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Radiologic Hazards Predicted for a Given Height Burst of an Atomic Bomb

Description: Abstract: An appraisal is made of the radiologic hazard created by a 1000-ft. high air burst of a nominal sized nuclear bomb. Three sets of graphs are included which show the relations between dose rate (milliroentgens per hour), time post-shot, and distance from Ground Zero for a soil having given constituents. Estimates are given for fall-out activity (gamma) for distances up to about 200 miles from Ground Zero immediately after fall-out. It is pointed out that the radiologic hazard due to fall-out in the example cited is insignificant; further, that the radiologic hazard from similar nuclear bombs bursting at different heights above the ground will vary to a considerable extent.
Date: April 6, 1951
Creator: Perry, Charles H.
Partner: UNT Libraries Government Documents Department
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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
Partner: UNT Libraries Government Documents Department
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open access Some Observations on the Reactivity of Plutonium Dioxide

Description: The index of refraction of PuO2 made by thermal decomposition of PU(C2O2, 6H2O gradually increases from a value < 1.9 to 2.40 as the decomposition temperature is increased from 150 degree to l000 degree C. This change in refractive index parallels a gradual change in the x-ray diffraction pattern from weak, diffuse lines for PuO2 ignited at 150° to sharp, well resolved lines for PuO2 ignited at 1000°C. Similar results are observed for PuO2 made by thermal decomposition of Pu2(C2O4)3*11H2O. The refractive index of PuO2 made from Pu metal at 170°C is 2.40 and is not affected by further ignition at higher temperatures, although crystal growth does occur. The rate of solution of PuO2 in an HCl-KI solution is greatest for samples prepared at low temperatures and decreases markedly for oxides ignited at higher temperatures. These observations hive been interpreted to mean that ignition at higher temperatures causes a gradual perfection of the originally highly distorted and impurity-containing PuO2 lattice obtained by low temperature decomposition of the oxalates and promotes the slow growth of crystallites. Both factors decrease the reactivity of the PuO2.
Date: November 1, 1954
Creator: Bjorklund, C.W. & Staritzky, Eugene
Partner: UNT Libraries Government Documents Department
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Emission Probabilities of Prompt Neutrons from Spontaneous and Neutron-Induced Fission

Description: A method is developed for using the relatively easily measured fission parameters, together with the mass equation of fission and the evaporation model of the nucleus, to determine the emission probabilities of the fission neutrons. The distribution of the kinetic energies of the fragment pairs enters into these calculations in a sensitive manner. Neutron emission probabilities are computed for the fission of the compound nuclei U/sup 234/ U/sup 236/, and Pu/sup 240/, for which cases reasonably adequate data on the fragment pair energies are available. Although the corresponding data for the fission of the compound nuclei Th/sup 233/, U/sup 238/, and U/sup 239/ are considerably poorer, neutron emission probabilities are also computed. The calculated results from this method are in good agreement with direct measurements of fission neutrons.
Date: December 1954
Creator: Leachman, R. B.
Partner: UNT Libraries Government Documents Department
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Some Observations on the Reactivity of Plutonium Dioxide

Description: The index of refraction of PuO2 made by thermal decomposition of PU(C2O2, 6H2O gradually increases from a value < 1.9 to 2.40 as the decomposition temperature is increased from 150 degree to l000 degree C. This change in refractive index parallels a gradual change in the x-ray diffraction pattern from weak, diffuse lines for PuO2 ignited at 150° to sharp, well resolved lines for PuO2 ignited at 1000°C. Similar results are observed for PuO2 made by thermal decomposition of Pu2(C2O4)3*11H2O. The refractive index of PuO2 made from Pu metal at 170°C is 2.40 and is not affected by further ignition at higher temperatures, although crystal growth does occur. The rate of solution of PuO2 in an HCl-KI solution is greatest for samples prepared at low temperatures and decreases markedly for oxides ignited at higher temperatures. These observations hive been interpreted to mean that ignition at higher temperatures causes a gradual perfection of the originally highly distorted and impurity-containing PuO2 lattice obtained by low temperature decomposition of the oxalates and promotes the slow growth of crystallites. Both factors decrease the reactivity of the PuO2.
Date: September 1, 1954
Creator: Bjorklund, C.W. & Staritzky, Eugene
Partner: UNT Libraries Government Documents Department
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Extraction of Americium Nitrate with Tributyl Phosphate

