The purpose of this memorandum is to present and analyze, in terms of the current status of knowledge of radiation damage to graphite, the data available at the present time on the expansion status of the graphite in the piles, and suggest, in terms of this analysis, several possibly feasible curative and preventive measures. The portion of the data to be covered in this memorandum consists of that obtained during the last four years from pile motion measurements and from tube bowing measurements, and particularly that from graphite mining operations during the last six months. The objective to be attained is twofold: (1) the information developed here should permit a better understanding of the need for and development of future corrective measures to be applied to the present piles, and (2) this summary will serve as a basis for further experimental work necessary to place the conclusions on a more firm foundation. This memorandum is being issued at this time, although present ideas and conclusions are in a somewhat uncertain state, in the hope that the currently most feasible preventive measure might be applied to the DR Pile before startup.

This report constitutes a summary and discussion of radiation damage to graphite and its effects on pile distortion. The data covered in this report consist of that obtained from some pile motion measurements and tube bowing measurements, but particularly of that information obtained from direct sampling of pile graphite.

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In the reaction of silicon halides with graphite to form silicon carbide, thermodynamic conditions were determined for the formation of SiC, free of elemental silicon. The use of these conditions was designed to limit the rate of coating formation by the rate of diffusion of carbon through the coating, and render the operation independent of the vapor-flow factors which normally limit the uniformity of vapor-deposited coatings. Although a wide range of pressure- temperaturecomposition conditions was explored, it was not possible to duplicate the success previously obtained in applying the method to NbC, TaC, TiC, and ZrC coatings. Fundamental differences in the characteristics of the carbides which may account for the difference in behavior are the lack of a range of homogeneity in beta SiC crystal structure, and the fact that SiC undergoes a modification from the cubic beta to a hexagonal form at l900 to 2000 deg C.There remains the prospect of forming a uniform SiC ''sponge'' by the present process which can be subsequently impregnated with metallic silicon to form an oxidation-resistant cpating. (auth) l6200 Preliminary results were obtained on the value that commercially pure Pu (95% Pu/sub 235/ and 5% Pu/subp 240/) has when used as nuclear fuel. …

Some lectures on theoretical physics are presented, mostly in the field of elementary particles and field theory, delivered during the summer of 1958 by visitors at the Argonne National Laboratory. The lectures are essentially summaries or reviews of published material. Lectures included are on collision theory for composite particles, quantum theory of fields, inquiries into field theory, classical relativistic theory of elementary particles, and bound states of many-particle systems. (W. D. M.)

The characteristics of Rankine space power plants in the zero gravity aspect of the environment of space were lnvestigated. The expected effects of Rankine space power plants are described. Discussions of experimental techniques for studying these phenomena show that this information can be obtained rapidly and economically. Recommendations for a program to supplement SNAP II and slmllar Ranklne space power development efforts in this vital area are made, and consist of: the development and testing of a small system that adequately simulates a complete Ranklne system, first in zero grayity and finally, in the complete orbltal environment; followed by, the development and similar testing of a complete Rankine system using SNAP ll hardware. (auth)

Effects due to elementary particle-like collisions within nuclear matter have been observed in several nuclear reactions caused by pions and protons. Simple nuclear reactions of the form ZA(a,an)Z/sup A-1/ and Z/sup A/(a,ap)(Z-1)/ sup A-1/ have excitation functions that are sensitive to changes in the elementary-particle cross sections. The excitation function for the reaction C/ sup 12/( pi /sup -/, pi /sup -/n)C/sup 11/ is measure d from 53 to 1610 Mev by bombarding targets of plastic scintillator with pions. The intensity of the pion beam is monitored with a two-counter telescope and 40 Mc scaling system. The scintillator target is mounted on a phototube and becomes the detector for the carbon-11 positron activity. Corrections are made for muon contamination in the beam, coincidence losses in the monitor system, carbon-11 activity produced by stray background at the accelerator, carbon-1l activity produced by secondaries in the target, and the efficiency of the carbon-11 detection system. The C/sup 12/( pi /sup -/, pi /sup -/n)C/sup 11/ cross sections rise to a peak of abo ut 70 mb at 190 Mev, that corresponds to the resonance in freeparticle pi /sup -/n scattering at 190 Mev. Calculations based on a knock-on'' collision mechanism and sharp-cutoff …

This is the monthly report for the Hanford Laboratories Operation March 1963. Reactor fuels, chemistry, dosimetry, separation processes, reactor technology, financial activities, biology operation, physics and instrumentation research, operations research and synthesis, programming, and radiation protection operation are discussed.

The monthly report for the Hanford Laboratories Operation, May 1963. Reactor fuels, chemistry, dosimetry, separation processes, reactor technology, financial activities, biology operation, and physics and instrumentation research, and applied mathematics, and programming operation are discussed.

This is the monthly report for the Hanford Laboratories Operation, July 1963. Metallurgy, reactor fuels, chemistry, dosimetry, separation processes, reactor technology, financial activities, visits, biology operation, physics and instrumentation research, and employee relations are discussed.

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The preparation of particles coated with pyrolytic carbon from methane at low temperature was studied on a laboratory scale to develop improved coated particles for potential use in Rover graphiite-matrix fuel elements.

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