Download or read book Investigating the Effect of Oxide Texture on the Corrosion Performance of Zirconium Alloys written by Alistair John Garner and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Texture and Microstructure of Zircnoium sic Alloys on Their Oxidation and Oxide Texture written by Jianlong Lin and published by . This book was released on 2005 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigating the Effect of Zirconium Oxide Microstructure on Corrosion Performance written by Alistair Garner and published by . This book was released on 2018 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scanning precession electron diffraction in the transmission electron microscope has been used to simultaneously map the phase, orientation, and grain morphology of oxides formed on Zircaloy-2 after three and six cycles in a boiling water reactor in unprecedented detail. For comparison, a region of a preoxidized autoclave-formed oxide was also proton-irradiated at the Dalton Cumbrian Facility. The proton irradiation was observed to cause additional stabilization of the tetragonal phase that was attributed to the stabilizing effect of irradiation-induced defects in the oxide. In the reactor-formed oxides, no extra stabilization of the tetragonal grains was observed under neutron irradiation, as indicated by the similar tetragonal phase fraction and transformation twin-boundary distributions between the nonirradiated and reactor-formed oxides. It is suggested that the damage rate is too low in the newly formed oxide to cause significant stabilization of the tetragonal phase. This technique also reveals that the oxide formed under reactor conditions has a more heterogeneous microstructure, and the growth of well-oriented columnar monoclinic grains is significantly reduced compared with a nonirradiated oxide. High-angle annular dark-field scanning transmission electron microscopy also revealed the development of extensive networks of intergranular porosity and eventually grain decohesion in the reactor-formed oxides. These results suggest that the tetragonal-monoclinic transformation is not responsible for the accelerated corrosion exhibited under reactor conditions. It is proposed that the usual out-of-reactor oxide growth and nucleation processes are significantly modified under reactor conditions, resulting in a more heterogeneous and randomly oriented oxide microstructure with reduced columnar grain growth. It is suggested that this disordered oxide microstructure allows for the formation of extensive intergranular porosity that could lead to accelerated in-reactor corrosion.
Download or read book Zirconium in the Nuclear Industry written by Gerry D. Moan and published by ASTM International. This book was released on 2002 with total page 891 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation The 41 papers of this proceedings volume were first presented at the 13th symposium on Zirconium in the Nuclear Industry held in Annecy, France in June of 2001. Many of the papers are devoted to material related issues, corrosion and hydriding behavior, in-reactor studies, and the behavior and properties of Zr alloys used in storing spent fuel. Some papers report on studies of second phase particles, irradiation creep and growth, and material performance during loss of coolant and reactivity initiated accidents. Annotation copyrighted by Book News, Inc., Portland, OR.
Download or read book Texture and Anisotropy written by U. F. Kocks and published by Cambridge University Press. This book was released on 2000-08-15 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: A successful book covering an important area of materials science, now available in paperback.
Download or read book The Cause for Enhanced Corrosion of Zirconium Alloys by Hydrides written by HK. Woo and published by . This book was released on 2002 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cause of the accelerated corrosion of zirconium alloys by hydrides is studied by investigating the corrosion of three section planes of Zr-2.5Nb tubes with different texture: the longitudinal normal section (LS) plane, the transverse normal section (TS) plane, and the radial normal section (RS) plane. Corrosion tests were conducted on those section planes taken from the unhydrided and prehydrided Zr-2.5Nb tubes with up to 450 ppm H in water at 350°C or in steam at 400°C. For Zr-2.5Nb tube with a strong circumferential texture, the deleterious effect of hydrides on enhanced corrosion was most striking on the LS specimen, while beneficial and little hydride effect on the corrosion was observed on the TS and RS specimens, respectively. However, for Zr-2.5Nb tube with a comparatively radial texture, the deleterious effect of hydrides on enhanced corrosion was observed on all the three section planes. The lattice broadening and the interplanar spacing in the zirconium matrix were measured by using X-rays on those section planes taken from Zr-2.5Nb tubes with a circumferential texture before and after charging with hydrogen. The precipitation of hydrides in the Zr-2.5Nb tube subjected the LS plane to residual tensile stress, expanding the zirconium lattice in the LS, and the TS plane to compressive stress, contracting it in the TS. Based on these results, the corrosion acceleration by hydrides is discussed by correlating the change in the zirconium lattice distance or lattice distortion including residual stress and the corrosion on each plane before and after charging with hydrogen. This finding leads us to the conclusion that the major controlling factor to the corrosion of zirconium alloys is the lattice coherency between the metal and the oxide.
