Results of experimental programs indicate that it might be desirable in the future to modify the existing reactors by replacing the aluminum process tubes with tubes made of a zirconium alloy. The zirconium tubes would be more corrosion resistant than the aluminum ones and would also be stronger at higher temperatures. These new tubes would have the same outer diameter as the present tubes (for ease of handling and in order to provide adequate graphite cooling) but would have a thinner wall (since zirconium alloy is both stronger and more expensive than aluminum). The inner diameter of the new tubes would, therefore, be greater than in the present tubes. In addition to the tube change, it might also be desirable to replace the existing solid fuel elements with those known as ``I&E`` alements. These pieces would be similar to the present elements except for a longitudinal hole which would allow the passage of cooling vater through the center. The element would then be Internally and Externally cooled, and would have a more uniform temperature distribution. The combination of the larger tube inside diameter and the central hole in the fuel element would result in reduced friction loss for the reactor …

The top grid of the PWR reactor core assembly is treated as a simply supported circular plate. The theory of plate is applied to the grid umder mechanical loads. The thermal stress problem is analyzed by treating the plate as under combined action of a laterally distributed load and forces in the middle plane of the plate. The load distribution is calculated from the temperature variation over the grid. The thermal stress problem then is equivalent to two problems: one, of bendimg of plate; and, the other, a plane stress problem. The theoretical formulation for plates under nonuniform heating is developed by neglecting the effect of uneven expansion in the direction perpendicular to the plane of the plate. In replacing the partial dffferential equations by difference equations, the latter are modified to take into account the change in tbickmess and spacing of the grid webs near the boundary. Twentythree difference equations for the twenty-three stations in one octant of the grid are obtained for each second order partial differential equation. The difference equations are solved by assuming that the twisting moments and shearing stresses in the plane of the grid vanish at the boundary. The stresses and deflections due to …

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This report describes the physical description and functions of the capillary flowmeter.

A method has been developed for the uniform coating of graphite tubes with carbides of niobium, tantalum, and zirconinm by thermal decomposition of their respective halide vapors. Conditions of coating temperature and pressure are so chosen as to prevent the deposition of metal, but to permit the formation of the carbide as rapidly as carbon can diffuse to the surface. If the carbon diffusion can be made the rate-limiting step, the coating process becomes self- regulating and uniform thickness results. The limits of the temperature-pressure range have been determined experimentally for the thermal decomposition of zirconium iodide and of the chlorides and bromides of niobium, tantalum, and zirconium. With the successful development of coating equipment and definition of conditions, 99 blowpope test specimens were coated with uniform, continuous, and adherent layers of the carbides in three ranges of thickness, light (0.001 in.), medium (0.005 in.), and heavy (0.01 in.). Determinatlons were made of the coefficient for the diffusion of carbon in zirconium carbide as a function of temperature. Exploratory work on small specimens of graphite impregnated with 7 wt.% uranium indicated that the coating results were essentially unchanged, but that loss of uranium occurred. Means of avoiding the loss of …

The purpose of the investigation was to determine the temperature dependence of the lattice parameters of U from room temperature to the melting point and to provide experimental data on the general characteristics and kinetics of the allotropic transformations in U. Toward this end high-temperature x-ray diffraction, electrical resistance, and sonic experimental techniques were employed. The data presented are interpreted in terms of the known physical, mechanical, and structural properties of the metal and are intended as a contribution toward the complete experimental and theoretical description of the allotropic transformation processes in pure U. (auth)

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The May, 1957 monthly report for the Chemical Processing Department of the Hanford Atomic Products Operation includes information regarding research and engineering efforts with respect to the Purex and Redox process technology. Also discussed is the production operation, finished product operation, power and general maintenance, financial operation, engineering and research operations, and employee operation.(MB)

A continuous process for the dissolution of irradiated fuel elements is a potential means of solving criticality limitations in the dissolution of enriched uranium slugs and of achieving higher dissolver capacity in the Redox and Purex Plants. This report summarizes development studies aimed at determination of dissolution rates, effluent compositions, and effects of changes in operating conditions on mercury-catalyzed dissolution in a tower-type unit.

