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Book Hydrogen Entry in Zircaloy 4 Fuel Cladding

Download or read book Hydrogen Entry in Zircaloy 4 Fuel Cladding written by Jennifer Anne Jarvis and published by . This book was released on 2015 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corrosion and hydrogen pickup of zirconium alloy fuel cladding in water cooled nuclear reactors are life-limiting phenomena for fuel. This thesis studies the fate of hydrogen liberated by waterside corrosion of Zircaloy-4 fuel cladding in Pressurized Water Reactors (PWRs): are the adsorbed protons incorporated into the oxide and eventually the metal, or are they evolved into molecular hydrogen and released into the coolant? Water chemistry modeling was used to understand effects of radiolysis and CRUD. Density functional theory (DFT) was used to investigate the role of oxidized Zr(Fe,Cr)2 second phase particles. Chemical potentials and the electron chemical potential were used to connect these two modeling efforts. A radiolysis model was developed for the primary loop of a PWR. Dose profiles accounting for fuel burnup, boron addition, axial power profiles, and a CRUD layer were produced. Dose rates to the bulk coolant increased by 21-22% with 12.5-75 pim thick CRUD layers. Radially-averaged core chemistry was compared to single-channel chemistry at individual fuel rods. Calculations showed that local chemistry was more oxidizing at high-power fuel and fuel with CRUD. Local hydrogen peroxide concentrations were up to 2.5 ppb higher than average levels of 5-8 ppb. Radiolysis results were used to compute chemical potentials and the corrosion potential. Marcus theory was applied to compare the band energies of oxides associated with Zircaloy-4 and the energy levels for proton reduction in PWR conditions. Hydrogen interactions with Cr203 and Fe203, both found in oxidized precipitates, were studied with DFT. Atomic adsorption of hydrogen was modeled on the Cr and Feterminated (0001) surfaces. Climbing Image-Nudged Elastic Band calculations were used to model the competing pathways of hydrogen migration into the subsurface and molecular hydrogen formation. A two-step mechanism for hydrogen recombination was identified consisting of: reduction of an adsorbed proton (H+) to a hydride ion (H-) and H2 formation from an adjacent adsorbed proton and hydride ion. Overall, results suggest that neither surface will be an easy entrance point for hydrogen ingress and that Cr203 is more likely to be involved in hydrogen evolution than the Fe203.

Book The Significance of Corrosion and Hydrogen Uptake for Zircaloy Fuel Cladding in Normal Operation of Boiling Water Reactors

Download or read book The Significance of Corrosion and Hydrogen Uptake for Zircaloy Fuel Cladding in Normal Operation of Boiling Water Reactors written by F.W. Trowse and published by . This book was released on 1974 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Investigation Effect of External Stress on Hydrogen Solvus in a Zircaloy 4 Fuel Cladding Alloy Application of in Situ Diffraction Technique and Mesoscale Phase field Simulation

Download or read book Investigation Effect of External Stress on Hydrogen Solvus in a Zircaloy 4 Fuel Cladding Alloy Application of in Situ Diffraction Technique and Mesoscale Phase field Simulation written by Jun-Li Lin and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A Proposed Criterion for the Oxygen Embrittlement of Zircaloy 4 Fuel Cladding

Download or read book A Proposed Criterion for the Oxygen Embrittlement of Zircaloy 4 Fuel Cladding written by A. Sawatzky and published by . This book was released on 1979 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Under the condition postulated for a loss-of-coolant accident (LOCA), Zircaloy-4 fuel cladding may experience a temperature transient during which it absorbs an appreciable amount of oxygen from the coolant. Theoretical models for predicting cladding behavior during loss-of-coolant (LOC) are being developed, but until the failure mechanisms can be clearly established, an empirical criterion must be employed.

