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An Analysis of Project Data on the Corrosion of Uranium in Various Media

Description: This is a summarizing and reviewing report in which almost all the experimental data representing Project work done prior to 1949 on the corrosion of pure uranium are brought together and analyzed. New data obtained in this laboratory on corrosion rates in laboratory atmosphere and on the identification of corrosion products by electron diffraction are included. The data for corrosion in each of several different media have been plotted according to logarithm-of-the-rate versus reciprocal-temperature coordinates; and from these plots values for the energies and entropies of activation of the corrosion reactions have been obtained. By theoretical treatment of the role of oxygen as a negative catalyst, it is shown that this element may be expected to "poison" the corrosion rection and then act as a corrosion inhibitor. A practical significance of these data analyses is that they explain why machined uranium parts stored in inert atmospheres (helium or argon) containing only very small amounts of water vapor will corrode relatively rapidly with the formation of loose powdery oxide, whereas similar parts may be kept in dry air almost indefinitely with formation on their surface of only a discoloring, but adhered, oxide coating.
Date: December 22, 1948
Creator: Waber, James T. (James Thomas), 1920-
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Angular Distribution of Fragments from Neutron-Induced Fission

Description: The angular distribution of fission fragments from the neutron-induced fission of several isotopes has been studied. Distributions were observed for thermal neutrons on U233 and U235, Lady Godiva leakage neutrons on U235 and U238, and 14 Mev neutrons on U233, U235, U238, Th232, and Np237. No anisotropy was observed for thermal neutron fission, whereas for Lady Godiva neutrons and 14 Mev neutrons the probability of fission along the axis of the neutron beam was determined to be higher than for fission in the orthogonal direction. Experimental results are given on pages 10 and ll.
Date: May 7, 1953
Creator: Brolley, John Edward, 1919- & Dickinson, W. C.
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Average Fission Cross Section U238 for Fission Neutrons

Description: By means of measurements with a double ionization chamber, the average fission cross section of U238 for neutrons from the fission of U235 was determined in terms of v, the average number of neutrons per fission of U235. the number of fission of U238 was measured in one of the ionization chambers while the number of fissions from the fission neutron source of U235 was measured in the other chamber. In the nine runs made to determine the cross section, a variety of different methods was used to determine the number of fissions and the mass of U238.
Date: January 1953
Creator: Leachmanm R. B. & Schmitt, H. W.
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A Ball Holder for Coating Operations

Description: A device has been designed which will support small spheres and cylinders in a vacuum system during a plating operation. While supporting the object to be plated, the device automatically shifts the position of the supports so that the coating is evenly distributed. This report describes the mechanism by which this motion is achieved.
Date: April 8, 1953
Creator: Lilienthal, James R.
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Bibliography : Impact Testing of Materials

Description: The bibliography provided investigates the following sources: Chemical Abstracts 1947-1950., Metallurgical Abstracts Vols. 1-18., ASM Review of Metals Literature Vols. 1-6., J. Institute of Metals Vols. 78-80 (No. 7)., Physics Abstracts 1937-1950.
Date: June 8, 1952
Creator: Fick, Jean
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Burst Characteristics Associated with the Slow Assembly of Fissionable Materials

Description: This technical report is a sequel to LA-596, "Efficiency for Very Slow Assembly" by K. Fuchs. Herein are given estimates of temperature rise and pressure developed as a result of active material slowly being driven supercritical. Marginal assembly rates can thus be determined for both metal and solution assemblies above which the disassembly by thermal expansion is explosive in the sense that the active material or containing vessel is ruptured.
Date: July 1952
Creator: Hansen, G. E.
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Calcium Oxalate Carrier Precipitation of Pu

Description: This technical report describes a plant-scale procedure for concentrating plutonium and americium in slag and crucible (metal reduction residues) and other recovery solutions by a calcium oxalate carrier precipitation Conclusions from exploratory laboratory tests on the variables affecting the efficiency are included.
Date: February 25, 1954
Creator: Maraman, W. J.
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A calculation to simulate the underground Bernalillo shot

Description: From abstract: "Detailed calculations were undertaken in an attempt to explain some post-shot observations of the underground Bernalillo shot. A procedure was developed to calculate with a one-space dimensional code both the flow of energy up and down the hole and the energy loss into the walls of the hole."
Date: 1961
Creator: Brownlee, Robert R.
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Calculations of the Critical Mass of UF6 as a gaseous Core, with Reflections of D2O, Be and C

