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.

A report about a thermionic converter which has been constructed for the purpose of evaluating the effect of radiation shields in the interelectrode space.

Certain types of neutron diffusion calculations were considerably simplified when the Serber.Wilson Method was introduced about eight years ago. This method, semi-empirical In nature and named after its co-discoverers, was first formulated for the one-velocity isotropic theory and applied to spherical geometries. Within these limits it has in general proved to be a fairly accurate method. If restricted source-free case it has, in addition, turned out to be quite manageable both analytically and numerically.

Measurement of the color intensity of the uranium thiocyanate complex is discussed as a method for the quantitative determination of uranium. Two procedures for amounts from 1 microgram to 1 milligram are described, and standard curves are shown. The effects of numerous foreign ions are shown, and methods of removal for some of these are discussed.

The coefficient of linear expansion of alpha plutonium has been determined for the range -180 to +100 degree C by the silicon-tube and dial-indicator method. The value of the expansion coefficient is reported as [formula]. Included are a detailed description of the apparatus and a discussion of the method.

The coefficient of linear expansion of alpha plutonium has been determined for the range -180 to +100 degree C by the silicon-tube and dial-indicator method. The value of the expansion coefficient is reported as [formula]. Included are a detailed description of the apparatus and a discussion of the method.

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.

High purity, homogeneous uranium-molybdenum alloys have been made successfully in the reduction bomb. The preparation of the alloys and some of their properties are described.

A method for determining zirconium in plutonium-zirconium alloys was required as part of an investigation of alloys containing fissionable material, with possible use in nuclear reactors. Alloys of these two elements were brought into solution with a bisulfate fusion and the zirconium was separated by precipitation with p-bromomandelic acid. Determinations were completed by weighing the zirconium oxide obtained after ignition of the precipitate at 925 degree C. The precision of this recommended procedure was estimated in terms of the standard deviation for quadruplicate determinations, made with weight aliquots from dissolved alloy samples. The range for the standard deviation was 0.5 to 1.7 parts per thousand for samples from which aliquots each containing 9 to 15 mg of zirconium were selected. The complete recovery of zirconium from solutions of pure zirconyl chloride and plutonium trichloride was shown by the 95 percent confidence limits of 99.9 +- 0.3 percent for the average of four determinations, observed with samples containing 5 to12 mg of zirconium in the presence of 10 to 20 mg of plutonium. It was found the Mo, La, PU(III), and K2Cr2O7 do not interfere with zirconium determinations made according to the recommended procedures, but Pu(IV) does interfere slightly. It was …

A method using photographic emulsions for the study of neutron distributions is described. The construction of a simple machine for producing experimental critical assemblies in which the method has been used is reported. Sources of error are discussed. Curves of the perturbations when small spheres of various materials are placed in the center of the assembly are shown.

The total neutron cross sections for normal uranium, U235, and Pu239 are reported as a continuous function of energy for neutron energies between 40 and 7500 Kev. Three additional measurements were made between 17 and 20 Mev. The data were obtained from a good geometry transmission experiment in which 1-in.-diameter cylindrical samples were interposed midway between a neutron source and a neutron counter spaced at about 20 in. separation. In general, the statistical errors were within +- 0.2 barn. Measurements on normal uranium were in agreement with those made at Wisconsin in 1950 (LA-1060). The total cross section curves are almost identical for the three materials and very similar to those of other heavy elements. This suggests that the total neutron cross section for other heavy elements can be predicted with some accuracy.

One characteristic of the corrosion of uranium is the accelerating destruction of the metal under both dry and humid conditions and throughout a wide temperature range. Another corrosion property is the fracturing and fragmentizing of the oxide products. This results in an accelerating or decelerating growth law being operative at a particular time. This time is determined by whether the oxide ruptures rapidly or slowly compared to the rate of growth of the unfractured oxide. The reaction with dry air is essentially a reaction with the contained oxygen. In water, under oxygen-free conditions, linear oxidation laws are observed. In steam, because UO/ sub 2/ is the product at temperatures below 250 C and U/sub 3/O/sub 8/ at temperatures above 250 C, different reaction rates occur in the two temperature ranges. The effects of a few alloying elements on the corrosion resistance of uranium are reviewed. Wartime research indicates that small additions of aluminum, molybdenum, nickel, and titanium have a slightly beneficial effect. Niobium, silicon, and zirconium increase substantially the corrosion resistance in water provided the alloy has had adequate heat treatment. There is some information that the addition of small amounts, less than 2%, of aluminum or silicon increases the …

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.

Magnesium oxide reduction crucibles have been developed that increase the processing efficiency of uranium and plutonium production. The characteristics of the crucibles are described.

A modification of the specimen support for the Norelco diffractometer permits X-ray diffraction studies to be made of specimens prepared for metallographic examination. The unit has been successfully used to identify phases present in specimens of plutonium-uranium alloys.

Optical and morphological properties of 28 compounds of uranium, plutonium, americium and some related elements, belonging to 21 isomorphous groups, are described. Additional data are given on 5 compounds of similar type described in the National Nuclear Energy Series, Division IV, Volume w, Chapter 19, “Actinide Elements.”

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.

This technical report summarizes the apparent hematological changes in 10 individuals, exposed to total-body gamma radiation in near tolerance amounts, over a period of four and one-half years. Two control groups, in addition to the exposed group, were used for comparative purposes. Control group I received essentially no gamma or beta radiations. Control group II received exposures at least a factor of 10 below those of the exposed group. The average total leukocyte count, absolute neutrophil value, and absolute lymphocyte value, were determined for each individual and for all groups. Analysis of data indicates a significant depression of the absolute lymphocyte value of the exposed group as compared with those of the control groups.

Simple expression are derived for the time dependence of slowing down of neutrons in a simple media. In Section I, a method suggested by age theory is used, while in section II, a two parameter scattering function is employed. Results are compared with exact calculations.

This technical report describes the preparation and properties of plastic bonded RDX mixtures containing approximately 30 weight percent RDX. These mixtures may readily be prepared by a method adaptable to existing ordnance plant equipment. they are roughly comparable to Compositions A and B in sensitivity and explosive performance, but are much stranger physically than these or similar explosives.

A technique for the fusion welding of uranium has been under development and several methods of fusion welding have been investigated. The inert gas, shield arc method has proven to be the most satisfactory of the processes thus far examined. Uranium properly weld by this method was free from porosity, cracks, and oxide inclusions. Certain precautions and some special techniques were required to make good welds.

High purity, homogeneous alloys of uranium and columbium have been produced by adding powdered columbium metal or columbium/sub 2/O/sub 5/ to a regular reduction charge. Alloys up to 20.0 at.% columbium were produced. The preparation of the alloys, some of their properties, and casting results are described.

A neutron burst from an untamped cylindrical Oy assembly occurred at the Pajarito Remote Control Laboratory at 1800 hours on 18 April 1952. The circumstances causing the burst and a description of the assembly involved are given There was no personnel hazard. Normal operations could have been resumed on other assemblies withing two or three hours after the burst. No evidence of damage to the oy was observed. It was determined that the burst resulted in 1.5 x 10(16) fissions in the oy. Also reported are some results of the computations and post-burst tests and a discussion of probable time behavior of power level during the burst.