In its current design, the high-level nuclear waste containers include an external layer of Alloy 22 (NO6022). This material was selected to provide long-term corrosion resistance since if water enters in contact with the containers, they may undergo corrosion. The model for the degradation of the containers includes three modes of corrosion, namely general corrosion, localized corrosion and environmentally assisted cracking (EAC). The objective of the current research was to quantify the susceptibility of Alloy 22 to EAC in several environmental conditions with varying solution composition, temperature and electrochemical potential. The susceptibility to EAC was evaluated using constant deformation (deflection) U-bend specimens in both the wrought and welded conditions. Results show that after more than five years exposure in the vapor and liquid phases of alkaline (PH {approx} 10) and acidic (pH {approx} 3) multi-ionic environments at 60 C and 90 C, Alloy 22 was free from EAC.

The Scaled Thermal Explosion Experiment (STEX) has been developed to quantify the violence of thermal explosion under well defined and carefully controlled initial and boundary conditions. Here we present results with HMX-based explosives (LX-04 and PBX-9501) and with Composition B. Samples are 2 inches (50 mm) in diameter and 8 inches (200 mm) in length, under confinement of 7,500-30,000 psi (50-200 MPa), with heating rates of 1-3 C/hr. We quantify reaction violence by measuring the wall velocity in the ensuing thermal explosion, and relate the measured velocity to that expected from a detonation. Results with HMX-based explosives (LX-04 and PBX-9501) have shown the importance of confinement and HMX solid phase, with reaction violence ranging from mild pressure bursts to near detonations. By contrast, Composition B has shown very violent reactions over a wide range of conditions.

The technique of using a nsec prepulse to create and ionize the plasma followed by a psec pulse to heat the plasma has enabled us to achieve saturated laser output for low-Z neon-like and nickel-like ions driven by small lasers with less than ten joules of energy. In this work we model recent experiments done using the COMET laser at Lawrence Livermore National Laboratory to illuminate slab targets of Pd up to 1.25 cm long with a 2 joule, 600 ps prepulse followed 700 psec later by a 6 joule, 6 psec drive pulse. The experiments measure the two-dimensional near-field and far-field laser patterns for the 14.7 nm Ni-like Pd x-ray laser line. This line has already demonstrated saturated output. The experiments are modeled using the LASNEX code to calculate the hydrodynamic evolution of the plasma and provide the temperatures and densities to the CRETIN code, which then does the kinetics calculations to determine the gain. Using a ray tracing code to calculate the near and far-field patterns, the simulations are then compared with experiments. We also present several new schemes that we are modeling. The first scheme is Pd-like Nd that has a promising 5d-5p laser line near 24.3 …

We have studied the non-ideal propagation of detonation waves in LX-10 and in the insensitive explosive TATB. Explosively-driven, 5.8-mm-diameter, 0.125-mm-thick aluminum flyer plates were used to initiate 38-mm-diameter, hemispherical samples of LX-10 pressed to a density of 1.86 g/cm{sup 3} and of TATB at a density of 1.80 g/cm{sup 3}. The TATB powder was a grade called ultrafine (UFTATB), having an arithmetic mean particle diameter of about 8-10 {micro}m and a specific surface area of about 4.5 m{sup 2}/g. Using PMMA as a transducer, output pressure was measured at 5 discrete points on the booster using a Fabry-Perot velocimeter. Breakout time was measured on a line across the booster with a streak camera. Each of the experimental geometries was calculated using the Ignition and Growth Reactive Flow Model, the JWL++ Model and the Programmed Burn Model. Boosters at both ambient and cold (-20 C and -54 C) temperatures have been experimentally and computationally studied. A comparison of experimental and modeling results is presented.

