Download or read book A Study of the Effects of Irradiation and Radiolytic Oxidation of the Pore level Structure of Gilsocarbon Nuclear Graphite written by Katie Jones and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radiation Damage in Graphite written by J. H. W. Simmons and published by Elsevier. This book was released on 2013-10-22 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear Energy, Volume 102: Radiation Damage in Graphite provides a general account of the effects of irradiation on graphite. This book presents valuable work on the structure of the defects produced in graphite crystals by irradiation. Organized into eight chapters, this volume begins with an overview of the description of the methods of manufacturing graphite and of its physical properties. This text then presents details of the method of setting up a scale of irradiation dose. Other chapters consider the effect of irradiation at a given temperature on a physical property of graphite. This book discusses as well the changes in dimensions produced by irradiation and the effects of irradiation on the mechanical properties of graphite. The final chapter deals with the accumulation of stored energy, which is one of the main problems caused by the irradiation of graphite in nuclear reactors. This book is a valuable resource for physicists and chemical physicists.
Download or read book Thermophysical Property and Pore Structure Evolution in Stressed and Non stressed Neutron Irradiated IG 110 Nuclear Graphite written by and published by . This book was released on 2016 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: The nuclear graphite, IG-110, was irradiated with and without a compressive load of 5 MPa at ~400 C up to 9.3x1025 n/m2 (E>0.1 MeV.) Following irradiation physical properties were studied to compare the effect of graphite irradiation on microstructure developed under compression and in stress-free condition. Properties included: dimensional change, thermal conductivity, dynamic modulus, and CTE. The effect of stress on open internal porosity was determined through nitrogen adsorption. The IG-110 graphite experienced irradiation-induced creep that is differentiated from irradiation-induced swelling. Irradiation under stress resulted in somewhat greater thermal conductivity and coefficient of thermal expansion. While a significant increase in dynamic modulus occurs, no differentiation between materials irradiated with and without compressive stress was observed. Nitrogen adsorption analysis suggests a difference in pore evolution in the 0.3-40 nm range for graphite irradiated with and without stress, but this evolution is seen to be a small contributor to the overall dimensional change.
Download or read book Comprehensive Nuclear Materials written by Todd R Allen and published by Elsevier. This book was released on 2011-05-12 with total page 3552 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive Nuclear Materials, Five Volume Set discusses the major classes of materials suitable for usage in nuclear fission, fusion reactors and high power accelerators, and for diverse functions in fuels, cladding, moderator and control materials, structural, functional, and waste materials. The work addresses the full panorama of contemporary international research in nuclear materials, from Actinides to Zirconium alloys, from the worlds' leading scientists and engineers. Critically reviews the major classes and functions of materials, supporting the selection, assessment, validation and engineering of materials in extreme nuclear environment Fully integrated with F-elements.net, a proprietary database containing useful cross-referenced property data on the lanthanides and actinides Details contemporary developments in numerical simulation, modelling, experimentation, and computational analysis, for effective implementation in labs and plants
Download or read book The Radiolytic Graphite Co2 Reaction written by J. V. Best and published by . This book was released on 1975 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization Treatment and Conditioning of Radioactive Graphite from Decommissioning of Nuclear Reactors written by International Atomic Energy Agency and published by IAEA. This book was released on 2006 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Graphite has been used as a moderator and reflector of neutrons in more than 100nuclear power plants and in many research and plutonium-production reactors. It is usedprimarily as a neutron reflector or neutron moderator, although graphite is also used for other features of reactor cores, such as fuel sleeves. Many of the graphite-moderated reactors are now quite old, with some already shutdown. Therefore radioactive graphite dismantling and the management of radioactive graphite waste are becoming an increasingly important issue for a number of IAEA Member States. This report provides a comprehensive discussion of radioactive graphite waste characterization, handling, conditioning and disposal throughout the operating and decommissioning life cycle.
