From abstract: "The extraction of acids with long-chain amines is described. Preliminary results on the extraction of the amine salts of polonium, plutonium and uranium are given."

From abstract: "The variation of the reactivity of a pile as a function of width of a transverse gap is obtained. The method involves first finding the boundary condition satisfied by the flux at the gap face. This, in principle, provides enough information for a complete solution of the pile equations. A method for calculating the reactivity change is presented. The calculated reactivity is compared with experiment and a brief discussion of the validity of the approximations is given."

Technical report describing a rapid and quantitative radiochemical method for the analysis of neptunium (237). This method is based on the extraction of neptunium (IV) with thenoyl-trifluoracetone in xylene. Neptunium (237) is separated free from other alpha emitters and from non-radioactive interferences, and the method may be readily adapted to remote control. [From Abstract]

Technical report outlining the investigation of corrosion on MTR type fuel elements for the Shielding Reactor in filtered water. Report includes two basic types of protection: element pretreatment by either anodizing or alodizing, and solution control using nitric acid to maintain a pH of 5.5 to 6.5 or the addition of 60 ppm sodium chromate as an inhibitor. [From Abstract]

Technical report calculating "effective removal cross sections" for Pb, Fe and O from measurements of fast neutron does in the water surrounding the BSF reactor. The values for Pb and Fe agree quite well with those previously determined from Lid tank data, whereas that for O is somewhat lower. [From Abstract]

Technical report covering classified work of the Critical Experiments Program in the Physics Division for the period December 20, 1950 to March 20, 1951. Report outlines investigations of properties of critical assemblies composed of uranium and various reflectors and moderators, preliminary measurements of the effective energy for fission in the assembly. [From Introduction and Summary]

The 300A and loop were operated for 2862 hr with thorium oxide slurry at 1500 psi and 280ºC to determine the effects vane inlet and exit geometries on impeller wear, the wear rate of aluminum oxide bearings in this size pump, and the operating characteristics of the loop. The thoris, a 1600*C-fired oxide, had a mean particle size of approximately 2 u. Average circulating slurry concentration was approximately 450 grams of thorium per kilogram of water and average flow rate was approximately 300 gpm.

The preliminary process design of a PRFR pilot leaching plant, which is proposed to be located in Cell B of Building ORNL, is considered. Chemical, physical, and nuclear parameters are investigated in order that the leaching operations may be carried out without any chemical or nuclear hazards.

The Turco 4501 process is recommended for the decontamination of the PRFR pilot leaching plant equipment. The caustic-tartrate-nitric acid process is recommended for the decontamination of the cell and the equipment exterior.

The results of a parametric study on a gas cooled reactor are reported on herein. The system considered was a helium cooled, UO2 fueled arrangement with the fuel assemblies consisting of clusters of long cylindrical elements, each element covered b a stainless steel jacket. The axial power distribution was assumed to be a "chopped cosine" having an axial peak-to-average power 1.32.

A series of neutron multiplication measurements with arrays of 1 by 8 by 10 in. slabs of 93.4% U235-enirched uranium metal have been made to provide data from which safety criteria for the storage of these fissile units can be established. Each slab contained 22.9 kg of U235. A maximum of 125 unites was assembled. The arrays studied were cubic lattices of the units and were usually parallelepipedal in shape.

Tests were conducted to determine methods of removing scale deposits from the HRT heat exchangers. A mockup of the heat exchanger header was cleared of a deposit of iron rust by reverse flushing at a flow rate below 75 gpm. A tube bundle consisting of 109 1/4in. O.D. x 0.049 in. wall tubes was plugged with rust. Approximately 80% of these tubes were unplugged by using a 70 psi water pressure differential in combination with vibration from a pneumatic rivet gun. No mechanical method was employed in the tests which could clear the remaining tubes.

A method for determining the concentration of Li6 in aqueous solution has been tested using the nuclear reactions Li6 (n,α)H3 and O16 (H3,n)F18. Annihilation 7 radiation of induced 1.87 hour F18 radioactivity was counted with a well-type scintillation counter, and the radioactivity per millimole of lithium was found to be independent of lithium concentration below about 0.2moles/liter. The sensitivity limit for detecting lithium is less than 0.1 micromole (0.0075 micromole Li6).

In the preliminary stages of getting up a time-of-flight system for measuring neutron spectra from proton reactions, a study of the time dependence of the beam in the 86Inch Cyclotron was made. This study revealed the expected bunching of the protons to produce a short burst of beam on each cycle of the 13.4 Mc/s accelerating voltage. In addition to the 13.4 Mc/s structure, however, there was a 360 c/sec modulation of the beam pulses and a complicated pattern built upon that.

