Activities in a program to develop techniques in the use of pulsed neutron sources to measure shutdown parameters related to large thermal power reactors are reported. The development of pulsed neutron source techniques for large power reactors has led to a new theoretical model recently developed by E. Garelis and J.L. Russell, Jr. The theory is presently based on a bare, one-group model with m-delayed precursors and takes all spatial modes into account. Results indicate, however, that the application of this model is much broader. Experiments were designed and carried out to both verify this new theory and to demonstrate the performance of the experimental hardware in a large power reactor.

The United States and the European Atomic Energy Community (Euratom), on May 29, and June 18, 1958, signed an agreement which provides a basis for co-operation in programs for the advancement of the peaceful applications of atomic energy. The work described in this report represents the Joint U.S.-Euratom effort. The over-all development program is designed to obtain the test data and operating experience necessary to eventually realize a 50 percent increase in the output of the Garigliano Nuclear Power Station located at Sessa Aurunca (Campania, Italy). Two tasks are in progress: Task III-F involves the preparation of test specimens of reactor vessel material for irradiation; Task IV consists of the formulation of specification for a complete data logging and computer system.

Introduction: The Transition Boiling Heat Transfer Program is sponsored jointly by the USAEC and Euroatom and is being conducted by the General Electric Company. The work commenced on this program February 11, 1963. The objective of this program is to perform basic investigation and measurement of the transition boiling regime in high pressure bulk boiling water flows, with particular emphasis i the high range of steam qualities.

From introduction: "Development of nuclear reactor cores having high power density, long fuel life, and low fabrication costs is the objective of this program sponsored by the AEC."

The following conclusions are based on the out-of-pile general corrosion and localized attack studies completed to-date on several 300 series stainless steels: (1) Utilizing a sodium chloride-cycle test that produces a type failure that can occur in a superheat reactor system, Types 347 and vacuum-melted 304 SS have failed while vacuum-melted 310 SS was acceptable. (2) An improved chloride cycle test utilizing ferric chloride as the additive has been developed that produces an intergranular type failure similar to that experienced in the fuel cladding failures in the SADE and ESADE facilities. types 304 and 315 SS have failed in the test. (3) Present methods of ultrasonic testing will find through cracks but are not completely dependable for assessing lesser degrees of intergranular attack. (4) It is hypothesized that a definite interplay exists between chemical attack and stress. The application of stress will orient intergranular attack preferentially in a direction perpendicular to the stress.

Abstract: Hydrodynamic flow studies were conducted on a full scale model of the SM-2 reactor vessel and core. Test fluid was water at 200 psi and 200 degree F. Test facilities, model, and instrumentation design are discussed. Flow distribution in the stationary fuel elements, lattices, and control rods of the second pass was investigated. Pressure losses through the various core components were measured and are compared with calculated values. Observed over-all pressure drop was 71 feet of water at 200 degree F, 31% higher than predicted, part of which was due to presence of instrument leads. Element to element flow distribution varied approximately +-8% from pass average. Channel-to-channel stationary element flow distribution varied approximately +-10% from element average and control rod flow distribution varied from +-8.9% to +-6.4 and -11.6% depending upon rod locations. These variations exceed the original goals of a +-10% and +-12% combined deviation for stationary and control rod elements respectively, but are satisfactory in relation to thermal design. There was no indication of unsatisfactory structural performance of any components under hydrodynamic loadings up to 130% of design values. The test program was terminated after determining flow distribution in the reference core design, omitting any work on …

This preliminary Hazards Summary Report presents to the Atomic Energy Commission (AEC), Division of Licensing and Regulation, a description of the Nuclear Development Center, the characteristics of the proposed site, and an evaluation of the potential hazards associated with operating the test reactor at this location.

This report presents the thermal and hydraulic analyses, both steady state and transient, for the CETR. Methods of calculations are discussed and results of analyses are presented. Steady state analyses are included for: pressure drops, flow distribution, orificing, burnout, fuel central melting, local boiling, and bulk boiling. Transient analyses are performed for several loss of forced coolant flow incidents.

Abstract: Continued irradiation experience under the AEC - Euratom, UO2 High Performance Program provided five separate and distinct sets of data on UO2 thermal conductivity. Four of these results are expressed in terms of the value of the thermal conductivity. The first two of these measurements were applicable -- strictly -- to poly crystalline UO2. Recently, three additional sets of measurements have been obtained -- all pertinent to UO2 after the formation of large columnar grains. The extent of melting in the experiments on which the results are based ranges from slight, to greater than 70 percent of the fuel cross section. The conclusions from all of these thermal conductivity measurements considered together are: (1) The true value of the UO2 conductivity integral form 0 degrees C to melting (2805 - 15 degrees C) lies in the range from 90 to 96 W/cm. The most probable value is closer to 90 W/cm. To ensure no central melting and the associated clad swelling the maximum thermal performance level for solid pellet, UO2 fuel rods should not exceed 90 W/cm. (2) Any improvement in thermal conductivity due to the formation of large, columnar UO2 grains is small and not detectable within the …

The United States and the European Atomic Energy Community (Euratom), on May 29, and June 18, 1958, signed an agreement which provides a basis for co-operation in programs for the advancement of the peaceful applications of atomic energy. The work described in this report represents the Joint U.S.-Euratom effort. The over-all development program is designed to obtain the test data and operating experience necessary to eventually realize a 50 percent increase in the output of the Garigliano Nuclear Power Station located at Sessa Aurunca (Campania, Italy). One task is in progress: Task I - Data Logging and Computer System. The work on the other tasks is being planned and initiated.

