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 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 Materials Considerations for the National Spallation Neutron Source Target written by and published by . This book was released on 1997 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The National Spallation Neutron Source (NSNS), in which neutrons are generated by bombarding a liquid mercury target with 1 GeV protons, will place extraordinary demands on materials performance. The target structural material will operate in an aggressive environment, subject to intense fluxes of high energy protons, neutrons, and other particles, while exposed to liquid mercury and to water. Components that require special consideration include the Hg liquid target container and protective shroud, beam windows, support structures, moderator containers, and beam tubes. In response to these demands a materials R and D program has been developed for the NSNS that includes: selection of materials; calculations of radiation damage; irradiations, post irradiation testing, and characterization; compatibility testing and characterization; design and implementation of a plan for monitoring of materials performance in service; and materials engineering and technical support to the project. Irradiations are being carried out in actual and simulated spallation environments. Compatibility experiments in Hg are underway to ascertain whether the phenomena of liquid metal embrittlement and temperature gradient mass transfer will be significant. Results available to date are assessed in terms of the design and operational performance of the facility.

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 Energy Research Abstracts written by and published by . This book was released on 1993-02 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 New Developments In Applied Superconductivity Proceedings Of The International Symposium written by Yukitaka Murakami and published by World Scientific. This book was released on 1989-06-01 with total page 830 pages. Available in PDF, EPUB and Kindle. Book excerpt: This symposium focused on new superconductors, electronics, magnet technology, energy and new applications. Recent discoveries in HTc, with transition temperatures over 90 K, have spawned a search for practical new applications. These applications extend from current uses such as that of the medical MRI to future applications, represented by research on new high-temperature materials. They span from microcircuit applications to the proposed SMES and fusion reactor applications.

Download or read book Advances in Cryogenic Engineering Materials written by K.D. Timmerhaus and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sixth International Cryogenic Materials Conference (ICMC) was held on the campus of Massachusetts Institute of Technology in Cambridge in col laboration with the Cryogenic Engineering Conference (CEC) on August 12-16, 1985. The complementary program and the interdependence of these two dis ciplines foster the conference. Its manifest purpose is sharing the latest advances in low temperature materials science and technology. Equally im portant, areas of needed research are identified, prioriti-es for new research are set, and an increased appreciation of interdisciplinary, interlaboratory, and international cooperation ensues. The success of the conference is the result of the. able leadership and hard work of many people: S. Foner of M.I.T. coordinated ICMC efforts as its Conference Chairman. A. I. Braginski of Westinghouse R&D Center planned the program with the assistance of Cochairmen E. N. C. Dalder of Lawrence Livermore National Laboratory, T. P. Orlando of M.I.T., D. O. Welch of Brookhaven National Laboratory, and numerous other committee members. A. M. Dawson of M.I.T., Chairman of Local Arrangements, and G. M. Fitzgerald, Chairman of Special Events, skillfully managed the joint conference. The contributions of the CEC Board, and particularly its conference chairman, J. L. Smith, Jr. of M.I.T., to the organization of the joint conference are also gratefully acknm.ledged.

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 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Neutron source Characterization for Fusion materials Studies written by and published by . This book was released on 1981 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron-flux and energy-spectrum measurements are conducted for all major fusion-materials irradiation facilities, including fission reactors and accelerators. Dosimetry-characterization experiments and integral cross section measurements have been performed. Multiple activation and helium-production measurements are performed routinely to provide materials experimenters with neutron-exposure parameters including fluence, spectrum, displacements, gas production, and transmutation with typical accuracies of 10 to 15%. Such data are crucial to the fusion-materials program in order to correlate materials-property changes between irradiations and facilities and to confidently predict the performance of materials in fusion reactors.

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 Calculations of Radiation Damage in Target Container and Window Materials for Spallation Neutron Sources written by and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Neutron Flux Spectra for Radiation Effects Studies written by Joseph Turner Graham and published by . This book was released on 2011 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of neutron displacement damage on materials are sensitive to neutron energy spectra. In controlled neutron damage experiments, a well characterized neutron flux spectrum is critical in determining the equivalent dose for displacement damage. Two techniques were used to characterize the neutron flux spectra in the University of Texas at Austin TRIGA research nuclear reactor. The first technique uses a standard method of measuring the reaction rates of two identical metal foils, one of which was irradiated in a Cd cover, the other of which was irradiated bare. Assuming an analytic form of the neutron spectrum the reaction rates were used to determine an approximate spectrum. The second technique uses the reaction rates measured from a set of activated metal foils along with two spectral unfolding techniques to approximate and then refine the neutron spectrum. A Matlab code was developed which fits radiative capture reaction rates to an approximate spectrum using a least squares approach. The result was used as an initial guess in a second Matlab code which refines the epithermal and fast energy ranges of the spectrum using reaction rates from threshold reactions. Errors in the reaction rates calculated from the resulting spectrum to the measured reaction rates were used to assess the accuracy of the final neutron spectrum.

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 Physics Briefs written by and published by . This book was released on 1992 with total page 1812 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book INIS Atomindex written by and published by . This book was released on 1986 with total page 1438 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dosimetry Issues for an Ultra high Flux Beam and Multipurpose Research Reactor Design written by and published by . This book was released on 1993 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advanced Neutron Source is a new user facility for all fields of neutron research, including neutron beam experiments, materials analysis, materials testing, and isotope production. The complement and layout of the experimental facilities have been determined sufficiently, at a conceptual design level, to make reliable cost and schedule estimates. The source of neutrons will be a heavy water reactor, constructed largely of aluminum, with an available thermal neutron flux 5--10 times higher than existing research reactors. Among the dosimetry issues to be faced are damage prediction and surveillance for component life attainment; measurement of fluence and spectra in regions where both change substantially over a distance of a few centimeters; and characterization and measurement of the radiation field in the research areas around the neutron beam experiments.