From introduction: "This report describes the second phase of the work on the application of protective coatings to uranium by vapor deposition to reduce or prevent its corrosion by water."

Abstract: "Refinement of grain size of the base uranium-chromium eutectic alloy (uranium-5 w/o chromium) by ternary additions is discussed. Thirteen additions to the base alloy were investigated, and three additions were found to exhibit worthwhile grain-refinement tendencies. The three alloys, uranium-5 w/o chromium-0.2 w.o molybdenum, uranium-5 w/o chromium-0.2 w/o germanium, and uranium-5 w/o chromium-0.2 w/o niobium, were heat treated to produce final grain-size structures of between 0.015 and 0.033 mm."

The following report focuses on an investigation made to determine if vacuum melting was an absolutely necessary step in the metallurgical process of melting and casting uranium.

Abstract: "A study of plastic flow during the extrusion of tubing was made by extruding colored Plasticine billets in a small-scale extrusion press. Decreasing the included angle of the conical die and tapering the ram end of the billet decreased the amount of coextrusion of the backer block into the tubing, lubricating the billet also decreased coextrusion."

The following report studies the dissolution of aluminum-canned thorium, providing results that suggest a dissolution cycle that permits the separation of the canned-slug components.

Abstract: "By a simple illustration it is pointed out that, conceivably, the real coupled character of the general magnetohydrodynamic equations may lead to much slower instability growth rates, if not stabilization, than predicted from the linearized set of equations."

The following report provides results from investigations of torsional vibration stresses in the drive shafts of two Westinghouse motor generator sets in 1952.

A digital computer program for calculating least-squares solutions and making analyses of variance of sets of overdetermined linear equations is described. The entire code is reproduced with sufficient description of the program to enable anyone familiar with the Electrodata Datatron Computer to use it for similar problems.

This report follows experiments on K[infinity], measuring the element for several red sizes, enrichments, and water-to-uranium volume ratios-(1, 2), by making use of the relation k[infinity] = 0M-[2]B-[2] (M-2 = migration area, B = buckling). The purpose of this report is to compare the experimental data for k[infinity] with values calculated from the four-factor formula k[infinity] = [eta][epsilon]pf.

A MO calculation of the electronic states of CH4, CH3, CH2, CH, and their respective ions provided the basis for the application of correlation rules to an analysis of the existing appearance potential data for methane. An interpretation of the methane mass spectrum has been proposed which is based on the high value of the heat of sublimation of carbon. It is shown that the excited electronic states of the molecule- and radical-ions are prominent in the decomposition reactions.

Part I. Experimental Reactors: The effect of prompt-neutron lifetime upon reactor safety was investigated for the HRT. It was found that for a given pressure rise the allowable rate of reactivity addition was relatively insensitive to the average prompt-neutron lifetime, although the rate de creased somewhat with decreasing lifetime for the higher pressure rises. With only source neutrons present and the reactor initially subcritical, the allowable rate was practically independent of the initial value of k£. For a core-pressure rise of 400 psi, the corresponding rate of reactivity addition was about 0.8% per second; for a pressure rise of 4000 psi, the rate was 2.5 to 3.0% per second. Part II. Thorium Breeder Reactor: An economic study of one-region thorium breeder reactors was completed. Where possible, the process characteristics and cost factors were the same as those used previously in studies of two-region-type reactors. The mini mum-cost reactor is about 12 ft in diameter, operating with 260 g of thorium per liter on a chemical processing cycle of about 450 days. The ratio of U232 to U233 produced is approximately 2 x 10~4 VIM in the minimum-cost one-region system, compared with 4 x 10 5 in the two-region system. The …

Two 500-kw fused-fluoride-to-Nak heat exchangers, two 500-kw NaK-to-air radiators, and a 20-tube high-velocity heat exchanger were fabricated for a heat-exchanger development program. A construction procedure, utilizing both inert-arc-welding and high temperature dry-hydrogen brazing, was used successfully on all of the units. The tube-to-header joints were welded and back-brazed; the manifold joints were inert-arc-welded with full penetration; and the tube-to-fin joints were brazed. A detailed description of the fabrication of each type of component is discussed and a cost analysis of the 500-kw units is presented.