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Transport mirrors within the National Ignition Facility, a 192-beam 4-MJ fusion laser at 1053 nm, will be exposed to backscattered light from plasmas created from fusion targets and backlighters. This backscattered light covers the UV and visible spectrum from 351-600 nm. The transport mirror BK7 substrates will be intentionally solarized to absorb >95% of the backscattered light to prevent damage to the metallic mechanical support hardware. Solarization has minimal impact on the 351- and 1053-nm laser-induced damage threshold or the reflected wavefront of the multilayer hafnia silica coating. Radiation sources of various energies were examined for BK7 darkening efficiency within the UV and visible region with 1.1 MeV gamma rays from a Cobalt 60 source ultimately being selected. Finally, bleaching rates were measured at elevated temperatures to generate a model for predicting the lifetime at ambient conditions (20 C), before solarized BK7 substrates exceed 5% transmission in the UV and visible region. Over a 30-mm thickness, BK7 glass will bleach in 10 years to 5% transmission at 600 nm, the most transmissive wavelengths over the 351-600 nm regions.

We have developed a Nd:doped cladding pumped fiber amplifier, which operates at 938nm with greater than 2W of output power. The core co-dopants were specifically chosen to enhance emission at 938nm. The fiber was liquid nitrogen cooled in order to achieve four-level laser operation on a laser transition that is normally three level at room temperature, thus permitting efficient cladding pumping of the amplifier. Wavelength selective attenuation was induced by bending the fiber around a mandrel, which permitted near complete suppression of amplified spontaneous emission at 1088nm. We are presently seeking to scale the output of this laser to 10W. We will discuss the fiber and laser design issues involved in scaling the laser to the 10W power level and present our most recent results.

The objective of this study was to measure the leaching and adsorption characteristics of uranium in six near-surface sediment samples collected from the 300 Area of the Hanford Site. Scanning electron micrographs of the samples showed that the uranium contamination in the sediments is most likely present as co-precipitates and/or discrete uranium particles. Molecular probe techniques also confirm the presence of crystalline discrete uranium bearing phases. In all cases, the uranium is present as oxidized uranium (uranyl [U(VI)]). Results from the column leach tests showed that uranium leaching did not follow a constant solubility paradigm. Four of the five contaminated sediments showed a large near instantaneous release of a few percent of the total uranium followed by a slower continual release. Steady-state uranium leachate concentrations were never measured and leaching characteristics and trends were not consistent among the samples. Dissolution kinetics were slow, and the measured leach curves most likely represent a slow kinetically controlled desorption or dissolution paradigm. Batch adsorption experiments were performed to investigate the effect of pH and uranium and carbonate solution concentrations on uranium adsorption onto the uncontaminated sediment. Uranium adsorption Kd values ranged from 0 to > 100 ml/g depending on which solution parameter was …

Solute effect on the creep resistance of two-phase lamellar TiAl with an ultrafine microstructure creep-deformed in a low-stress (LS) creep regime [where a linear creep behavior was observed] has been investigated. The resulted deformation substructure and in-situ TEM experiment revealed that interface sliding by the motion of pre-existing interfacial dislocations is the predominant deformation mechanism in LS creep regime. Solute segregation at lamellar interfaces and interfacial precipitation caused by the solute segregation result in a beneficial effect on the creep resistance of ultrafine lamellar TiAl in LS creep regime.

A model-based detection scheme is developed to passively monitor an ocean acoustic environment along with its associated variations. The technique employs an embedded model-based processor and a reference model in a sequential likelihood detection scheme. The monitor is therefore called a sequential reference detector. The underlying theory for the design is developed and discussed in detail.

The knowledge gained from scientific observation, experiment, and simulation is linked to the ability to analyze, understand, and manage the generated results. These abilities are increasingly at odds with the current, and future, capabilities to generate enormous quantities of raw scientific and engineering data from instruments, sensors, and computers. Many researchers are currently engaged in activities that seek to create new and novel methods for analyzing, understanding, and managing these vast collections of data. In this work, we present some of our research in addressing a particular type of problem in this broad undertaking. Much the scientific data of interest is in the form of observed, measured, or computed multivariate or multi-component vector field data--with either as physical or color data values. We are currently researching methods and techniques for working with this type of vector data through the use of a novel analysis technique. Our basic approach is to work with the vector field data in its natural physical or color space. When the data is viewed as a functional mapping of a domain, usually an index space, to a range, the physical or color values, potentially interesting characteristics of the data present themselves. These characteristics are useful in …

