The short- and intermediate-range order as well as atomic dynamics in various phosphate glasses were investigated using neutron diffraction and inelastic scattering. The 3-D network of corner-sharing PO{sub 4} tetrahedra in g-P{sub 2}O{sub 5} is highly unstable and hygroscopic. Depolymerization of the network to chain-like structure and eventually to unconnected PO{sub 4} units by incorporating alkali, alkali-earth or transition-metal modifiers is clearly evident in the structure factor S(Q) in the Q < 4 {angstrom}{sup -1} region. The dynamic response to such structural changes is equally strong: e.g., the broad P-O stretching band extending to 170 meV in g-P{sub 2}O{sub 5} is sharpened and shifted down to {approximately}125 meV in the orthophosphate composition. The correlation between the microscopic structure and physical properties for a series of P-glasses is discussed.

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Inelastic scattering data have been collected at incident neutron energies of 50, 150, 300 and 600 meV for hydrogarnet [Sr{sub 3}Al{sub 2}(O{sub 4}H{sub 4}){sub 3}], a model compound for silicate hydrogarents found in the Earth`s crust and mantle. The vibrational spectrum is characterized by a relatively sharp O-H stretch at {approximately}460 meV, which is consistent with the weak O...H bond ({approximately}2.65 {angstrom}) and other complex features in the 20-100 meV region. The mode assignment for isostructural grosslar and the infrared spectra for hydrogarnet were used as a basis for the intreperation of many of the neutron spectral features.

This safety analysis report for packaging (SARP) documents the safety of shipments of irradiated fuel elements in the MUlticanister Overpack (MCO) and MCO Cask for a highway route controlled quantity, Type B fissile package. This SARP evaluates the package during transfers of (1) water-filled MCOs from the K Basins to the Cold Vacuum Drying Facility (CVDF) and (2) sealed and cold vacuum dried MCOs from the CVDF in the 100 K Area to the Canister Storage Building in the 200 East Area.

The DKPRO code solves the general problem of modeling complex nuclear wastes streams using ORIGEN2 radionuclide production files. There is a continuing need for estimates of Hanford radionuclides. Physical measurements are one basis; calculational estimates, the approach represented here, are another. Given a known nuclear fuel history, it is relatively straightforward to calculate radionuclide inventories with codes such as the widely-used Oak Ridge National Laboratory code ORIGEN2.

This characterization report summarizes information on the historical uses, current status, and sampling and analysis results of waste stored in tank 241-BY-111.

Following termination of the Advanced Neutron Source (ANS) Project, a program of upgrades to the Department of Energy`s High Flux Isotope Reactor (HFIR) was devised by a team of researchers and reactor operators and has been proposed to the department. HFIR is a multipurpose research reactor, commissioned in 1965, with missions in four nationally important areas: isotope production, especially transuranic isotopes; neutron scattering; neutron activation analysis; and irradiation testing of materials. For neutron scattering, there are two major enhancements and several smaller ones. The first is the installation of a small, hydrogen cold neutron source in one of the four existing beam tubes: because of the high reactor power, and the use of new design concepts developed for ANS, the cold source will be as bright as, or brighter than, the Institute Laue Langevin liquid deuterium vertical cold source, although space limitations mean that there will be far fewer cold beams and instruments at HFIR. This project is underway, and the cold source is expected to come on line following an extended shutdown in 1999 to replace the reactor`s beryllium reflector. The second major change proposed would put five thermal neutron guides at an existing beam port and construct a …

The authors developed a computer program to calculate the thermal diffuse scattering (TDS) intensity distribution for single crystal specimens in a diffractometer with no energy analysis. They assumed that the phonon frequencies are approximated by those of elastic waves and that the elastic constants, density and lattice parameters of the system under study are known. The results of the calculations were compared to experimental data obtained for single crystals of Si, diamond and NiAl at the Wide Angle neutron Diffractometer at the HFIR at Oak Ridge National Laboratory. Excellent agreement was found between the calculations and the experimental observations.

