The magnitude of the energy gap in nuclear matter associated with a highly correlated ground state of the type believed to be important in the theory of superconductivity has been evaluated theoretically. The integral equation of Cooper, Mills, and Sessler is linearized and transformed into a form suitable for numerical solution. The energy gap, calculated by using an appropriate single-particle potential and the Gammel-Thaler two-body potential, is found to be a very strong function of the density of nuclear matter, and of the effective mass at the Fermi surface. It is concluded that the magnitude of the energy gap for nuclear matter should not be compared directly with experimental values for finite nuclei, although the results suggest that if the theory is extended to apply to finite nuclei it probably would be in agreement with experiment.

This document details activities of the Fuels Preparation Department during the month of February 1960. (FI)

This document contains information about flooding of the Columbia River. It focuses attention on the following; increased elevation due to rainfall, seepage which destabilized the constructed dike, flooding of cellars, evacuation of people to emergency shelters, tug boat collision damage to power lines, and the washout of the Van Giesen Street Bridge on Yakima River.

This document details activities of the Fuels Preparation Department during the month of April 1960. (FI)

Preliminary studies have, in general, indicated the need for modifications and improvements to the reactor last ditch coolants systems in order to provide adequate safety of operation at power levels programmed for the future. These studies have indicated the need for improved reliability as well as increased capacity for the last ditch coolant systems. A design study is being prepared by Reactor Modification Design to define the scope of the modifications required to provide adequate last ditch systems for the older areas. Adequate last ditch cooling will be provided for the 100-K Areas under Project CGI-844 which is currently in progress. The purpose of this document is to set forth the operating conditions and objectives on which the study will be based.

In the Hanford production reactors, failure of fuel element cladding is known as subcooled burnout since the bulk coolant temperature is below the saturation temperature at time of failure or burnout of the fuel cladding. The heat generation rate at which subcooled burnout occurs, establishes a limit to allowable reactor power level. This document compares present and potential power level limits at the Hanford production reactors with power level limits established by subcooled burnout.

Tests in which aluminum-jacketed, Al-Si bonded uranium fuel elements were baked at various temperatures have shown there is a time-temperature relationship for Al-Si layer decomposition. For heat transfer and secondary coolant barrier considerations, the extent of bonding layer deterioration during fuel element irradiation is important. Currently, Al-Si bonded fuel elements show evidence of spire bond separation, and to a lesser degree, can bond separation following irradiation. Such evidence has aroused concern for the ability of the currently produced Al-Si bonded fuel elements to withstand future reactor operating conditions. Several potential uranium fabrication and canning process improvements are being developed to further advance fuel element stability and performance. Optimization of process conditions based on these improvements may provide the necessary margin of safety for good bond layer integrity. Before a decision can be made to continue improvement of the present process or convert to a new canning process, more information on the stability of the present fuel element bond is needed. This report presents the design of a test to more fully evaluate Al-Si bond integrity under anticipated future reactor operating conditions.

An investigation of the emission spectrum from radiation-daniaged xylene led to the conclusion that no gross corrections are needed for xylene when used as a scintillation solvent. Data are included from measurements of nonradioactive energy transfer in p-xylene and diphenyloxazole organic scintillation solutions. Measurements were made of the energy resolution of a twinscintillation fast neutron spectrometer. Accurate values of electron drift velocity in purified noble gases and nitrogen were obtained by measuring the transit time of photoelectrons across the gap of a parallel-plate condenser. Information concerning the transport collision cross section of low-energy electrons on noble gases was obtained from drift-velocity data. A method is discussed for the determination of traces of Freon-12 by positive ion emission techniques. Data are reported from late observations of the distribution of radium in the human body; the microscopic distribution of the dose in the skeleton arising from deposited calcium-45, strontium90, and radium-226 as measured autoradiographically; and determinations of individual alpha emitters in mixtures of alpha emitters. Data are tabulated from measurements of gross fission product radioactivity in air samples and in samples of soils collected from August through November 1959. The soil and air fall-out data are discussed. Measurements were made of the …

Construction of the NUMEC Plutonium Facility was essentially completed. Methods for the preparation of Pu, U, and Th oxides of high purity and the fabrication of these materials into fuel shapes is discussed. (For preceding period see NUMEC-P-10.) (W.L.H.)