An experimental primary {gamma}-ray spectrum vs. excitation-energy bin (P(E{sub x}, E{sub {gamma}}) matrix) in a light-ion reaction is obtained for {sup 56,57}Fe isotopes using a subtraction method. By factorizing the P(E{sub x}, E{sub {gamma}}) matrix according to the Axel-Brink hypothesis the nuclear level density and the radiative strength function (RSF) in {sup 56,57}Fe are extracted simultaneously. A step structure is observed in the level density for both isotopes, and is interpreted as the breaking of Cooper pairs. The RSFs for {sup 56,57}Fe reveal an anomalous enhancement at low {gamma}-ray energies.

The primary purpose of the HOPE code is to calculate opacities over a wide temperature and density range. It can also produce equation of state (EOS) data. Since the experimental data at the high temperature region are scarce, comparisons of predictions with the ample zero temperature data provide a valuable physics check of the code. In this report we show a selected few examples across the periodic table. Below we give a brief general information about the physics of the HOPE code. The HOPE code is an ''average atom'' (AA) Dirac-Slater self-consistent code. The AA label in the case of finite temperature means that the one-electron levels are populated according to the Fermi statistics, at zero temperature it means that the ''aufbau'' principle works, i.e. no a priory electronic configuration is set, although it can be done. As such, it is a one-particle model (any Hartree-Fock model is a one particle model). The code is an ''ion-sphere'' model, meaning that the atom under investigation is neutral within the ion-sphere radius. Furthermore, the boundary conditions for the bound states are also set at the ion-sphere radius, which distinguishes the code from the INFERNO, OPAL and STA codes. Once the self-consistent AA …

Recent high temporal resolution Ni-like x-ray laser experiments have yielded important insights into the output characteristics of picosecond pumped x-ray lasers. However, current experimental observations do not fully explain the plasma dynamics which are critical to the gain generation within the x-ray laser medium. A theoretical study of the Ni-like Silver x-ray laser has therefore been undertaken to compliment our experimental results, in an attempt to further our understanding of the processes at play in yielding the observed x-ray laser output. Preliminary findings are presented within this paper.

HADES is a computer code that simulates transmission radiography through a mesh and/or solid bodies. This code is a successor to an old code called XRAY. HADES is designed to be backward compatible with XRAY (i.e. it will accept and correctly parse XRAY input decks), but HADES has many more features that greatly enhance its versatility and its simulation of experimental effects. HADES can simulate X-Ray radiography, neutron radiography or GeV proton radiography using ray-tracing techniques. A short article has been published which discusses HADES' capabilities. HADES also has some capability for simulating pinhole imaging and backlight imaging. The best way to obtain HADES is to ask one of the authors for a copy. This manual covers all features in version 2.5.0 of HADES.

The capsule targets for ignition experiments at the National Ignition Facility must meet very exacting requirements. Primary among them is an extremely high degree of symmetry at all length scales for the 2-mm-diameter 150-{micro}m-walled capsule. At LLNL work is in progress to produce both polyimide and sputtered beryllium targets that meet these specifications. Both of these targets require a thin-walled spherical-shell plastic mandrel upon which the beryllium or polyimide ablator is deposited. In this paper we report on recent progress in developing NIF capsules that meet the demanding design requirements.

