The development of nuclear reactors and other sources of nuclear particles has provided the analyst with a new method which has been successfully applied to the determination of microgram and even submicrogram quantities of many elements. In this method, known as "radioactivation analysis," the element to be determined is "activated" through some type of nuclear reaction which produces a radioactive isotope of the element. Since the radioisotope produced decays with its own characteristic radiation and half-life, it is possible, through radiochemical measurements following radioactivation, to devise a method of analysis which is very specific for particular elements. Whenever necessary, the radioisotope is separated by chemical means and its radioactivity is then measured by some type of radiation counter.

The solution of the monoenergetic Boltzmann equation in an infinite homogeneous, nonmultiplying medium with linearly anisotropic scattering and an isotropic plane source is given and compared with the corresponding solution for isotropic scattering. The effective source strength for the asymptotic flux turns out to be the same as that for isotropic scattering to first order in Σa/Σ.

The ORNL analog computer was used to simulate four widely different experiment conditions in the small EGCR in-pile loops. Various control and safety systems were evaluated in each case. Curves are included which show the response to postulated accidents and component failures. The results indicate that one standard control and safety system will probably be adequate for a wide variety of test conditions.

An investigation is made to determine the adequacy of presently used analog circuits in solving dynamic fluid flow heat transfer equations. A mathematical analysis is made of dynamic heat transfer in pipes with zero losses, with losses proportional to pip temperature, and with heat inputs. The results of this analysis are compared with analog results by means of generalized temperature versus time graphs. The analog circuit is found to be adequate for most conditions, but sometimes requires modification when heat inputs are considered.

An approximation is derived for the time constant which characterizes the rate of energy loss of fast ions moving through a plasma. Using particle and energy-balance equations a simple approximate criterion is derived for the estimation of the importance of energy degradation during plasma buildup in a DCX type machine. Next, there is derived the steady-state ion energy distribution for a case in which energy losses are to electrons at a given temperature and particle losses are by charge exchange. The distribution function is used to compute loss rate, upper critical current, ionization rate, and other functions of interest. Quantitative application is made to DCX-2 under various conditions of operation of carbon and deuterium arcs.

The use of the DD^3 amplifier with the RIDL 200- and 400-channel analyzers has been found advantageous for certain applications. In order to use the DD2, certain modifications to the input circuits of the Analog-to Digital Converter Unit are necessary. In addition, the modifications improved the linearity of the analyzer in the low channels. Using the analyzer with the RIDL Type 30-7 Scintillation Pulse Amplifier, it was noted that non-linearity of as much as 5 or 6 channels was present below channel 20. With the modifications made and with the use of the DD2, this non-linearity has been reduced to less than 1/2 channel.

This memorandum presents a description of several additional miscellaneous HRT core maintenance tools, not in an earlier report (1). These tools were used in the removal of the cut up diffuser plates, probing the core wall, gauging the size of the holes, and other simple tasks. Function, design, and operation are described for the following items.

The Model Q-1212C Pulser is a single frequency (60 pps) generator whose output waveform is characterized by a rise-time of less than 4 mµsec and, depending upon the method of termination, an exponential decay having a time constant of 300 or 600µsec. The waveform approximates that produced by a radiation detector. The waveform approximates that produced by a radiation detector. The maximum available output from the instrument is 10 volts, positive or negative polarity, and is continuously adjustable by means of step switches and a 10-turn potentiometer. The potentiometer has a linearity of 0.1%.

A mathematical model is presented for the prediction of heat transfer coefficients for fully developed turbulent flow of fluids in circular pipes by analogy to the transfer of momentum. There is also presented an empirical velocity distribution equation derived from existing experimental data for use in the analogy model. Heat transfer coefficients for fluids with Prandtl numbers ranging from 0.01 to 100 and Reynolds numbers ranging from 5x10^3 to 10^7 are presented in tabular and graphical forms for both the case of constant heat flux at the pipe wall and the case of constant temperature at the pipe wall. The heat transfer coefficients computer in this investigation are compared with existing experimental dat, and a discussion of the parameters affecting the heat transfer characteristics of fluids in turbulent motion in circular pipes is presented.

