Abstract: "This quarterly report, ARF 1194-10, covers the work performed in the time period December 15, 1961 to March 14, 1962, on Contract No. AT(11-1)-578. In this period, Phase II, the detailed evaluation of various fields of radioisotope research, has been extended. Preliminary results on the use of radioisotopes in the industrial applications, apparatus and techniques, and metallurgy categories are presented. These preliminary studies indicate the quantity of research, growth rates, and specialized areas of interest in various countries of the world. More detailed evaluations of these categories will be presented in the final report."

The following report is one of a series of quarterly reports following the progress and development of improved zirconium alloys for service in superheated water and steam. This report covers the period between January 1 to March 31, 1961.

Abstract: "Measurements have been made on pseudo-cylindrical graphite-enriched uranium unreflected systems. These measurements include both critical mass determinations and time dependent measurements using a pulsed neutron source to drive the assemblies."

An electrical conductivity technique was developed to determine the dilution-displacement rate of an electrolyte in a well from which data the velocity of the water through the well can be calculated. The electrical current flow between two of the electrodes in a well drops proportionately with the dilution and the displacement of the electrolyte by fresh water entering the well. The drop of electrical current flow over a period of time was applied to a derived equation to obtain a value for ground water velocity. The technique gives results comparable to other methods and some problems of the standard methods of measuring ground water velocity are eliminated. However, a correction factor for porosity of the aquifier must be used in the derived equation. Porosity values are not adequately known in most cases, therefore the ground water velocity figures are generally relative rather than absolute.

The objective of this report is to set forth the design of automatic mechanical equipment developed for use with HAPO nondestructive test instruments.

The large scale application of Zircaloy-2 pressure tubes for structural use either in or out of reactor service, is without precedent. For more common materials, there normally are adequate data and long operating histories on which to base design and service limits. In the absence of such information for Zr-2, several investigative programs have been devised to provide much of the information from which design and service limits may be defined for Zr-2 pressure tubes. These investigations encompass in-and-out-of-reactor creep and stress-rupture testing, pre-and-post irradiation testing, and bust strength, as well as the effect of flaws or defects (from both fabrication and service origins) on burst strength and fracture characteristics. Already creep and stress rupture testing of unirradiated Zircaloy-2 is well advanced, and some experimental pre-irradiation burst testing has been carried out and will be extended rapidly as improved equipment becomes available. One irradiated KER tube sample has been burst tested and the requirement for post irradiation burst testing equipment have been defined.

A method to determine the correction to Grüneisen's law corresponding to the effect of the electrons at high pressure. It is assumed that the lattice contribution to the pressure is small and that the equation of state of the solid can be approximated by results of the statistical Thomas-Fermi atom model for the electron pressure.

Limitations on the maximum temperature of the pile moderator have been imposed to prevent or control the gasification reaction of the graphite stack with the pile gas atmosphere. An uncontrolled reaction would cause a loss of structural strength, density, and thermal conductivity and would thus result in an unnecessary shortening of the effective operating life of the HAPO piles. Numerous studies have been made to define the rates of reaction of the pile stack with various components of the pile gas and the influence on these rates of various pile operating conditions. Based on these studies, maximum graphite temperature has been so restricted that after 10 years of pile operation the graphic stack has sustained less than 1% oxidation (based on recent experimental data). As pile power levels increased, the maximum graphite temperature has also increased and will increase still more as present and future power level programs are completed. In order to evaluate the effect on the graphite stack of the present programs, and to some extent determine the feasibility of future programs, a more realistic approach to the question of structural integrity and oxidation versus pile life is necessary. It is the purpose of this report to summarize …

A general program has been written to plot curves on the Oracle curve plotter. A description of the code and complete instructions for preparation of input tapes and operation of the code are given. The code tape is available from the Mathematics Panel or from the author.