Nuclear excavation is the name given to the concept of using large scale nuclear explosion craters for useful projects, such as harbors, canals, and roadway cuts. It is one of the principal applications of the Plowshare Program for industrial, or peaceful, uses of nuclear explosives. Plowshare is sponsored by the U.S. Atomic Energy Commission and is under the technical direction of the Lawrence Radiation Laboratory at Livermore, California. The purpose of this paper is to describe cratering concepts and the present state of nuclear excavation technology. The general nature of the safety hazards associated with nuclear excavation are also discussed.

Thermal oxidation of graphite in flowing CO2 is being studied at 650 to 850 C, in a single-pass gas system at atmospheric pressure, by observing weight loss rates. The method is used to provide comparative data for candidate reactor graphites. The effects on oxidation rates of graphite purity, structure, coke type, graphitization temperatures and other manufacturing variables are determined. In addition, the effects of gas flow rates and graphite surface to volume ratios are observed.

It is anticipated that neptunium will be recovered in the Purex process by solvent extraction or ion exchange methods as a nitric acid solution of greater than 0.1 g. Np/1 and containing varying amounts of fission products, plutonium, uranium, and thorium, including Th234 (UX1). At the present time this solution is thermally concentrated in the Purex L-cell package to several grams of neptunium per liter. In this operation the solution is contaminated rather badly with plutonium and stainless steel corrosion products. The present specifications are for the neptunium final product to contain less than 0.1 weight percent plutonium, to be relatively free of gross metallic contaminates, and to be low enough in fission product game activity and Th234-Pa234 (UX1-UX2) beta activity to be handled without resorting to remote techniques.

A portable, light weight transistorized alpha, beta, and gamma survey meter was designed and fabricated.

This report discusses the production of plutonium metal through the reduction of plutonium tetra fluoride with calcium metal and sulfur. It elaborates that iodine, which was originally used instead of calcium metal, presented several practical problems, but reductions completed with calcium were unsatisfactory.

Introduction: "The adoption of aluminum nitrate as salting agent in the Redox process made it imperative that a method be available for determining plutonium in the presence of aluminum. However, large amounts of aluminum have been found to interfere with the determination of plutonium by the lanthanum fluoride procedure. Previous attempts to increase the accuracy of the lanthanum fluoride method, by precipitating LaF3 from 4 M HF (rather than 2 M), have been successful only when the initial plutonium level was high."

Abstract: A new feeder chute on the continuous casting apparatus, and the use of outgassed zirconium chips resulted in a stable arc and quiet pool. Ingots up to 9 1/2 inches in length were made, and some correlation between tension on the ingot and the "necking" effect was determined. Conversions of zirconium iodide to zirconium in the arc dissociation apparatus ran from 41 to 48.2 percent with a maximum of 474 grams of metal produced in 4 hours.

Abstract. A review of all work on uranium hydride published in the CC, CT, CN and CE reports to January 1, 1944, is presented. Some additional information not yet published has been included, so this report includes all data known from the above sources and at Ames to the above date. This report supersedes all previous report on uranium hydride coming out of the Ames laboratory.

The average energies of neutrons emitted from a graphite column at 22 degrees C were compared by measurement of the cross section of boron for neutrons which are stopped by cadmium. At a distance from the neutron source great enough to insure that the neutrons were in thermal equilibrium the average energies of the emerging neutrons were found to be proportional to the temperature within the limits of the experimental error. A measurement made with boron absorbers which had been thus standardized in the graphite column indicated neutrons emerging from the chain reacting pile to have an average temperature approximate 60 +- 50 degrees above that of thermal neutrons emerging from the graphite column at 22 degrees C. Such a measurement made inside the chain reacting pile indicated the average temperature of neutrons therein to be about 65 degrees +- 15 degrees above the average temperature of neutrons in the graphite column.

The temperature coefficient is calculated for various lattice arrangements, taking into account the variation of [formula], suggested by Fermi. Four contributions are included: leakage, levelling of the dip in thermal neutron density in the lump, resonance absorption, and hardening of the neutrons as they penetrate a metal lump. The departure of neutron temperature from lattice temperature decreases the total coefficient. Values are given for 3 typical piles; in general, the larger the uranium elements, the less stable the pile. A rod lattice tends to be more stable. A pile with metal lumps over 50 lbs. will be unstable.