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15,322 Matching Results
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Vacuum pumping system for TPX
The design of the vacuum pumping system for is discussed, and progress in the research and development effort is summarized. The TPX vacuum system will use cryocondensation pumps for hydrogenic divertor pumping and turbomolecular pumps for torus evacuation, glow discharge cleaning, and deuterium-helium divertor pumping. A set of poloidally and toroidally symmetric vacuum ducts will connect the torus to the vacuum pumps; this symmetry will permit simultaneous equal pumping speed at the upper and lower divertors, and it will minimize toroidal variations in divertor pumping speed. At the divertor plena the total cryocondensation pumping speed for D{sub 2} at 65 C and 1 mTorr will be 80 m{sup 3}/s and the total turbomolecular pumping speed for D{sub 2} or He at 65 C and 1 mTorr will be 18 m{sup 3}/s; the system will be compatible with upgrades to improve pumping speed, to operate continuously, or to operate with D-T fuel. The cryocondensation pumps will be custom units capable of completing a low temperature regeneration cycle in 1 hour.
Date:
December 31, 1995
Creator:
St. Onge, K.D.
Object Type:
Article
System:
The UNT Digital Library
Validation of detailed thermal hydraulic models used for LMR safety and for improvement of technical specifications
Detailed steady-state and transient coolant temperatures and flow rates from an operating reactor have been used to validate the multiple pin model in the SASSYS-1 liquid metal reactor systems analysis code. This multiple pin capability can be used for explicit calculations of axial and lateral temperature distributions within individual subassemblies. Thermocouples at a number of axial locations and in a number of different coolant sub-channels m the XXO9 instrumented subassembly in the EBR-II reactor provided temperature data from the Shutdown Heat Removal Test (SHRT) series. Flow meter data for XXO9 and for the overall system are also available from these tests. Results of consistent SASSYS-1 multiple pin analyses for both the SHRT-45 loss-of-flow-without-scram-test and the S14RT-17 protected loss-of-flow test agree well with the experimental data, providing validation of the SASSYS-1 code over a wide range of conditions.
Date:
December 31, 1995
Creator:
Dunn, F.E.
Object Type:
Article
System:
The UNT Digital Library
Validation of the generic TRUEX model using data from TRUEX demonstrations with actual high-level waste
The main objective of the Generic TRUEX Model (GTM) is to calculate TRUEX solvent extraction flowsheets based on input of a specific feed and a specific set of process goals and constraints. The output will be (1) the compositions of all effluent streams, (2) the compositions of both phases (organic and aqueous) in each stage of the contacting equipment at steady state, and (3) estimates of the space and cost requirements for installing the flowsheet in a plant situation. Other options are available to calculate aqueous-phase speciation and thermodynamic activities, distribution ratios of extractable species, and solvent radiolytic and hydrolytic degradation. Calculation of these options is based on initial aqueous- and organic-phase compositions and other important variables supplied by the user. Three demonstrations of the TRUEX process have been run by Power Reactor and Nuclear Fuel Development Corp. (PNC) researchers at the Tokai Works using actual PUREX raffinates. A 19-stage mixer settler was used for the extraction and scrub sections, and a 16-to-19-stage unit for stripping. Stagewise data were collected on the behavior of nitric acid and several fission-product and actinide radioisotopes during these runs; Run 2 was the best documented and the one with which most comparisons were made. …
Date:
December 31, 1995
Creator:
Vandegrift, G.F. & Regalbuto, M.C.
Object Type:
Article
System:
The UNT Digital Library
Valve for controlling flow of cryogenic fluid
A valve is provided for accurately controlling the flow of cryogenic fluids such as liquid nitrogen. The valve comprises a combination of disc and needle valves affixed to a valve stem in such a manner that the disc and needle are free to rotate about the stem, but are constrained in lateral and vertical movements. This arrangement provides accurate and precise fluid flow control and positive fluid isolation.
Date:
December 31, 1995
Creator:
Knapp, P.A.
Object Type:
Patent
System:
The UNT Digital Library
Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, July 1--September 30, 1995
There is significant current interest in general area of coal pyrolysis, particularly because of the central role of pyrolysis in all thermally driven coal conversion processes-gasification, combustion, liquefaction, mild gasification, or thermal beneficiation. There remain several key data needs in these application areas. Among them is a need for more reliable correlation for prediction of vapor pressure of heavy, primary coal tars. The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. A significant amount of time has been devoted during this quarter to extending the work on measurements of vapor pressures …
Date:
December 31, 1995
Creator:
Suuberg, E.M.
Object Type:
Report
System:
The UNT Digital Library
Velocity and concentration studies of flowing suspensions by nuclear magnetic resonance imaging. Technical progress report, quarter ending December 31, 1995
Task 1: PARTICLE SELECTION. Poly(dimethylsiloxane) was examined as a possible liquid to use with pills for studying granular flows. It however has a weak silicon-29 signal, and it will be difficult to measure a flowing sample. Among the other contrast mechanisms that will be pursued is the spin-lattice relaxation time T{sub 1}. Task 5: FLOWS IN COMPLEX GEOMETRIES. NMR imaging was used to measure the concentration and velocity profiles flowing through a straight pipe into and out of 4:1 contraction and expansion. Complex spatial variations could be induced in particle concentration in this way, and it may be difficult to maintain a well-mixed suspension while filling a vessel from an inlet tube with a cross section smaller than the vessel. Demixing effects are much larger in suspensions of coarse particles than in suspensions of finer particles.
Date:
December 31, 1995
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Verification of RADTRAN
This document presents details of the verification process of the RADTRAN computer code which was established for the calculation of risk estimates for radioactive materials transportation by highway, rail, air, and waterborne modes.
