Download or read book Neutron Measurements and Radiation Damage Calculations for Fusion Materials Studies written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusion reactors will generate intense neutron fields, especially at the inner surfaces of containment vessels. With a typical wall loading of 1 MW/m2, the yearly neutron fluence will be about 1026 n/m2. In a material like stainless steel this irradiation will produce about 10 atomic displacements-per-atom (DPA), 100 appM helium, 500 appM hydrogen, and various other transmutations. The gas-to-DPA ratios are very high compared to fission reactors due to the 14 MeV neutrons from the d-t fusion reaction. No existing neutron source can produce both the high fluence and high gas rates needed to simulate fusion damage. Consequently, fusion material studies are underway in a variety of facilities including fission reactors and accelerator-based neutron sources. A Subtask Group has been created by DOE to characterize these diverse facilities in terms of neutron flux and energy spectrum and to calculate DPA and transmutation for specific irradiations. Material property changes can then be correlated between facilities and extrapolated to fusion reactor conditions.
Download or read book Recent Developments in Neutron Dosimetry and Radiation Damage Calculations for Fusion materials Studies written by and published by . This book was released on 1983 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper is intended as an overview of activities designed to characterize neutron irradiation facilities in terms of neutron flux and energy spectrum and to use these data to calculate atomic displacements, gas production, and transmutation during fusion materials irradiations. A new computerized data file, called DOSFILE, has recently been developed to record dosimetry and damage data from a wide variety of materials test facilities. At present data are included from 20 different irradiations at fast and mixed-spectrum reactors, T(d, n) 14 MeV neutron sources, Be(d, n) broad-spectrum sources, and spallation neutron sources. Each file entry includes activation data, adjusted neutron flux and spectral data, and calculated atomic displacements and gas production. Such data will be used by materials experimenters to determine the exposure of their samples during specific irradiations. This data base will play an important role in correlating property changes between different facilities and, eventually, in predicting materials performance in fusion reactors. All known uncertainties and covariances are listed for each data record and explicit references are given to nuclear decay data and cross sections.
Download or read book Recent Research in Neutron Dosimetry and Damage Analysis for Materials Irradiations written by LR. Greenwood and published by . This book was released on 1987 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron fluence measurements and damage calculations are being routinely performed for fusion materials irradiations in fission reactors, at 14 MeV sources, and at high-energy accelerator neutron sources. Neutron activation cross sections are being developed for dosimetry at fission reactors, fusion reactors, and high-energy accelerator neutron sources. Integral and differential measurements are being combined to determine new cross sections and to adjust discrepant data. These data are needed to adequately define the neutron exposure and radiation damage in materials. The production of long-lived radioisotopes is being measured at 14 MeV for fusion reactors and reactions are being developed for plasma diagnostics. At high energies, spallation cross sections are being measured for dosimetry and damage analysis at accelerator neutron sources. Helium production cross sections are being tested and a new thermal helium effect has been discovered in copper similar to the well-known effect in nickel. Damage calculations are routinely provided by the SPECTER computer code and new calculations are being performed to extend our damage cross sections to higher energies for accelerator neutron sources and to include alloys and compounds.
Download or read book Neutron source Characterization and Radiation damage Calculations for Material Studies written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In our quest to understand radiation damage in materials, it is vital that we characterize radiation sources in terms of neutron flux and spectra as well as the more-fundamental displacement damage, gas production, and transmutation rates. Such data are crucial to correlations of materials-property changes in different environments and to predictions of materials performance in inaccessible environments, such as fusion reactors. Dosimetry techniques have been developed to measure the neutron flux and spectra in diverse facilities including thermal, fast, and mixed reactors, T (d, n) and Be (d, n) accelerator sources, and high-energy spallation sources. Displacement-damage cross sections have been calculated for 36 elements spanning the periodic table. All of these exposure parameters can now be routinely measured with 10 to 15% relative accuracy at all existing radiation-effect facilities. 4 tables.
Download or read book Status of Neutron Dosimetry and Damage Analysis for the Fusion Materials Program written by and published by . This book was released on 1979 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The status of neutron flux and spectral measurements is described for fusion material irradiations at reactor, T(d, n), Be(d, n), and spallation neutron sources. Such measurements are required for the characterization of an irradiation in terms of displacement damage, gas and transmutant production. Emphasis is placed on nuclear data deficiencies with specific recommendations for cross section measurements and calculations.