Some results have been obtained which may be of use in studying the escape of fission fragments from slurry particles which contain fissioning material. Assuming that the fission fragments are of fixed range H, that they are generated uniformly and isotopically in a sphere of diameter D, the escape probability , mean path length, and path length distribution function have been derived.

A proposed modification to the experiment off-gas system for the EGCR-LITR Capsule Experiment is evaluated by comparing the atmospheric radiation doses to laboratory personnel that could result in the event of an experiment failure while utilizing the present off-gas system to those doses that would result if various modifications to the existing system were effected. The modifications considered include the addition of an iodine vapor adsorber and a krypton-xenon adsorber. The addition of an iodine vapor adsorber to the off-gas system, which presently includes an absolute filter, reduces the atmospheric dose to the thyroid from 510 mr to 1.4mr. The total body dose is also reduced from 2.2 to 1.3 mr. The total body dose can be further reduced to 0.7 mr if a large krypton-xenon adsorber is included. Basd upon these calculated atmospheric radiation doses it is concluded that the addition of an activated charcoal iodine vapor adsorber will reduce the atmospheric hazard to an acceptable level.

Departures from the usual precipitation method produced crystalline uranium peroxide in several forms. Three types of segregated needles were used in the preparation of three pellets for pellet-type elements. Densities of the pellets ranged from 93 to 97% of theoretical, depending on conditions of precipitation.

Uranium extractions from carbonate solutions were effective and phase separation rates were rapid using a new commercial quaternary extractant, Alamine 336. Extraction coefficients were approximately proportional to the quaternary concentration. Addition of -0.5 mole tridecanol/mole quaternary to the solvent gave optimum extraction efficiency and phase separation rates.

The addition of a surface active agent to an aqeous-organic interface produced a resistance to mass transfer equivalent to slightly more than 1 cm of water. Five semicontinuous Druhm runs were made with 1/2in. thick MgO liners and terminated due to either failures of the UFe nozzle or a top gasket leak. In preliminary scale-up tests of the flame calcination equipment, a maximum feed rate equivalent to 720 g oxides/hr was achieved using a 3-in. i.d. magnesia reflector with an outside wall temperature of 1500°C.

Section 9.0 is the "Chemical Processes for Fission Product Concentration, Removal or Fixation" section of the Status Report on the Disposal of Radioactive Wastes. The report is divided into four areas: (1) Introduction; (2) Summary of waste processes; (3) Concept of a multipurpose waste processing facility; and (4) Details of some of the waste processes.

An annual report is given on the operation and costs of waste-disposal facilities at ORNL laboratories and operating buildings in the Bethel Valley area. The operations of the hot-chemical and metal-waste systems, the process-waste system, and the radioactive-gas-disposal system which utilized the 250-ft stack located in the Radioisotope area are discussed. The miscellaneous operations which include the SS (source and special nuclear) material control, SS material recovery, off-shift service for research divisions, water demineralization plant operations, and hydrogen liquefaction are included. However, the disposal of cooling water from LITR, off-gases from the Hot Pilot Plant, and the ORNL Graphite Reactor building are not covered by the report.

This report presents a summary of certain physical properties that have been determined experimentally on the fluoride mixture that have been formulated at ORNL (Rers. 1, 2). These properties include the density, enthalpy, heat capacity, heat of fusion, thermal conductivity, viscosity, Prandtl number, electrical conductivity and surface tension. In addition to the experimental data, values have been predicted for the heat capacity and density of the other mixtures from the correlations of these properties. Estimates of the viscosity have also been made for a number of the mixtures on which no experimental data were available.

Progress report of the Oak Ridge National Laboratory Aircraft Nuclear Propulsion Project providing updates on various projects, experiments, and other work. This report includes summaries of project activities in: aircraft reactor test design, ART physics, ART instruments and controls, component development and testing, procurement and construction, ART, ETU, and in-pile loop operations, phase equilibrium studies, chemical reactions in molten salts, physical properties of molten materials, production of fuels, compatibility of materials at high temperatures, chemistry, analytical chemistry, metallurgy, dynamic corrosion studies, general corrosion studies, fabrication research, welding and brazing investigations, mechanical properties studies, ceramic research, nondestructive testing studies, heat transfer and physical properties, radiation damage, fuel recovery and reprocessing, critical experiments.

