Abstract

The latest PIE results of Zry-2 and HiFi alloy (0.4 %Fe-Zry2) showed that iron addition reduces the hydrogen pick-up ratio. In order to clarify this lower hydrogen absorption mechanism, three types of experiments were carried out for both alloys:

(1) Measurements of the hydrogen pick-up ratio in the pre-transition region using an autoclave.

(2) CPD (Contact Potential Difference) and FBP (Flat-band Potential) measurements of oxide film using a High Temperature Kelvin system and Photocurrent system.

(3) Investigation of hydrogen absorption properties by Sieverts system and corrosion properties by autoclave for intermetallic compounds simulating SPP's Fe/Cr and Fe/Ni ratio in Zry-2 and HiFi.

Autoclave tests showed that the corrosion behaviors of both alloys were similar. However, the hydrogen pick-up ratio depended on not only iron addition but also surface treatment (with and without pickling). Iron addition and non-pickling (as-received) reduced the hydrogen pick-up ratio.

ΔCPD and FBP shifted to the positive side as the result of iron addition, and FBP changed with and without pickling. This difference in surface potential might be caused by the existence of anion vacancy concentration in the oxide film and furthermore may affect the electrochemical potential gradient over the oxide film. This potential gradient might control the proton diffusion in the oxide film.

In the results of the hydrogen absorption tests on intermetallic compounds, Zr(Fe,Cr)2 with a higher Fe/Cr ratio showed lower hydrogen absorption, and Zr2(Fe,Ni) showed higher hydrogen absorption than Zr(Fe,Cr)2. In the results of corrosion tests on intermetallic compounds, Zr2(Fe,Ni) showed a much larger corrosion rate than Zr(Fe,Cr)2. It is considered that Zr2(Fe,Ni)-type precipitate might be oxidized easily in the oxide film, thus it might not contribute to the window for hydrogen absorption, and Zr(Fe,Cr)2 with a higher Fe/Cr ratio would reduce the amount of hydrogen penetrating through SPP at the oxide/metal interface.

Based on these results, a tentative hydrogen absorption mechanism is proposed, explaining both roles of the electrochemical potential gradient over oxide film and the SPP window for the hydrogen absorption.

Issue Section:
Research Papers
Keywords:
hydrogen absorption, corrosion, zirconium alloy, electrochemical property, intermetallic compound

References

1.
Itagaki
,
N.
,
Kakiuchi
,
K.
,
Mozumi
,
Y.
,
Furuya
,
T.
, and
Kubota
,
O.
, “
Development of New High Corrosion Resistance Zr Alloy HiFi for High Burn-up BWR Fuel
,”
Proceedings European Nuclear Society TOPFUEL
,
Würtzburg
,
03
2003
.
2.
Hatano
,
Y.
,
Sugisaki
,
M.
,
Kitano
,
K.
, and
Hayashi
,
M.
, “
Role of Inermetallic Precipitates in Hydrogen Transport through Oxide Films on Zircaloy
,”
Zirconium in the Nuclear Industry: 12th International Symposium
, ASTM STP 1354,
G. P.
 
Sabol
 and
G. D.
 
Moan
, Eds.,
ASTM International
,
West Conshohocken, PA
,
2000
, pp.
901
-
917
.
3.
Murai
,
T.
,
Isobe
,
T.
,
Takizawa
,
Y.
, and
Mae
,
Y.
, “
Fundamental Study on the Corrosion Mechanism of Zr-0.2Fe, Zr-0.2Cr, and Zr-0.1Fe-0.1Cr Alloys
,”
Zirconium in the Nuclear Industry: 12th International Symposium
, ASTM STP 1354,
G. P.
 
Sabol
 and
G. D.
 
Moan
, Eds.,
ASTM International
,
West Conshohocken, PA
,
2000
, pp.
623
-
640
.
Google Scholar
Crossref
Search ADS
 
4.
“
Corrosion of Zirconium Alloys in Nuclear Power Plants
,” IAEA-TECDOC-684.
5.
Cox
,
B.
, “
Mechanism of Hydrogen Absorption by Zirconium Alloys
,”
Atomic Energy of Canada Limited
, Report No. AECL-8702,
1985
.
6.
Baur
,
K.
,
Garzarolli
,
F.
,
Ruhmann
,
H.
, and
Sell
,
H. J.
, “
Electrochemical Examinations in 350 Water with Respect to the Mechanism of Corrosion-Hydrogen Pickup
,”
Zirconium in the Nuclear Industry: 12th International Symposium
, ASTM STP 1354,
G. P.
 