Download or read book Recent Developments in Neutron Dosimetry and Damage Calculations for Fusion Materials Irradiations written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusion materials experiments require accurate neutron dosimetry measurements and damage calculations. Neutron cross section measurements are described for application at fission reactors, accelerator neutron sources, fusion reactors, and spallation neutron sources. For fission reactors work is in progress to resolve integral/differential discrepancies and to develop new reactions for dosimetry. Reactions for fusion reactors are designed for plasma diagnostics and waste generation. Spallation reactions are being measured to extend our techniques to 800 MeV for spallation neutron sources. The SPECTER computer code has been developed to routinely calculate displacement damage, gas production, recoil spectra, and total dose for 38 elements with a user specified neutron spectrum. New helium measurements and calculations are described. A new procedure is discussed for the thermal production of helium by nickel including previously neglected damage from the energetic 56Fe recoils.
Download or read book Fusion Energy Update written by and published by . This book was released on 1979 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Fusion Reactor Materials Program Plan written by Task Group on Damage Analysis and Fundamental Studies and published by . This book was released on 1978 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Accurate Calculations of Neutron Kerma Kinetic Energy Released in MAterials and Damage from ENDF written by and published by . This book was released on 1990 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate calculations of kerma (Kinetic Energy Released in MAterials) factors and displacement cross sections are fundamental to studies of neutron heating and neutron radiation damage. Damage and heating studies are important elements in both fission and fusion reactor design. For fusion reactor studies, heating in the blanket helps determine the efficiency, and heating studies in the superconducting magnet regions determine properties of the blanket and shield, thereby affecting the economics of the reactor. Radiation damage is important for reactor core lifetime studies and is related directly to the economy and safety of both fusion and fission reactors. Calculation of kerma factors and displacement cross sections require nuclear data for neutron-induced reactions. These data are normally obtained from evaluated nuclear data libraries, such as ENDF/B (US), JENDL (Japan), JEF/EFF (Europe) and BROND (USSR). Unfortunately, most of these evaluated libraries do not contain sufficient information for a direct calculation of these quantities, and various approximations must be employed. The accuracy of the kerma factors and displacement cross sections, and thus the heating and damage functions, are directly related to the available information from the data libraries. In this paper we describe improvements incorporated in the latest version of the US library, ENDF/B-VI, which allow exact calculations of these quantities for many of the structural materials included in the library. 11 refs., 6 figs.
Download or read book Neutron Dosimetry Damage Calculations and Helium Measurements for the HFIR MFE 60J 1 and MFE 330J 1 Spectral Tailoring Experiments written by and published by . This book was released on 1995 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective is to provide dosimetry and damage analysis for fusion materials irradiation experiments. Neutron fluence measurements and radiation damage calculations are reported for the joint US -Japanese MFE-60J-1 and MFE-330J-1 experiments in the hafnium-lined removable beryllium (RB{sup *}) position of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. These experiments were continuations of the ORR-6J and 7J irradiations performed in the Oak Ridge Research Reactor. The combination of irradiations was designed to tailor the neutron spectrum in order to achieve fusion reactor helium/dpa levels in stainless steel. These experiments produced maximum helium (appm)/dpa(displacement per atom) levels of 10.2 at 18.5 dpa for the ORR-6J and HFIR-MFE-60J-1 combination and 11.8 at 19.0 dpa for the ORR-7J and HFIR-MFE-330J-1 combination. A helium measurement in one JPCA sample was in good agreement with helium calculations.
