The objectives of this project are to determine the long-term chemical reactivity and mechanical durability of a fluidized version of Phillips Petroleum Company`s proprietary Z-SORB sorbent for the desulfurization of coal-derived gases in a high-pressure (20 atm) fluidized-bed reactor under simulated U-Gas conditions and at a moderate operating temperature of 538 degrees C.

J-integral fracture mechanics techniques and electron microscopy observations were used to investigate the effects of tritium and its radioactive decay product, {sup 3}He, on Types 316L, 304L and 21Cr-6Ni-9Mn stainless steels. Tritium-exposed-and-aged steels had lower fracture-toughness values and shallower sloped crack-growth-resistance curves than unexposed steels. Both fracture-toughness parameters decreased with increasing concentrations of {sup 3}He. The fracture-toughness reductions were accompanied by a change in fracture mode from microvoid-nucleation-and-growth processes in control samples to grain-and-twin-boundary fracture in tritium-charged-and-aged samples. Type 316L stainless steel had the highest fracture-toughness values and Type 21Cr-6Ni-9Mn had the lowest. Samples containing {sup 3}He but degassed of tritium had fracture toughness properties that were similar to uncharged samples. The results indicate that helium bubbles enhance the embrittlement effects of hydrogen by affecting the deformation properties and by increasing localized hydrogen concentrations through trapping effects.

Temperatures, densities and confinement of deuterium plasmas confined in tokamaks have been achieved within the last decade that are approaching those required for a D-T reactor. As a result, the unique phenomena present in a D-T reactor plasma can now be studied in the laboratory. Recent experiments on the Tokamak Fusion Test Reactor (TFTR) have been the first magnetic fusion experiments to study plasmas with reactor fuel concentrations of tritium. The injection of {approximately}20 MW of tritium and 14 MW of ceuterium neutral beams into the TFTR produced a plasma with a T/D density ratio of {approximately}1 and yielded a maximum fusion power of {approximately}9.2 MW. The fusion power density in the core of the plasma was {approximately}1.8 MW m{sup {minus}3} approximating that expected in a D-T fusion reactor. A TFTR plasma with T/D density ratio of {approximately}1 was found to have {approximately}20% higher energy confinement time than a comparable D plasma, indicating a confinement scaling with average ion mass, A, of {tau}{sub E} {approximately} A{sup 0.6}. The core ion temperature increased from 30 keV to 37 keV due to a 35% improvement of ion thermal conductivity. Using the electron thermal conductivity from a comparable deuterium plasma, about 50% of …

Advanced coal-based power systems, such as integrated gasification and pressurized fluidized-bed combustion, require particulate removal at high temperatures and high pressure under adverse chemical conditions. To facilitate the development of advanced coal-based power systems, then Morgantown Energy Technology Center (METC) has assembled a Particulate Cleanup Program, which conducts technology demonstration projects and applied research to address the adverse filtration conditions and filter system issues, as well as the future performance demands of these systems.

We present results for semi-leptonic form-factors obtained on statistical sample of 63 32{sup 3} {times} 64 lattices at {beta} = 6.0 using quenched Wilson fermions. We find f{sub +}{sup D{yields}Klv} (q{sup 2} = 0) = 0.73 {plus_minus} 0.06, A{sub 2}/A{sub 1}(D {yields} K*lv) = 0.79 {plus_minus} 0.23, V/A{sub 1}(D{sub s} {yields} {phi}lv) = 1.89 {plus_minus} 0.04, and A{sub 2}/A{sub 1}(D{sub s} {yields} {phi}lv) = 0.70 {plus_minus} 0.09, where the error estimate includes statistical errors and errors due to extrapolation to q{sup 2} = 0 and to physical values of (m{sub u} + m{sub d})/2 and m{sub s}. The remaining sources of systematic errors are those due to O(a) discretization errors and those due to quenching, which our results indicate may be small. We also comment on the validity of pole-dominance in these form-factors.