Nanostructured powders of automotive catalytic system CuO0Al{sub 2}O{sub 3}, targeted for nitrogen oxides (NOx) removal under lean-burn engine conditions, were investigated using neutron diffraction and small-angle neutron scattering. The crystal phases, structural transformations and microstructure of 10 mol% Cu-Al{sub 2}O{sub 3} powders are characterized according to the heat-treatment conditions. These properties are correlated with the pore structure and NOx removal efficiency determined by nitrogen adsorption isotherm, electron spin resonance, and temperature programmed reaction measurements. The {gamma}-(Cu, Al){sub 2}O{sub 3} phase and the mass-fractal-like aggregate of particles (size {approx} 26 nm) at annealing temperatures below 900{degrees}C were found to be crucial to the high NOx removal performance. The transformation to bulk crystalline phases of {alpha}-Al{sub 2}O{sub 3} + CuAl{sub 2}O{sub 4} spinel above {approximately}1050{degrees}C corresponds to a drastic drop of Nox removal efficiency. The usefulness of neutron-scattering techniques as well as their complementarity with other traditional methods of catalytic research are discussed.

Rocky Flats Environmental Technology Site (RFETS), has approximately 10,000 High Efficiency Particulate Air (HEPA) Filters installed in a variety of filter plenums. These ventilation/filtration plenum systems are used to control the release of airborne particulate contaminates to the environment during normal operations and potential accidents. This report summarizes the results of destructive and non-destructive tests on HEPA filters obtained from a wide variety of ages and service conditions. These tests were performed to determine an acceptable service life criteria for HEPA filters used at Rocky Flats Environmental Technology Site (RFETS). A total of 140 filters of various ages (1972 to 1996) and service history (new, aged unused, used) were tested. For the purpose of this report, filter age from manufacture date/initial test date to the current sample date was used, as opposed to the actual time a filter was installed in an operating system.

Intrinsic bioremediation is a risk management option that relies on natural biological and physical processes to contain the spread of contamination from a source. Evidence is presented in this report that intrinsic bioremediation is occurring at the Sanitary Landfill is fundamental to support incorportion into a Corrective Action Plan (CAP).

A lattice dynamical investigation of zircon (ZrSiO{sub 4}) has been carried out to obtain a microscopic understanding of its thermodynamic properties, as well as to examine possible soft modes that may contribute to the phase transformation to scheelite type under high pressure. We have measured the neutron weighted phonon density of states of zircon from a polycrystalline sample. The neutron spectra reveal one-phonon excitations extending to 1130 cm{sup -1}, with phonon bands centered at 226, 298, 363, 540, 661, 726, 945, and 1081 cm{sup -1}. A quantitative analysis of the neutron results was carried out using a lattice dynamical rigid-ion model. 4 refs., 3 figs.

The structure of NdP{sub 5}O{sub 14} consists of cross-linked double chains of corner-sharing PO{sub 4} tetrahedra extending parallel to the crystallographic a-axis. Each Nd atom is coordinated by 8 oxygen atoms. The NdO{sub 8} polyhedra are isolated from each other and share no common oxygen atoms. High-gain and long-lifetime laser action had been reported in NdP{sub 5}O{sub 14} crystals. The neutron excitation spectra reveal a one-phonon density of states extended to about 180 meV with several distinct P-O stretching bands at high energies. These features reflect the existence of different P-O bond lengths among the terminal and bridging configurations and the associated atomic dynamics. Furthermore, magnetic scattering from Nd ions permitted the determination of the energy-level structure of the crystal-field-split Nd:{sup 4}I{sub 9/2} ground term.

