The effects of the angular range of data taking in reconstructions in planar positron cameras using the deconvolution method and the matrix method, respectively, are investigated. It is found that in the absence of any a priori information there are undetermined components in the reconstruction if the field of view of the positron camera is limited. However, most of the undetermined components are recovered in the case in which the transverse spacing of the object is discrete, and all of them are recovered if the fact that the object extent is finite is utilized. It is concluded that the two reconstruction methods are mathematically equivalent. The results obtained can be applied to other transmission and emission imaging devices.

Fabrication of experimental breeder reactor fuel pellets by the common cold-press-and-sinter technique for irradiation testing in EBR-II is discussed. Fuel types include mixed thoria-plutonia, UO/sub 2/ enriched with 22 weight percent /sup 233/U in U, UO/sub 2/ enriched with thirty-four weight percent /sup 235/U in U, and mixed urania-plutonia.

A computer system to control and acquire data from one x-ray diffraction, five neutron scattering, and four neutron diffraction experiments located at the Brookhaven National Laboratory High Flux Beam Reactor has operated in a routine manner for over three years. The computer system is configured as a network of computer processors with the processor interconnections assuming a star-like structure. At the points of the star are the ten experiment control-data acquisition computers, referred to as application nodes. At the center of the star is a shared service node which supplies a set of shared services utilized by all of the application nodes. A program development node occupies one additional point of the star. The design and implementation of a network subsystem to support development and execution of operating systems for the application nodes is described. 6 figures, 1 table.

The potential impact of fire can be characterized by (I) the probability of ignition, (II) the probability distribution of fire growth as a function of time, and (III) the conditional probability distribution of losses given that a fire has broken out. The original ignition of unwanted fires has four principal causes of ignition: loss of control of wanted fire, arson, spontaneous combustion, and malfunction of equipment. Loss of control refers to ignitions which start with a planned or wanted ignition, but which, due to human error causing a sufficient heat transfer to the target fuel, results in unwanted spread. Malfunction refers to equipment failures such as overloaded electrical circuits or exploding heaters. A fault tree example based on the results of the National Household Fire Survey is constructed for the common situation of fire starting in a kitchen. The minimum cut sets of the fault tree are a listing of the possible fire scenarios to which probability of occurrence can be quantitatively assigned by using fire statistics from the field.

Versatile, portable, rugged, and compact test and control modules for use in the development and testing of detection equipment for high-energy physics experiments are frequently needed at SLAC. The basic system developed is based on an LSI-11 microcomputer with 24K RAM, 4K ROM, 2 serial interfaces (one to the console terminal, the other to the large SLAC IBM computer complex (the TRIPLEX)), a programable clock, and a CAMAC crate controller. Data logging support is provided for magnetic tape, floppy disk, and an interactive program (ACQUIRE) which runs on the TRIPLEX under the timesharing system ORVYL. Data are read from various CAMAC modules, collected, buffered, and optionally logged. At a lower priority, the data read are sampled and analyzed in real-time on the LSI-11 to produce various histograms and tables. Concurrently, a more extensive analysis can be performed by the TRIPLEX program on the data which are logged to it. Interactive facilities provided by the microcomputer operating system enable the user to change CAMAC module addresses and the function codes used with them, specify various data cuts and transformations that are to be performed on the sample data, and specify new histogram limits and titles. Results of the real-time analysis, by …

The angular distribution of the avalanche around the anode wire in the gas proportional counter is determined by measuring the distribution of positive ions arriving on cathode strips surrounding the anode wire for each single event. The shape and width of the distribution depend on such factors as the gas gain, the anode diameter, the counting gas and the primary ionization density. Effects of these factors are studied systematically, and their importance for practical counter applications is discussed.

Distinctive mounds of till occur 100 to 240 meters above the present Columbia River along the western margins of the Pasco and Quincy basins. These mounds were formed by melting of grounded icebergs after inundation of the basins by the catastrophic glacial Lake Missoula flood(s). Most of the bergmounds are circular in plan and range in size from small clusters of erratics to mounds 50 meters in diameter and up to 4 meters high. The detritus is composed predominantly of granite, slate, argillite, quartzite, gneiss, and basalt, with grain size ranging from clay-size paticles to boulders up to 3 meters intermediate diameter. The pebbles and cobbles are glacially polished and fine-grained clasts are often striated. The bergmounds can be grouped into 4 classes on the basis of clast lithology. The most commonly occurring bergmounds are composed of 85 to 100 percent granitic debris. Bergmounds exhibiting mixed lithologies are also common. Less common are bergmounds composed of greater than 85 percent basalt and mounds composed predominantly of quartzite. The bergmounds occur in groups and are rarely found as isolated mounds. The elevation and distribution of bergmounds are related to fluvial currents and depths of the flood waters with iceberg grounding in …