We are investigating the evaporation of pore water representative of the designated high-level-nuclear-waste repository at Yucca Mountain, NV to predict the range of brine compositions that may contact waste containers. These brines could form potentially corrosive thin films on the containers and impact their long-term integrity. Here we report the geochemistry of a relatively complex synthetic Topopah Spring Tuff pore water that was progressively evaporated in a series of experiments. The experiments were conducted in a closed vessel, heated to 95 C, and purged with atmospheric CO{sub 2}. Aqueous samples of the evaporating solution were taken and analyzed to determine the evolving water chemistry, and the final solid precipitate was analyzed by X-ray diffraction. The synthetic Topopah Spring Tuff water evolved towards a complex brine that contains about 3 mol% SO{sub 4}, and 2 mol% Ca, 3 mol% K, 5 mol% NO{sub 3}, 40 mol% Cl, and 47 mol% Na. Trends in the solution data and identification of CaSO{sub 4} solids (anhydrite and bassanite) suggest that fluorite, carbonate, sulfate, and Mg-silicate precipitation minimize the corrosion potential of ''sulfate type pore water'' by removing F, Ca, and Mg during the early stages of evaporation.

The Federal Emergency Management System (FEMIS) is an emergency management planning and response tool. The FEMIS System Administration Guide provides information on FEMIS System Administrator activities as well as the utilities that are included with FEMIS.

We report on a series of experiments, using the COMET picosecond facility, designed to characterize and develop different x-ray laser sources. This work encompasses collisional pumping of slab and gas puff targets.

Newsletter of the Texas Department of Health discussing the news, activities, and events of the organization and other information related to health in Texas.

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The goal of the radiation modeling effort was to develop and implement a radiation algorithm that is fast and accurate for the underhood environment. As part of this CRADA, a net-radiation model was chosen to simulate radiative heat transfer in an underhood of a car. The assumptions (diffuse-gray and uniform radiative properties in each element) reduce the problem tremendously and all the view factors for radiation thermal calculations can be calculated once and for all at the beginning of the simulation. The cost for online integration of heat exchanges due to radiation is found to be less than 15% of the baseline CHAD code and thus very manageable. The off-line view factor calculation is constructed to be very modular and has been completely integrated to read CHAD grid files and the output from this code can be read into the latest version of CHAD. Further integration has to be performed to accomplish the same with STAR-CD. The main outcome of this effort is to obtain a highly scalable and portable simulation capability to model view factors for underhood environment (for e.g. a view factor calculation which took 14 hours on a single processor only took 14 minutes on 64 processors). …

For more than half a century, since nuclear science helped us win World War II and ring in the Atomic Age, scientists have known that !he Nation would need a secure, permanent facility in which to dispose of radioactive wastes. Twenty years ago, when Congress adopted the Nuclear Waste Policy Act of 1982 (NWPA or ''the Act''), it recognized the overwhelming consensus in the scientific community that the best option for such a facility would be a deep underground repository. Fifteen years ago, Congress directed the Secretary of Energy to investigate and recommend to the President whether such a repository could be located safely at Yucca Mountain, Nevada. Since then, our country has spent billions of dollars and millions of hours of research endeavoring to answer this question. I have carefully reviewed the product of this study. In my judgment, it constitutes sound science and shows that a safe repository can be sited there. I also believe that compelling national interests counsel in favor of proceeding with this project. Accordingly, consistent with my responsibilities under the NWPA, today I am recommending that Yucca Mountain be developed as the site for an underground repository for spent fuel and other radioactive wastes. …

The Ashtabula Environmental Management Project (AEMP) at Department of Energy-Ohio (DOE-OH) requested technical assistance from the EM-50 Lead Lab to aid in defining new cost and time effective approaches in the following problem areas: soils, concrete, and groundwater/Corrective Action Management Unit (CAMU) at RMIES in Ashtabula, Ohio. Attachment 1 provides the site request for assistance. The technical assistance team assembled for this request is provided in Attachment 2. These individuals reviewed key site information prior to convening with DOE and contractor personnel (RMIES and Earthline) for a three-and-a-half-day meeting to better understand baseline technologies, limitations, and site-specific issues. After listening to presentations about the nature and extent of known contamination, the team broke out into several groups to brainstorm ideas and develop viable solutions. This executive summary details unresolved issues requiring management attention as well as recommendations to address soils, concrete, and groundwater/CAMU. It also provides a summary of additional technical assistance that could be provided to the site. More details are presented in the body of this report.