Download or read book Defect Evolution in High temperature Irradiated Nuclear Graphite written by Steve Johns and published by . This book was released on 2020 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Graphite has historically been used as a moderator material in nuclear reactor designs dating back to the first man-made nuclear reactor to achieve criticality (Chicago Pile 1) in 1942. Additionally, graphite is a candidate material for use in the future envisioned next-generation nuclear reactors (Gen IV); specifically, the molten-salt-cooled (MSR) and very-high-temperature reactor (VHTR) concepts. Gen IV reactor concepts will introduce material challenges as temperature regimes and reactor lifetimes are anticipated to far exceed those of earlier reactors. Irradiation-induced defect evolution is a fundamental response in nuclear graphite subjected to irradiation. These defects directly influence the many property changes of nuclear graphite subjected to displacing radiation; however, a comprehensive explanation for irradiation-induced dimensional change remains elusive. The macroscopic response of graphite subjected to displacing irradiation is often modeled semi-empirically based on irradiation data of specific graphite grades (some of which are obsolete). The lack of an analytical description of the response of nuclear graphite subjected to irradiation is due in part to the complex microstructure of synthetic semi-isotropic graphites. Chapter One provides a general overview of the application, processing, and irradiation-induced property changes of nuclear graphite. The key properties affected by displacing irradiation include, but are not limited to, coefficient of thermal expansion (CTE), irradiation creep, and irradiation-induced dimensional change. Additionally, historical models of radiation damage in nuclear graphite, including their inadequacies in accurately describing property changes, are discussed. It should be noted that a comprehensive explanation for all irradiation-induced property change is beyond the scope of this work, which is focused on the evolution of novel atomic-level defects in high-temperature irradiated nuclear graphite and the implications of these defects for the current understanding of irradiation-induced dimensional change. Chapter Two is focused on the development of a novel oxidation-based transmission electron microscopy (TEM) sample-preparation technique for nuclear-grade graphite. Conventionally, TEM specimens are prepared via ion-milling or a focused ion beam (FIB); however, these techniques require the use of displacing radiation and may result in localized areas of irradiation damage. As a result, distinguishing defect structures created as artifacts during sample preparation from those created by electron- or neutron-irradiation can be challenging. Bulk nuclear graphite grades IG-110, NBG-18, and highly oriented pyrolytic graphite (HOPG) were oxidized using a new jet-polishing-like setup where oxygen is used as an etchant. This technique is shown to produce self-supporting electron-transparent TEM specimens free of irradiation-induced artifacts; thus, these specimens can be used as a baseline for in situ irradiation experiments as they have no irradiation-induced damage. Chapter Three examines the dynamic evolution of defect structures in nuclear graphite IG-110 subjected to electron-irradiation. As use of fast neutrons for irradiation experiments is dangerous, expensive, and time consuming, electron-irradiation is arguably a useful surrogate; however, comparisons between the two irradiating particles is also discussed. In situ video recordings of specimens undergoing simultaneous heating and electron-irradiation were used to analyze the dynamic atomic-level defect evolution in real time. Novel fullerene-like defect structures are shown to evolve as a direct result of high-temperature electron-irradiation and cause significant dimensional change to crystallites. Neutron-irradiated nuclear graphite IG-110 was supplied by Idaho National Laboratory as part of the Advanced Graphite Creep capsule experiments (AGC-3). Chapter Four reports the preliminary characterization of IG-110 neutron-irradiated at 817°C to a dose of 3.56 displacements per atom (dpa). Shown is experimental evidence of a 'ruck and tuck' defect occurring in high-temperature neutron-irradiated nuclear graphite. The 'ruck and tuck' defect arises due to irradiation-induced defects. The interaction of these defects results in the buckling of atomic planes and the formation of a structure composed of two partial carbon nanotubes. The "buckle, ruck and tuck" model was first theoretically predicted via computational modeling in 2011 as a plausible defect structure/mechanism occurring in high-temperature neutron-irradiated graphite by Prof. Malcolm Heggie et al. Chapter Four shows the first direct experimental results to support the "buckle, ruck and tuck" model. Chapter Five further characterizes nuclear graphite IG-110 neutron-irradiated at high temperature (>=800 °C) at doses of 1.73 and 3.56 dpa. Results show further evidence to support the 'buckle, ruck and tuck' model and additionally show the presence of larger concentric shelled fullerene-like defects. Fullerene-like defects were found to occur in disordered regions of the microstructure including within nanocracks (Mrozowski cracks). These results agree with high-temperature electron-irradiation studies which showed the formation of fullerene-like defects in-situ and give additional validity to the use of high-flux electron-irradiation as a useful approximation to neutron-irradiation. Furthermore, Chapter Five gives valuable insight to unresolved quantitative anomalies of historical models of graphite expansion and may improve the understanding of current empirical and theoretical models of irradiation-induced property changes in nuclear graphite."--Boise State University ScholarWorks.
Download or read book A Comparison of the Effects of Oxidation and the Effects of Neutron Irradiation on Graphite written by Gerhart Hennig and published by . This book was released on 1952 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The changes of the electrical properties of oxidized graphite have been compared with the changes produced by neutron irradiation. It has been possible to separate the neutron-induced damage into the damage produced by electron removal and that produced by scattering centers. A model for radiation damage has been proposed.