Since the inception of the hypothesized transition phase, for the late stages of a postulated LMFBR accident, there has been a continual effort to characterize the anticipated conditions of such a hypothetical state. To date, several techniques and methods have been employed to analyze the potential for energetic criticality. As part of this effort, an arbitrary criterian of monotonical dispersiveness has been employed as the measure of diminished recriticality potential. The various attempts to demonstrate monotonic dispersiveness have included experimental demonstrations, theoretical approaches, and integrated analysis using both. As part of this treatment, flow regime maps have been devised as a convenient method for inferring the state of dispersiveness. They included bubbly, churn turbulent, foam and drop fluidized regimes. Of these, foam and drop fluidized regimes were considered the most dispersive. The main thrust of the analysis to date, including flow regime maps, relates primarily to the open pool configuration. However, the bottled configuration may be the pertinent geometry. To date, no reliable escape path has been demonstrated for the advanced stages of core disruption, although strong potential escape mechanisms have been identified and are currently being analyzed. The bottled pool is examined in this paper.

Transport by groundwater is the most likely means of escape for radioactive waste contained in a geologic repository. The rock formations through which the groundwater flows are characterized by inhomogeneities on all distance scales. Large scale inhomogeneities cause pulses of dissolved pollutants to spread both in the direction of motion and transverse to it. This phenomenon is known as macroscopic dispersion. Similarly, inhomogeneities in the chemical properties of the rock will cause this spreading to be greater for species whose movement through the rock is retarded by waste rock chemical interactions. Previous risk analyses of nuclear waste disposal which have ignored macroscopic dispersion found that predicted radiation doses to individuals are very sensitive to the waste dissolution time. When macroscopic dispersion is incorporated into the analysis, however, the sensitivity of risk to dissolution time is greatly reduced. 6 figures, 2 tables.

A complete charge-division mechanism, including both the diffusion and the electromagnetic wave propagation on resistive electrodes, is presented. The charge injected into such a transmission line divides between the two ends according to the ratio of resistancies and independently of the value of the line resistance, of the propagation mechanism and of the distribution of inductance and capacitance along the line. The shortest charge division time is achieved for Rl = 2..pi.. (L/C)/sup 1///sub 2/, where R, L, C are resistance, inductance and capacitance per unit length and l is the length of the line.

The proposed system consists of a gas-filled cell through which the singly-charged ions pass to strip off some additional electrons. This beam, consisting of several charge states, is then passed through a spectrometer which selects only that charge state chosen for further acceleration. The spectrometer is designed to use an annular-gap magnet which matches the geometry of the beam. Preliminary calculations for the acceptance and resolution of the spectrometer are shown.

The growing acceptance of containment and surveillance as a means to increase safeguards effectiveness has provided impetus to the development of improved surveillance and containment devices. Five recently developed devices are described. The devices include one photographic and two television surveillance systems and two high security seals that can be verified while installed.

In order to be economically viable, sodium-cooled reactors must operate at fairly high temperatures (500/sup 0/C) and with long, uninterrupted fuel cycles. These conditions increase the potential for radioactive corrosion product transport; achieving the goal of long uninterrupted fuel cycles means that release and transport of fission products from breached fuel pins will undoubtedly have to be controlled. This ppaper shows that control of radioactive material transport is an achievable goal.

The system consists of a data input subsystem, a display subsystem and a spectrometer control subsystem. The data input subsystem consists of a two-dimensional analog-to-digital converter with the analog section remote from the rest of the system. The analog-to-digital converter clock runs at 100 MHz. There can be up to 1024 channels in each dimension for a maximum array size of approx. 1 million words. Arrays of this size may be easily handled by a multiport memory with 6.71 x 10/sup 7/ words of address space. The read/increment/write time for data in this array is 2.5 ..mu..sec per event. The display and neutron spectrometer subsystem are also briefly described.

Deep Level Transient Spectroscopy (DLTS) has been applied for the first time to high-purity germanium p-i-n diodes. Using the correlator technique, a large number of peaks due to acceptor levels in the forbidden band have been observed. The levels due to substitutional copper, to copper--hydrogen complexes and to divacancy-hydrogen defects have been positively identified. Several unknown levels have been discovered. The results obtained with DLTS are in excellent agreement with results from Hall-effect measurements. DLTS is the perfect tool to follow the creation and annealing of radiation defects.

An extractor for accelerating 50 A of deuterium ions to 10 keV for injection into a metal-vapor charge-exchange cell has been designed. The beam-forming electrodes are convection cooled and capable of continuous service.