Download or read book Corrosion of Zirconium Alloys in 900 Steam written by J. Paul Pemsler and published by . This book was released on 1958 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Hydrogen on the Corrosion Performance of Zirconium Alloys written by Jianfei Wei and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation of Variables That Influence Corrosion of Zirconium Alloys During Irradiation written by VF. Urbanic and published by . This book was released on 1991 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The in-reactor corrosion of Zircaloy-2 and Zr-2.5Nb pressure tube materials is being studied by exposing small specimens in water-cooled loops in the NRU research reactor. Experiments are designed to investigate the effects of fast-neutron irradiation, water chemistry, temperature, and pre-oxidation on the corrosion behaviour. Preliminary results show that inreactor corrosion rates of both alloys increase with increasing concentrations of dissolved oxygen in the water. In the absence of irradiation, only Zr-2.5Nb is sensitive to its presence. Excursions to oxidizing (?300 (?g/kg oxygen) water chemistry in nominally low oxygen tests are seen to induce high oxidation rates for both Zircaloy-2 and Zr-2.5Nb during irradiation. The consequences of oxygen excursions are less pronounced on material prefilmed in 673 K steam. The oxides formed in different chemistry regimes are characterized using scanning electron microscopy and capacitance techniques.
Download or read book Zirconium in the Nuclear Industry Tenth International Symposium written by A. M. Garde and published by ASTM International. This book was released on 1994 with total page 805 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1985 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Abstract effect of hydrogen on the corrosion performance of zirconium alloys written by Jianfei Wei and published by . This book was released on 2012 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Hydride Precipitation on the Corrosion Kinetics of Zircaloy 4 written by Michael Jublot and published by . This book was released on 2018 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydride precipitation at the oxide-metal interface is frequently proposed as causing the corrosion acceleration of Zircaloy-4 at high burnup in pressurized water reactors (PWRs). In order to identify the local mechanisms possibly involved, we studied the nanostructure of oxides formed on massive zirconium hydrides and reference Zircaloy-4 with an innovative grain mapping technique with the use of transmission electron microscopy (TEM). In autoclave PWR conditions, the presence of a precipitated hydride phase, previously formed by a cathodic charging technique at the surface of Zircaloy-4, clearly increased the corrosion rate, and a higher oxygen diffusion flux along oxide grain boundaries is observed compared with the reference Zircaloy-4. The texture, grain size, and adjacent grain misorientation in the oxide layer were studied in detail along the direction of the oxide growth using an automated crystal orientation mapping technique associated with TEM for both prehydrided and reference Zircaloy-4 samples. The texture in the growth direction is similar on prehydrided and reference samples, but the grain-to-grain misorientations showed differences. Indeed, on the prehydrided sample, the misorientation of 90° with respect to the [001] monoclinic axis is less probable than in the reference oxide, and more misorientations of 50-70° and 120-150°, corresponding to larger mismatches between neighboring grain boundaries, are observed. A smaller average diameter of the columnar monoclinic grains is also clearly revealed for the oxide grown on the prehydrided sample that leads to a larger number of diffusion paths for oxidizing species. These results are discussed and used for simulating oxygen diffusion flux through the polycrystalline microstructure of the oxide layer as a function of the grain size.
Download or read book Understanding of Corrosion Mechanisms of Zirconium Alloys After Irradiation written by Marc Tupin and published by . This book was released on 2014 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: The irradiation damage in the fuel cladding material is mainly caused by the neutron flux resulting from the fission reactions occurring in the fuel. From an experimental point of view, the neutrons have the disadvantage to activate materials by neutron capture rendering them difficult to handle. To avoid these constraints inherent in the handling of radioactive material, the radiation effects on the corrosion resistance of zirconium alloys can be studied by irradiating the materials with ions. A new experimental approach using ion irradiation was performed in the Microscopy and Irradiation Damage Studies Laboratory of the CEA in Saclay, with the aim to study more specifically the influence of the irradiation damages in the oxide on the corrosion rate of the zirconium alloys. This study was, moreover, focused on a particular distribution of defects in the oxide layer, basically, localised close to the metal/oxide interface. From the results of the irradiation of the metal/oxide interface, it was clearly shown that, whatever the incident ion, the irradiation of the internal interface results in a significant increase of the oxygen diffusion flux ratios between the most irradiated Zircaloy-4 and the unirradiated one, whereas that of the oxide formed on M5TM induces a big decrease of the oxygen diffusion flux in the film. These effects are less marked with helium ions compared to protons (M5TM is a trademark of AREVA NP registered in the United States and in other countries). Finally, the oxide irradiation impact on the oxygen diffusion through the layer could explain the corrosion acceleration factor observed on Zy4 during the first cycles of irradiation, but cannot alone explain observed corrosion accelerations under high burn-up conditions. The discussion on the oxide irradiation effects puts forward the probable role of the residual charge left by ion implantation.
Download or read book Corrosion of Zirconium Alloys written by and published by . This book was released on 1964 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Beneficial Effect of Alloy Additions to Zirconium on the Corrosion Resistance in 600 F Water written by D. S. Kneppel and published by . This book was released on 1952 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
