It is proposed to reduce the initial wall hangup and consequent plasma contamination of a stabilized pinched discharge by reducing the Bz pressure difference across the current sheath to nearly zero at early times. Two methods for accomplishing this are proposed, both involving multistage programming of the Bz system.

The stability of a linear pinch is investigated by means of the "6W" formalism of E. A. Frieman. It turns out that when attention is confined to the surface layers of the plasma, convenient stability criteria can be deduced for very general cylindrically symmetric distributions of magnetic field and plasma.

Delta-stabilized plutonium can be welded to itself or almost any other metal using the inert-gas metal-arc process. Equipment and procedures suitable for the welding of delta-stabilized plutonium under various conditions are described.

A sphere of LiD 2 feet in diameter was irradiated by 2 x 10<sup>15 14 Mev neutrons. Samples of Li<sup>7 metal were positioned at various radii for the irradiation. An analysis of these samples for tritium led to a determination of the number of tritons produced by 14 Mev neutrons acting on Li<sup>7 in a LiD system.

Recent measurements on the long counter efficiency in which comparisons were made with the (n, p) scattering cross section, additional variations in efficiency were found which varied slowly with neutron energy but were still correlated with the total neutron cross section of carbon. Because of these variations in efficiency there are errors in the fission cross sections reported in LA-1714. Corrections to these data have been given here.

By use of small magnetic probes inserted into the discharge, the magnetic field distributions in the interior of a high-power pinched discharge have been measured as a function of time. From these data the current distributions can be deduced. By applying a static pressure calculation, in the cases when the radical pinch accelerations are small, the plasma pressure nkT in the pinch has been determined, with superimposed axial magnetic fields, and for stable and unstable configurations.

The use of quartz tubing for sampling molten plutonium and for casting rods is described. These procedures offer cheap and easy-to-use methods for obtaining molten samples and for casting long rods with small diameters.

A measurement of the [Lithium-7] reaction cross section by absolute counting of the tritium betas is described. The cross section was measured at several neutron energies between 4 Mev and 15 Mev. A comparison with results by emulsion techniques is given.

From abstract: "An apparatus is described which automatically separates a flow of drops into a series of equal samples."

The work of the Laboratory has greatly expanded into applications of nuclear energy which are significant for national defense and security, but are not directly connected with weapons development. It was felt, therefore, that a description of the non weapons activities of the Laboratory would serve a useful purpose at this time. For classification reasons, it has been necessary to issue the report in three parts; the third part concerns power reactor experiments.

A uranium metal critical assembly consisted of a 15 inch diameter core with an average U235 content of 16-1/4%, surrounded by a 3 inch thick natural uranium reflector. The critical mass was 692 kg of core material.

The work of the Laboratory has expanded into applications of nuclear energy which are significant for natural defense and security, but are not directly connected with weapons development. It was felt, therefore, that a description of the nonweapons activities of the Laboratory would serve a useful purpose at this time.. For classification reasons, it has been necessary to issue the report in three parts; this is the first and is concerned with controlled thermonuclear reactions.

A new method to procure RaLa sources was proposed by Group CMR-10, Los Alamos Scientific Laboratory. This method depended upon irradiation of small-diameter U235 wire in the Materials Testing Reactor, Arco, Idaho. A procedure for cladding and sealing U235 wire in stainless steel tubing, by drawing, plugging the tube ends, and welding, was developed, tested, and proved to be satisfactory.

Certain oralloy (Oy) lattices were immersed in infinite water for determining critical masses at various low-Oy densities. Three Oy unit sizes were used. In a broad sense the experiment shows safe and unsafe conditions for handling heterogeneous Oy-water mixtures.

The transition region between short, but controlled, pile periods and uncontrolled, highly-supercritical conditions has been investigated with an unreflected, spherical uranium assembly (Godiva). This study was undertaken because knowledge of the behavior of supercritical systems is important in evaluation of reactor hazards and also the hazards of less standard operations involving possibly critical quantities of active material.

In this report, the stability of a pinched fluid is studied theoretically, under the combined influence of a longitudinal magnetic field and conducting exterior shell. Conditions allowing complete stability are found.

As an alternative to recovering Ba140 from the spent MTR fuel assemblies a new enriched-uranium fuel pin was designed for irradiation. Two specimens, each containing about 3 g. of uranium (93% enriched), were irradiated to 1.3% and about 18% burnup. Examination after irradiation indicated that design improvements were needed; photographs are presented to illustrate the damage incurred during irradiation. A simple inorganic chemical process using precipitation and filtration techniques was developed to separate Ba140 from other fission products and uranium.

The two plutonium-metal critical assemblies that have been studied at Pajarito Site are Jezebel, bare plutonium; and Popsy, a plutonium core in a thick normal uranium reflector. These assemblies and their properties are described.

The experiments described in this report were designed to explore the feasibility of precipitating plutonium from 35 percent TBP in Gulf BT using peroxide, fluoride, sulfide, sulfite, sulfate, cocalate, hydroxide, iodate and phosphate ions from anhydrous, dilute and concentrated aqueous sources.

A detailed study of the activation of low-reactivity UO2 particles toward HF by successive oxidation and reduction was carried out. The effect of repeated successive oxidation and reduction on the reactivity of the UO2 source material toward HF was evaluated by hydrofluorination.

Thermal neutron measurements made on five weapons during Operation Teapot indicated that these neutrons contribute at most 2 per cent of the total neutron dose in air. However, the total fluxes were high and thermal neutrons may become important under shielding conditions and may significantly affect the responses of the film badges and certain sensitive dose detectors, especially when the neutron to gamma flux ratio is high.

An analytical procedure for 0.04 to 1.6 percent ruthenium in plutonium metal was developed. Determination of ruthenium in metallic plutonium was investigated as part of a program for securing analytical procedures for various metals in plutonium. However, results of the investigation are given in this report with emphasis on the determination of ruthenium in plutonium chloride solutions. Specifically, this report is primarily concerned with the separation and determination of 40 to 400 micrograms of ruthenium in a hydrochloric acid solution of 25 to 100 milligrams of plutonium.

Reflected cylindrical exponential columns of bare and natural uranium were constructed of stacked plates of oralloy (93.4%) and tuballoy. Average concentrations of U235 ranging from 0,72% to 9.18% were investigated. Flux distributions, buckling values, and spectral indices were obtained. The indicated U235 concentration for infinite critical mass is about 5.5%.

A spectrophotometric method is described for the determination of aluminum in plutonium-aluminum alloys. The alloys are dissolved in parchloric acid and the diluted solution electrolyzed using a mercury cathode to remove any iron present which would interfere in the subsequent analysis. Then plutonium is then separated from the aluminum by precipitation as the insoluble iodate, and the aluminum determined in the supernatant solution using aluminon as a color reagent.