Technical report. From Abstract : "Thermal, metallographic, and vapor pressure data were obtained to establish the phase boundaries and the standard free energy, enthalpy, and entropy of formation for the compounds in the yttrium-zinc system."

Technical report. From Abstract : "A step phenomenon in the nuclidic mass excess surface associated with magic numbers N, Z = 8 and 20 is shown to exist, whereas only breaks occur at higher magic numbers. Excited states are included which reveals possible smooth trends within Shell-Model subshells."

Technical report. From Abstract : "A system has been developed to program a digital computer in much the same manner as an analog computer is programmed. Properties of a general purpose analog computer and a digital differential analyzer are combined to yield a program which employs, as input, standard data cards prepared from a diagram analogous to an analog computer diagram. The capacity of the system is much greater than that of most analog computers, making it applicable to large simulation problems. No scaling is required. The system is compatible with the Fortran symbolic language and may be used as part of a larger digital computer program. It may be applied to the more general types of boundary value problems arising in process simulation in addition to the initial value problems ordinarily solved on analog computers. It is particularly well adapted to non-linear problems and to control problems involving large transport delays. The program operates in basic machine language and, when used by itself, requires no compilation time."

From abstract: "To investigate the deviation of the internal conversion coefficients of E2 transitions from theoretical computations and their dependence on nuclear deformation, the total internal conversion coefficient of the 121.8-kev 2+-0+ transition in ellipsoidal Sm152[over]90 was measured to be 1.135 ± 0.010 with a high accuracy coincidence-sum method. The K-shell to total internal conversion ratio was determined to be 0.588 ± 0.003 with a [beta] spectrometer...The experiment revealed no deviation from theory nor indications of strong dependence on nuclear deformation; it therefore did not confirm recent beliefs in this regard. The details of the coincidence-sum method were described. The K electron to total electron capture ratio, from Eu152 to the 1.53 Mev state in Sm152 was also measured to be 0.79±0.02."

From introduction: "In order to locate systematic trends of states with a certain angular momentum and parity Jπ in nuclei having constant neutron excess, both the ground state and the level energies will be considered simultaneously: we plot the total nuclear binding energy or nuclidic mass excess of excited states, whereby the ground states appear as a special case. Such a natural correlation of level schemes has been employed before Inglis already in 1953."

From introductory paragraph: "This report concerns the hydrolysis of rare-earth dicarbides, sesquicarbides, solid solutions of carbon in rare-earth metals as well as rare-earth carbon alloys of varying compositions. Many of the carbide samples used in this study were those which had been studied by Gschneider (9)(7) and had been preserved in evacuated, sealed tubes. Some additional preparations of the sesquicarbides were made especially for these studies. The hydrolytic reactions were carried out in water and hydrochloric acid solutions of varying concentrations. Assay of the gaseous products was by mass spectrometry and gas chromatography. Both instruments were carefully calibrated with pure hydrocarbons and hydrogen and mixture thereof."

From introduction: "The basic interactions which give rise to the interesting magnetic properties of dilute alloys, such as cobalt in palladium, have received a great deal of attention both theoretically and experimentally. This problem has many facets which are peculiarly interrelated. For example, there is the problem of Curie points of the order of magnitude of 10°K for concentrations of 'magnetic' ions of 0.1%. It has been proposed that this problem involves virtual d-states (Friedel) which permit one to understand much of what is observed."

From abstract: "Distillation procedures used for purifying yttrium metal, producing metal containing less than 150 ppm oxygen and lower concentrations of most of the other common impurities, are discussed. Some of the physical and mechanical properties of the distilled yttrium indicate: (1) a melting point of 1510°C, (2) a solid state transformation at 1459°C obtained from high temperature resistivity data, (3) a Rockwell H hardness of 60 and (4) improved rolling and swagging characteristics."

Investigation of whether the multi-thousand psi pressure pulses that occurred in the BORAX-I and SPERT-I destructive power excursion could have been generated by thermal mechanisms in the geometries of unmolten reactor cores. These pressure pulses were "at least as high as 6,000 psi, and probably higher than 10,000 psi " in BORAX I, and "between 3,000 and 4,000 lb/in" in SPERT I. An experimental investigation was undertaken of pressure pulse generation by purely thermal means.

Many measurement of neutron spectra have been made in water assemblies. In these system a large part of the spectrum is given by an essentially Maxwellian distribution at the moderator temperature which is insensitive to the scattering model. Hence, the test of the energy exchange scattering kernel is in the difference of the spectrum and the fundamental or Maxwellian component. The figure shows the spectrum for the Nelkin model. Once the fundamental has been subtracted neither theoretical model seems to fit the data extremely well. Below kT the Nelkin model is a closer fit than the gas model but it underestimates the deviation from the Maxwellian whereas in the joining region it overestimates the distortion.

Abstract Line spectra of vanadium, niobium, titanium, molybdenum and rhenium of sufficient intensity to allow detection at the 1–10 p.p.m. level can be excited in fuel-rich, oxy-acetylene flames. For the strongest lines of tungsten, the sensitivity of detection is 90 p.p.m. Weak lines of zirconium, hafnium, osmium, tantalum and uranium are also observed in these flames. Recordings of the spectra are given along with wavelength tables of the strongest lines.

The report is about the geophysical year oceanographic program of the Argentine Republic.

A guide for operators of the vehicle-mounted TU-5-A gamma-ray logging unit.

The following report discusses thorium and rare earth resources in the Lemhi Pass thorium area where over 200 samples were collected.