The U.S. Department of Energy (DOE) and the Electric Power Research Institute (EPRI), in cooperation with nuclear power plant utilities and the Nuclear Energy Institute, have prepared equipment aging evaluations of nuclear power plant equipment for life extension considerations. Specifically, these evaluations focused on equipment considered important for plant license renewal (U.S. Code of Federal Regulations 10CFR54). {open_quotes}Industry Reports{close_quotes} (IRs), jointly funded by DOE and EPRI, evaluated the aging of major systems, structures, and components (e.g., reactor pressure vessels, Class I structures, PWR and BWR containments, etc.) and contain a mixture of technical and licensing information. {open_quotes}Aging Management Guidelines{close_quotes} (AMGs), funded by DOE, evaluate aging for commodity types of equipment (e.g., pumps, electrical switchgear, heat exchangers, etc.) and concentrate on technical issues only. AMGs are intended for systems engineers and plant maintenance staff. A significant number of technical issues were resolved during IR interactions with the U.S. Nuclear Regulatory Commission (NRC). However, certain technical issues have not been resolved and are considered {open_quotes}open{close_quotes}. Examples include certain issues related to fatigue, neutron irradiation embrittlement, intergranular stress corrosion cracking (IGSCC) and electrical cable equipment qualification. Direct NRC interaction did not take place during preparation of individual AMGs due to their purely technical …

Poly(acrylonitrile) fibers have been pyrolyzed under various conditions to form flexible carbon yarns capable of intercalating lithium ions. These fibers have also been formed into both woven and non woven cloths. Potentiostatic, potentiodynamic and galvanostatic tests have been conducted with these materials in several electrolytes. In some tests, a potential hold was used after each constant current charge and discharge. These tests have shown some of these flexible materials to reversibly intercalate lithium ions to levels that are suitable for use as a practical battery anode.

A method to obtain and process `mountain range` displays of beam signals is described. A custom-made trigger generator and a digital oscilloscope are used for the data acquisition and the graphical interface package LabVIEW is used to process the data. High resolution displays of wall monitor signals updating every AGS cycle have proven very powerful as a beam diagnostic.

The ternary phase diagram of Hf-V-Nb system has been established and the C15 and C14 Laves phase regions located. The structural stability of the cubic Laves phase HfV{sub 2}+Nb was examined using heat capacity measurements and transmission electron microscopy. It is found that the binary C 15 has a martensitic transformation at 115K and that Nb addition can eliminate the martensitic transformation and stabilize the C15 structure. The elastic properties vs. temperature of the C15 HfV{sub 2}+Nb were studied using the resonant ultrasound technique. It is observed that the shear and Young`s moduli increase abnormally with increasing temperature, the bulk modulus is virtually constant, and the Poisson`s ratio is very high and decreases abnormally with increasing temperature. The elastic properties of the C15 compound can be qualitatively understood using the electronic structure obtained from ab initio calculations. The relation between the phase stability and anomalous elastic properties is discussed based on these results.

Experimental studies are under way at the Oak Ridge National Laboratory (ORNL) which are designed to measure the time evolution, ionization efficiencies, and release efficiencies of implanted elements diffused from refractory target materials which are candidates for forming radioactive ion beams (RIBs) at the Holifield Radioactive Ion Beam Facility (HRIBF). The diffusion coefficients are derived by comparing experimental data with numerical solutions to a one-dimensional form of Fick`s second law for ion implanted distributions. In this report, we describe the experimental arrangement and provide time release data and diffusion coefficients for releasing ion implanted Cl from Zr{sub 5}Si{sub 3} and {sup 75}As, {sup 79}Br, and {sup 78}Se from Zr{sub 5}Ge{sub 3}.

Clear regulatory guidance exists for structuring a radiological air monitoring program, however, there is no parallel guidance for radiological liquid monitoring. For Department of Energy (DOE) facilities, there are no existing applicable federal regulations, DOE orders, or DOE guidance documents that specify at what levels continuous monitoring, continuous sampling, or periodic confirmatory measurements of radioactive liquid effluents must be made. In order to bridge this gap and to technically justify and document liquid effluent monitoring decisions at DOE`s Savannah River Site, Westinghouse Savannah River Company has proposed that a graded, dose-based approach be established, in conjunction with limits on facility radionuclide inventories, to determine the monitoring and sampling criteria to be applied at each potential liquid radioactive effluent point. The graded approach would be similar to--and a conservative extension of--the existing, agreed-upon SRS/EPA-IV airborne effluent monitoring approach documented in WSRC`s NESHAP Quality Assurance Project Plan. The limits on facility radionuclide inventories are based on--and are a conservative extension of--the 10 CFR 834, 10 CFR 20, and SCR 61-63 annual limits on discharges to sanitary sewers. Used in conjunction with each other, the recommended source category criteria levels and facility radionuclide inventories would allow for the best utilization of resources and …

