"In order to determine the factors involved in the scale-up of cores with concentric inlet and outlet pipes, a 48 inch carbon steel flow model, geometrically similar to a 6 foot diameter core, has been assembled and tested...Visual studies were made of dye and gas behavior in the sphere, and quantitative measurements of point residence times were obtained through the use of conductivity cells actuating a Brush recorder. Static pressure drop across the core was measured."

From abstract: "A method for fabricating 30-in.-long stainless steel - uranium dioxide sheet was developed and the properties of the fabricated sheet were investigated."

Abstract: "Observations on the metabolism of chyle cholesterol in the rat show that exogenous cholesterol entering the systemic circulation in chyle exists in lipoproteins of low density (including chylomicrons) migrating with a high Sf rate (i.e.>400) in the ultracentrifuge. Following entry into the systemic circulation these molecules are rapidly removed from the plasma. This "clearing" of serum chyle cholesterol is a tissue phenomenon, the liver being the predominant site. Within the liver the chyle cholesterol esters are at least partially hydrolyzed; hydrolysis apparently does not occur in the plasma to any appreciable extent. After its entry into the liver exogenous cholesterol, if normally metabolized, presumably mixes with and becomes indistinguishable from cholesterol produced by endogenous synthesis."

A preliminary study has been made of a solid homogeneous reactor for stationary power plant application. The core consists of graphite spheres impregnated with uranium and thorium, and the coolant is bismuth. This concept possible offers advantages over other solid fuel reactor systems with respect to simplification of core structure, fuel fabrication and fuel handling, and reduction of fuel inventory external to the reactor. From the results of this preliminary study, it appears that the potential cost of electric power from this reactor is competitive with that from other reactor systems which have been proposed for the same application. The Po210 produced in the coolant presents a decontamination problem, but is also possibly a valuable by-producgt.

None

"A series of thermal neutron diffusion length measurements has been made on non-multiplying lattice of lead-cadmium alloy rods in D2O. One-inch diameter rods in square lattice spacing of 4, 9, 6, 9, and 12 inches were used. Excellent agreement was found between theoretical and experimental values of the diffusion length. The analysis o the diffusion length measurement required a correction for the epithermal neutrons entering the exponential tank. These epithermal neutrons provided a distributed source of thermal neutrons upon slowing down in the lattice."

The following quarterly report covers the period of January, February and March of 1954, discussing medical and health physics such as: the metabolic properties of various materials, biological studies of radiation effects, lipoprotein studies, health chemistry, and health physics.

Summary of miscellaneous updates related to the project. This includes information on the following. Simplified equations for modeling reactor conditions. Solubility tests involving thorium, bismuth, and protactinium. various other measurements and tests involving thorium, uranium, protactinium, bismuth, aluminum, and various other salts.

"A series of shock tube studies demonstrate that two types of pressure gauges respond to dust carried with shock waves by indicating an increase in dynamic pressure. This contribution to the dynamic pressure is approximately the product of the dust density and the square of the dust velocity under the experimental conditions. Besides this information studies give insight into the interaction of a square shock wave with dust when that dust is placed in a plane before and parallel to the shock front. It is found that the shape of the pressure wave is little changed except for a rounding of the front. The dust, after accelerating, is carried as a pulse with the mass flow velocity of the air."

From introduction: "The present paper deals with a classical calculation in which some of the meson effects can be included to all orders in the meson-nucleon coupling coupling constant, in particular those having to do with the gyration of the nucleon spin and isotopic spin. Such a treatment leads to results qualitatively different from the weak coupling calculations."

None

Report discussing the progress made on various research projects at North American Aviation during the quarter from January to March 1954.

Abstract: A visualized electron beam has been reflected by a conventional magnetic mirror. Visualization of the beam path from the electron gun to and including the region of reflection was achieved by the "thread ray" technique of Wehnelt. The total current passing through a magnetic mirror has been measured as a function of the beam energy and angular momentum for H₂ over a range of pressures from 0.5 to 5 microns.

The purpose of this report is to present the information obtained relative to the characteristic adsorption of radioisotopes in a long (forty feet) laboratory soil column treated with a high salt, process waste of high activity density. The movement of adsorbed cations in a soil column subjected to prolonged leeching by water also was determined.

Equipment has been designed and constructed for the purpose of leaching pure uranium minerals in both acidic and basic circuits. This equipment provides a means for removal of a series of samples during any one run, control over speed of agitation, indication of gas over pressure, and automatic temperature control. These units may be operated up to 1500 p.s.i. Solid UO2 samples were prepared by sintering under hydrogen to 1800 degree C. Preliminary results of the leaching of sintered UO2 in a basic Na2CO3-NaHCO3 circuit resulted in the formation of an insoluble yellow precipitate (probably Na2UO4) for low concentrations of Na2-NaHCO3. At higher carbonate concentrations no insoluble precipitate was formed and the rate of leaching was found to increase vary rapidly above 300 p.s.i. oxygen over pressure.