Download or read book New Ideas in Dosimetry and Damage Calculations for Fusion Materials Irradiations written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear data and techniques are being developed to improve our ability to characterize fusion materials irradiations in terms of neutron fluence and spectra as well as damage parameters such as atomic displacements, gas production, and other transmutation. The production of long-lived isotopes are being measured near 14 MeV, including reactions from Al, Fe, and Mo to 26Al, 53Mn, and 94Nb, and measurements for other reactions are in progress. These data can be used for fusion reactor dosimetry, plasma diagnostics, and the estimation of radioactivity in fusion reactor materials. Dosimetry cross sections are being measured for fission reactors using Be(d, n) sources (E/sub d/= 7 to 40 MeV) and monoenergetic neutron sources from 1 to 14 MeV. These data can be used to adjust activation cross sections. Spallation cross sections are being measured for higher-energy accelerator neutron sources. Helium production cross sections are being tested at all fusion irradiation facilities. We have recently discovered a new thermal helium production in copper, similar to the well-known effect in nickel. Recommended procedures have been published for the calculation of helium from both copper and nickel in mixed-spectrum reactors. A new program SPECOMP has recently been developed to calculate displacement damage for compounds. This program uses the SPECTER recoil atom distributions and integrates over secondary displacement functions for each combination of incident ion and matrix material to determine displacement cross sections for alloys, insulators, and breeder materials.
Download or read book Neutron Physics written by M Yeater and published by Elsevier. This book was released on 2012-12-02 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear Science and Technology, Volume 2: Neutron Physics provides information pertinent to neutron and reactor physics. This book presents a discussion of the general area of energy sources, surveying the fusion problem. Organized into 16 chapters, this volume starts with an overview of the broad range of other research related to nuclear technology, radiation effects, solid state work, chemistry, and materials research. This book then examines the experimental data for the cross sections and fission parameters of the fissile nuclides. Other chapters outline the role of fast choppers in time-of-flight spectrometers and consider the total cross section measurements. This book discusses as well the various experiments performed to test the operation of the system. The final chapter deals with the long-range prospects of fusion power. This book is a valuable resource for graduate students, physicists, nuclear engineers, researchers, scientists involved in fusion research will find this book extremely useful.
Download or read book Analysis of Radiation Damage in Fusion simulation Neutron Spectra written by and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Various parameters which are relevant to an understanding of radiation effects in metals have been evaluated utilizing available neutron spectrum information for several existing sources, e.g., EBRII, HFIR, and LAMPF, as well as the hypothetical spectrum at a fusion reactor first wall, and measured Li(d, n) spectra. Recoil energy distributions were calculated for several metals including Al, Cu, and Nb. The recoil energy range was divided into groups, and the fraction of recoils occurring in each energy group was compared with the fraction of the damage energy contributed by that group. From this comparison it was possible to conclude that the significant recoil range differs by about an order of magnitude between fission and fusion sources. The analysis further confirms that basic defect production characteristics depend upon the neutron spectrum, and that integral calculations of radiation-effect parameters do not provide a complete description of the dependence. This is equally true for comparisons between fusion-related spectra or fission-reactor spectra independently. Four recoil-dependent parameter functions which describe different aspects of radiation damage were used in the calculations. The relative effectiveness of neutron sources was found to depend upon the choice of parameter function. Fission-reactor spectra comparisons are relatively insensitive to the parameter functions used whereas spectra with an appreciable component of high-energy neutrons are much more sensitive. (auth).
Download or read book Radiation Damage in Materials written by Yongqiang Wang and published by MDPI. This book was released on 2020-12-28 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: The complexity of radiation damage effects in materials that are used in various irradiation environments stems from the fundamental particle–solid interactions and the subsequent damage recovery dynamics after the collision cascades, which involves multiple length and time scales. Adding to this complexity are the transmuted impurities that are unavoidable from accompanying nuclear processes. Helium is one such impurity that plays an important and unique role in controlling the microstructure and properties of materials used in fast fission reactors, plasma-facing and structural materials in fusion devices, spallation neutron target designs, actinides, tritium-containing materials, and nuclear waste. Their ultra-low solubility in virtually all solids forces He atoms to self-precipitate into small bubbles that become nucleation sites for further void growth under radiation-induced vacancy supersaturations, resulting in material swelling and high-temperature He embrittlement, as well as surface blistering under low-energy and high-flux He bombardment. This Special Issue, “Radiation Damage in Materials—Helium Effects”, contains review articles and full-length papers on new irradiation material research activities and novel material ideas using experimental and/or modeling approaches. These studies elucidate the interactions of helium with various extreme environments and tailored nanostructures, as well as their impact on microstructural evolution and material properties.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 420 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 1984 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book SPECTER Neutron Damage Calculations for Materials Irradiations written by Lawrence Greenwood (R.) and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