Book Zirconium in the Nuclear Industry

Download or read book Zirconium in the Nuclear Industry written by D. G. Franklin and published by ASTM International. This book was released on 1984 with total page 866 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Hydrogen Distribution in Zircaloy Under a Temperature Gradient

Download or read book Hydrogen Distribution in Zircaloy Under a Temperature Gradient written by Evrard Lacroix and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: During normal operation in nuclear reactors, the nuclear fuel cladding corrodes as a result of exposure to high temperature cooling water. During this process, hydrogen can enter the zirconium-alloy of the fuel cladding, and under proper conditions, precipitate as brittle hydride platelets which can severely impact cladding ductility and fracture toughness. Hydrogen tends to migrate to and precipitate at colder spots. Because high local hydride concentrations increase the risk of cladding failure, it is important to predict the local hydrogen distribution. Hydrogen transport depends on different phenomena. Even though migration can only occur when the hydrogen is in solid solution, the cladding temperatures during operating condition allow a portion of the hydrogen to be in solid solution. Therefore, as hydrogen is picked up during the corrosion reaction between the cladding and the coolant, it can migrate following Ficks law and the Soret effect. Once the local hydrogen content reaches the terminal solid solubility for precipitation, the hydrogen will start precipitating as zirconium hydride. Previous work in our laboratory implemented a model that describes these different phenomena, into the 3D fuel performance code BISON. A first attempt to benchmark this model has been made in this study by comparing the results given by BISON to the hydrogen distribution measured in a nuclear fuel rod, which underwent a five cycle exposure at the Gravelines nuclear power plant. This was feasible because of the very detailed information about that reactor and fuel pin were available from the thesis of J.-H. Zhang in 1992. The benchmark performed with BISON showed very good agreement between the calculations experimental observation.The calculation above used a value of the precipitation kinetics parameter 2 based on a fit that ignored discrepancies in the early part of the precipitation process. The calculation was revised according to a new model. The new model, which assumes an initial dependence of the precipitation rate on (C_ss-TSS_p )^2 , provides a better fit for this date and we believe a more precise value of 2, which varies mildly with temperature.

Book Zirconium in the Nuclear Industry

Download or read book Zirconium in the Nuclear Industry written by and published by ASTM International. This book was released on with total page 849 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Analysis of the Secondary Cladding Hydrogenation During the Quench LOCA Bundle Tests With Zircaloy 4 Claddings and Its Influence on the Cladding Embrittlement

Download or read book Analysis of the Secondary Cladding Hydrogenation During the Quench LOCA Bundle Tests With Zircaloy 4 Claddings and Its Influence on the Cladding Embrittlement written by M. Walter and published by . This book was released on 2014 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: LOCA simulation tests were performed in the QUENCH facility of KIT on fuel rod bundle scale. The first two tests using Zircaloy-4 claddings, out of a series of six tests with different cladding alloys, were already performed. The test conditions and results are described. The secondary hydrogenation of the Zircaloy-4 cladding tubes was investigated by means of neutron imaging. In the cladding of the inner rods, hydrogen enriched bended bands were found. They are non-symmetrical to the tube axis. The bands are located at the position where significant inner oxidation ends. X-ray diffractometry (XRD) measurements show that the hydrogen remains at least partially in the zirconium lattice. The formation of the hydrogen enriched bands results in an embrittlement of the cladding tubes and in changes of the fracture mode in tensile tests. The micro-hardness of the cladding increases at the band position. The reasons of the formation of these hydrogen enriched bands and the dependence of its appearance on the temperature scenario are discussed.

Book Contribution to a Better Understanding of the Detrimental Role of Hydrogen on the Corrosion Rate of Zircaloy 4 Cladding Materials

Download or read book Contribution to a Better Understanding of the Detrimental Role of Hydrogen on the Corrosion Rate of Zircaloy 4 Cladding Materials written by D. Noel and published by . This book was released on 2000 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt: The kinetics of waterside corrosion of Zircaloy-4 in PWR systems reveal accelerated reaction rates at high burnup levels. In such cases, a thick and dense hydride layer is observed beneath the metal/oxide interface. Laboratory corrosion tests on samples prehydrided using gaseous and cathodic charging techniques clearly indicate a deleterious effect of hydrogen on the corrosion rate. This effect increases with the hydrogen level, particularly in the case of dense hydride layers formed by cathodic charging. The purpose of the present work was to confirm the detrimental effect of hydrogen over a wider range of experimental conditions [steam, primary light water (2 ppm Li, 1000 ppm B), heavy water and air] to determine whether or not it is due to matrix damage during the charging process and to contribute to the understanding of the mechanisms involved.