Thermal stress testing was performed on two fuel plates, one cut from a brazed SM-1 dummy fuel element and the other from a TIG Welded SM-2 reference element. The test specimens were subjected to transverse temperature differences of up to 200 deg F, and distortion and strain at various locations were measured. The effect of the thermal stress was to increase the amplitude of original distortions. Adddtional distortions due to thermal stress were proportional to temperature differential and to ripple length. Tensile stresses in the side plate sections were measured as approximately 10,000 psi at maximum reactor temperature difference. Individual weld loadings in shear were measured as 38 lb per weld. Results of the tests were considered inconclusive because of unrepresentative initial plate distortion. (M.C.G.)

Abstracts were prepared on 26 of 28 papers presented at the Conference on the Physics of Breeding held at Argonne National Laboratory on October 19 to 21, 1959. (C.J.G.)

Direct recording of nuclear pulse height data on magnetic tape is being investigated. The characteristics of various brands of commercial tape are being investigated and a waveform analysis is being performed in an attempt to determine the most favorable frequency range for available tapes. Use of the magnetic modulator head is being investigated to minimize variations due to short term tape speed variations. (W.L.H.)

>The materials and methods used for the long-term nuclide pairs are essentially the same as those previously described. (April - June Report). The split planchet method was used to determine the resolving time of the tracerlab superscalar counting apparatus which is currently in use. A planchet was split in two and a sample of nuclide placed in each half and counted. From these results a formula for calculating true counting rates was evolved. Data on resolving time loss for the Superscalar are tabulated. Transmission values of Sr/ sup 89/- Ct/sup 14/ mixture were measured to determine the degree to which error in these values can be reduced by long counting periods. Data on P/sup 32/ and C/ sup 14/ tagged rubber age counts are tabulated. Also, rubber samples were prepared by adding Ca/sup 45/, Cl/sup 36/, Nb/sup 95/, and T c/sup 99/, mixing and vulcanizing and isotope pairs (Ca/sup 45/- Cl/sup 36/ and Nb/sup 99/-Tc/sup 99/) were similarly incorporated in other samples. Ground and suspended samples of these preparations were age counted. The results obtained by incorporating radioisotopes into rubber can not show close correlation between observed and calculated time. Probable reasons for errors and inconsistencies are discussed along with …

The third quarter of 1959 was occupied with putting the finishing touches on components of the Two-Way Model, adjusting the magnetic field to the required magnitude at all points, and life testing completed components. The present status of the model components is given including the magnet, vacuum tank, equipment for acceleration, and injector. Status of various study groups is discussed. A list of papers published, submitted for publication, and presented at meetings for the period Oct. 1958 to Oct. 1959 is given. (W.D.M.)

A lecture intended to provide a general background in weapons effects is presented. Specific areas of nuclear explosion phenomena pertinent to the design of hardened systems discussed include nuclear radiation and shielding, fireball growth and effects, thermal radiation, air blast, cratering and throwout, ground shock effects, fallout, and afterwinds. (J.R.D.)

The papers prepared and presented by the Atomic Energy Commission and Contractor Personnel are presented. The meeting covered a broad range of problems encountered in the AEC and SS Materials Management work. (W.L.H.)

