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The purpose of this report is to develop a new dry cooling tower surface.

The major fission-product parameters [sigma/sub th/, RI, tau/sub 1/2/, E- bar/sub $beta$/, E-bar/sub $gamma$/, E-bar/sub $alpha$/, decay and (n,$gamma$) branching, Q, and AWR] abstracted from ENDF/B-IV files for 824 nuclides are summarized. These data are most often requested by users concerned with reactor design, reactor safety, dose, and other sundry studies. The few known file errors are corrected to date. Tabular data are listed by increasing mass number. (auth)

An investigation was made of a series of binary americium alloys with AB$sub 2$ stoichiometry (B = Al, Co, Fe, Rh and Ru) prepared from the $sup 243$Am isotope. The C-15 (MgCu$sub 2$-type) structure appears in AmAl$sub 2$, AmCo$sub 2$, AmFe$sub 2$, and AmRh$sub 2$, whereas AmRu$sub 2$ is isostructural with AmOs$sub 2$ which has the C-14 (MgZn$sub 2$-type) structure. The magnetic properties of the cubic americium laves phases were studied by means of magnetization and nuclear gamna-ray resonance (Moessbauer effect) measurements between 2.5 and 300$sup 0$K. All the cubic Laves phases studied, except AmFe$sub 2$, exhibit almost temperature-independent paramagnetism. The AmFe$sub 2$ sample is ferromagnetic with an estimated Curie temperature of approximately 400$sup 0$K. The hyperfine field at the Am site in all the compounds is small. The bulk magnetic moment of AmFe$sub 2$ (approximately 3 $mu$/sub B//F.U.) is thus associated only with the Fe atoms. The magnetic properties of the compounds are consistent with the assumption that the Am ion is in the +3 state (5f6). (auth)

The automated spectrophotometer described is the first in a planned series of automated instruments for determining plutonium and uranium in nuclear fuel cycle materials. It has a throughput rate of 5 min per sample and uses a highly specific method of analysis for these elements. The range of plutonium and uranium measured is 0.5 to 14 mg and 1 to 14 mg, respectively, in 0.5 ml or less of solution with an option to pre-evaporate larger volumes. The precision of the measurements is about 0.02 mg standard deviation over the range corresponding to about 2 rel percent at the 1-mg level and 0.2 rel percent at the 10-mg level. The method of analysis involves the extraction of tetrapropylammonium plutonyl and uranyl trinitrate complexes into 2-nitropropane and the measurement of the optical absorbances in the organic phase at unique peak wavelengths. Various aspects of the chemistry associated with the method are presented. The automated spectrophotometer features a turntable that rotates as many as 24 samples in tubes to a series of stations for the sequential chemical operations of reagent addition and phase mixing to effect extraction, and then to a station for the absorbance measurement. With this system, the complications of …

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The Savannah River Plant (SRP) has routinely and continuously monitored the local environment (land, water, air, flora, and fauna) since 1951. As part of this intensive program, a three-part study was made to assess the tritium migration from an onsite burial ground for solid nuclear wastes and the resulting dose-to-man. A major source of tritium is buried, massive, Li-Al residues (referred to as melts) from the thermal extraction step in the SRP tritium production process. A melt with its extraction crucible and lid were immersed in water to measure the amounts of tritium released as HTO and HT to the water and to air. The result was a rapid release of 23 curies, of which approximately 99 percent was HTO that remained in the immersion water, and 1 percent was HT that passed into the air. (auth)

Specifications, operation, characteristics, cost, and experience with the NAL 15-ft bubble chamber are described. Beam availability and some experimental proposals are discussed. (WHK)

CHIT is the Los Alamos Scientific Laboratory's cost accounting computer program for nondestructive and destructive examinations of irradiated fuel pins. The program allows immediate retrieval of fuel pin examination information and provides itemized listings for completed and projected fuel pin examinations, detailed cost accounting summaries for each investigator, fuel pin examinations during a specified time interval, and various subsets of the information. CHIT has been in successful operation for the past two years, providing precise information on cost accounting more efficiently than possible with a manual technique. (auth)

The work done with element 106 is reviewed, and a new experiment which bears on the properties of the isotope of mass 260 with atomic number 104 is discussed. It is noted that in the case of element 106 a link is demonstrated to the granddaughter as well as the daughter. (JFP)

