Calculations are given for eighteen stainless steel clad helium bonded specimens of UO2-ThO2 containing normal U to be placed in 6 holes in a holder in a position of the ORR not to exceed a peak unperturbed flux of 4 x 10^14 n.cm^2/sec and irradiated to a peak nvt of 1.96 x 10^21 neutrons/cm^2

Several experiments have been performed at ORNL with light water solutions of uranyl nitrate (highly enriched in either U^233 or U^235) in an essentially bare sphere 27 inches in diameter. This report presents the results of several calculations with elementary bare reactor theory and a discussion of the observed discrepancies between the calculated and experimental results. If the observed critical concentration is used in the calculations, the calculated effective multiplication constant is less than unity' thus a higher critical concentration would be predicted than is actually observed.

The "absolute" containment of ions in the DCX magnetic mirror field resulting from the cylindrical symmetry of the field is discussed. The regions of confinement in space and momentum are plotted for 300 Kev deuterons.

Either system appears to be fairly satisfactory from a containment standpoint. Current results indicate probable over-all rates of about 0.2mils/mo for titanium vs. 1.5-3.0 mils/mo for Ni-o-nel. Tests are not 100% comparable due to changes made in flowsheet conditions, but have been of sufficient variation and length as to allow good predictions to be made. Both metals show some tendency toward local attack in Thorex solutions. These tendencies are increased by poor welding techniques.

In a discussion about design of cyclotron resonators, the suggestion has been made that a wide range variable-frequency system might be constructed with two coupled resonant circuits. It also would present the possibility of tuning without the switching of high-current contacts, a troublesome item now commonly used for cyclotrons. One of the circuits would be the dee and its stem which might, or might not, be tuned. The second circuit could be located out of the magnet gap in a region where more space is usually available. Tuning could be accomplished by variation of the coupling between the two circuits and/or by, say, variable capacitance of the tuned, or tunable, circuit.

The use of mercury as a solvent in the recovery of uranium from spent fuels is of the interest at Oak Ridge National Laboratory. The vapor pressure of mercury is lowered by increased concentration of uranium. By dew-point measurements, the vapor pressure at 175°C was found to very between 2 and 8mm of mercury, and at 375°C, between 300 and 1100 mm of mercury, depending upon composition as described below. Plots of the log of mercury vapor pressure vs. the reciprocal of absolute temperature gave a family of straight lines. Each line corresponded to one of the composition: UHg2, UHg3, UHg4, and a saturated solution of UHg4 in Hg. No Mutual solubility of the intermetallics was indicated.

The power and estimated reprocessing load are tabulated for existing and proposed United States and United States-built reactors of 10 Kw or greater thermal power.

By using a large central fuel and blanket reprocessing facility, slurry-fueled aqueous homogeneous reactors can attain an estimated minimum fuel cycle cost of 1.4-1.6 mills/kwh; with solution-fueled two-region reactors, a doubling time of 14 years may be obtained at a fuel cycle cost of 2.0 mills/kwh. On-site processing appears desirable only for large power stations made up of reactors designed for short doubling times. For instance, a solution-fueled two-region reactor can attain a 12-year doubling time at an estimated fuel cycle cost of 1.5 mills/kwh at a 2000 Mw electricity station with an on-site processing plant.

In conjunction with Gas-Cooled Reactor heat-transfer studies, local and mean heat-transfer factors are predicted from the heat transfer-mass transfer analogy using subliming naphthalene in air. Experimentation was conducted on 1-in.-dis septafoil rods in a 4-in. -dis flow channel with rod center-to center spacings of 1.10, 1.25, and 1.40 in. at a Reynolds modulus of approximately 60,000. Ratios of local mass transfer to mean mass transfer for a given rod vary as much as from 0.7 to 1.3 (outer rod, 1.10-in. spacings). Mean values of the mass-transfer factor are, in general, above that predicted by the correlation j-0.023 NRe^-0.2; as much as 46% got the outer rod t 1.25-in. spacing. The data indicate that for maximum mass transfer and minimum variation of the mass-transfer factor, an optimum rod spacing exists; the best observes is at 1.40-in.

Samples containing 5 to 10 mg of uranium were extracted with hexone (methyl isobutyl ketone) and titrated coulometrically in sulphate media. Relative standard deviations of 0.45% for samples containing 5 mg and 0.56% for 10 mg were determined by precision studies.

The initial and long-term nuclear characteristics of two internally cooled heterogeneous, graphite-moderated, two-region, molten-salt reactors have been studied. These reactors have doubling times of 22.5 years and 27.5 years. Methods of decreasing the doubling times by removing the Pa233 from the core and be increasing the specific power of the reactor are described.