Book Hydrogen pickup in brazed zircaloy fuel cladding

Download or read book Hydrogen pickup in brazed zircaloy fuel cladding written by N. A. Graham and published by . This book was released on 1989 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A chf look-up table, applicable for both the loss-of-regulation (lor) and loss-of-coolant (loc) accident conditions, has been derived for a string of horizontal, candu-type, 37-element bundles. the bundle-chf look-up table is primarily based on the chf table for tubes and the correction factors accounting for the differences in geometry (between tubes and bundles) and in channel orientation (between vertical and horizontal flows). experimental results of chf in bundles are subsequently used to improve the accuracy of the table. the table-chf values have been adjusted to provide a correct and smooth parametric trend. within the ranges of experimental data, the prediction accuracy of the chf look-up table for bundles is excellent: rms errors are 4.6 percent for the data from the 6-m uniformly heated bundles, 5.8 percent from the 3-m uniformly heated bundles, 7.4 percent from the 1-m uniformly heated bundles and 6.8 percent for the initial dryout data from the 6-m non-uniformly heated bundles. predictions from the chf look-up table for bundles have also been compared against the bundle chf results obtained with freon-12, using the h2o/f-12 modelling parameters. these freon chf tests covered a range of mass flux from 1200-7450 kg.m-2.s-1 (water equivalent conditions). the overall rms error for four separate horizontal bundle-chf tests is 6.33 percent and for five vertical bundle-chf tests it is 5.09 percent. outside the ranges of the data base, the effect of flow stratification has been accounted for in the bundle-chf table by employing a semi-empirical correction factor which is obtained from a balance of turbulent force and gravitational forces. at conditions corresponding to stratified smooth or stratified wavy flow, the table values are equal to zero.

Book Hydrogen Trapping at Neutron Irradiation Produced Defects in Recrystallized Alpha Annealed Zircaloy 4

Download or read book Hydrogen Trapping at Neutron Irradiation Produced Defects in Recrystallized Alpha Annealed Zircaloy 4 written by Bruce F. Kammenzind and published by . This book was released on 2018 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen is absorbed into zirconium alloy-clad fuel elements and structural components as a result of water-side corrosion in both pressurized water reactor (PWR) and boiling water reactor (BWR) environments. Increasing hydrogen concentrations in the zirconium alloy affect both its mechanical properties and dimensional stability. It is well known that hydrogen can diffuse relatively rapidly through zirconium base alloys (in relation to the lifetime of the components) in response to solid solution concentration, temperature, and stress gradients. Migration of hydrogen within a component through its life must be considered to reliably predict the performance of the component through life and even post-service life. Many of the physical properties needed to describe this process, such as the solubility of hydrogen in zirconium alloys, diffusion coefficients of hydrogen through zirconium alloys, and the Soret effect within zirconium alloys, already have been published. Many of these measurements have been made outside of the reactor core environment on nonirradiated zirconium alloys.

Book Materials in Energy Conversion Harvesting and Storage

Download or read book Materials in Energy Conversion Harvesting and Storage written by Kathy Lu and published by John Wiley & Sons. This book was released on 2014-08-07 with total page 625 pages. Available in PDF, EPUB and Kindle. Book excerpt: First authored book to address materials' role in the quest for the next generation of energy materials Energy balance, efficiency, sustainability, and so on, are some of many facets of energy challenges covered in current research. However, there has not been a monograph that directly covers a spectrum of materials issues in the context of energy conversion, harvesting and storage. Addressing one of the most pressing problems of our time, Materials in Energy Conversion, Harvesting, and Storage illuminates the roles and performance requirements of materials in energy and demonstrates why energy materials are as critical and far-reaching as energy itself. Each chapter starts out by explaining the role of a specific energy process in today’s energy landscape, followed by explanation of the fundamental energy conversion, harvesting, and storage processes. Well-researched and coherently written, Materials in Energy Conversion, Harvesting, and Storage covers: The availability, accessibility, and affordability of different energy sources Energy production processes involving material uses and performance requirements in fossil, nuclear, solar, bio, wind, hydrothermal, geothermal, and ocean energy systems Issues of materials science in energy conversion systems Issues of energy harvesting and storage (including hydrogen storage) and materials needs Throughout the book, illustrations and images clarify and simplify core concepts, techniques, and processes. References at the end of each chapter serve as a gateway to the primary literature in the field. All chapters are self-contained units, enabling instructors to easily adapt this book for coursework. This book is suitable for students and professors in science and engineering who look to obtain comprehensive understanding of different energy processes and materials issues. In setting forth the latest advances and new frontiers of research, experienced materials researchers and engineers can utilize it as a comprehensive energy material reference book.