A new semi-classical method, the so-called uniform semiclassical approximation, is described briefly and then applied to two nuclear physics problems. The basic features of this method are that the dynamics of the problem is treated completely classically (that is, one solves classical equations of motion), but the quantum mechanical superposition principle is retained by evaluating a phase along the classical trajectory and adding probability amplitudes for indistinguishable processes rather than probabilities themselves. The first problem considered is the backscattering from a deformed nucleus and the excitation of rotational states in the target at energies up to the Coulomb barrier. The multiple Coulomb excitation calculations are in quantitative agreement with a very different method (the de Boer-Winther code). A nuclear optical potential is also considered and the nuclear-Coulomb interference for heavy ions is studied. The second problem considered is the tunneling through a two-dimensional barrier. This problem (which is supposed to simulate the penetration through a two-dimensional fission barrier) is investigated by a fully quantum-mechanical coupled-channel calculation and by the uniform semiclassical approximation. A quantitative agreement is found. (auth)

The folded-Yukawa model for the nuclear interaction potential is generalized to diffuse density distributions which are generated by folding a Yukawa function into sharp generating distributions. The effect of a finite density diffuseness or of a finite interaction range is studied. The Proximity Formula corresponding to the generalized model is derived and numerical comparison is made with the exact results. (8 figures) (auth)

A generalized, three-dimensional Monte Carlo model and computer code (SPOOR) are described for simulating atmospheric transport and dispersal of small pollutant clouds. A cloud is represented by a large number of particles that we track by statistically sampling simulated wind and turbulence fields. These fields are based on generalized wind data for large-scale flow and turbulent energy spectra for the micro- and mesoscales. The large-scale field can be input from a climatological data base, or by means of real-time analyses, or from a separate, subjectively defined data base. We introduce the micro- and mesoscale wind fluctuations through a power spectral density, to include effects from a broad spectrum of turbulent-energy scales. The role of turbulence is simulated in both meander and dispersal. Complex flow fields and time-dependent diffusion rates are accounted for naturally, and shear effects are simulated automatically in the ensemble of particle trajectories. An important adjunct has been the development of computer-graphics displays. These include two- and three- dimensional (perspective) snapshots and color motion pictures of particle ensembles, plus running displays of differential and integral cloud characteristics. The model's versatility makes it a valuable atmospheric research tool that we can adapt easily into broader, multicomponent systems- analysis codes. …

The Fort St. Vrain program has progressed through construction, preoperational testing, fuel loading, initial criticality, and operational testing at power levels up to 2 percent related power. To date, all tests necessary before the rise to full power have been completed, and the rise-to- power program is expected to be resumed again in late 1975. Major plant systems, including the prestressed concrete reactor vessel and circulators, have demonstrated adequate performance. Extensive tests on the reactor core at zero power and up to 2 percent power have demonstrated the accuracy in the design predictions of such core characteristics as critical rod position, control system worths, neutron flux distributions, and temperature coefficients. Gaseous fission product release measurements to date have confirmed the extensive analytical estimates. 6 references (auth)

SOLVEX is a FORTRAN IV computer program that simulates the dynamic behavior of solvent extraction processes conducted in mixer-settlers and centrifugal contactors. Two options permit terminating dynamic phases by time or by achieving steady state, and a third option permits artificial rapid close to steady state. Thus the program is well suited to multiple phases of dynamic problems and multiple input of steady state problems. Changes from the previous problem are the only inputs required for each succeeding problem. Distribution data can be supplied by two-variable third-power polynomial equations or by three- variable tables in any one of 16 different combinations involving phase concentrations or distribution coefficients (ratio of phase concentrations) or their logarithms. (auth)

Progress in HTGR safety research is reported under the following headings: fission product technology; primary coolant impurities; structural investigation; safety instrumentation and control systems; phenomena modeling and systems analysis. (JWR)

Load relaxation experiments were performed in the region where the grain matrix plastic deformation is important on type 316 stainless steel and a zircaloy specimen, and the data are being analyzed. Anelastic deformation in pure aluminum was investigated. A dislocation glide-controlled anelastic component is identified which may be governed by the same laws as those for plastic deformation at low temperature and/or high plastic strain rate. The investigation of grain boundary sliding in type 316 stainless steel is being continued. Experimental data without the influence of thermal aging are successfully obtained. Load relaxation data on single crystal and polycrystal nickel specimens show that the constant hardness curves of these specimens belong to two different families. The growth of the grain boundary cavity under applied stress and irradiation has been analyzed. It is found that the normal stress at the grain boundary which is the driving force for atomic transport controlled cavity growth can be relaxed by grain boundary sliding. (auth)