The US Department of Energy, Richland Operations Office, has established the Tank Waste Remediation System to resolve environmental and safety issues related to underground waste-storage tanks at the Hanford Site. The Tank Waste Remediation System has identified the use of an advanced-technology, long-reach manipulator system as a low-water-addition retrieval alternative to past-practice sluicing.

Reciprocal space mapping can be efficiently carried out using a position-sensitive x-ray detector (PSD) coupled to a traditional double-axis diffractometer. The PSD offers parallel measurement of the total scattering angle of all diffracted x-rays during a single rocking-curve scan. As a result, a two-dimensional reciprocal space map can be made in a very short time similar to that of a one-dimensional rocking-curve scan. Fast, efficient reciprocal space mapping offers numerous routine advantages to the x-ray diffraction analyst. Some of these advantages are the explicit differentiation of lattice strain from crystal orientation effects in strain-relaxed heteroepitaxial layers; the nondestructive characterization of the size, shape and orientation of nanocrystalline domains in ordered-alloy epilayers; and the ability to measure the average size and shape of voids in porous epilayers. Here, the PSD-based diffractometer is described, and specific examples clearly illustrating the advantages of complete reciprocal space analysis are presented.

Low-energy ion processing produces damaged, microroughened semiconductor surfaces due to the production of point defects. The authors present a study of point defect production and annealing on the Ge(001)-2x1 surface during low-energy inert ion bombardment as a function of ion energy, ion mass and substrate temperature. Ion-induced surface point defect production was quantified experimentally in real time using in situ Reflection High Energy Electron Diffraction. The observed surface defect yield decreased abruptly around room temperature as the substrate temperature was increased from 175 K to 475 K. The authors have developed Monte Carlo simulations of defect diffusion to model defect recombination both in the bulk and on the surface. Bulk defect production statistics generated by a binary collision simulator, TRIMRC, were coupled with our bulk diffusion simulator to predict the number of ion-induced surface defects. A comparison between the experimental results and the simulation predictions indicated that defects produced in the bulk may represent a significant contribution to the observed surface defect yield and suggested that TRIMRC may overestimate the depth distribution of the defects. The simulations further indicated that the abrupt drop in the experimental yield with increasing substrate temperature does not arise from bulk defect recombination. The Monte …

This paper overviews applications of desiccant technology for dehumidifying commercial and institutional buildings. Because of various market, policy, and regulatory factors, this technology is especially attractive for dehumidification applications in the 1990s. After briefly reviewing the principle of operation, the authors present three case studies-for supermarkets, a hotel, and an office building. The authors also discuss recent advances and ongoing research and development activities.

Investigations are being performed on a high current (16 kA), mildly relativistic (400kV), L-band klystron source. Experiments are in an early stage, and thus far have progressed to beam modulation studies. This paper discusses general klystron design considerations, beam propagation results, initial modulation results, and various extraction techniques being considered.

Within the last decade, there has been a resurgence of interest in the study of noise in Mesoscopic devices, both experimentally and theoretically. Noise in solid state devices can have different origins: there is 1/f noise, which is believed to arise from fluctuations in the resistance of the sample due to the motion of impurities. On top of this contribution is a frequency independent component associated with the stochastic nature of electron transport, which will be the focus of this paper. If the sample considered is small enough that dephasing and inelastic effects can be neglected, equilibrium (thermal) and excess noise can be completely described in terms of the elastic scattering properties of the sample. As mentioned above, noise arises as a consequence of random processes governing the transport of electrons. Here, there are two sources of randomness: first, electrons incident on the sample occupy a given energy state with a probability given by the Fermi-Dirac distribution function. Secondly, electrons can be transmitted across the sample or reflected in the same reservoir where they came from with a probability given by the quantum mechanical transmission/reflection coefficients. Equilibrium noise refers to the case where no bias voltage is applied between the …