Atmospheric turbulence severely limits the resolution of ground-based telescopes. Adaptive optics can correct for the aberrations caused by the atmosphere, but requires a bright wavefront reference source in close angular proximity to the object being imaged. Since natural reference stars of the necessary brightness are relatively rare, methods of generating artificial reference beacons have been under active investigation for more than a decade. In this paper, we report the first significant image improvement achieved using a sodium-layer laser guide star as a wavefront reference for a high- order adaptive optics system. An artificial beacon was created by resonant scattering from atomic sodium in the mesosphere, at an altitude of 95 km. Using this laser guide star, an adaptive optics system on the 3 m Shane Telescope at Lick Observatory produced a factor of 2.4 increase in peak intensity and a factor of 2 decrease in full width at half maximum of a stellar image, compared with image motion compensation alone. The Strehl ratio when using the laser guide star as the reference was 65% of that obtained with a natural guide star, and the image full widths at half maximum were identical, 0.3 arc sec, using either the laser or …

This Site Integration Management plan provides the Los Alamos Response to the Defense Nuclear Facility Safety Board (DNFSB) Recommendation 97-1. This recommendation addresses the safe storage and management of the Departments uranium 233 ({sup 233}U) inventory. In the past, Los Alamos has used {sup 233}U for a variety of different weapons related projects. The material was used at a variety of sites in varying quantities. Now, there is a limited need for this material and the emphasis has shifted from use to storage and disposition of the material. The Los Alamos program to address the DNFSB Recommendation 97-1 has two emphases. First, take corrective action to address near term deficiencies required to provide safe interim storage of {sup 233}U. Second, provide a plan to address long term storage and disposition of excess inventory at Los Alamos.

Thermo-mechanical processing of ductile irons is a potential method for enhancing their mechanical properties. A ductile cast iron containing 3.6% C, 2.6% Si and 0.045% Mg was continuously hot-and-warm rolled or one-step press-forged from a temperature in the austenite range (900{degrees}C-1100{degrees}C) to a temperature below the A, temperature. Various amounts of reduction were used (from 60% to more than 90%) followed by a short heat ent at 600`C. The heat ent lead to a structure of fine graphite in a matrix of ferrite and carbides. The hot-and- warm worked materials developed a pearlitic microstructure while the press-forged material developed a spheroidite-like carbide microstructure in the matrix. Cementite-denuded ferrite zones were developed around graphite stringers in the hot-and-warm worked materials, but such zones were absent in the press-forged material. Tensile properties including tensile strength and total elongation were measured along the direction parallel and transverse to the rolling direction and along the direction transverse to the press-forging direction. The tensile ductility and strength both increased with a decrease in the amount of hot-and-warm working. The press- forged materials showed higher strength (645 MPa) than the hot-and-warrn worked materials (575 MPa) when compared at the same ductility level (22% elongation).

The results of crystal field calculations in the framework of exchange charge model (ECM) are reported for trivalent lanthanide and actinide ions doped into LaCl{sub 3}. Whereas the scalar strength of the model crystal field parameters are consistent with that previously determined by fitting the experimental data, the sign of the second-order parameter is found to be negative, in contrast to previous reports. The contribution from long-range electrostatic interactions exceeds that from the nearest neighboring ligands and leads to the negative sign of the second-order crystal field parameter. Other interaction mechanisms including overlap, covalence, and charge exchange are less important to the second order parameter, but dominate the fourth- and sixth-order parameters. This work provides a consistent interpretation of the previously controversial experimental results for both lanthanide and actinide ions in this classical host.

A uranium enrichment plant utilizing Atomic Vapor Laser Isotope Separation (AVLIS) technology is currently being planned. Deployment of the Plant will require tens of thousands of commercial and custom optical components and subsystems. The Plant optical system will be expected to perform at a high level of optical efficiency and reliability in a high-average-power-laser production environment. During construction, demand for this large number of optics must be coordinated with the manufacturing capacity of the optical industry. The general requirements and approach to ensure supply of optical components is described. Dynamic planning and a closely coupled relationship with the optics industry will be required to control cost, schedule, and quality.

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