Report issued by the Argonne National Laboratory discussing progress made by the Reactor Development Program during April 1963. Reactor physics, experiments, and safety studies are presented. This report includes tables, and illustrations.

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)

Abstract. the direct and inert-gas radiolysis, as well as the vacuum ultra-violet photolysis of CD3CH2CD3, CH3CD2CH3 and C3H2+C3D3 mixtures have been investigated in the presence of radical scavengers. The major conclusions are : (a) at atmospheric pressures, neutral propane decomposition contributes to the observed products although to a lesser extent than parent ion decompositions ; (b) a variation in pressure has a pronounced effect on the fragmentation of the parent ion ; (c) the hydrogen atoms in the ethyl ion are randomized in the direct as well as in the inert-gas sensitized radiolysis ; (d) rearrangement in the parent ion is of minor importance in the radiolysis ; (e) although the formation of propylene is related to the propyl ion, it is not necessarily produced by the neutralization of this ion.

Report summarizing "the utilization of the Health Physics Research reactor and a Co60 source during Operation BREN" and offers related meteorological data relating radiation emissions.

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 physics calculations to be performed on the Consumers On-Line Process Computer are reported. As a result of these calculations, a three-dimensional power shape is simulated, a reactivity balance is approximated, and the neutron exposure of each third of fuel bundle and control rod are accumulated. The work was reported as a part of the Consumers Research and Development Program.

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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Report documenting the process of decontaminating low-activity fuel waste water via the Scavenging-Precipitation Ion-Exchange process. This includes analyses of the costs of the process as well as a description of the operation of the pilot plant.

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: …

From Introduction : "In this paper we describe a choice of normal elliptic integrals which appears to be very well suited for use in integral tables as well as for numerical work."

When beryllium is irradiated by fast neutrons, helium is produced by the (n,2n) and (n,α) transmutation reactions. Electron microscopy techniques have been used to study the nucleation and distribution of helium bubbles in several different grades of beryllium, after irradiation at temperatures in the range 75 — 700ºC. The effect of post-irradiation annealing is also reported. It is shown that for similar neutron doses and irradiation temperatures, there were wide variations in helium bubble size and distribution in specimens of beryllium fabricated by different methods. The most satisfactory material was that fabricated from Pechiney powder by direct hot extrusion followed by annealing for one hour at 800ºC and air cooling, it is suggested that the helium bubbles nucleate on second phase precipitates and that the distribution of this phase is strongly affected by fabrication and heat treatment.

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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