We present a precise measurement of the left-right cross section asymmetry (A{sub LR}) for Z boson production by e{sup +}e{sup {minus}} collisions. The measurement was performed at a center-of-mass energy of 91.26 GeV with the SLD detector at the SLAC Linear Collider (SLC). The luminosity-weighted average polarization of the SLC electron beam was (63.0 {plus_minus} 1.1)%. Using a sample of 49,392 Z decays, we measure A{sub LR} to be 0.1628 {plus_minus} 0.0071(stat) {plus_minus} 0.0028(syst) which determines the effective weak mixing angle to be sin{sup 2} {theta}{sub w}{sup eff} = 0.2292 {plus_minus} 0.0009(stat) {plus_minus} 0.0004(syst).

Integrated Gasification Combined Cycles (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) are being developed and demonstrated for commercial, power generation application. Hot gas particulate filters are key components for the successful implementation of IGCC and PFBC in power generation gas turbine cycles. The objective of this work is to develop and qualify through analysis and testing a practical hot gas ceramic barrier filter system that meets the performance and operational requirements of PFBC and IGCC systems. This paper updates the assessment of the Westinghouse hot gas filter design based on ongoing testing and analysis. Results are summarized from recent computational fluid dynamics modeling of the plenum flow during back pulse, analysis of candle stressing under cleaning and process transient conditions and testing and analysis to evaluate potential flow induced candle vibration.

The National Solar Thermal Test Facility (NSTTF) at Sandia National Laboratories in Albuquerque, New Mexico, USA conducts testing of solar thermal components and systems, funded primarily by the US Department of Energy. Activities are conducted in support of Central Receiver Technology, Distributed Receiver Technology and Design Assistance projects. All activities are performed in support of various cost-shared government/industry joint ventures and, on a design assistance basis, in support of a number of other industry partners.

The objective of the Gasification Product Improvement Facility (GPIF) project is to provide a test site to support early commercialization of the Integrated Gasification Combined Cycle (IGCC) technology. The design of this facility will by based on PyGas{trademark}, a patented air blown fixed bed gasification process. The GPIF will be capable of processing run-of-mine high swelling coals that comprise 87% of all Eastern US coals. The GPIF project is expected to deliver a gasifier design that will satisfy the criteria for good process performance and cost effectiveness. The PyGas{trademark} process was conceived to handle high swelling coals, crack tars, and reduce ammonia and trace metal emissions. The GPIF program will generate useful scale up data. Initially, the PyGas{trademark}-IGCC systems will be offered as modular units for the repowering markets which will reduce the financial burden on utilities in comparison to large plants. In addition, modular designs will also reduce the plant construction schedules.

The Kondo insulating materials present a particularly simple limiting case of the strongly correlated electron lattice problem: one occupied f-state interacting with a single half-filled conduction band. Experiment shows that the solution to this problem has some remarkably simple aspects. Optical conductivity data display the strong coupling nature of this physics.

Angular and momentum distributions have been measured for electron-positron pairs created in peripheral collisions of 6.4 TeV bare sulfur ions with thin targets of Al, Pd, and Au. Singly- and doubly-differential cross sections are presented for 1--17 MeV/c electrons and positrons detected independently and in coincidence as pairs. Various physical parameters are deduced from the coincident electron and positron data, including probability distributions for the pair transverse momentum, the pair total energy, and the positron fraction of the pair energy.

This paper reviews the results and physics of two contributed papers to ICHEP94. Both papers relate to charm meson hadroproduction at Fermilab fixed target energies. The first (from E769) addresses the total forward cross section for charm mesons (D{sup {plus_minus}} and D{sub s}{sup {plus_minus}}) produced by {pi}{sup {plus_minus}}, K{sup {plus_minus}}, and proton beams. The second paper (from E791) deals with the asymmetries in the differential cross sections for charged D mesons produced in the forward direction by {pi}{sup {minus}} beam. The physics most directly related to the results of the E769 paper are the gluon distributions in the incident hadrons as well as perturbative QCD calculations of charm quark production and the charm quark mass. The E791 results address the details of the hadronization process after production of the charm quarks.