This quarterly progress report discusses ongoing work at the Metallurgy Division at the Oak Ridge National Laboratory. Topics discussed include thorium research, the preferred orientation of uranium, studies in the ceramics laboratory, the homogenous reactor program, studies in the x-ray laboratory, studies in the metallographic laboratory, the experimental plate-cladding program, and fuel and control element fabrication.

From abstract: "An investigation of the radiation stabilities of aqueous solutions of sodium ethylenediamine tetraacetate and sodium acetate was made using a 3000-curie Co⁶⁰ source...A study of the behavior of the standard-size Beckman type glass pH electrodes in a solution containing 0.36 curie of Ce¹⁴⁴-Pr¹⁴⁴ activity per milliliter showed the useful electrode life to be of the order of two to eight days."

Introduction: "Based on experimental data and on conservative theoretical considerations, an estimate has been made of the relation of the mining U-235 critical mass to the hydrogen moderation for uranium material at the U-235 assays for which experimental information is available. These estimates have been used in indicating maximum safe amounts for conditions where definite moderation limitations can be established."

From introduction comments: The present analysis is intended to examine the relations for "adiabatic" injection in general from a different point of view.

In order to utilize the advantages of the electron microscope for the study of respirable particles, it is desirable to have an instrument capable of sampling from atmospheres having very sparse dispersions of particles at a rate sufficiently high to result in precipitation densities of approximately one particle per 10/u² of microscope screen for a 10 minute sampling period. In order to avoid qualitative or quantitative alteration of the aerosol, it was desired that the instrument collect the sample directly on an electron microscope screen rather than on a filter material for subsequent transfer to the screen. This paper summarizes work aimed at the development of such an instrument.

The following report proposes various methods in injecting and heating in mirror machines, using high-energy ion beams.

Diffusion in an arc plasma across a magnetic field is investigated. The geometry is similar to that reported in ORNL-1890 but with the addition of magnetic mirrors on the ends of the arc chamber. It is shown that mirrors do not eliminate the "short circuit" effect. Comparison of the e-folding length, rₒ, of the radial ion density with and without mirrors, affords a direct measurement of ℓ/λ where ℓ is the arc length and λ the mean-free-path. In addition rₒ is independent of gas pressure with mirrors and varies as √p without mirrors. The condition for the elimination of the "short circuit" effect is discussed, as well as the case in which the "short circuit" is still present but the ions diffuse (rather than stream) to the end walls. In this case rₒ is directly proportional to the gas pressure. These effects are compared to some experimental results of Neidigh

Report discussing low and high acceleration flight mechanics for interplanetary missions, as well as the energy limitation for electric propulsion systems powered by a nuclear energy source. From abstract: "An optimization procedure for low acceleration systems is given which leads to a simple relationship between mission requirements, payload fraction, power plant specific power, and exhaust velocity."

Soil chemistry studies have been carried on at Hanford for a number of years in support of the disposal of low and intermediate level liquid wastes to the ground. Equilibrium type experiments were carried out to investigate the mechanisms of the reactions of Sr, Cs, and rare earth ions with soils (1, 3, 4, 5). Experiments were also conducted with simulated and actual wastes in soil columns and an empirical method was developed for prediction of radionuclide breakthrough from ground disposal facilities into ground water on the basis of short, laboratory soil columns and equilibrium experiments (6,7). In this method it is assumed that the shape and position of the breakthrough curve is the same under laboratory conditions as in the larger scale field case. It is also assumed that the "column volume" or amount of soil effectively used for fission product sorption is that directly under a disposal facility without considering any spreading of waste solutions. These assumptions are known to be on the conservative side, but the degree of conservativeness is not known.

From abstract: "Steady temperatures and thermal stresses are determined for long hexagonal tubes having round holes for the case of uniform internal heat generation and a fluid-cooled inside surface. Thermal stresses are also determined for thick plates pierced by holes on an equilateral triangular pattern and for hexagonal tubes having a hexagonal hole with rounded inside corners. Stresses in the end regions of tubes are also investigated."

The development of nuclear reactors and other sources of nuclear particles has provided the analyst with a new method which has been successfully applied to the determination of microgram and even submicrogram quantities of many elements. In this method, known as "radioactivation analysis," the element to be determined is "activated" through some type of nuclear reaction which produces a radioactive isotope of the element. Since the radioisotope produced decays with its own characteristic radiation and half-life, it is possible, through radiochemical measurements following radioactivation, to devise a method of analysis which is very specific for particular elements. Whenever necessary, the radioisotope is separated by chemical means and its radioactivity is then measured by some type of radiation counter.