Description: The extraction of americium nitrate with tributyl phosphate has been investigated for aqueous solutions containing sodium nitrate and nitric acid. Americium nitrate is found in the organic phase as free molecules or ions and as the complex (Am(NO3)3. Aqueous solutions containing nitric acid introduce a competitive factor through the formation of the TBP-KNO3 complex in the solvent layer. In addition. americium nitrate is complexed in the aqueous phase by nitric acid.
Date: January 4, 1955
Creator: Walsh, K. A.
Partner: UNT Libraries Government Documents Department
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Effects of Certain Variables Upon the Reactions for Preparation, by the Dry Method, of UF4 from U3O8

Description: The effects of certain process variables on the production of uranium tetrafluoride from U3O8 on the 250 g. (uranium) scale, and smaller scales in a few cases, have been studied. It was found that the initial step (reduction of U3O8 to UO2 by hydrogen) is essentially complete in 15 minutes at 700 degree C. The rate of conversion was shown to be temperature dependent, the greatest increase in rate of conversion occurring in the vicinity of 500 degree C. In the conversion of UO2 to UF4 by hydrogen fluoride, the optimum temperature was found to be abut 600 degree C. For a reaction time of 5-1/2 hours, both higher and lower temperatures yielded less completely converted products. An increase in rate of conversion, both in reduction and hydro-fluorination, resulted when smaller quantities of material were used. Changes resulting from the present study and yielding an increased efficiency in the production process are described.
Date: November 1954
Creator: Fry , O. E. & Kewish , R. W.
Partner: UNT Libraries Government Documents Department
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Specific Surface and Bulk Density of U3O8 and UO2 as Factors in UF4 Production on the 250 Gram Uranium Scale

Description: Specific surface and bulk density measurements were made on samples of 22 U308 materials which had been prepared by calcination at 900°C of widely differing uranium peroxide precipitates and had been evaluated as to "reactivity" by successive treatment with hydrogen and a mixture of anhydrous hydrogen fluoride and hydrogen in a production-type batch process for the preparation of UF4. Specific surface and bulk density measurements were also made on samples of the 22 corresponding U02 intermediates. The ranges of values encountered in the U308 samples and in the U02 samples were 0.05 m /g to 0.37 m /g and 0.03 m /g to 0.33 m /g, respectively, for specific surface and 3.7 g/cm to 1.8 g/cm and 4.9 g/cm to 2.7 g/cm3, respectively, for packed bulk density. Specific surface varied inversely with packed bulk density for U308, the data showing a good correlation. A very poor correlation between specific surface and packed bulk density of U02 was obtained. The conversion of U308 to UF4 n the standard process varied from 22% for the lowest specific surface, highest bulk density oxide to 98 to 99% for the high specific surface, low bulk density oxides. The observed values for properties of the U308 samples correlated better with conversion of U308 to UF4, U02 than did the observed values for properties of the corresponding intermediates.
Date: December 1954
Creator: Bard, R. J.; Fry, O. E. & Kewish, R. W.
Partner: UNT Libraries Government Documents Department
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Infinite Conductivity Theory of the Pinch

Description: With the assumption of infinite conductivity a simple model may be constructed for the dynamic construction of a current carrying plasma, i.e., the pinch effect. The magneto-hydrodynamic equations of this model are discussed and solved. It is also shown that the infinite conductivity model can be derived from a picture of particles orbiting without collisions in the fields set up by their motions.
Date: September 14, 1954
Creator: Rosenbluth, M.; Garwin, R. & Rosenbluth, A.
Partner: UNT Libraries Government Documents Department
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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.
Partner: UNT Libraries Government Documents Department
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Polarographic Behavior of Various Metal Ions in Plutonium Solutions

Description: The reported procedures for the polarographic determination of uranium, vanadium, and titanium in plutonium were investigated to ascertain if they could be used to determine other common metals in plutonium. It was found that the procedure using hydroxylamine hydrochloride to reduce plutonium to the (III) oxidation state could be used to determine bismuth, platinum, rhodium, copper, tin, lead, thallium, iridium, and cadmium. The procedure using zinc and zinc amalgam in hydrochloric acid to reduce the plutonium to the (III) oxidation state is quite limited, but it might be used to determine molybdenum.
Date: July 1953
Creator: Warren, C. G.
Partner: UNT Libraries Government Documents Department
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Determination of Thorium in Plutonium-Thorium Alloys