Description: A class of critical assemblies has been considered in which the core consists of an oralloy bearing gas at more or less standard pressure and temperature and the reflector is an efficient moderator with a small thermal capture cross section. Age and diffusion theory have been applied to compute the probability that a fast neutron is thermalized by the reflector and them captured by the core. It is first assumed that fast or epithermal neutrons do not interact wit the core and it is later shown that this assumption should be a good one for many cases. The reflector may be a thick spherical shell. It is shown that oralloy masses of a few kilograms can be critical within thick reflectors of D2O, Be, C or combinations thereof. Curves are attached which enable one to estimate critical configurations.
Date: February 1955
Creator: Bell, George I., 1926- & Goldstein, Max
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The Calibration of Tritium Monitoring Devices

Description: The increased use of tritium monitoring devices has made it necessary to devise a scheme for the calibration of such instruments. Several methods for setting up known concentrations of tritium were considered. A dynamic system containing tritium as HTO vapor or gaseous HT was selected because of the ease of control of variables. The variables that have been considered are: ,1. The effect of rate of air flow through the instruments. 2. The effect of humidity on instrument response. 3. The effect of ion collection ahead of the ion chamber. 4. The variation of “hold time” from the generation of tritium to its passage through the ion chamber. 5. The instrument response to several concentrations of tritium as HTO vapor and gaseous HT. The following three types of monitoring devices have been calibrated:1. Model 101 Sniffer of Group P-1. 2. Cl-1 Vibrating Reed Electrometer of Group CMR-7. 3. Modified TIB of Group H-6.
Date: June 1954
Creator: Robbins, M. Chain
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Collected Reports on Fission Cross Sections of U237 in Thermal Neutron, Intermediate Neutron, and Degraded Fission Neutron Spectra

Description: Part 1. The neutron fission cross section of U237 has been measured in a thermal neutron spectrum and in a somewhat degraded fission spectrum. The fission cross section for thermal neutrons is found to be <2 barns; the ratio of the fission cross section of U237 to that of U235 in the degraded fission spectrum is found to be 0.476 +- 15% which corresponds to [formula] in this spectrum equal to 0.66 +- 0.10 barns. Part 2. The average neutron fission cross section of U237 has been measured in a neutron energy range extending from approximately 100 ev to fission spectrum. the average fission cross section in this spectrum is found to be 0.70 +- 0.07 barns. Part 3. The low thermal fission cross section for U237 (<2 barns) indicated that the excitation function for fission probably shows an effective threshold. If the excitation function is like all other heavy element (Z > 90) neutron fission excitation functions, it will exhibit a region of approximate constancy starting at a neutron energy of 0.5 to 1 Mev above its effective threshold and extending to a neutron energy in the neighborhood of 5.5 Mev. A hypothetical excitation function for neutron fission of U237 is suggested which has a roughly constant plateau value of 0.6 to 0.8 barns. The plateau value would be reached at <200 Kev neutron energy if there is no maximum in the excitation function larger than the plateau value. The effective threshold for fission would occur at some higher energy if such a maximum exists.
Date: January 1, 1955
Creator: Cowan, G. A. (George A.), 1920-2012
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The Colorimetric Determination of Boron in Zirconium Hydride

Description: The quantitative estimation of submicrogram amounts of boron in zirconium hydride using a colorimetric procedure is described. Solution of the sample in sulfuric acid or hydrofluoric acid and subsequent distillation of methyl borate without boron loss or contamination is shown to be possible. Using the curcumin color reaction, quantities of boron as low as 0.01 microgram can be detected. The method should apply equally well to zirconium metal and compounds, providing they can be dissolved under conditions that do not result in loss of boron and if the resulting solution will permit the quantitative removal of boron by distillation as methyl borate.
Date: July 1954
Creator: Waterbury, Glenn R. & Metz, Charles F.
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Consolidation and shaping of boron ; summary of previous work

Description: From abstract: "The deposit on the rods is in the form of a brittle uneven tube which is cracked off and subsequently pulverized to a 200-mesh powder. This report is chiefly concerned with methods of consolidating this powder and shaping it into forms required, though it also discusses to some extent other methods of shaping boron or born-rich materials."
Date: October 8, 1945
Creator: Kamm, Robert L.
open access

