Download or read book Overview of Irradiation Effects Research on Insulating Ceramics written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Insulating ceramics have many uses in fusion reactors. Although various environmental conditions can degrade these materials, the most severe problems lie in the area of irradiation damage. Such damage can be detrimental to dimensional stability, strength, thermal conductivity, and various electrical properties; failure of an insulator can result from deleterious changes in any of these areas. Degradation of electrical properties falls into two categories: permanent effects, and transient effects that occur only when irradiation fluxes are actually impinging on the material. Consequences of irradiation damage can be severe not only for power reactors but for nearer-term machines such as ITER. Fusion reactors will require electrical ceramics to serve as insulators in rf heating systems and neutral beam injectors, diagnostic components, lightly-shielded magnetic coils, and current breaks between metallic structural elements. When these insulators are subjected to radiation fields (neutron, gamma, or ion bombardment) various physical properties can be degraded; these are discussed.
Download or read book Proceedings of the Ninth IEA Workshop on Radiation Effects in Ceramic Insulators written by and published by . This book was released on 1997 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several IEA workshops have been held over the past few years to discuss the growing number of experimental studies on the intriguing phenomenon of radiation induced electrical degradation (RIED). In the past year, several new RIED irradiation experiments have been performed which have a significant impact on the understanding of the RIED phenomenon. These experiments include a HFIR neutron irradiation experiment on 12 different grades of single- and poly-crystal alumina (450 C, (approximately)3 dpa, 200 V/mm) and several additional neutron, electron and light ion irradiation experiments. The primary objective of the IEA workshop was to review the available RIED studies on ceramic insulators. Some discussion of recent work in other areas such as loss tangent measurements, mechanical strength, etc. occurred on the final afternoon of the workshop. The IEA workshop was held in conjunction with a US-Japan JUPITER program experimenter's workshop on dynamic radiation effects in ceramic insulators.
Download or read book Report on the Effect of Radiation on Electrical Insulation Materials written by C. L. Hanks and published by . This book was released on 1969 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Structural Effect in Neutron Irradiation of Insulating Ceramics written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A vacuum gap irradiation capsule was designed and built to maintain a temperature of 740°C during 6 weeks irradiation at EBR-II. Sixty-eight samples of 15 ceramic or metal-ceramic combinations were irradiated to a fluence of approximately 3 x 1021 neutrons/cm2, E greater than 0.1 MeV. Measurements of sample dimensions before and after irradiation were used to determine volume swelling. This parameter and the physical appearance of the samples are discussed. A primary application of insulating ceramics in proposed fusion powder devices is the first wall insulating lining in the RTPR reactor. A satisfactory material for this application must bear substantial thermal stresses in cyclical fashion. Calculated values of pertinent parameters are presented and compared for several of the irradiated materials in non-irradiated form. Work to prepare apparatus for the measurement of thermal and mechanical properties of these materials following neutron irradiation is described. Silicon nitride is representative of a class of refractory ceramics distinguished by its high thermal conductivity, resistance to thermal shock, and elevated temperature strength retention. Recent work has suggested that Si3N4 hot pressed with additions of Y2O3, rather than the usual MgO, may offer improved high temperature strength. A project to prepare samples of this material with optimized Y2O3 concentration and pressing conditions is described. Samples of Si3N4 hot pressed with 0, 5, 10, 15, and 20 wt percent Y2O3 additions have been prepared for an irradiation experiment being carried out by ORNL at EBR-II.
Download or read book Summary of Radiation Effects on Thermionic Insulator Materials written by John T. Mayer and published by . This book was released on 1968 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Summary of the 9th IEA Workshop on Radiation Effects in Ceramic Insulators written by and published by . This book was released on 1997 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Twenty one scientists attended an IEA workshop in Cincinnati, Ohio on May 8-9, 1997, which was mainly devoted to reviewing the current knowledge base on the phenonenon of radiation induced electrical degradation in ceramic insulators. Whereas convincing evidence for bulk RIED behavior has been observed by two research groups in sapphire after electron irradiation, definitive levels of bulk RIED have not been observed in high purity Al2O3 by several research groups during energetic ion or fission neutron irradiation. Possible reasons for the conflicting RIED results obtained by different research groups were discussed. It was conducted that RIED does not appear to be of immediate concern for near-term fusion devices such as ITER. However, continued research on the RIED phenomenon with particular emphasis on electron irradiations of single crystal alumina was recommended in order to determine the underlying physical mechanisms. This will allow a better determination of whether RIED might occur under any of the widely varying experimental conditions in a fusion energy device. Several critical issues which are recommended for future study were outlined by the workshop attendees.
Download or read book Effects of Irradiation on Ceramics for Fusion reactor Applications written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this study, coordinated with efforts of LANL and Grumman Aircraft, was to lay some basic groundwork to study the irradiation effects on the engineering properties of some useful classes of ceramic materials; ANL's efforts were pointed towards multiphase materials (glass ceramics and partially-stabilized zirconias). The materials were irradiated at 400 and 550°C to fast (E> 0.1 MeV) neutron fluences of approx. 2 x 1022n/cm2. Fluorophlogapite mica based glass ceramics (Macor, etc.) were found susceptible to weakening due to void formtion between mica plates. Composition variations within this class of glass ceramics seemed to cause sharp variations in the magnitude of the effect. Lithium silicate glass ceramic (ReX) showed sharp contrasts between the effects of ionization irradiation and displacement damage, neutron irradiation having little effect on the ReX structure while electron irradiation creating lithium silicate vitrification and rapid structural annealing.
Download or read book Summary of the IEA Workshop on Radiation Effects in Ceramic Insulators written by and published by . This book was released on 1996 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: A brief summary is given of research on radiation effects in ceramic insulators for fusion energy application performed during the last two years in Europe, Canada, Japan, the Russian Federation, the Ukraine and the United States. The IEA round-robin radiation induced electrical degradation (RIED) experiment on Wesgo AL995 polycrystalline alumina has been completed by 5 research groups, with none of the groups observing clear indications of REID.
Download or read book Radiation effects in electrically insulating ceramics written by G. P. Pells and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Irradiation induced Defects on Fusion Reactor Ceramics written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural, thermal, and electrical properties critical to performance of ceramics in a fusion environment can be profoundly altered by irradiation effects. Neutron damage may cause swelling, reduction of thermal conductivity, increase in dielectric loss, and either reduction or enhancement of strength depending on the crystal structure and defect content of the material. Absorption of ionizing energy inevitably leads to degradation of insulating properties, but these changes can be reduced by alterations in structural or compositional makeup. Assessment of the irradiation response of candidate ceramics Al2O3, MgAl2O4, SiC and Si3N4 shows that each may find use in advanced fusion devices. The present understanding of irradiation-induced defects in ceramics, while far from complete, nevertheless points the way to methods for developing improved materials for fusion applications.
Download or read book Irradiation effects upon selected ceramic cements and ceramic insulated wires for radiation resistant written by M. E. Yancey and published by . This book was released on 1980 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Irradiation Spectrum on the Microstructural Evolution in Ceramic Insulators written by and published by . This book was released on 1995 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study is to determine and examine the effect of variations in the ionizing and displacive radiation environments on the microstructure of oxide ceramic insulators. Cross section transmission electron microscopy has been used to investigate the microstructure of MgAl2O4 (spinel) and Al2O3 (alumina) following irradiation with ions of varying mass and energy at room temperature and 650°C. These results clearly indicate that light ion and electron irradiations produce microstructures which are not representative of the microstructure that would form in these ceramics during fission or fusion neutron irradiation.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1961 with total page 1274 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 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1976 with total page 1314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
