Optimization of the reactor process involves the knowledge of the longitudinal flux distribution on a semicontinuous, routine basis. The nonpoisonous spline was proposed as a way for obtaining flux traverses at any time during reactor operation, in virtually any location in the core. This report summarizes the findings of a feasibility study conducted in conjunction with PITA-18 and thus serves as a termination of the test phase of spline traversing.

Production of {Lambda} + K{sup 0}, {Sigma}{sup 0} + K{sup 0}, and {Sigma}{sup -} + K{sup +} by 1170-MeV/c {pi}{sup -} mesons has been studied in the Lawrence Radiation Laboratory 72-inch hydrogen bubble chamber, Cross sections, angular distributions, and polarizations are presented. The polarization of the {Sigma}{sup 0} is determined at four center-of-mass angles and found to be small everywhere. Based on published results for the reaction {pi}{sup +} + p {yields} {Sigma}{sup +}, K{sup +}, a comparison of the polarizations of {Sigma}{sup +}, {Sigma}{sup -}, and {Sigma}{sup 0} is made from the charge-independence triangle. A conclusion is reached that the {Sigma}{sup -} polarization should be large, and that the {Sigma}{sup -} and {Sigma}{sup +} polarizations should be opposite in sign.

In uranium with alloying additions of up to 400 ppm Fe and up to 800 ppm of either Si or Al, the various U-containing phases were examined with the electron microscope. These phases were also extracted chemically and identified by electron diffraction. During gamma -phase heat treatments, the alloying additions, as well as impurity atoms, segregate into networks of incipient'' precipitates that can be seen only afier certain etching treatments. (auth)

Design and construction specifications to be followed in the development of the reactor, its associated systems and experimental facilities, and the housing and required services for the facility are presented. The testing procedures to be used are outlined. (D.C.W.)

The basic assumption of the Serber model in the description of high- energy nuclear reactions is that the interactions of incident particles with complex nuclei can be described in terms of individual particle-particle collisions within the nucleus. Calculations were performed making use of the basic assumption of the Serber model, a more realistic nuclear model, recent cross-section data, and an exact statistical sampling technique. The sampling technique has not been used previously in calculations of this type. Calculations were performed for incident e (as Fe/sup 59 /sup +/, e (as Fe/sup 59 /sup -/, neutrons, and protons on nuclei from lithium to uranium. The energy range of the incident particles varied from about 50 to 350 Mev, i.e., the energy region in which pion production is not likely. Free-particle cross sections were used in determining the collisions within the nucleus, and statistical sampling techniques were used throughout, The problem was coded for the IBM-7090. Extensive comparisons with experiment were made and the results indicate that the calculation can be used to predict most of the cascade data for incident nucleons on complex nuclei, but only the gross features of the data are predictable for incident pions on nuclei. The effects …

ABS>A detailed description of the printed output sheets from the intranuclear cascade calculation described in ORNL3383 is given. The three analysis codes --analysis codes I and II and an evaporation code --that were written to organize the raw data of the output tape are considered. (auth) A tabulation of the neutron total cross section of U/sup 233/ as a function of neutron energy from 0.07 to 10,000 ev, measured with the ORNL fast chopper time- of-flight neutron spectrometer is given. (auth)

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Empirical evidence on the nonmesic decay of LAMBDA hypernuclei is analyzed in terms of the spin and isospin dependence of the weak interactions A + p yields n + p and LAMBDA + n yields n + n. The nonmesic decay rates for / sub LAMBDA /He/sup 4/ and /sub LAMBDA /H/sup 4/ were obtained by treating the A de-excitation by different nucleons as incoherent and assuming the validity of the DELTA I = 1/2 selection rule for these interactions. The ratios of nonmesic to pi /sup -/ decay modes and of the first reaction to the second were calculated as 1.68 plus or minus 0.36 and 0.5, respectively, for He/sup 6/ decay. The later ratio for H/sup 4/ was predicted to be 1/(8.8 plus or minus 3.2). Interpretation of the rates is discussed, and it is concluded that if the LAMBDA I = 1/2 rule holds for the LAMBDA -N yields N-N weak interaction and if present ideas about the current-current nature of weak interactions are valid, then the higher-order mesonic corrections to this primary four-fermion interaction must mask the simplicity of their primary form. (D.C.W.)

BS>The average energy required to form an ion pair, W, when alpha particles are absorbed in mixtures of argon with other gases is studied. The other gases were selected on the basis of their ionization potentials. One group consists of representative gases that have ionization potentials below that of Ar (15.77 ev) and above the doublet metastable state of Ar (11.49 and 11.66 ev). This list includes methane, carbon dioxide, nitrous oxide, xenon, and krypton. The other group of special interest consists of some gases with ionization potentials below the metastable state of Ar. All gases tested in these two groups cause an increase in ionization, i e., a decrease in W, when added to argon. As an illustration of this effect, the addition of 1/2% of acetylene to Ar will increase the ionization by 23% The experimental data, i.e., W as a function of relative concentration of the two gases, were fitted to a model in which it is assumed that energy is transferred from two excited levels in argon to the additive gases in collision processes. Good agreement between the experimental data and calculations based on the model is taken as additional evidence that the excited state notion …

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Three Fortran programs, written for the IBM-704 computer, process the data from multichannel pulse-height analyzers in order to derive the Q values and differential cross sections of the groups observed. The standard deviations of the derived Q values and of the differential cross sections are also computed. With another program that was written, the effects of impurities can be subtracted from pulse-height spectra observed when a target contains a mixture of nuclides. A fifth program computes the centerof-mass transformation quantities by means of the exact relativistic equations. (auth)

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This is an analysis, based on a test conducted by LASL personnel, to determine whether relative expansion of two pieces of graphite under bundling loads would result in failure of the graphite.