Progress report of the Oak Ridge National Laboratory Aircraft Nuclear Propulsion Project providing updates on various projects, experiments, and other work. This report includes summaries of project activities in: aircraft reactor test design, ART physics, ART instruments and controls, component development and testing, procurement and construction, ART, ETU, and in-pile loop operations, phase equilibrium studies, chemical reactions in molten salts, physical properties of molten materials, production of fuels, compatibility of materials at high temperatures, chemistry, analytical chemistry, metallurgy, dynamic corrosion studies, general corrosion studies, fabrication research, welding and brazing investigations, mechanical properties studies, ceramic research, nondestructive testing studies, heat transfer and physical properties, radiation damage, fuel recovery and reprocessing, critical experiments.

The ORNL Graphite Reactor operated very well during 1955. The downtime was low, only 8.6%. The fuel in the bonded slugs did not perform as well in 1955 as in 1954. Much of the trouble was undoubtedly due to growth of slugs which were not beta-transformed. It is known that some slugs had grown over 1/2 in. The automatic central system installed in 1954 continued to operate satisfactorily. The cooling system gave minor trouble when one of the 900-hp fan meters had to be replaced because of shorts in the rotor. The high radiation in the canal was the largest source of trouble. Approximately 55 tons of slugs discharged from the reactor in 1952 was sent to the Metal Recovery Plant. Enough slugs had raptured, due to their long exposure in the canal and reactor, to badly contaminate of water. Most of the contamination was removed by the end of the year, but the radioactivity which had soaked into the canal wells was enough to give high radiation fields. A solution to this problem was being sought at the end of the year. A study is under way on the possibility of increasing the flux of the ORNL Graphite Reactor …

Diffusion in an arc plasma across a magnetic field is investigated. The geometry is similar to that reported in ORNL-1890 but with the addition of magnetic mirrors on the ends of the arc chamber. It is shown that mirrors do not eliminate the "short circuit" effect. Comparison of the e-folding length, rₒ, of the radial ion density with and without mirrors, affords a direct measurement of ℓ/λ where ℓ is the arc length and λ the mean-free-path. In addition rₒ is independent of gas pressure with mirrors and varies as √p without mirrors. The condition for the elimination of the "short circuit" effect is discussed, as well as the case in which the "short circuit" is still present but the ions diffuse (rather than stream) to the end walls. In this case rₒ is directly proportional to the gas pressure. These effects are compared to some experimental results of Neidigh

This report presents data obtained from processing 33 Clementine Reactor fuel elements in the ORNL Metal Recovery Plant to recover approximately 15 kg of plutonium and 0.16 g of americium.

Several plates of 98.7% Th - 1.2% U 235 (clad in aluminum) were irradiated in the MTR for an integrated flux of 2.6 x 10 21 neutrons/cm2. Although these samples represent an early development in bonding of aluminum to thorium and there are better methods at present, the bond proved to be quite strong and both clad and core were dimensionally stable under irradiation. The production of uranium 233 was as much as theory would indicate and the total amount of fissionable material material after irradiation and after decay of the protactinium 233 was greater than before irradiation. A fuel element of this nature appears to offer excellent potentialities from the standpoint of radiation stability.

The indicated methods for determining the following constituents of Diban, which is an aqueous solution of dibasic aluminum nitrate, Al(OH)2NO3, were evaluated statistically: 1aluminum by gravimetric, volumetric, and spectrophotometric procedures, 2. basicity (hydroxyl value) by formation of an aluminum complex and titration of the free acid with standard alkali solution, 3. total nitrogen by the Kjeldahl method, 4. ammonia by the Kjeldahl method, and 5. nitrates by means of a cation-exchange resin and titration of the liberated acid with standard alkali solution. Recommendations are made regarding the preferred methods of determining the constituents in dibasic aluminum nitrate and regarding means of minimizing errors in these analyses.