This course on reactor controls is for the purpose of acquainting the student with some of the elementary considerations involved in setting up a control and safety system for a nuclear reactor. This material is the outgrowth of the notes prepared for the lectures on Reactor Controls given in the Oak Ridge School of Reactor Technologu. The lectures given by T. E. Cole in 1953-1955 are the basis of portions of the subject matter on reactor kinetics. Many suggestions and ideas contributed by E. R. Mann are included throughout almost every section. In addition, several members of the Oak Ridge National Laboratory, and of the Reactor Controls Department in particular, have provided information which has been included in these lectures notes.

From abstract: Liquid alkali metals were circulated in a series of structural alloy loops under reactor radiation at high temperature. The first of these loops was a lithium-stainless steel (type 316) system, and the remainder were sodium-Inconel. No effect of radiation other than radioactivation was found. Mass transfer and metallurgical processes attributable to the operating temperatures were observed."

The use of a scalloped cross-sectional coolant channel has been suggested as possible solution of the fuel-element bowing problem inherent in the septafoil type of geometry. Using simplified assumptions, a method has been developed for calculating the rod spacing and scallop size necessary to produce equal average fuel-element surface temperatures in the central and peripheral regions of the coolant flow channel at the mid-section of each fuel-rod cluster under a given set of reactor flow conditions. Since the extent of row-bowing is related to the surface temperature distribution, this requirement should minimize fuel-element deflection.

The problem of controlling the surface temperatures of core vessels in two-region aqueous homogeneous reactors has been examined by analyzing several possible systems for cooling the wall: (1) direction of the inlet core fluid along the wall at a high velocity; (2) passage of heavy water through the wall of a double-wall core vessel; and (3) flow of cool blanket slurry past the wall.

Report documenting ongoing experiments, designs, and tests undertaken by the Oak Ridge National Laboratory for the Molten-Salt Reactor Project.

The nuclear characteristics and fuel costs of a number of aqueous homogeneous reactors have been estimated. Most of the reactors studied were cylindrical, two-region power-breeders variously having between 0 and 300 g/l of thorium in the core and between 500 and 1000 g/l of thorium in the blanket. The results of the calculations, including breeding ration, fuel inventories, doubling times, and net fuel costs, are summarized in this report.

Report documenting ongoing research and development carried out by the Instrumentation and Controls Division of the Oak Ridge National Laboratory.

The ORIC (Oak Ridge Relativistic Isochronous Cyclotron) radiofrequency system for which Model III represents the resonator is the third system which has received enough consideration to warrant construction of a model. The purpose of the model is to check the calculations for the frequency range and excitation power of the resonator. After an introductory description of the r-f system and model, the detailed calculations of the properties of the model will be given followed by the data from measurements of the model characteristics.

Report containing reports from the Physics Division of the Oak Ridge National Laboratory that cover a wide variety of subjects.

Data on waste volumes and heat generation of several reactor fuels which may be reprocessed in the Power Reactor Fuel Reprocessing Pilot Plant at ORNL are tabulated.

The radiation hazards associated with recycled nuclear reactor fuels will greatly complicate the handling and refabrication of these fuels. This problem is most serious with U-233 and plutonium fuels where the presence of U-232 and the heavier isotopes of plutonium contribute energetic alpha, gamma, and neutron radiations at levels many times that from isotopically pure U-233 and Pu-239. This report summarizes present knowledge of the radiation hazards associated with recycled fuel and the additional data needed to make a thorough evaluation of these hazards.

In the operation of nuclear reactors, nuclear fuel reprocessing plants and in-pile experiments, special provision must be made for disposal of gaseous fission products to prevents contamination of the atmosphere to an unacceptable degree. A disposal process is described in which the noble gas fission products, krypton and xenon, are delayed relative to the sweep gas by physical adsorption as they pass through an adsorbent such as activated charcoal. A theoretical plate analysis, and has been verified experimentally. The retention time for a gas present in trace concentration is proportional to the amount of charcoal in the adsorber bed and to the adsorption coefficient which is evaluated experimentally for a particular combination of materials and conditions. The retention time is inversely proportional to the volume flow rate if the sweep gas.

A self-contained developmental or the formation of the problem of inelastic neutron scattering by crystals is presented. although nearly all of the methods and results used in the present discussion have appeared in a variety of previously published papers, additional mathematical details are given here which have been found by thee authors to aid in understanding the final results.