of Deformation Mechanism, Texture and Mechanical Anisotropy in Zirconium and Zirconium Base Alloys
,”
14th International Symposium of Zirconium in the Nuclear Industry, ASTM STP 1467
2006
,
P.
Rudling
and
B.
Kammendzind
, eds.,
ASTM International
,
West Conshohocken, PA
, pp.
25
52
.
17.
Joy
,
D. C.
,
Romig
,
A. D.
, and
Goldstein
,
J. I.
,
Principles of Analytical Electron Microscopy
,
Plenum Press
,
New York
,
1986
.
18.
Versaci
,
R.
and
Ipohorsky
,
M.
, “
Polytype Structure of Intermetallic Precipitates in Zircaloy-4 Alloys
,”
J. Nucl. Mater.
 0022-3115, Vol.
80
,
1979
, pp.
180
183
. https://doi.org/10.1016/0022-3115(79)90234-4
19.
Etoh
,
Y.
and
Shimada
,
S.
, “
Neutron Irradiation Effects on Intermetallic Precipitates in Zircaloy as a Function of Fluence
,”
J. Nucl. Mater.
 0022-3115, Vol.
200
,
1993
, pp.
59
69
. https://doi.org/10.1016/0022-3115(93)90009-N
20.
Adamson
,
R. B.
, “
Effects of Neutron Irradiation on Microstructure and Properties of Zircaloy
,”
Zirconium in the Nuclear Industry, 12th International Symposium, ASTM STP 1354
,
2000
,
G. P.
Sabol
and
G. D.
Moan
, eds.,
ASTM International
,
West Conshohocken, PA
, pp.
15
31
.
21.
Chen
,
S. P.
,
Vossenberg
,
M. S.
,
Vermolen
,
F. J.
,
van der Langkruis
,
J.
, and
van der Zwaag
,
S.
, “
Dissolution of β Particles in an Al-Mg-Si Alloy During DSC Runs
,”
Mater. Sci. Eng., A
 0921-5093, Vol.
272
,
1999
, pp.
250
256
. https://doi.org/10.1016/S0921-5093(99)00518-3
22.
Vermolen
,
F.
and
Vuik
,
K.
, “
A Numerical Method to Compute the Dissolution of Second Phases in Ternary Alloys
,”
J. Comput. Appl. Math.
 0377-0427, Vol.
93
,
1998
, pp.
123
143
. https://doi.org/10.1016/S0377-0427(98)00076-4
23.
Vermolen
,
F. J.
,
Vuik
,
C.
, and
van der Zwaag
,
S.
, “
A Mathematical Model for the Dissolution of Stoichiometric Particles in Multi-Component Alloys
,”
Mater. Sci. Eng., A
 0921-5093, Vol.
328
,
2002
, pp.
14
25
. https://doi.org/10.1016/S0921-5093(01)01652-5
24.
Gilbon
,
D.
and
Simonot
,
C.
Effect of Irradiation on the Microstructure of Zircaloy-4
,”
Zirconium in the Nuclear Industry, Tenth International Symposium, ASMT STP 1245
,
1994
,
A. M.
Garde
and
E. R.
Bradley
, eds.,
ASTM International
,
West Conshohocken, PA
, pp.
521
548
.
25.
Motta
,
A.
and
Lemaignan
,
C.
, “
A Ballistic Mixing Model for the Amorphisation of Precipitates in Zircaloy Under Neutron Irradiation
,”
J. Nucl. Mater.
 0022-3115, Vol.
195
,
1992
, pp.
277
285
. https://doi.org/10.1016/0022-3115(92)90519-Q
26.
Yan
,
Z. J.
,
He
,
S. R.
,
Li
,
J. R.
, and
Zhou
,
Y. H.
, “
On the Crystallization Kinetics of Zr60Al15Ni25 Amorphous Alloy
,”
J. Alloys Compd.
 0925-8388, Vol.
368
,
2004
, pp.
175
179
. https://doi.org/10.1016/j.jallcom.2003.08.074
This content is only available via PDF.
You do not currently have access to this content.