Download or read book Nuclear Graphite written by Brindusa Elena Mironov and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Graphite written by and published by . This book was released on 2014 with total page 340 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 1982 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Oxidation on Oxidation Resistant Graphite written by and published by . This book was released on 2015 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advanced Reactor Technology (ART) Graphite Research and Development Program is investigating doped nuclear graphite grades that exhibit oxidation resistance through the formation of protective oxides on the surface of the graphite material. In the unlikely event of an oxygen ingress accident, graphite components within the VHTR core region are anticipated to oxidize so long as the oxygen continues to enter the hot core region and the core temperatures remain above 400°C. For the most serious air-ingress accident which persists over several hours or days the continued oxidation can result in significant structural damage to the core. Reducing the oxidation rate of the graphite core material during any air-ingress accident would mitigate the structural effects and keep the core intact. Previous air oxidation testing of nuclear-grade graphite doped with varying levels of boron-carbide (B4C) at a nominal 739°C was conducted for a limited number of doped specimens demonstrating a dramatic reduction in oxidation rate for the boronated graphite grade. This report summarizes the conclusions from this small scoping study by determining the effects of oxidation on the mechanical strength resulting from oxidation of boronated and unboronated graphite to a 10% mass loss level. While the B4C additive did reduce mechanical strength loss during oxidation, adding B4C dopants to a level of 3.5% or more reduced the as-fabricated compressive strength nearly 50%. This effectively minimized any benefits realized from the protective film formed on the boronated grades. Future work to infuse different graphite grades with silicon- and boron-doped material as a post-machining conditioning step for nuclear components is discussed as a potential solution for these challenges in this report.
Download or read book Development of the Pore Structure of MkII Reactor Moderator Graphite by Radiolytic Oxidation in CO CO2 Mixtures written by B.R. Kelly and published by . This book was released on 1975 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Management of Ageing in Graphite Reactor Cores written by Gareth B. Neighbour and published by Royal Society of Chemistry. This book was released on 2007 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This product is not available separately, it is only sold as part of a set. There are 750 products in the set and these are all sold as one entity. This product is not available separately, it is only sold as part of a set. There are 750 products in the set and these are all sold as one entity.
Download or read book The Role of Pore Structure in the Oxidation of Graphite by Irradiated Carbon Dioxide written by J.M. Hutcheon and published by . This book was released on 1962 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Relationship Between Microstructure and Young s Modulus of Nuclear Graphite written by William Bodel and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In addition to its role as moderator within British nuclear reactors, polycrystalline graphite is also a major structural component of the core, enabling access for control rods, coolant gas and fuel. Aging processes, primarily fast neutron irradiation and radiolytic oxidation lead to distortion of the graphite components and property changes which ultimately reduce the material's effectiveness and can lead to component failure. Despite much research into the material, graphite behaviour under irradiation conditions is not fully understood and has resulted in an overestimation of the extent of component failures in Magnox reactors, and a subsequent underestimation of component failures in the following generation Advanced Gas-cooled Reactors (AGRs). A greater understanding of the material is therefore required in order to make more informed evaluations as part of on-going safety cases. Young's modulus is one property which varies as a complex function of radiolytic oxidation and fast neutron irradiation dose; this work investigates investigate the Young's modulus behaviour of nuclear grade graphites through property measurement and microstructural characterisation. Physical properties are dependent on microstructure, which is in turn a result of the manufacturing processes and raw materials used in its fabrication. Because of this, this thesis begins with a microstructural study of AGR graphite artefacts from varying points during the manufacturing process and post-irradiation, utilising X-ray diffraction to observe changes in crystallinity, microscopy to directly observe the microstructure and pycnometry to gauge porosity variations. Increases in crystallinity towards graphitisation are seen, with a subsequent decrease after irradiation; and significant changes are observed from inspection of optical and scanning electron micrographs. Young's modulus property data are obtained using a combination of static and dynamic techniques to accumulate data from a variety of techniques. An experiment designed to track changes to the speed of sound under compressive load was carried out on Magnox and AGR graphite, showing different behaviour between the grades, and variation with irradiation. A final series of tests combine compressive testing with in-situ microscopy to try and better understand the reasons behind this varied in behaviour and relate microstructural changes to graphite behaviour under compressive loading.
Download or read book INIS Atomindeks written by and published by . This book was released on 1980 with total page 1098 pages. Available in PDF, EPUB and Kindle. Book excerpt:
