UMo/Al nuclear fuel plate behavior under thermal treatment (425-550°C)

2013 ◽  
Vol 28 (S2) ◽  
pp. S371-S393 ◽  
Author(s):  
H. Palancher ◽  
A. Bonnin ◽  
C.V. Colin ◽  
V. Nassif ◽  
V. Honkimäki ◽  
...  

Nuclear fuel plates based on a γU-Mo/Al mixture are proposed for research reactors. In this work their thermal behavior in the [425; 550°C] temperature range has been studied mainly by neutron and high energy X-ray diffraction. Even if complementary studies will be necessary, the kinetics of first the growth of the interaction layer between γU-Mo and Al and second of the γU-Mo destabilization have been accurately measured. This basic work should be helpful for defining manufacturing conditions for fuel plates with optimized composition.

Author(s):  
A. Bonnin ◽  
H. Palancher ◽  
V. Honkimäki ◽  
R. Tucoulou ◽  
Y. Calzavara ◽  
...  

2006 ◽  
Vol 13 (02n03) ◽  
pp. 155-166 ◽  
Author(s):  
WOLFGANG BRAUN ◽  
KLAUS H. PLOOG

X-rays are ideal to study the structure of crystals due to their weak interaction with matter and in most cases allow a quantitative analysis using kinematical theory. To study the incorporation of atoms during crystal growth and to analyze the kinetics on the crystal surface high primary beam intensities available at synchrotrons are required. Our studies of the molecular beam epitaxy growth of III–V semiconductors reveal that, despite their similarity in crystal structure, the surface kinetics of GaAs (001), InAs (001) and GaSb (001) differ strongly. GaAs shows an unexpectedly large coarsening exponent outside the predicted range of Ostwald ripening models during recovery. GaSb exhibits dramatically different surface morphology variations during growth and recovery. Overgrowth of GaAs by epitaxial MnAs demonstrates the ability of X-ray diffraction to follow an interface as it is buried during heteroepitaxy, which is not possible by reflection high-energy electron diffraction.


2006 ◽  
Vol 519-521 ◽  
pp. 1569-1578
Author(s):  
Dorte Juul Jensen

By 3 dimensional X-ray diffraction (3DXRD) using high energy X-rays from synchrotron sources it is possible to study in-situ the nucleation and growth during recrystallization. In this paper it is described and discussed how 3DXRD can supplement EBSP measurements of nucleation and growth. Three types of studies are considered: i) orientation relationships between nuclei and parent deformed matrix, ii) recrystallization kinetics of individual bulk grains and iii) filming of growing grains in deformed single crystals.


Materialia ◽  
2021 ◽  
pp. 101251
Author(s):  
P. Barriobero-Vila ◽  
R. Jerez-Mesa ◽  
A. Guitar ◽  
O. Gavalda-Diaz ◽  
J.A. Travieso-Rodríguez ◽  
...  

2010 ◽  
Vol 62 (8) ◽  
pp. 617-620 ◽  
Author(s):  
Y.D. Wang ◽  
Y. Ren ◽  
E.W. Huang ◽  
G. Wang ◽  
Z.H. Nie ◽  
...  

2010 ◽  
Vol 65 ◽  
pp. 184-193 ◽  
Author(s):  
L. Perazolli ◽  
G.F. Pegler ◽  
M.R.A. Silva ◽  
R.A.F. Ingino ◽  
J.A. Varela

A Photocatalyst ceramic powder that presented high photoactivity based on TiO2 modified with 25% molar of SnO2 and up to 5% molar of Ag2O was obtained in the present work. The aforementioned ceramic powder was obtained using all commercial oxides as well as the oxides mixture technique. The powders were ground in high energy mill for one hour with subsequent thermal treatment at 400°C for four hours. They were, furthermore, characterized using surface area of around 6m2/g, where the X-Ray diffraction results provided evidence for the presence of anatase and rutile phases, known to be typical characteristics of both the TiO2 and SnO2 used. During the thermal treatment, Ag2O was reduced to metallic silver. The photodegradation rehearsals were carried out using a 0.01 mmol/L Rhodamine B solution in a 100mg/L photocatalyst suspension in a 500ml beaker, which was irradiated with 4W germicide Ultraviolet light of 254nm. In addition, samples were removed after duration of about 10 minutes to an hour, where they were analyzed thoroughly in UV-vis spectrophotometer. The analysis of the results indicated that for the compositions up to 2.5% molar of Ag2O, the photoactivity was found to be greater than that of Degussa P25 photocatalyst powder, and as such it was then used as a reference. Taking into account 90% degradation of Rhodamine B, a duration period of 11 minutes was obtained for the developed photocatalyst powder compared to the 38 minutes observed for the Degussa P25. FEG-SEM micrographies enabled the verification of the morphology as well as the interaction of the oxide particles with the metallic silver, which led us to propose a model for the increase in photoactivity observed in the photocatalyst powder under investigation.


2014 ◽  
Vol 777 ◽  
pp. 112-117 ◽  
Author(s):  
Donald W. Brown ◽  
Levente Balogh ◽  
Darrin Byler ◽  
Chris M. Hefferan ◽  
James F. Hunter ◽  
...  

Near-field high energy x-ray diffraction microscopy (nf-HEDM) and high energy x-ray micro-tomography (μT) have been utilized to characterize the pore structure and grain morphology in sintered ceramic UO2nuclear fuel material. μT successfully images pores to 2-3μm diameters and is analyzed to produce a pore size distribution. It is apparent that the largest number of pores and pore volume in the sintered ceramic are below the current resolution of the technique, which might be more appropriate to image cracks in the same ceramics. Grain orientation maps of slices determined by nf-HEDM at 25 μm intervals are presented and analyzed in terms of grain boundary misorientation angle. The benefit of these two techniques is that they are non-destructive and thus could be performed before and after processes (such as time at temperature or in-reactor) or even in-situ.


2014 ◽  
Vol 986-987 ◽  
pp. 88-91
Author(s):  
Yan Wang ◽  
Shi Wei Wu ◽  
Hao Yu ◽  
Na Na Gong ◽  
Zhong Qiu Cao ◽  
...  

We report on the preparation and hydrogen desorption/absorption kinetics of nanocrystalline magnesium hydride (MgH2) added commercial TiO2by high-energy ball milling. The phase and composition of the as-milled powders are characterized by X-ray diffraction (XRD). The results show that the milled sample contained MgH2phase, small amount of Mg and various phases of TiO2such as tetragonal and orthorhombic structure. The effect of the milling time (10, 20 and 30 h) on the hydrogen desorption property of MgH2has been investigated and found that the milling time of 20 h has excellent dehydrogenation properties, which can release 3.3 wt% H2within 60 min at 300oC, which indicates that the kinetics of hydrogen desorption of MgH2-TiO2composite has been greatly enhanced compared to the pure MgH2. Moreover, hydrogen absorption kinetics of the sample milled 20 h has been studied and the hydrogen content is 0.7, 0.8 and 1.2 wt% H2at 250, 280 and 300oC within 60 min, respectively.


1994 ◽  
Vol 364 ◽  
Author(s):  
S. Gialanella ◽  
M. D. Baró ◽  
L. Lutterotti ◽  
S. Suriñach

AbstractThe ordered structure of Fe–40A1 B2 powders was completely disordered by high energy ball-milling. The defect structures of the powders disordered to different extents were characterized using X-Ray diffraction. A significant lattice expansion was observed, which we tried to relate to the high concentration of point defects introduced into the material as a consequence of milling.A complete reordering was accomplished by heating up the specimens under an inert Ar atmosphere. We followed the kinetics of the disorder to order transformation by Differential Scanning Calorimetry and Thermogravimetric Magnetic Measurements. The two techniques allowed us to identify the temperature range and the apparent activation energy of the process. As expected, a decrease in the magnetic moment of the originally disordered powders as a consequence of the reordering treatments was also observed.


2008 ◽  
Vol 104 (4) ◽  
pp. 043520 ◽  
Author(s):  
G. B. González ◽  
J. S. Okasinski ◽  
T. O. Mason ◽  
T. Buslaps ◽  
V. Honkimäki

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