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Development of metal-clad filled evacuated panel superinsulation

Description: This Cooperative Research and Development Agreement (CRADA) was between Aladdin Industries, Inc. and Lockheed Martin Energy Research Corp. The purpose of the CRADA was to determine the thermal performance of various metal claddings used to encapsulate Filled Evacuated Panel (FEP) superinsulation and to optimize the cost versus thermal performance of the claddings. A FEP superinsulation is a new type of superinsulation with the potential for saving large amounts of energy in buildings, building equipment, transportation (refrigerated railcars and trucks), industrial applications, etc. The major disadvantage of metal claddings for FEPs is the heat loss through the cladding caused by the high thermal conductivity of most metals. In smaller FEPs, this heat loss can degrade the overall performance of the FEP by factors of two or more as compared with polymer-clad FEPs. On the other hand, metal claddings are essentially impermeable to ambient air, whereas polymer claddings are not. Thus, the longevity and reliability of metal-clad FEPs are much superior to polymer-clad FEPs. In addition, because of the very low vapor pressure of metals as compared to polymers, metal-clad FEPs can achieve and operate at lower internal pressures. These lower pressures allow use of less expensive and/or higher performance filler materials.
Date: March 1, 1997
Creator: Wilkes, K.E.; Strizak, J.P.; Weaver, F.J.; Besser, J.E. & Smith, D.L.
Partner: UNT Libraries Government Documents Department

Some guidelines for the evaluation of nuclear data

Description: Modern data evaluation methodology draws upon basic principles from statistics. It differs from earlier ad hoc approaches which are completely subjective (e.g., eye guides to data) or are objective in a limited sense (e.g., combinations of reported data by a simple least-squares procedure without regard to correlations in the data errors or a careful scrutiny of the data included in the evaluation). In addition to utilizing more rigorous mathematical procedures, modern evaluation methodology involves taking great care to insure that the data which are being evaluated are equivalent to what has been assumed in the evaluation model and that the values are consistent with respect to the use of standards and other fundamental physical parameters. This short memorandum cannot substitute for more comprehensive treatments o the subject such as can be found in the listed references. The intent here is to provide an overview of the topic and to impress upon the reader that the evaluation of data of any sort is not a straightforward enterprise. Certainly evaluations cannot be carried out automatically with computer codes without considerable intervention on the part of the evaluator.
Date: March 20, 1996
Creator: Smith, D.L.
Partner: UNT Libraries Government Documents Department

Influence of temperature and lithium purity on corrosion of ferrous alloys in a flowing lithium environment

Description: Corrosion data have been obtained on ferritic HT-9 and Fe-9Cr-1Mo steel and austenitic Type 316 stainless steel in a flowing lithium environment at temperatures between 372 and 538/sup 0/C. The corrosion behavior is evaluated by measurements of weight loss as a function of time and temperature. A metallographic characterization of materials exposed to a flowing lithium environment is presented.
Date: March 1, 1986
Creator: Chopra, O.K. & Smith, D.L.
Partner: UNT Libraries Government Documents Department

Evaluated nuclear-data file for niobium

Description: A comprehensive evaluated nuclear-data file for elemental niobium is provided in the ENDF/B format. This file, extending over the energy range 10/sup -11/-20 MeV, is suitable for comprehensive neutronic calculations, particulary those dealing with fusion-energy systems. It also provides dosimetry information. Attention is given to the internal consistancy of the file, energy balance, and the quantitative specification of uncertainties. Comparisons are made with experimental data and previous evaluated files. The results of integral tests are described and remaining outstanding problem areas are cited. 107 refs.
Date: March 1, 1985
Creator: Smith, A.B.; Smith, D.L. & Howerton, R.J.
Partner: UNT Libraries Government Documents Department

U.S. Contribution 1994 Summary Report Task T12: Compatibility and irradiation testing of vanadium alloys

Description: Vanadium alloys exhibit important advantages as a candidate structural material for fusion first wall/blanket applications. These advantages include fabricability, favorable safety and environmental features, high temperature and high wall load capability, and long lifetime under irradiation. Vanadium alloys with (3-5)% chromium and (3-5)% titanium appear to offer the best combination of properties for first wall/blanket applications. A V-4Cr-4Ti alloy is recommended as the reference composition for the ITER application. This report provides a summary of the R&D conducted during 1994 in support of the ITER Engineering Design Activity. Progress is reported for Vanadium Alloy Production, Welding, Physical Properties, Baseline Mechanical Properties, Corrosion/Compatibility, Neutron Irradiation Effects, Helium Transmutation Effects on Irradiated Alloys, and the Status of Irradiation Experiments. Separate abstracts have been prepared for individual reports from this publication.
Date: March 1, 1995
Creator: Smith, D.L.
Partner: UNT Libraries Government Documents Department

Analysis of the sensitivity of spectrum-average cross sections to individual characteristics of differential excitation functions

Description: A simple procedure for analyzing the sensitivity of computed spectrum-average cross sections to detailed properties of excitation functions for threshold nuclear reactions commonly used in reactor dosimetry is described. This procedure is shown to be useful in identifying specific needs for improved differential data and as a tool to be employed in performing evaluations. Several examples are presented to illustrate the subject matter.
Date: March 1, 1977
Creator: Smith, D. L.
Partner: UNT Libraries Government Documents Department

Development and testing of a deuterium gas target assembly for neutron production via the H-2(d,n)He-3 reaction at a low-energy accelerator facility