Transuranium elements have been introduced to the environment by a variety of ways including fallout from weapons testing, leakage from nuclear power reactors, waste effluent from nuclear fuel processing and leakage of radioactive waste from ocean dump sites. Several methods of curium detection and analysis in samples from marine ecosystems are contrasted and discussed in this paper.

Double-shelled inertial confinement fusion targets in which the outer shell is exploded have been studied with LASNEX. To achieve high DT density, configurations have been found in which the inner shell is ablatively driven by the hot outer shell. Calculations indicate that greater than 100 times liquid DT density can be achieved with the Shiva laser while still retaining some of the symmetry and stability advantages of the single-shelled exploding pusher target. The relative merits of transferring energy to the inner shell by electron conduction and by hydrodynamic work will be discussed.

(100) and (113) direction high-purity germanium crystals with dislocation densities > 10/sup 4/ cm/sup -2/ have been examined by Hall effect, Deep Level Transient Spectroscopy and gamma-ray spectrometer performance. High dislocation density in (100) crystals appears to give rise to acceptor levels which cause broadened and/or asymmetric photopeaks. (113) crystals with EPD > 10/sup 4/cm/sup -2/ do not show these effects.

Two processes that have the potential to produce degradation in the properties of pressure boundary materials are neutron irradiation and long-time thermal aging. This paper uses linear-elastic fracture mechanics techniques to assess the effect of these two processes upon the fatigue-crack growth behavior of a number of alloys commonly employed in reactor pressure boundaries. The materials evaluated include ferritic steels, austenitic stainless steels, and nickel-base alloys typical of those employed in a number of reactor types including water-cooled, gas-cooled, and liquid-metal-cooled designs.

The effect of microstructure of two phase alloys, consisting of a softer, ductile matrix and a harder interspersed phase, on erosion behavior was determined. The stress and strain distribution in a two phase alloy where the second, hard phase is a distribution of particles in a more ductile matrix was calculated. It was determined that a spheroidized 1075 carbon steel eroded 30 percent less than a pearlitic microstructure of the same steel even though the spherodized form was 21 R/sub B/ points of hardness lower than that of the pearlitic steel. The computerized calculation of stresses and strains from the impact of eroding particles on a two phase alloy surface were used to define the ability of the particle impact to induce voids and cracks in the target material that could cause material loss. The resultant predicted voids and cracks were related to experimentally determined behavior of spherodized steel.

A high yield lithium injection fusion energy chamber is described which can conceptually be operated with pulsed yields of several thousand megajoules a few times a second, using less than one percent of the gross thermal power to circulate the lithium. The concept is suitable for either lasers or heavy ion beams propagating in background gases. Because a one meter thick blanket of lithium protects the structure, no first wall replacement is envisioned for the life of the power plant. The induced radioactivity is reduced by an order of magnitude over solid blanket concepts. The design calls for the use of common ferritic steels and a power density approaching that of a LWR, promising shortened development times over other fusion concepts and reactor vessel costs comparable to a LMFBR.

At the Lawrence Livermore Laboratory, about 10% of the sampling effort in the environmental monitoring program represents replicate sample collection. Replication of field samples was initiated as part of the quality assurance program for environmental monitoring to determine the reproducibility of environmental measurements. In the laboratory these replicates are processed along with routine samples. As all components of variance are included in analysis of such field samples, comparison of the analytical data from replicate analyses provides a basis for estimating the overall reproducibility of the measurements. The replication study indicates that the reproducibility of environmental radioactivity monitoring data is subject to considerably more variability than is indicated by the accompanying counting errors. The data are also compared with analyses of duplicate aliquots from a well mixed sample or with duplicate aliquots of samples with known radionuclide content. These comparisons show that most of the variability is associated with the collection and preparation of the sample rather than with the analytical procedures.

The Department of Energy is proposing to demonstrate the acceptability of geologic disposal of radioactive waste by locating a Waste Isolation Pilot Plant (WIPP) in the salt beds 26 miles east of Carlsbad, New Mexico. The WIPP will serve as a permanent repository for defense generated transuranic contaminated waste and will also be used as a facility in which experiments and demonstrations with all radioactive waste types can be conducted. Rock salt has been the leading candidate for geologic disposal of nuclear waste since the National Academy of Science recommended in 1957 that salt for repositories receive further evaluation. Subsequent studies have failed to reveal any phenoomena which would disqualify salt beds as a repository medium. The present area being proposed for the WIPP is the second such location in the Delaware Basin for which new site data have been devloped; the first site proved geologically unacceptable. Ecologic and socioeconomic aspects have been investigated and extensive geophysical, geologic and hydrologic studies have been conducted to allow an evaluation of site acceptability. This paper will deal principally with the geotechnical aspects of site characterization. These studies are now sufficiently complete that the site can be recommended for further development of the …