Report discussing an experiment to reinvestigate the spontaneous fission of 48 (Pu-238) in an effort to determine a more accurate value for the spontaneous fission constant that was found in a previous experiment.

The following report describes the high pressure and temperature homogeneous reactor experiment which has been started at Los Alamos, as well as the hazards and safety aspects for the experiments.

Report discussing the reaction of uranium with pure water. The reaction was followed by using a method of measuring hydrogen evolution.

Abstract: In the study of a linear pinch, use of the equation of pressure balance has proven to be a powerful method of analyzing data taken with a magnetic probe. The toroidal pinch, however, is a geometrically more complicated object, and the use of the pressure balance equations is not so clean cut. It is the object of this note to analyze the pressure balance equations for a torus to the point where they might prove useful in interpreting probe data.

From summary: This report describes work done in the Pueblo National Topographic Map Series (NTMS) quadrangle, Colorado, by the Los Alamos Scientific Laboratory (LASL) as part of the nationwide Hydrogeochemical and Stream Sediment Reconnaissance (HSSR).

This technical report presents results of nuclear plate work carried out to determine the neutron energy distribution inside the Los Alamos fast reactor. Most of the distributions which were investigated are valid over the energy region from 0.4 to 6 Mev. The results show that at the center of the reactor pot about 65% of the neutrons are located below 1 Mev in a rather narrow energy region which has a maximum in the neighborhood of 0.5 to 0.6 Mev. Above 2 Mev the energy distribution is similar to that of a plutonium fission neutron spectrum, i.e. the spectrum decreases exponentially, diminishing by a factor of 10 in intensity over an energy range of about 4 Mev. The leading geometry of the reactor pot does not seem to appreciably affect the spectrum at the center of the pot. However, spectra determined outside the pot can be significantly altered by the particular viewing geometry employed to examine the neutrons coming from the center of the reactor.

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.

A polarographic method for the determination of titanium in the presence of plutonium has been devised. Hydrochloric acid solutions of plutonium and titanium are reduced with zinc, made one molar in tartaric acid, and further reduced in the polarographic cell with liquid zine amalgam. Plutonium is thus reduced to the non-interfering (III) oxidation state and a well defined anodic wave for the oxidation of titanium (III) to titanium (IV) is obtained. The height of this wave is directly proportional to the titanium concentration for plutonium-titanium solutions containing 20 grams plutonium per liter. The precision for the analyses of duplicate samples has been calculated at the 95 percent confidence level to be 2.9 percent for those containing 0.025 to 0.050 gm titanium per liter and 1.1 percent for those containing 0.089 to 0.51 gm titanium per liter.

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.

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 …

A theoretical study of the kinetics of a model of the Los Alamos Power Reactor Experiment (LAPRE) was made through integration of the dynamic equations with the IBM 701 computer. The stability is investigated under various conditions of power demand, rod-induced reactivity changes, and other conditions especially applicable to LAPRE. The results are given in graphical form, along with conclusions as to appropriate conditions of operation.

This report is a collection of data which were determined by several safety tests to assure safe procedures during the fabrication of Oy. These tests indicated that a 4 in. ID melting crucible which had become flooded from the cooling coils of the furnace would be critical with about 23.7 kg of Oy. A 5 in. ID crucible under similar conditions would be critical when it contained 21.3 kg. A series of measurements to simulate multiple crucibles in a melting furnace indicates that a flooded array of four charged crucibles with a spacing of 1.6 in. between the graphite heater jackets would have a neutron multiplication of 16.2. It has been shown that a 1 in. thick Oy plate in infinite paraffin tamping has a critical mass of 58 kg, and a 1 1/2-in. thick plate with the same tamping has a critical mass of 41 kg. Another test shows that a flooded Oy hemisphere 10 in. ID would be critical with a wall thickness of 1 in. at 60 kg. Also given in the last section are curves of Oy critical mass for various diameter cylinders with water, paraffin, and graphite tamping.

Various properties of BeH/sub 2/ are predicted, based on the properties of neighboring hydrides. Included are predictions of the stability of the Be-H bond, the stability of an ionic lattice for BeH/sub 2/, polymeric structure, and density.

Diagrams provided for a convenient overview and standardized framework of the United States transportation system.

Kilogram quantities of delta-stabilized and pure plutonium turnings can be cast directly into ingots of normal quality with high yields. This report describes the equipment and process used.