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.

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.

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.

The behavior of insoluble corrosion products in the HRT is generally understood and studies of the removal of these solids by hydroclones can logically be terminated after the effect of higher processing rates by the multiple hydroclone has been determined. Chemical descaling may be required to supplement solids removal by hydroclones. Laboratory studies to find suitable reagents will be continued in conjunction with decontamination work presently in progress.

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.

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.

The purpose of this study was to develop equations for calculating fision product heating in the HRT-CP underflow pot from measured temperatures and to attempt to correlate the rat of solids accumulation in the underflow pot with fission heating and reactor power. Using fission heating data calculated from relating solids accumulation and heating have been tested. In one case an error of no greater than 26% was incurred in the calculation of the total weight of solids collected during chemical plant runs 17-4, 17-5, and 17-6. Further development work will be done on this correlation.

Equilibrium loading of uranium on Dowex 21K has been studied in a sulfate system for uranium concentrations from 0.0005 M to 0.0005 M, total sulfate concentrations of 0.45 M to 0.6M, and sulfuric acid concentration of 0.020 M. Loading data have been fitted to Langmuir adsorption isotherms and Langmuir constants have been evaluated. Resin was equilibrated with uranium feed solutions by flowing the feed through a shallow fixed bed of resin.

This report presents a detailed study of HRT Run 14, which was abruptly terminated by the formation of a hole in the Zircaloy-2 core tank. In this run the reactor was operated at high temperature and pressure for ten days from March 25 to April 4, 1958. Nuclear power operation extended from March 29 until April 4, when fuel solution leaked into the heavy-water blanket. The maximum power level attained was 6.4 Mw.

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 "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.

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.

Calculations indicate that single-transfer line concatenated pulse column systems can be operated with static pressures that are not excessive if a sufficient number of vessels are employed in the system. The required number of vessels can be attained by using a series of short columns or by using holdup pots in conjunction with a limited number of columns.

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.

The feasibility of using electroless nickel, a chemical deposit containing about 10 wt% phosphorous in nickel, as the brazing alloy for assembling tubular stainless steel fuel elements of the type specified in Core I of the N. S. Savannah was investigated. This material was nelected primarily because of the case of braze-metal preplacement by chemical deposition of the alloy on type 304 stainless steel ferrule spacers, prior to fuel-bundle assembly. Brazed joints produced by this method were generally characterized by a relatively ductile solid-solution region at the thinnest portions of the fillet. This ductile zone should minimize the possibility of complete propagation of hairline cracks, which form in the brittle, eutectic regions of fillet.

A method was developed for the spectrophotometric determination of 30 to 100 ug of osmium as OSO4 is extracted with CHCl3 and diphenylcarbazide is then added to the organic extract. A blue-violet reaction product is formed, the absorbancy of which is measured at 560 mu. A suitable reagent concentration is from 3 to 5 ml of 0.2% diphenylcarbazide in a volume of 25 ml and the preferred solvent for the reagent is ethanol. Beer's law is followed over a range of 8 to 130 ug of osmium with a coefficient of variation of about 4%. After a 2-hour color-development period the molar absorbancy in less than 2 hours were unsuccessful. A study was made of the effects of foreign elements and only Ru(VIII) was found to interfere.

A method was developed for the determination of osmium by measuring the absorbancy of osmium tetroxide in CHCl3. The osmium is first oxidized to the octavalent state and the osmium tetroxide which is formed is extracted selectively with CHCl3. The ultraviolet absorption spectrum of OsO4 in CHCl3 has a series of absorption bands with peak absorbancies at 282. 289, 297, 304 and 312 mu, and molar absorbancy indices of 1870, 1760, 1640, 1400 and 1000, respectively. For each wavelength the optimum concentration range for the determination of osmium was evaluated by the method of Ringbom. Only chloride and octavalent ruthenium interfere in the determination. By this method, from 0.4, to 3 mg of cesium can be determined with a coefficient of variation of 3 per cent.

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.

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

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

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

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."

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.

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.