Corrosion of Uranium in Moist Air

Description: The corrosion of uranium in moist air is more rapid than had been thought previously. Earlier recommendations were based on test of 300 hr duration. In tests which were conducted for over 1000 hr, moisture has less effect than in those tests made over shorter periods. The corrosion of uranium by dry and moist air has been studied at 38, 57, and 75 degrees C. Although moisture increases the rate of initial attack, after 200 to 500 hr the effect is reduced and an accelerating corrosion rate overshadows the initial effects of moisture.
Date: January 1952
Creator: Waber, James T. (James Thomas), 1920-
open access

Critical Masses of Graphite-Tamped Heterogeneous Oy-Graphite Systems

Description: Critical mass measurements on graphite-tamped, heterogeneous oralloy-graphite systems have been made as a safety guide for certain oralloy casting procedures. Various concentrations were obtained by alternately stacking 10.5 in. diameter oralloy and graphite plates. In the relation Oralloy critical mass = constant x (fraction of oralloy in the core volume) -n values for the exponent, n, in the neighborhood of 0.70 were obtained.
Date: May 1954
Creator: Hoogterp, J. C.
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The DD and TD Cross Sections

Description: The total cross sections of the reactions DDp, DDn, TD at 10 kev to 10 Mev are estimated from a review of the experimental data up to January 1951. Maxwell averages for DDp and TD computed from these estimates are given, together with some fitted analytic expressions provided for machine use. A collection of the identifiable earlier estimates is also included for reference and for comparison with the new figures. For relative order of magnitude purposes, cross sections and the derived Maxwell averages are given down to 50 ev using the theoretical Gamow slopes for the extrapolation. Gamow plots for the derived cross sections above l0 kev arc also given. Much of the primary experimental data exists in the form of thick target yields and we find the most uncertain factor in converting these thick targets yields into cross sections is the magnitude of the D/sub 2/O stopping cross section. The particular D/sub 2/O stopping cross section relation used in this derivation together with some of the earlier stopping cross sections are given. Thick target yields are included for both DD and TD on D/sub 2/ targets, at 0.01 to 1 Mev, experimental values being supplemented by calculated values.
Date: May 10, 1951
Creator: Tuck, J L
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The Decontamination of Uranium from Fission Products by the Use of the Uranyl Oxalate Precipitation Reaction

Description: Abstract: "Decontamination factors of the order of 10-4 were obtained for Beta and Gamma emitters present as fission products when uranium was precipitated from 50 mC activity level solutions as uranyl oxalate under normal uranium yield conditions for three cycles (~60%). Factors of the order of 10-3 were obtained by the use of this reaction with similar solutions under relatively high uranium yield conditions for three cycles (~90%). The uranium peroxide precipitation reaction proved to be of no value on such solutions, yielding decontamination factors of only 17.1 Beta emitters and 1.2 for Gamma emitters for three cycles."
Date: May 10, 1951
Creator: Kelchner, B. L.
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Dependence of the Oxidation of Uranium on Oxygen Pressure

Description: The oxidation of uranium metal has been studied from the standpoint of the oxygen dependence of the reaction rate in an effort to establish the mechanism. The experimental data of Perkins agree with the theoretical dependence of the oxygen pressure derived this report. This agreement supports the hypothesis that the rate-controlling step in the migration of cations in the DO2 lattice, although the observed time dependence is not necessarily in agreement with this conclusion. Experimental entropies of activation are corrected for the observed pressure dependence. No firm conclusion could be reached as to whether the rate of diffusion or adsorption is rate-controlling.
Date: March 20, 1952
Creator: Waber, James T. (James Thomas), 1920-
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A Design for a Rotary Reactivity Control for a Test Reactor

Description: Tests made on the Oy-Tu reacting assembly at Pajarito indicate that the lateral displacement of two halves of the active material within the assembly can be used as a control mechanism on this type of reacting assembly. This report describes a reacting assembly using a rotary control mechanism based on this principle and indicates the sensitivity of control possible with such a device.
Date: September 18, 1950
Creator: Josephson, V. (Vernal)
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Detailed geochemical survey data release for the San Andres-Oscura Mountains special study area, New Mexico

Description: Discussing samples collected by the Los Alamos National Laboratory for a detailed geochemical survey of uranium in the northern San Andreas Mountains and the Oscura Mountains of south-central New Mexico.
Date: April 1981
Creator: LaDelfe, Carol M.; Apel, Charles T.; Hansel, James M.; Fuka, Mary A.; Denton, Michael M. & Cheadle, Jesse M.
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