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We have performed experiments investigating detonation corner turning over a range of high-explosives including LX-17, Composition B, LX-04 and Tritonal. The primary diagnostic utilized here was a new high-resolution x-ray system that was capable of recording a time sequence of the detonation process as it negotiated the corner of interest and propagated. For LX-17 our data detail the formation of a significant dead-zone. Although the detonation eventually turned the corner in LX-17, the dead zone persisted to late times and evidence exists that it never was consumed by either detonation or fast combustion processes. In LX-17 the detonations ability to corner-turn increases as the density is reduced. Furthermore, lowering the density decreases the size of the dead-zone and alters its shape. The other high-explosives investigated were able to turn the corner immediately with no indication of any dead-zone formation.

This paper is the final report for a project to do characterization studies on the KrF laser system. The project did experimental work on KrF lasers in support of modeling studies, with the objective being to see if this technology could be competitive for use in the ICF program. This program has provided LANL with data critical for their model development. Section 2 describes the laser extraction experiments together with the calibration of the diagnostics and the re-examination of the analysis procedure. Section 3 discusses the gain and transient absorption measurements, and Section 4 gives the conclusion for this program.

The stability properties of partial toroidal flux ropes are studied in detail in the laboratory, motivated by ubiquitous arched magnetic structures found on the solar surface. The flux ropes studied here are magnetized arc discharges formed between two electrodes in the Magnetic Reconnection Experiment (MRX) [Yamada et al., Phys. Plasmas, 4, 1936 (1997)]. The three dimensional evolution of these flux ropes is monitored by a fast visible light framing camera, while their magnetic structure is measured by a variety of internal magnetic probes. The flux ropes are consistently observed to undergo large-scale oscillations as a result of an external kink instability. Using detailed scans of the plasma current, the guide field strength, and the length of the flux rope, we show that the threshold for kink stability is governed by the Kruskal-Shafranov limit for a flux rope that is held fixed at both ends (i.e., qa = 1).

The Fermi FEL will depend critically on precise timing of its RF, laser and diagnostic subsystems. The timing subsystem to coordinate these functions will need to reliably maintain sub-100fs synchronicity between distant points up to 300m apart in the Fermi facility. The technology to do this is not commercially available, and has not been experimentally demonstrated in a working facility. Therefore, new technology must be developed to meet these needs. Two approaches have been researched by different groups working with the Fermi staff. At MIT, a pulse transmission scheme has been developed for synchronization of RF and laser devices. And at LBL, a CW transmission scheme has been developed for RF and laser synchronization. These respective schemes have advantages and disadvantages that will become better understood in coming years. This document presents the work done by both teams, and suggests a possible system design which integrates them both. The integrated system design provides an example of how choices can be made between the different approaches without significantly changing the basic infrastructure of the system. Overall system issues common to any synchronization scheme are also discussed.

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The carbon isotope ratios of carbon dioxide fluxes from terrestrial ecosystems are key measurements needed to constrain interpretations of carbon sinks in North American carbon cycle analyses. The completed research was a multi-faceted effort addressing photosynthetic and respiratory isotope exchanges across the biosphere-atmosphere boundary at five AmeriFlux sites (Harvard Forest, Howland Forest, Rannalls Ranch, Niwot Ridge Forest, and Wind River Crane Site), spanning the dominant ecosystem types of the United States. The sampling and analysis protocols developed in this project have become the fundamental analytical approach for all sites measuring ecosystem isotope studies across the United States and Canada. It is the first network of long-term observations to characterize the isotopic composition of the biosphere-atmosphere CO2 flux. We focused on understanding the magnitude of changes in the carbon isotope ratio of respiration and of photosynthetic discrimination on seasonal and interannual bases. Focusing at AmeriFlux sites provided a direct link to NEE measurements associated with studies of the North American carbon cycle and an opportunity to provide mechanistic insights relating observed isotope changes and the controls over carbon sequestration and loss on seasonal and interannual bases. An additional component of our research linked directly with eddy covariance monitoring to partition NEE …

Following the shutdown of the B Pile in March 1946 a method was devised for monitoring the sub-critical reactivity such that any significant change in neutron flux would be detected. This report summarizes the status of the unit until its start up in July 1948.