Preliminary experiments have been conducted to evaluate the use of the nuclear reactions Li6 (n,α)H3 and O16(H13,n)F18 to determine the thickness of oxide films on metals. Sheets of thin paper and of aluminum, imbedded in powdered LiF, were irradiated with pile neutrons at a flux of 6 x 10^11 n/cm^2/sec and counted with an end-window proportional counter. A saturation activity of 1.87 hr F18 of 150 dis/min per microgram of oxygen was observed in the paper, but radioactivity due to impurities masked F18 in the aluminum. It is concluded that a 1 A (0.01 μgm/cm^2) oxide film thickness may be measured by a neutron irradiation at a flux of 10^14 n/cm^2/sec but chemical separation of induced radioactivity from the bulk metal is essential.

The rate of uranium sorption by a strong-base anion-exchange resin (Dovex 21K) from a uranyl sulfate solution (U 0.005 M, H2SO4 0.02M, SO4 0.2 M) was studied using a stirred vessel technique and measuring the U235 gamma radiation on each bead. Resin initially in the chloride form and the sulfate for was studied.

High heat flux electrical cartridge heaters were tested with direct air cooling under simulated ORR Loop conditions. The cartridges and the heater design were found to be satisfactory. A gas cooled of concentric pipe design utilizing air, water, and air-water mixtures as the coolant was also evaluated and found to be satisfactory.

The compatibility of zirconium diboride, boron carbide, and boron nitride with type 304 stainless steel was evaluated as a function of temperature (1000-1200°C), time (1-3 hr). Appropriate loadings of the boron compounds and stainless steel powder were blended and fashioned into a compact powder metallurgically. Each compact was roll clad into a plate and subsequently heat treated at a temperature equal to the initial sintering temperature. Metallographic examination of the fabricated and heat-treated plates demonstrated that none of the systems were metallurgically stable. The instability was generally manifested by the (1) interaction of the discrete boron compounds with the matrix and (2) precipitation of a hypothetically boron-rich phase throughout the stainless steel matrix material.

The nuclear safety portion of this report is inclined to ignore the factors by which safety limits can be increased. It makes no mention of the control that can be exercised by limiting the assay of the U-235 being processed in the plant. From some of the previous reports, it is apparent that this plant is not anticipating processing U-235 of assay greater than approximately 20%. At this value, many of the numbers that are presented in the tables could be increased markedly. Rough examination indicates that these values all refer to top product U-235. The general discussion is, however, excellent. The references apparently used are those unclassified references with which we are all familiar and think highly of. We would recommend the inclusion of TID-7016.

In connection with the program of the measurement of eta for U233, several critical experiments have been performed by R. Gwin and D. W. Magnuson of ORML with light water solutions of uranyl nitrate (highly enriched in either U233 or U35) in an essentially bare sphere 27 inches in diameter. This report presents the results of two multigroup-diffusion-theory calculations for the above experiments performed by C. B. Mills and associated at Los Alamos. Assumer cross sections, material concentrations detailed neutron balances and a comparison with elementary theory are included. The agreement between the calculated and experimental multiplication constants is excellent for the multigroup calculation but only fair for the elementary calculation. The latter method overestimates the fast leakage so that the computed multiplication constant is less than that found experimentally.

The nil-ductility-transition (NDT) temperature, as defined by the Naval Research Laboratory drop-weight test, was determined on the A212B carbon-silicon steel used in the pressure vessel of the N. S. Savannah nuclear reactor. Correlations were made with the Charpy-V-notch impact energy at NDT. Specimens taken at two different thickness location from materials used in the upper closure head of the reactor vessel yielded NDT temperatures of 0 - 20°F which correspond to Charpy-V-notch impact energies of 11-19 ft-lb. Testing of as-received material used in the lower closure head indicated that the NDT temperature was 50°F which was equivalent to an average Charpy-V-notch impact energy of 12 ft-lb. After normalizing and stress-relieving this material, in order to more closely approximate the final condition of the reactor vessel, NDT was reduced to less than 10°F.

Progress report of the Oak Ridge National Laboratory Analytical Chemistry Division providing updates on various projects, experiments, and other work in ionic analyses, analytical instrumentation, radiochemical analyses, activation analyses, spectrochemical analyses, inorganic preparations, optical and electron microscopy.

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 …

Report discussing the progress of various research projects by members of the Mathematics Panel at Oak Ridge National Laboratory for the quarter ending April 30, 1952.