Methods for the determination of plutonium and uranium in highly radioactive scrup dissolver solutions have been developed. Plutonium was separated from the dissolver solutions by solvent-extraction and ion-exchange techniques and determined by potentiometric titration. Uranium was separated by ion exchange and determined by potentiometric titration. Solutions that were similar to the actual dissolver solutions and that contained known amounts of plutonium and uranium were analyzed by these methods. Evaluation of the data secured for the determination of plutonium and uranium by the methods given herein indicated that, within the limits of the precision of the methods, there was no bias. The precision of the data obtained for the determination of plutonium, expressed as the relative standard deviation, was better than 2% for plutonium in the concentration range of 0.27 to 0.64 mg/ml. The precision for uranium was estimated to be about 0.2% for uranium concentrations of 425 mg/ml. These methods and the data obtained by then are discussed in this report; the procedures are appended.

A theoretical and experimental investigation of the coefficient for diffusion of ions across a magnetic field Is described. The resultant diffusion coefficient is found to vary inversely as the square of the magnetic field strength, in accord with the usual collison-diffusion theory. The magnitude of the coefficient is much larger (x700) than the coefficient predicted by the usual ambipolar diffusion theory. This discrepancy is resolved by showing that diffusion across a magnetic field is not ambipolar in character in most arc experiments. The final experimental and theoretical values are in good agreement, and it is unecessary to postulate any additional diffusion mechanisms, such as plasma oscillations.

The development of the reactor layout is continuing. New features that have been incorporated because of stress, fluid flow, or fabricability considerations include an elliptical fuel expansion tank, a rounded dome to enclose the top of the reactor, a newly designed sodium pump impeller, and other related items. Recently completed heat exchanger tests yielded consistent data from which a series of heat exchangers is being designed. The most promising of these will be chosen for the ART.

This report is a manual describing the methods developed by Stokes (1) and Warren and Averbach (2) (3) for the determination of the effects of cold work by x-ray diffraction methods. Only the method of mathematical analysis is presented while the method of obtaining the necessary x-ray diffraction patterns is not mentioned. This manual will be used for an experimental study of irradiation damage to uranium.

This report describes the results of evaluation tests made on several glass-coated bayonet heaters supplied to Separations Equipment Development by the Pfaudler Company. The glass-coated heaters were found to be resistant to thermal shock, mild mechanical shock, and chemical attack by boiling 60% nitric acid.

A new model High Range Beta-Gamma Survey Instrument, refer to blueprint numbers H-4-2760 and H-4-2761, was designed which utilizes a circuit similar to that of the older model but incorporates three ranges of 0-5 R/hr, 0-50 R/hr, and 0-500 R/hr.

This paper presents values of the constant B², commonly called the buckling, when 0 vanishes on the surface of a right elliptic cylinder.

A new type of flexible hose connector consisting of a Teflon tube enclosed in a stainless steel wire braid sheath was proposed for use on 105-C rear face in late 1954. A test was initiated to determine the suitability of Teflon, and specifically Fluoroflex Teflon compound for rear face application. Probable useful life limit is estimated at 10⁶ R, which would be attained in about three years in contact with fresh effluent.

The primary objective of the tests described herein was to determine if the standard five bend connector (drawing H-1-23475) and/or the T. F. Robinson three bend connector (drawing SK-1-20855) fabricated from Type 304 stainless steel tubing would satisfy the requirements of the K reactors. Results of the tests show that the standard five bend connector made from Type 304 stainless steel 0.065 inch wall tubing, in the as bent condition, with either cadmium plated Parker brass nuts and sleeves or cadmium plated high carbon steel nuts and sleeves, is suitable for installation of the K reactors.

A design study has been made of a graphite superheating reactor, a graphite moderated reactor with a heat rating of 305 Mw which produces superheated steam. It is designed for the production of plutonium and electrical power or for the production of electrical power only. The fuel elements for dual- purpose operation are U metal, while for single purpose action, they are uranium oxide. The fuel elements are cooled by a 7-pass system in which preheated water enters the bottom of the first pass and is discharged as superheated steam at the top of the seventh pass. The reactor control consists of shim control by the gas system, vertical gas-cooled control rods, vertical safety rods, and a ball safety system. Rough cost estimates indicate that the capital cost of the reactor should be comparable to other reactors of similar heat output.

Fillerwelding is a fusion welding process that provides for the automatic addition of controlled amounts of fillerwire during inert-gas-shielded tungsten-arc welding. Fillerwelding aluminum jacketed fuel elements has been successfully demonstrated and is being used on a routine basis. This manual was written to provide the necessary information to operate and maintain the fillerweld equipment.

This report constitutes the Quarterly Progress Report covering April-June 1955, for the Health Instruments Division research and development activities. Most of the studies described concern the biological fate, environmental transport of radioactive effluents, or development of instrumentation for radiation detection.