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We describe a highly-detailed experimental characterization of the impulsively driven Rayleigh-Taylor instability, called the Richtmyer-Meshkov instability. This instability is produced by flowing a diffuse, vertical curtain of heavy gas (SF{sub 6}) into the test section of an air-filled horizontally oriented shock tube. The instability evolves after the passage of a Mach 1.2 shock past the curtain, and the development of the curtain is visualized by seeding the SF{sub 6} with small (d{approximately}0.5 and micro;m) glycol droplets using a modified theatrical fog generator. Because the event lasts only 1 ms and the initial conditions vary from test to test, rapid and complete data acquisition is required in order to characterize the initial and dynamic conditions for each experimental shot. Through the use of a custom-built pulsed Nd: YAG laser, we are able to image the flowfield at seven different times. We acquire a double-pulsed image of the flow with the use of a second pulsed Nd:YAG, which is used to determine the instantaneous velocity field using Particle Image Velocimetry (PIV). During a single experiment, high resolution images of the initial conditions and dynamic conditions are acquired using three CCD cameras. Issues of the fidelity of the flow seeding technique and the …

A fluidized bed incineration facility has been installed at the Rocky Flats Plant to develop and demonstrate a process for the combustion of transuranic waste. The unit's capacity is about 82 kg/hr of combustible solid waste, which is nine times higher than the rate for the operating pilot-scale unit. The facility utilizes nonaqueous, in situ neutralization of acid gases. These gases are generated during the combustion of halogen-containing materials. The low-temperature (550 /sup 0/C) operation eliminates refractory-lined equipment.

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Sphere-pac fuel consists of a blend of spheres of two or three different size fractions contained in a fuel rod. The smear density of the sphere-pac fuel column can be adjusted to the values obtained for light-water reactor (LWR) pellets (91-95%) by using three size fractions, and to values typical of the fast-reactor oxide fuel column ({approx}85%) by using two size fractions. For optimum binary packing, the diameters of the two sphere fractions must differ by at least a factor of 7 (ref. 3). Blending of spheres with smaller-diameter ratios results in difficult blending, nonuniform loading, and lower packing fractions. A mixture of about 70 vol% coarse spheres and 30 vol% fine spheres is needed to obtain high packing fractions. The limiting smear density for binary packing is 86%, with about 82% achieved in practice. Ternary packing provides greater smear densities, with theoretical values ranging from 93 to 95%. Sphere-pac technology was developed in the 1960-1990 period for thermal and fast spectrum reactors of nearly all types (U-Th and U-Pu fuel cycles, oxide and carbide fuels), but development of this technology was most strongly motivated by the need for remote fabrication in the thorium fuel cycle. The application to LWR …

This document details the activities of the Fuels Preparation Department during the month of June 1957.

In fusion reactors, the blanket design and its characteristics have a major impact on the reactor performance, size, and economics. The selection and arrangement of the blanket materials, dimensions of the different blanket zones, and different requirements of the selected materials for a satisfactory performance are the main parameters, which define the blanket performance. These parameters translate to a large number of variables and design constraints, which need to be simultaneously considered in the blanket design process. This represents a major design challenge because of the lack of a comprehensive design tool capable of considering all these variables to define the optimum blanket design and satisfying all the design constraints for the adopted figure of merit and the blanket design criteria. The blanket design techniques of the First Wall/Blanket/Shield Design and Optimization System (BSDOS) have been developed to overcome this difficulty and to provide the state-of-the-art techniques and tools for performing blanket design and analysis. This report describes some of the BSDOS techniques and demonstrates its use. In addition, the use of the optimization technique of the BSDOS can result in a significant blanket performance enhancement and cost saving for the reactor design under consideration. In this report, examples are …

The design status of the vacuum vessel for the Fusion Ignition Research Experiment (FIRE) is presented. The purpose and configuration of the various components of the vessel are described, along with the results of preliminary structural analysis. It appears that a vessel can be designed to meet the requirements within the rather restricted space constraints.

The primary purpose of the annual meeting between the corrosion monitoring personnel at the various DOE sites is to facilitate communications and promote technology transfer between the two sites. The close communications and good spirit of teamwork being exhibited between the parties representing the Hanford and Savannah River Sites has helped the Savannah River Site effort avoid many of the problems encountered during the initial development effort at Hanford. Similar benefits can be expected over the next few years as the ORNL program is developed. Expected products of this meeting as defined in Milestone A.4-1 of TTP RL0-9-WT-41 are reports on the status of technical work at the sites, discussions of emerging technical issues, and results of laboratory experiments and field trials. The formal meeting, informal discussions throughout the week, and the presentation materials shown in the attachment to this document fulfill the expectations of this meeting. At the conclusion of the meeting it was agreed that close communications should continue between the concerned parties at ORNL, SRTC and Hanford. Tentative plans were made to hold a similar meeting in approximately one year.

The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the safety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program will require the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear weapon design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable stockpile life extension programs and the resolution of significant finding investigations (SFIs). This requires a balanced system of technical staff, hardware, simulation software, and computer science solutions.