Description: This report describes the development and testing of a deuterium gas target intended for use at a low-energy accelerator facility to produce neutrons for basic research and various nuclear applications. The principle source reaction is H-2(d,n)He-3. It produces a nearly mono-energetic group of neutrons. However, a lower-energy continuum neutron spectrum is produced by the H-2(d;n,p)H-2 reaction and also by deuterons which strike various components in the target assembly. The present target is designed to achieve the following objectives: (1) minimize unwanted background neutron production from the target assembly, (2) provide a relatively low level of residual long-term activity within the target components, (3) have the capacity to dissipate up to 150 watts of beam power with good target longevity, and (4) possess a relatively modest target mass in order to minimize neutron scattering from the target components. The basic physical principles that have to be considered in designing an accelerator target are discussed and the major engineering features of this particular target design are outlined. The results of initial performance tests on this target are documented and some conclusions concerning the viability of the target design are presented.
Date: March 1, 1992
Creator: Feautrier, D. & Smith, D. L.
Partner: UNT Libraries Government Documents Department

Nuclear data and measurements series: Some comments on the effects of long-range correlations in covariance matrices for nuclear data

Description: Attention is called to the considerable sensitivity of many uncertainty calculations to the magnitude of the long-ranged correlations which appear in covariance matrices. If such correlations do exist, they must be included in order to properly assess the impact of the uncertainties in the data. If, however, certain assumed long-range correlations are unrealistic, then analyses involving such correlation information are almost certain to produce misleading results. The issue is discussed in general terms, and its importance is illustrated by examples based in part on recent work from this laboratory. Some practical suggestions are offered for dealing with the matter of correlations in instances where the available information is incomplete. 23 refs., 2 figs., 1 tab.
Date: March 1, 1987
Creator: Smith, D.L.
Partner: UNT Libraries Government Documents Department

A vector model for error propagation

Description: A simple vector model for error propagation, which is entirely equivalent to the conventional statistical approach, is discussed. It offers considerable insight into the nature of error propagation while, at the same time, readily demonstrating the significance of uncertainty correlations. This model is well suited to the analysis of error for sets of neutron-induced reaction cross sections. 7 refs., 1 fig.
Date: March 1, 1989
Creator: Smith, D.L. & Geraldo, L.P.
Partner: UNT Libraries Government Documents Department

MHD considerations for a self-cooled liquid lithium blanket

Description: The magnetohydrodynamic (MHD) effects can present a feasibility issue for a self-cooled liquid metal blanket of magnetically confined fusion reactors, especially inboard regime of a tokamak. This pressure drop can be significantly reduced by using insulated wall structure. A self-healing insulating coating has been identified, which will reduce the pressure drop by more than a factor of 10. The future research direction to further quantify the performance of this coating is also outlined.
Date: March 1, 1992
Creator: Sze, D. K.; Mattas, R. F.; Hull, A. B.; Picologlou, B. F. & Smith, D. L.
Partner: UNT Libraries Government Documents Department

Mechanical design and thermal hydraulic considerations for self-cooled lithium-lead blanket

Description: Liquid lithium-lead eutectic alloy (17 at % Li-83 at % Pb, referred to herein as Li-Pb) is currently being considered as a candidate breeding material for fusion reactors. Some important considerations in the design of a Li-Pb blanket are compatibility with the structure, tritium containment and recovery, and safety. Additional design complexities arise because of the high density of Li-Pb, the relatively high melting temperature (235/sup 0/C), and the high tritium over-pressure associated with this alloy. In this study, the Li-Pb eutectic was considered both as the breeder and as the coolant. Thermal hydraulic and stress analyses were conducted to assess the technical feasibility of using Li-Pb as the breeder and coolant based on DEMO reactor conditions. The results of the thermo-mechanical analyses showed that the elongated cylindrical blanket modules made from either HT-9 or vanadium alloy offer a viable first wall/blanket design concept.
Date: March 1, 1983
Creator: Misra, B.; Smith, D.L.; Burk, R.C. & Morgan, G.D.
Partner: UNT Libraries Government Documents Department

Fast neutron radiative capture cross section of /sup 232/Th. [30 keV to 2. 5 MeV]

Description: The /sup 232/Th(n,..gamma..) cross section was measured between 30 keV and 2.5 MeV. A large liquid scintillator was used to measure the shape of the cross section relative to Au(n,..gamma..) between 58 keV and 850 keV. The activation technique was used in measurements at 30 keV relative to Au(n,..gamma..) and above 240 keV relative to /sup 235/U(n,f). The activation results were utilized to normalize the shape data. The results agree well with recent experimental data by Lindner et al. and are substantially lower than the evaluated data file ENDF/B-IV in the several-hundred-keV range.
Date: March 1, 1978
Creator: Poenitz, W.P. & Smith, D.L.
Partner: UNT Libraries Government Documents Department

MHD considerations for a self-cooled liquid lithium blanket

Description: The magnetohydrodynamic (MHD) effects can present a feasibility issue for a self-cooled liquid metal blanket of magnetically confined fusion reactors, especially inboard regime of a tokamak. This pressure drop can be significantly reduced by using insulated wall structure. A self-healing insulating coating has been identified, which will reduce the pressure drop by more than a factor of 10. The future research direction to further quantify the performance of this coating is also outlined.
Date: March 1, 1992
Creator: Sze, D.K.; Mattas, R.F.; Hull, A.B.; Picologlou, B.F. & Smith, D.L.
Partner: UNT Libraries Government Documents Department