From abstract: "Critical assembly tests have been made on the Pajarito Universal Machine to determine the safety limits of handstacking cubes of 95% U-235 in spherical geometries preparatory to making critical assemblies of U-235 in an "infinite" tuballoy tamper. The U-235 cubes were stacked as pseudospheres in a cavity at the top of a tuballoy block 12" high and 8" on a side, and the assembly tamped by locating it inside a doughnut shaped water tank whose tamping effect is equivalent to the tamping caused by personnel necessary for hand stacking."

Report discussing a plasma containment configuration which appears to have no escape cone. From abstract: "Arguments are given to show how the containment process works, including experimental evidence deduced from published reports on "electromagnetic levitation."

Abstract. Slow neutron transmission measurements as a function of the time of flight of the incident neutron have been made for three different thicknesses of Beryllium. The energy region from 0.004 eV to 50 eV was investigated using the Columbia neutron beam spectrometer system. Particular emphasis was placed on the very low energy region (from 0.004 eV tp 0/2 eV or from 0.6 to 5 [length]) where pronounced crystal interference effects were observed. The effective slow neutron cross section (in the unity of X 10(-24)ce(2)atom) for several different energy values were: 6.1 at 0.2 [length], 3.5 at 1.5 [length], 2.3 at 2.5 [length] and 0.6 at 4.6 [length]. The positions of the discontinuities in the cross section agree fairly well with the values obtained from the X-ray measurements.

Report presenting results of a study regarding the critical masses and nuclear properties of plutonium as well as the use and effects of various tampers.

The purpose of this note is to recalculate the semi-empirical curve of neutron yield vs. deuteron energy originally obtained by H. York in order to predict, using it and the best available data, what yields may be expected for deuterons on uranium in the extrapolated energy region.

From introduction: "The measurement of the thermal conductivity of liquid TF6 presented unusual difficulties because of two of its properties which necessitated working with a closed system. The properties were (1) the liquid can exist as such only above 64.05°C. at which temperature its saturated vapor pressure is 1140 mm. of mercury, and (2) the compound reacts rapidly with moist air. Also because of the liquid's extremely corrosive nature, it was necessary to design a cell of special corrosion resistant materials."

This technical report describes development work done on method of particle separation by the Biology Division of the Oak Ridge National Laboratory and the Oak Ridge Gaseous Diffusion Plant during the period January 1 to June 30, 1963, under the Joint National Institute for Health-Atomic Energy Commission Zonal Centrifuge Development Program. The central effort has been to develop zonal centrifuge systems for the separation of cells and sub-cellular particles, including viruses, and bio-colloids, including proteins and nucleic acids.

This paper for the Project Vela Technical Symposium is intended to be a brief resume of the principle results of the Cowboy program. The material is taken from a report entitled "Use of Large Cavities to Reduce Seismic Waves from Underground Explosions" by Herbat, Werth, and Spring (1960). As a result, no effect is made to justify each step in the analysis; reference should be made to the complete report.

This report summarizes the operational experience and the data obtained on the 2AW Purex type process stream. The performance of an in-line alpha monitor for continuously monitoring Plutonium in Purex Process waste streams is described. The instrument has a lower limit of measurement of 1 x 10⁻⁶ grams of Plutonium per liter and can measure concentrations as high as 7.9 x 10⁻² grams/liter.

Weld rejects have accounted for a large percent of the total rejects in the production of fuel elements, and consequently, the investigation of the causes of these rejects was a desirable undertaking. Although previous investigations had made possible a satisfactory standardization of the welding process, it was felt of value to more sharply define the causes of weld rejects and to facilitate the control of these causes.

A portable shield has been designed, developed, fabricated and shop tested to provide the HRT with a facility for direct dry maintenance operations. It provides temporary replacement for any one of the lower roof plugs and should permit many operations to be performed without flooding the reactor cell with water.

The effect of adding small quantities of fuel or poison to the HRT has been estimated using perturbation theory. The results have been reduced to a single relation and a set of graphs which make the estimation of added reactivity relatively simple. The perturbation theory results are compared with multigroup results and reasonable agreement is demonstrated; however, there is some question concerning the prompt neutron lifetime.

The continuous dissolution of 304 stainless steel and stainless steel-UO2 alloy in dilute aqua regia was studied with subsequent stripping of the dissolver product to remove chloride ion. The process has the advantage of producing, by means of a simple head end treatment, a solvent extract feed in a conventional nitric acid medium so that existing solvent extraction processes, materials of construction and waste disposal methods can be used. The purposes of this study were to investigate the variables affecting the dissolution process and to obtain dissolver scale-up data, and to investigate the removal of chloride from the dissolver product and the variables affecting the stripping operation. A continuous flooded pot dissolver was used. It has the advantages of stability of operation and ease of control in comparison with column dissolvers and requires a minimum of mechanical processing prior to dissolution. Stripping of the dissolver product to remove chloride ion was studied in a 4-in. diameter Pyrex bubble-cap column containing 12 single bubble cap plates. Continuous dissolution rates and dissolver product stainless steel loading were correlated with aqua regia feed composition, acid feed rate and surface area exposed to reaction. Profiles of chloride concentration down the stripping column were obtained …