Description: A spectrophotometric method used in the determination of thorium was modified for the purpose of analyzing plutonium alloys which contained 0.01 to 0.8 percent thorium. Absorbance values were measured at 545 millimicrons for solutions containing thorium and thorin, the organic reagent added to form a colored complex with thorium in the presence of plutonium (III) . With plutonium-thorium 0.8 percent thorium, the average recovery of thorium was 99.6 +- 1.5 percent. For similar samples containing 0.01 to 0.2 percent thorium, the average recovery 101.0 +- 3.4 percent, after the thorium was separated from plutonium by precipitation of thorium fluoride with the aid of lanthanum fluoride as a carrier.
Date: September 1954
Creator: Bergstresser, K. S. (Karl Samuel), 1909-2004 & Smith, Maynard E. (Maynard Elliott)
Partner: UNT Libraries Government Documents Department
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On the Conductivity of ionized Gas

Description: The conductivity of ionized gases is treated by a method similar to that used by Alfven in his book "Cosmical Electrodynamics". The results differ from those of Alfven. In particular, it is shown that Alfven's conclusion, that whenever the Hall current disappears the conductivity becomes independent of the magnetic field, is not true in general. Moreover, it is not true under just the conditions of interest for the "Pinch Effect". The main conclusions of the present paper are (1) of currents down a tube, the ion component is the small fraction of m/M of the electron current, regardless of the magnitude of the magnetic field; (2) the conduction along the tube depends on the transverse motion of neutral mass, i.e. on the radial velocity of u(r) of the gas in the tube.
Date: September 15, 1954
Creator: Konopinski, Emil Jan, 1911-
Partner: UNT Libraries Government Documents Department
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Opacity of Air at High Altitudes and High Temperatures

Description: The opacity and thermodynamic properties of air at temperatures above 10 e.v. and densities below normal have been calculated under the guidance of H. Mayer in accordance with the prescription given in AECD 1870 (LA-647). Corresponding to given densities and temperatures, self-consistent distributions of electrons in bound states and their eigen energies are determined. With this information we compute the thermodynamic properties of air and the frequency-dependent absorption coefficients. Finally the opacity--a weighted average of the latter--is found
Date: August 5, 1954
Creator: Kivel, B. & Mayer, H.
Partner: UNT Libraries Government Documents Department
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A Sensitive Analytical Method for Carbon in Uranium

Description: The capillary trap method for the determination of carbon in metals (LA-1128) has been modified to give a fivefold improvement in sensitivity (0.1 microgram of carbon per millimeter). Samples from pure uranium buttons gave standard deviations ranging from 1.4 to 3.2 p.p.m. Varying sample size, in the range from 100 to 250 milligrams, did not affect the results significantly. The time required for an analysis is about 13-14 minutes. The method should be equally useful for plutonium.
Date: May 1954
Creator: Smiley, W. G.
Partner: UNT Libraries Government Documents Department
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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.
Partner: UNT Libraries Government Documents Department
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An Estimate of the Lapre Power and Steam Flow Characteristics

Description: A method of numerical solution is developed for calculating the Lapre coolant pressure drop and power output with variable coolant inlet pressure, flow rate, and reactor solution temperature. The results of a series of calculations are presented that show excessive pressure drops and sonic exit flow as the flow rate is increased and the inlet pressure is decreased. Both supercritical and subcritical coolant flow regions are investigated. Reactor power is shown to be strongly dependent on the solution temperature in the region of 70O-75O degree F. At the design flow of 12 gal/min, excessive coolant pressure drops are encountered at inlet pressures of 2000 lb/in. and below.
Date: August 1954
Creator: Durham, Franklin P.
Partner: UNT Libraries Government Documents Department
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Instability of a Pinched Fluid with a Longitudinal Magnetic Field