Hot die sizing is one of three solid state diffusion bonding (SSDB) processes that has been proposed as an alternate manufacturing process for fabricating HAPO metallic uranium, aluminum-clad fuel elements. This document establishes the provisional process specifications for the assembly of fuel elements by the hot die sizing process. These specifications were developed for the CDB2N model fuel element (CSN equivalent AlSi model) and do not necessarily apply to any other model.

The EBR-II plant includes an integral, remote-controlled Fuel Cycle Facility wherein spent fuel elements are to be pyrometallurgically refined, refabricated, inspected, and reassembled for return to the reactor. A description is given of the experimentally supported changes and refinements made in the prototype sodium-bonding and bondinspection equipment to ensure: (1) acceptable fuel elements for the initial core loading; and (2) equally acceptable elements in production quantities in the parent installation. More specifically, the mode of imparting bonding energy to the fuel element was changed from a vibratory action to a series of timed impacts. This reflected an increase in the yield of acceptable elements and a reduction of machine operation time. A nondestructive, eddy-current instrument was developed and demonstrated as capable of detecting all defects in the liquid sodium bond. The diameter of the lower restrainer knob in the fuel element was increased to eliminate eccentricity as a contributor to erratic level of the sodium bond. As a result, the sodium level can be detected to a tolerance of plus or minus /1/64 in. with a single, encircling eddy-current coil. Shrinkage voids in the sodium were not encountered. However, laboratory test data are presented in support of the conclusions that: …

The design and development of rocket reactors are considered. Topics included are: thermodynamic calculations of vapor pressure of uranium dioxide, uranium xeonosulfide, uranium monocarbide, zirconium monocarbide, beryllia, and tungsten; thermodynamic calculations of equilibrium interactions of the above materials with hydrogen or water; verification of muitigroup constants used in reactor physics calculations; relations pertaining to a heat transfer parameter study; a heat transfer coefficient correlation for hydrogen; a FORTRAN-II subroutine to compute thermal properties of hydrogen; considerations pertaining to reactor control; and fuel plate stress analyses. (N.W.R.)

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Standardized test facilities were developed and operate for investigating the compatibility of structural materials and flowing molten fluoride salts. The standard loop accommodates various combinations of materials, fluid, flow, rates, and temperature differentials and permits fabrication of components in sufficient quantity for cost reduction. The test loop consists of a pump, two heated sections, a cooled section, a drain tank, and a frozen-plug-type valve. Automatic controls and equipment were developed to prevent solidification of the salt mixtures (mp, 800 to 1100 un. Concent 85% F) in the event of a loss of power. Most test loops were fabricated of 0.5-in.-OD, 0.045-in.-wall tubing, and operate with a temperature differential of up to 200 un. Concent 85% F, a maximum wall temperature in the range 1200 to 1500 un. Concent 85% F, and a salt flow rate of up to 3 gpm. Twenty-five test loops were operated for an accumulated operating time of 290,00 hr. Individual loops were operated continuously for more than one year. (auth)

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One of the problems which may be encountered in the operation of NPR, or of any similar pressurized-water reactor, is the deposition of crud in the reactor core, particularly on the surfaces of the fuel elements. This crud consists primarily of iron oxides resulting from the corrosion of the piping. It has generally been found to deposit preferentially in a radiation field such as is present in the reactor core. Such deposition is undesirable for two reasons. First, the crud will become activated, and on subsequent release may create radioactivity levels in the ex-reactor components of the primary loop high enough to be a hazard to maintenance and operating personnel. Secondly, the crud deposit is a poor conductor of heat, and even a rather thin film can raise the cladding temperature by 100 -- 200{degree}C and result in accelerated corrosion of the cladding.

Progress is reported on research directed toward. the development of adhesives, which are compatible with explosives; the measurement of nuclear properties of polonium isotopes; residue adsorption; separation and purification of isotopes; thermal diffusion theory analyses; emission strength analyses for neutron sources; and krypton-85 counting methods development. (B.O.G.)

Separate abstracts were prepared for 7 sections of this report. A list is included of publications during the period covered by this report. (C.H.)

It is shown that vector mesons may become Regge particles in higher orders of renormalizable perturbation theory. (auth)

Centrifugally cast stainless steel piping was selected for the primary piping of Spert III, a 2500-psi, 650 deg F water moderated and cooled nuclear reactor system, because of the significant cost advantage of using cast piping and because of favorable results from metallurgical examinations of the material. Essentially no operating experience was available at that time on the performance of cast piping in elevated pressure and temperature service. Presented are a brief history of operational experience with this piping in Spert III, the results of a recent plant inspection, and the results of the initial metallurgical examination of centrifugally cast material. On the basis of the Spert experience, it can be concluded that centrifugally cast stainless steel pipe has given adequate service under cyclic operation and probably is equal to high-pressure stainless steel piping fabricated by other methods. However, due to the limited general use of this material, no statement can be made as to the usual commercial quality of cast piping or to its performance under conditions other than those reported. (auth)