Waveforms and population distributions have been calculated by a numerical model and compared with experiment for an electric-discharge-initiated, pulsed NF$sub 3$ + H$sub 2$ chemical laser. The model treats each vibrational- rotational state separately, allowing rotational relaxation between adjacent states as well as vibrational relaxation and lasing according to P-branch selection rules. Calculated waveforms agree with experiment and show several features not seen when rotational equilibrium is assumed: simultaneous lasing on many transitions, cascade behavior, spikes due to laser relaxation oscillations, non-Boltzmann rotational distributions, and ''hole burning'' in the population distributions. The calculations give insight into the physical phenomena governing the shape and duration of the waveforms. The effect of varying certain parameters, relaxation rates, temperature, pressure, and diluents, is studied. Best fit to experimental waveforms is obtained when the rotational relaxation rate and collisional line broadening rate are approximately equal at about 10 times the hard sphere collision rate. The IXION computer code, developed for these calculations, is described in detail. In addition, an analytic model is presented which accounts for major features of the total (all transitions) output waveform of the laser assuming rotational equilibrium, a steady state laser model, and constant temperature. A second computer code, MINOTAR, …

Separate abstracts were prepared for 25 sections of the progress report. (SFL)

A computational method to determine cross-section requirements quantitatively is described and applied to the Tokamak Fusion Test Reactor (TFTR). In order to provide a rational basis for the priorities assigned to new cross- section measurements or evaluations, this method includes quantitative estimates of the uncertainty of currently available data, the sensitivity of important nuclear design parameters to selected cross sections, and the accuracy desired in predicting nuclear design parameters. Perturbation theory is used to combine estimated cross-section uncertainties with calculated sensitivities to determine the variance of any nuclear design parameter of interest. (auth)

A comprehensive development program plan for a high-temperature nuclear process heat system with a very high temperature gas-cooled reactor heat source is presented. The system would provide an interim substitute for fossil-fired sources and ultimately the vehicle for the production of substitute and synthetic fuels to replace petroleum and natural gas. The dwindling domestic reserves of petroleum and natural gas dictate major increases in the utilization of coal and nuclear sources to meet the national energy demand. The nuclear process heat system has significant potential in a unique combination of the two sources that is environmentally and economically attractive and technically sound: the production of synthetic fuels from coal. In the longer term, it could be the key component in hydrogen production from water processes that offer a substitute fuel and chemical feedstock free of dependence on fossil-fuel reserves. The proposed development program is threefold: a process studies program, a demonstration plant program, and a supportive research and development program. Optional development scenarios are presented and evaluated, and a selection is proposed and qualified. The interdependence of the three major program elements is examined, but particular emphasis is placed on the supportive research and development activities. A detailed description of …

As part of the Lawrence Livermore Laboratory program to assess the environmental impact of various types of nuclear power plants, methods are being investigated for the real-time analysis of reactor plume isotopic exposure rates. The Biomedical and Environmental Research Division mobile laboratory that was developed for terrestrial radioactivity measurements has been modified for atmospheric studies. The existing Ge(Li) spectrometer and high-pressure argon- ion chamber-detector systems have been augmented by the addition of wind speed and direction measuring capability and a second, remotely operable, ion chamber. The mobile laboratory and techniques for plume measurements are discussed. (auth)

Further studies of the structure of nuclei in the A = 180-200 shape transitional region have been performed. The principal project completed during the current year was an extensive in-beam $gamma$-ray investigation of high-spin levels in the nine nuclei $sup 186$Pt to $sup 194$Pt by ($alpha$,xn$gamma$) reactions on enriched Os targets. Acute backbending observed in the positive parity yrast sequences of $sup 188$,$sup 190$,$sup 192$,$sup 194$Pt has been attributed to the intersection of rotation-aligned ($nu$i-$sup 2$/sub 13/2/) and ($pi$h$sup -2$/sub 11/2/) bands with the ground bands. In all four odd-A Pt nuclei, decoupled $nu$i$sup -1$/sub 13/2/ bands and many other low-lying high- spin positive parity levels have been established, and low-spin positive parity levels have been located in complementary decay studies. A model of an i/sub 13/ 2/ neutron hole coupled to a triaxially deformed core has been found to be rather successful in reproducing these complex level spectra. Other topics dealt with include new $mu$s isomers in $sup 187$,$sup 189$,$sup 191$Pt, the decays of $sup 191$Au, /sup 194m/Ir and 1.7 h $sup 186$Ir and the level structure of $sup 191$Au from an $sup 191$Ir(alpha,4n$gamma$) study. (auth)

The effects of geometry, absorption and multiple scattering in (n,X$gamma$) reaction measurements with solid-cylinder samples are investigated. Both analytical and Monte-Carlo methods are employed in the analysis. Geometric effects are shown to be relatively insignificant except in definition of the scattering angles. However, absorption and multiple-scattering effects are quite important; accurate microscopic differential cross sections can be extracted from experimental data only after a careful determination of corrections for these processes. The results of measurements performed using several natural iron samples (covering a wide range of sizes) confirm validity of the correction procedures described herein. It is concluded that these procedures are reliable whenever sufficiently accurate neutron and photon cross section and angular distribution information is available for the analysis. (13 figures, 5 tables) (auth)