Description: The stability of a pinched plasma equilibrium with a longitudinal magnetic field superimposed on the characteristic azimuthal magnetic field of the pinch current is studied theoretically. The linearized solutions are developed as helical perturbations of the plasma surface, and the behavior of these is given for the different cases of uniform longitudinal, longitudinal field zero inside the plasma, and for helices of the same and opposite sense to the helix which describes the total magnetic field. Very approximately, the conclusions are: that the longitudinal field has the effect of stabilizing short-wave perturbations, but that some long-wave perturbations remain unstable no matter how large the externally imposed longitudinal magnetic field.
Date: November 1953
Creator: Kruskal, Martin D. (Martin David), 1925-2006 & Tuck, J. L.
Partner: UNT Libraries Government Documents Department
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The Influence of a Precipitation Hardening Heat Treatment on the Hardness of Several Uranium-Molybdenum Alloys

Description: Four uranium alloys containing nominally 0.5, 1.0, 1.5, and 2.0 w/o molybdenum were investigated with respect to their response to hardening by heat treatment. The several alloys were heated at elevated temperatures to secure solid solution, then quenched and reheated at lower temperatures to obtain hardening. The procedure followed the well known industrial practice of solution treatment and precipitation hardening. The results showed that all the alloys could be hardened by a suitable heat treatment. No specific temperatures are recommended; however, within the limits of the investigations, a solution treatment at 850 degree C followed by a water quench and reheat at 450 degree C gave a considerable increase in hardness. The time at temperature to secure maximum hardness would need to be determined as a function of mass and section shape. It is presumed that other mechanical properties of the alloys would be influence by heat treatment in a similar manner corresponding tot he effect upon hardness.
Date: August 1954
Creator: Jones, T. I.; Hoffman, C. G.; Taub, J. M.; Doll, D. T. & Montoya, F. M.
Partner: UNT Libraries Government Documents Department
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Material Replacement Measurements in Topsy and Godiva Assemblies

Description: This report brings together an extensive accumulation of material replacement (danger coefficient) data for the various oralloy critical assemblies at Pajarito. Corresponding values of effective absorption and transport cross sections are derived. In certain favorable cases, inelastic scattering contributions to the effective absorption cross sections are estimated. Special applications of material replacement data include computation of the relationship between oralloy critical mass and concentration of a diluent and hydrogen isotopic analysis of heavy water and heavy polythene.
Date: June 1954
Creator: Engle, L. B.; Hansen, G. E.; Paxton, Hugh Campbell; Hoogterp, J. C. & Young, D. S.
Partner: UNT Libraries Government Documents Department
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Effect of Plutonium on the Fluorometric Determination of Uranium

Description: The fluorometric method for determining microgram quantities of uranium dissolved in concentrated sulfuric acid was reinvestigated for the purpose of measuring any interference caused by plutonium in uranium samples. No plutonium fluorescence, and therefore no positive errors due to plutonium, were observed. Limited transmittance of hexavalent plutonium in sulfuric acid at 513, and especially at 360 millimicrons, produces variable negative errors in uranium determinations.
Date: July 1954
Creator: Bergstresser, K. S. (Karl Samuel), 1909-2004
Partner: UNT Libraries Government Documents Department
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Plant-Scale Concentration of Am and Pu III Using Tributyl Phosphate

Description: Am III and Pu III have been recovered on a plant scale by extraction with tributyl phosphate from slag and crucible and other recovery solutions. Process losses were 0.03% Am and 0.01% Pu. The product stream contained 0.08 gram Am per liter and 0.15 gram Pu per liter. The final solution cleanup to allow discard (total alpha activity equivalent to less than 10(-4) gram Pu per liter) was accomplished by tributyl phosphate extraction of Pu III under conditions of low acidity and high nitrate.
Date: August 2, 1954
Creator: Maraman, W. J.; Beaumont, A. J. & Day, R. S.
Partner: UNT Libraries Government Documents Department
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Determination of the 14-Mev Li7 (n,n'a)T Cross Section from Sphere Multiplication and Transmission Measurements

Description: By utilizing lithium spherical shell transmission and multiplication measurements, the Li7(n,n'y)Li7 and the He6-production cross sections, it is possible to deduce that the 14-Mev Li (n,n'a)T cross section is 325 ± 75 mb. A spectrum for neutrons degraded in energy between 0 and 12 Mev is also given.
Date: July 1054
Creator: Thomas, R. G.
Partner: UNT Libraries Government Documents Department
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