Gas desorption and electron emission coefficients were measured for 1 MeV potassium ions incident on stainless steel at grazing angles (between 80 and 88 from normal incidence) using a new gas-electron source diagnostic (GESD). Issues addressed in design and commissioning of the GESD include effects from backscattering of ions at the surface, space-charge limited emission current, and reproducibility of desorption measurements. We find that electron emission coefficients {gamma}{sub e} scale as 1/cos({theta}) up to angles of 86, where {gamma}{sub e} = 90. Nearer grazing incidence, {gamma}{sub e} is reduced below the 1/cos({theta}) scaling by nuclear scattering of ions through large angles, reaching {gamma}{sub e} = 135 at 88. Electrons were emitted with a measured temperature of {approx}30 eV. Gas desorption coefficients {gamma}{sub sigma} were much larger, of order {gamma}{sub sigma} = 104. They also varied with angle, but much more slowly than 1/cos({theta}). From this we conclude that the desorption was not entirely from adsorbed layers of gas on the surface. Two mitigation techniques were investigated: rough surfaces reduced electron emission by a factor of ten and gas desorption by a factor of two; a mild bake to 230 had no effect on electron emission, but decreased gas desorption by …

The authors developed a transient model to describe the process of gas generation due to radiolysis and bubble formation in crystalline silicotitanate (CST) ion exchange (IX) columns using the Aspen Custom Modeler (ACM) software package. The model calculates gas concentrations and onset of bubble formation for large CST IX columns. The calculations include cesium loading as a function of time, gas generation as a function of cesium loading, and bubble formation as a function of gas solubility. This report summarizes the model development and predictions.

In this paper we evaluate the gas production potential ofdisperse, low-saturation (SH<0.1) hydrate accumulations in oceanicsediments. Such hydrate-bearing sediments constitute a significantportion of the global hydrate inventory. Using numerical simulation, weestimate (a) the rates of gas production and gas release from hydratedissociation, (b) the corresponding cumulative volumes of released andproduced gas, as well as (c) the water production rate and the mass ofproduced water from disperse, low-SH hydrate-bearing sediments subject todepressurization-induced dissociation over a 10-year production period.We investigate the sensitivity of items (a) to (c) to the followinghydraulic properties, reservoir conditions, and operational parameters:intrinsic permeability, porosity, pressure, temperature, hydratesaturation, and constant pressure at which the production well is kept.The results of this study indicate that, despite wide variations in theaforementioned parameters (covering the entire spectrum of suchdeposits), gas production is very limited, never exceeding a few thousandcubic meters of gas during the 10-year production period. Such lowproduction volumes are orders of magnitude below commonly acceptedstandards of economic viability, and are further burdened with veryunfavorable gas-to-water ratios. The unequivocal conclusion from thisstudy is that disperse, low-SH hydrate accumulations in oceanic sedimentsare not promising targets for gas production by means ofdepressurization-induced dissociation, and resources for early hydrateexploitation should be focused elsewhere.

This report summarizes both general corrosion of Alloy 22 from 60 to 220 C and the stability of the passive (oxide) film from 60 to 90 C over a range of solution compositions that are relevant to the in-drift chemical environment at the waste package surface. The general corrosion rates were determined by weight-loss measurements in a range of complex solution compositions representing the products of both the evaporation of seepage water and also the deliquescence of dust previously deposited on the waste canisters. These data represent the first weight-loss measurements performed by the program at temperatures above 90 C. The low corrosion rates of Alloy 22 are attributed to the protective oxide film that forms at the metal surface. In this report, changes in the oxide film composition are correlated with weight loss at the higher temperatures (140-220 C) where film characterization had not been previously performed. The stability of the oxide film was further analyzed by conducting a series of electrochemical tests in progressively more acidic solutions to measure the general corrosion rates in solutions that mimic crevice or pit environments.

We report generation of density modulation at terahertz (THz) frequencies in a relativistic electron beam through laser modulation of the beam longitudinal phase space. We show that by modulating the energy distribution of the beam with two lasers, density modulation at the difference frequency of the two lasers can be generated after the beam passes through a chicane. In this experiment, density modulation around 10 THz was generated by down-converting the frequencies of an 800 nm laser and a 1550 nm laser. The central frequency of the density modulation can be tuned by varying the laser wavelengths, beam energy chirp, or momentum compaction of the chicane. This technique can be applied to accelerator-based light sources for generation of coherent THz radiation and marks a significant advance toward tunable narrow-band THz sources.

In a previous paper we developed a simple model describing the far-field from a video-pulse source near the ground and for grazing incidence. We report here on a recent field test in which we attempted to verify the model. Our results show quantitative agreement with the model for most of the tested parameter space. We have also extended our model to include all elevation angles, including up to vertical. The computed engagement envelope shows three distinct regions: At grazing angles the field is small and diminishes to near zero at the earth's surface; at low-to moderate angles strong lobing occurs; at high angles the video-pulse field approaches its free-space form. 6 refs., 16 figs.