Sabol
 and
G. D.
 
Moan
, Eds.,
ASTM International
,
West Conshohocken, PA
,
2000
, pp.
836
-
852
.
Google Scholar
Crossref
Search ADS
 
7.
Franklin
,
D. G.
 and
Lang
,
P. M.
, “
Zirconium-Alloy Corrosion: A Review Based on an International Atomic Energy Agency (IAEA) Meeting
,”
Zirconium in the Nuclear Industry: 9th International Symposium
, ASTM STP 1132,
C. M.
 
Eucken
 and
A. M.
 
Garde
, Eds.,
ASTM International
,
West Conshohocken, PA
,
1991
, pp.
3
-
32
.
Google Scholar
Crossref
Search ADS
 
8.
Inagaki
,
M.
,
Kanno
,
M.
, and
Maki
,
H.
, “
Effect of Alloying Elements in Zircaloy on Photo-Electrochemical Characteristics of Zirconium Oxide Films
,”
Zirconium in the Nuclear Industry: 9th International Symposium
, ASTM STP 1132,
C. M.
 
Eucken
 and
A. M.
 
Garde
, Eds.,
ASTM International
,
West Conshohocken, PA
,
1991
, pp.
437
-
460
.
Google Scholar
Crossref
Search ADS
 
9.
Lee
,
S.
,
Cho
,
E.
,
Ahn
,
S.
, and
Kwon
,
H.
, “
Photo-Electrochemical Analysis of the Passive Film on Zircaloy-4
,”
Electrochimica Acta
 0013-4686, Vol.
46
,
2001
, pp.
2605
-
2611
.
Google Scholar
Crossref
Search ADS
 
10.
Okui
,
M.
,
Nishizaki
,
T.
,
Uno
,
M.
,
Kurosaki
,
K.
,
Yamanaka
,
S.
,
Takeda
,
K.
, et al, “
Photoelectrochemical Study of Hydrogen in Zirconium Oxide
,”
Journal of Alloys and Compounds
 0925-8388, Vols.
330–332
,
2002
, pp.
645
-
648
.
11.
Isobe
,
Y.
,
Fuse
,
M.
, and
Kobayashi
,
K.
, “
Additive Element Effects on Electric Conductivity of Zirconium Oxide Film
,”
Journal of Nuclear Science and Technology
 0022-3131, Vol.
31
,
1994
, pp. 546.
12.
Suzuki
,
A.
,
Shibata
,
M.
,
Yamaguchi
,
K.
, and
Yamawaki
,
M.
, “
Effect of Oxygen Potential Change on the Surface Potential of YSZ, ZrO2-Y2O3
,”
Journal of Alloys and Compounds
 0925-8388, Vols.
262–263
,
1997
, pp.
185
-
190
.
13.
Kröger
,
F. A.
 and
Vink
,
H. J.
, “
Relation Between the Concentrations of Imperfections in Crystalline Solid
,”
Solid State Physic
 
3
,
1956
, p. 307.
14.
Taylor
,
D. F.
,
Cheng
,
B.
, and
Adamson
,
R. B.
, “
Nodular Corrosion Mechanisms and Their Application to Alloy Development
,”
International Atomic Energy Agency Technical Committee Meeting on Fundamental Environments Corrosion of Zirconium-Base Alloys in Water Reactor Environments Portland
,
Oregon
, September 11–15, 1989.
15.
Beie
,
H. J.
,
Mitwalsky
,
A.
,
Garzarolli
,
F.
,
Ruhmann
,
H.
, and
Sell
,
H. J.
, “
Examinations of the Corrosion Mechanism of Zirconium Alloys
,”
Zirconium in the Nuclear Industry: 10th International Symposium
, ASTM STP 1245,
A. M.
 
Garde
 and
E. R.
 
Bradley
, Eds.,
ASTM International
,
West Conshohocken, PA
,
1994
, pp.
615
-
643
.
Google Scholar
Crossref
Search ADS
 
16.
Uchida
,
M.
, “
Hydrogen Absorption by Zirconium Alloy Cladding Tube with Surface Oxide Film
,”
JAERI-M
08
1991
.
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