Preliminary engineering studies have indicated the need for modifications and improvements to the reactor coolant backup systems of the old areas in order to provide adequate safety of operation at power levels programmed for the future. These evaluations of the coolant backup systems were based on the recently adopted reactor cooling safety criteria. It was concluded that the secondary coolant systems would be adequate in capacity and reliability for the proposed future operating conditions except for certain cases of natural disaster such as earthquake damage. It was concluded that the last ditch coolant systems would be inadequate for the proposed future reactor operating conditions. The purpose of this report is to define the scope of modifications and improvements required to provide adequate last ditch systems in the old areas for future operating conditions as proposed by the Reactor Modification Program. Irradiation Processing Department, Fiscal Years 1961 through 1966. Adequate last ditch cooling will be provided for the 100-K Areas under Project CGI-844 which is currently in progress. The results of this study provide a basis for future budgeting action and project planning.

Chemical-Metalluaical Processing. A direct-cycle fuelreprocessing plant using pyrometallurgical procedures is being designed as part of the Experimental Breeder Reactor No. II project. The reduction of uranium oxide was investigated, using pure Mg and solntions of Mg in Zn and Cd. Cadinium solntions of U were shown to be stable in Types 405 and 410 stainless steel containers at temperatures up to 550 deg C. The liquid metal corrosion loop in which a U-Mg--Cd alloy is being circulated at 550 deg C has been in trouble-free operation for 3000 hrs. Recovery of Pu from Mg solution by distillation of Mg was demonstrated on 1-g Pu scale. The solubility of Th in liquid Cd was measured over the temperature range from 1.9 x 10/sup -3/ per cent at 348 deg C to 1.8 x 10/sup -2/ per cent at 658 deg C. The solubility of Mn in liquid Cd was found to range from 0.27% at 414 deg C to 1.43% at 661 deg C. The solubility of Ni in liquid Cd was measured. The partition of U between liquid Al and liquid Cd was studied as a function of U concentration. The reaction of Al with a liquid Cd solution containing …

A neutron-sensitive semiconductor counter was constructed by depositing a thin layer of Li/sup 6/F between two silicon surface-barrier counters. Neutrons are detected by observing the alpha + T pair resulting from the Li/sup 6/(n, alpha )T reaction; pulses from the two counters are added, and the sum pulse is amplified and recorded on a multichannel analyzer. Since the sandwich geometry permits simultaneous detection of both reaction products, the magnitude of the resulting sum pulse is proportional to the energy of the incoming neutron. Pulse-height spectra from slow neutrons and monoenergetic fast neutrons. in the energy region 0.6 to 3.5 Mev, were recorded from two counters of this type; in both counters the sensitive area was about 0.7 cm/sup 2/, with a Li/sup 6/F layer of order 150 mu g/cm thick. In all cases. a well defined neutron peak was observed in the pulse-height spectrum. In a typical case the full width at half maximum of the fast-neutron peak was about 300 kev. Counters of this type are relatively insensitive to background effects, notably gamma rays, and thus may prove to be useful in the detection and spectroscopy of fast neutrons. (auth)

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Report documenting the progress of the Army Gas-Cooled Reactor Systems Program to develop a mobile nuclear power plant for military field operation.

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Techniques for improving stability of scintillation counter chopper systems and their development for use in industrial control applications are being investigated. Tests are being performed to determine the causes of fluctuations. An integration and frequency converter is being developed in which the anode current of the photomultiplier tube is alternately switched between two integrating condensers by action of a commutator switch. The voltages developed across the two condensers are proportional to the respective intensities of the two radiation beams seen by the scintillation counter. Slective sampling by the use of Loss filters is scheduled for future investigations and a literature search on counter stabilization is also planned. (J.R.D.)

Progress is reported in corrosion studies of stainless steels, Nb, Zr, Al- Fe-Mo, Mo, Ni alloys, and Al- Ni by various materials including Na, Na-K, Li, Rb, and fused salts, Corrosion studies in pump loops of various materials by fused salts and liquid metals are reported, Fuel elements and shielding materials for ART and APPR are beirg developed. General studies in welding and brazing, nondestructive testing, fabrication, and inspection are described. Developments in high-temperature metals and ceramics, metallographic techniques, ceramic materials, and Zr alloys are reported, (T.R.H.)