Two methods for calculating the *reduction in η due to spectral hardening have been used. In the first method it is assumed that the absorption cross section of U-238 is l/v. This indicates no change in η within the error of the calculation. In the second it is assumed that the scattering cross section of uranium is constant. A decrease in η of 3.0% at the centerline of the slug is indicated by this calculation. The assumption U-238 is a l/v absorber is regarded as the most reasonable of the two.

Abstract: "A cylindrical coil has been designed for pulsed field operation suitable for use in a model thermonuclear reactor. The coil has an eight-inch inside diameter and a length of fifty-one inches. Magnetic mirrors at the ends consist of double-layer solenoids six and one-half inches long designed to slip over the main coil. Subsequent models of this coil have been fabricated which improved the electrical insulation provided by the bonding materials and the mechanical rigidity of the coil. Peak central fields of fifteen kilogauss and mirror fields of thirty kilogauss have been obtained."

Abstract: "Aluminum-clad nickel-plated uranium is corrosion resistant in boiling water. Samples with intentional defects in the aluminum-nickel clodding layers, after testing for more than 300 hr. showed no sign of rapid failure. The study of electroplated metals on uranium for aluminum cladding has defined the effects of several processing variables on the corrosion resistance. The quality of the uranium and the quality of the aluminum-nickel bond were important. Heat treatment and vacuum outgassing of the nickel-plated uranium prior to aluminum cladding were beneficial, and minimizing the amount of air present in the hot-press assembly was desirable. Variation in the steps for electroplating on uranium did not affect the corrosion resistance of aluminum-clad uranium."

The erection of a concrete biological shield at Hanford, Washington presented several unique construction problems. This shield encloses the radioactive core of a reactor and is designed to protect operating personnel from the harmful effects of pile neutrons and associated gamma radiation. Permanent steel forms were erected to close tolerance around the reactor and filled with high density concrete by means of prepacked method. Prefabricated sections of the steel forms, or crates, were five to eight feet deep and weighed up to 18 tons each. During erection, the process holes through successive crates were kept within 0.012 in. of their nominal distance. The left side, top shield, and right side of this biological shield were constructed integrally to form a rigid frame. The front and rear crates, which contain numerous process holes, were keyed into the side and top shields so as to permit relative expansions of shield components and to provide for their lateral support. These massive steel and concrete walls provide considerable resistance to blast and earthquake forces, support numerous process facilities, contain pile gas, as well as protect personnel from nuclear radiation.

The development of ionic methods for the determination of corrosion products in the highly radioactive Homogeneous Reactor (HR) fuels has been of major interest in the work of the Ionic Analyses Laboratory. Methods for the spectrophotometric determination of aluminum and for the polarographic determination of iron in HR fuels have been developed. The polarographic determination of molybdenum in uranyl sulfate solutions was studied. A polarographic method for the determination of zinc was developed. A fluorometric method for the determination of microgram amounts of fluoride was studied. Three organic reagents were investigated as precipitants for microgram quantities of zirconium in HR fuel. The automatic photometric titration technique was applied to the determination of thorium and of sulfate. A method was developed for the ionexchange separation and potentiometric titration of cobalt. The ultraviolet absorption spectra of technetium and rhenium were studied.

A comparison of the simple impact theories of line broadening by electrons with the detailed computations of Kivel, Bloom, and Margenau.

Fourier analyses are made on two functions. The first is a step function forward from periodic samples of a sinusoid. If the frequency of the sinusoid is less than one-half of the sampling frequency, it is shown that the step function has no frequency components less than one-half of the sampling frequency other than that of phase, and duration with respect to the interval of the analysis. It is shown that the insertion of a blank space in the period of analysis reduces greatly the uncertainty of the amplitude of the initial sinusoid as estimated from the results of the Fourier analysis. The results of the analyses are useful in the design and evaluation of certain analog data-analyzing systems.

A knowledge of the mechanical and physical properties of uranium is important in understanding and explaining its pile behavior. The effects of irradiation on the properties of uranium will be dealt with in another chapter. However, it is important to know and understand the pre-irradiation properties of uranium prior to investigating the effects of irradiation.

This report describes the evaluation of physical properties of AGHT and 185-W graphites that are important to pile construction and operation. On the basis of these data, purified AGHT graphite was allocated to either filler block positions in the central regions of the K piles or to the upper or lower reflectors. This decision was based on the similarities of physical properties between AGHT graphite and the other moderator components. A similar allocation could be made for 185-W graphite for some future pile if it can be successfully purified or if purification is not required.