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A batch process on the 2 kg scale was developed for the production of ZrO/sub 2/--UO/sub 2/ solid solution in the weight proportion of about 4 to 1. The product is tetragonal ZrO/sub 2/-- UO/sub 2/ solution, with no UO/sub 2/ lines showing on the x-ray powder diffraction patterns. The solid solution is prepared from a precipitate of Zr(OH)/sub 4/-- (NH/sub 4/)/sub 2/U /sub 2O/sub 7/ which is filtered, dried, milled, screened to minus 325 mesh, and heated at 9OO deg C in H/sub 2/ for 4 hours. The success of the preparation depends strongly on the conditions of the precipitation, with precipitation from dilute salt solution being necessary to avoid undissolved UO/sub 2/ in the final product. (auth)

Disposal of wastes from the processing of solid fuel elements and from solid blanket elements is discussed. The subjects considered include extraction of uranium by several methods, the removal of element jackets, the treatment of uraxium -zirconium fuel elements, disposal into deep wells, the hydraulics of wells, thermal considerations of disposal aquifers regional hydrology, potential deep-well disposal areas in the U. S., aud the cost of disposal. (J.R.D.)

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Nickel is more susceptible to mass transfer ina 100hr nonisothermal dynamic corrosion system than is Inconel when exposed to a NaCl-MgCl/sub 2/-UCl/ sub 3/ (50.01800 F. No nickel mass transfer was observed in a 500hr test at 1350 F, but Inconel showed some attack under s transfer was observed in both tests, being more severe at the higher temperature. On the bases of these preliminary tests, it appears that nickel is a more satisfactory container than Inconel for the chloride bath at temperatures in the region of 1350 F. Chromium is more susceptible to selective leaching from inconel at 1800 F during a short 100-hr test (0.26%Cr in bath) than in a 500-hr test (<0.001% Cr in bath) at a lower temperature (1350 ). (auth)

The general Wigner-Eisenbud theory is used to develop a method of analysis for the cross sections of fissionable nuclei. The method is employed in gdving a reasonable description of the low energy cross sections in U/sup 235/. The single level fit for U/sup 235/ is known to be unreasonable. Manylevel expressions for the cross sections are derived--the only approximation to the general theory being the neglect of all but a small group of resonances. It is shown that regardless of the number or definition of the fission channels the many-level expressions require few level parameters: the E/sub lambda /, GAMMA / sub lambda n/, GAMMA /sub lambda gamma / and GAMMA /sub lambda F/ of the single level theory for each resonance and a few additional parameters pertinent to the interference between levels. The interference terms are described and shown to be important. The shape and size of the U/sup 235/ cross sections below 2 ev are fitied to within one per cent using (a) only one negative energy resonance of smaller size than in the single level fits (b) no additional levels to fit the shape other than the observed levels at positive energiess (c) three interference purameters whose …

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This handbook prepared by the Armed Forces Special Weapons Project of the Department of Defense in coordination with other cognizant government agencies and published by the United States Atomic Energy Commission, is a comprehensive summary of current knowledge on the effects of nuclear weapons. The effects information contained herein is calculated for yields up to 20 megatons and the scaling laws for hypothetically extending the calculations beyond this limit are given. The figure of 20 megatons however is not be taken as an indication of capabilities or developments.

A methed is descrihed for the treatment of radioactive neutralized nitric acid waste solutions. The process consists of electrolysis of sodium nitrate solutions and recycle the caustic formed to neutralize incoming nitric acid ate. Removal of a large fraction of the bulk inert substances by this method allows greater reductions in waste volume than conventional treatment by evaporation alone. Process chemistry studies show that a large fraction of the nitrate ion in alkaline solution can be electrolytically reduced to gaseous nitrogen reduction products at reasonable current efficiencies. Process engineering studies have resulted in the development of a prediction equation for the design of electrolysis cells used in the process. Pilot plant studies using cold'' nitric acid waste have demonstrated the feasibility of the electrolytic recycle methed. A preliminary cost estimate was performed which iadicates a cost of from 75 to 95 per initial gallon of waste processed. Basis for this estimate is a conceptual design of a plant capable of handling the highlevel waste produced in reprocessing one ton of uranium metal per day. These costs are considered reasonable in a nuclear power economy, and indications are that ultimate disposal of the concentrated waste in clay may be possible. (auth)