Date:
December 31, 1995
Creator:
Kanipe, F.L. & Neuhauser, K.S.
Object Type:
Article
System:
The UNT Digital Library
Vertical cavity surface-emitting laser scanning cytometer for high speed analysis of cells
We have constructed a new semiconductor laser device that may be useful in high speed characterization of cell morphology for diagnosis of disease. This laser device has critical advantages over conventional cell fluorescence detection methods since it provides intense, monochromatic, low-divergence fight signals that are emitted from lasing modes confined by a cell. Further, the device integrates biological structures with semiconductor materials at the wafer level to reduce device size and simplify cell preparation. In this paper we discuss operational characteristics of the prototype cytometer and present preliminary data for blood cells and dielectric spheres.
Date:
December 31, 1995
Creator:
Gourley, P. L.; McDonald, A. E. & Gourley, M. F.
Object Type:
Article
System:
The UNT Digital Library
Vertical natural convection heat transfer data for an enclosed fluid
Natural convection flow of enclosed fluids with high temperature gradients can result in extremely high heat transfer rates. This phenomenon must be accurately modeled in order to predict the correct temperature distribution of structures in contact with the convecting flow. Ignoring the heat transfer by natural convection and assuming only the normal molecular heat conduction of stagnant water can result in an underestimate of the heat transfer by several orders of magnitude. Natural convection of enclosed fluids is different than free convection to a non-enclosed (i.e., open) ambient atmosphere since the recirculating fluid flow pattern can have a significant influence on the resultant heat transfer. Rayleigh numbers extending the entire range from conditions where free convection is a second order effect (e.g., Ra < 3000) to those where turbulent free convection dominates (e.g., Ra > 10{sup 5}) were tested and the results described. Inconsistencies between earlier investigations reported in the literature are resolved because of the wide test range capability. Correlations of the data in the form of Nusselt number as a function of Rayleigh number are provided for 0 < Ra < 10{sup l2}.
Date:
December 31, 1995
Creator:
Coffield, R. D. & Harry, J. A.
Object Type:
Article
System:
The UNT Digital Library
Very high intensity fiber transmission systems
Various applications are currently motivating interest in the transmission of very high laser intensities through optical fibers. As intensities within a fiber are increased, however, laser breakdown or laser-induced fiber damage will eventually occur and interrupt fiber transmission. For a number of years we have been studying these effects during the transmission of Q-switched, Nd/YAG laser pulses through step-index, multimode, fused-silica fiber. We have found that fiber transmission is often limited by a plasma-forming breakdown occurring at the fiber entrance face. This breakdown results in subtle surface modifications that can leave the surface more resistant to further breakdown or damage events. Catastrophic fiber damage can also occur as a result of a number of different mechanisms, with damage appearing at fiber end faces, within the initial ``entry`` segment of the fiber path, and at other internal sites due to effects related to the particular fiber routing. An overview of these past observations is presented, and issues requiring further study are identified.
Date:
December 31, 1995
Creator:
Setchell, R. E.
Object Type:
Article
System:
The UNT Digital Library
Vibration and stability of a group of tubes in crossflow
This paper presents an unsteady flow theory for flow-induced vibration and instability of tube arrays in crossflow. It includes measurements of motion-dependent fluid forces, mathematical model, and experiments on nonlinear response of tube arrays. The unsteady flow theory can be used to provide answers to complex vibration problems in steam generators.
Date:
December 31, 1995
Creator:
Chen, S.S. & Cai, Y.
Object Type:
Article
System:
The UNT Digital Library
Vibration control for precision manufacturing using piezoelectric actuators
Piezoelectric actuators provide high frequency, force, and stiffness capabilities along with reasonable Stroke limits, all of which can be used to increase performance levels in precision manufacturing systems. This paper describes two examples of embedding piezoelectric actuators in structural components for vibration control. One example involves suppressing the self excited chatter phenomenon in the metal cutting process of a milling machine and the other involves damping vibrations induced by rigid body stepping of a photolithography platen. Finite element modeling and analyses are essential for locating and sizing the actuators and permit further simulation studies of the response of the dynamic system. Experimental results are given for embedding piezoelectric actuators in a cantilevered bar configuration, which was used as a surrogate machine tool structure. These results are incorporated into a previously developed milling process simulation and the effect of the control on the cutting process stability diagram is quantified. Experimental results are also given for embedding three piezoelectric actuators in a surrogate photolithography platen to suppress vibrations. These results demonstrate the potential benefit that can be realized by applying advances from the field of adaptive structures to problems in precision manufacturing.
Date:
December 31, 1995
Creator:
Martinez, D.R.; Hinnerichs, T.D. & Redmond, J.M.
Object Type:
Article
System:
The UNT Digital Library
Virtual radiation fields for ALARA determination
As computing power has increased, so too has the ability to model and simulate complex systems and processes. In addition, virtual reality technology has made it possible to visualize and understand many complex scientific and engineering problems. For this reason, a virtual dosimetry program called Virtual Radiation Fields (VRF) is developed to model radiation dose rate and cumulative dose to a receptor operating in a virtual radiation environment. With the design and testing of many facilities and products taking place in the virtual world, this program facilitates the concurrent consideration of radiological concerns during the design process. Three-dimensional (3D) graphical presentation of the radiation environment is made possible through the use of IGRIP, a graphical modeling program developed by Deneb Robotics, Inc. The VRF simulation program was designed to model and display a virtual dosimeter. As a demonstration of the program`s capability, the Hanford tank, C-106, was modeled to predict radiation doses to robotic equipment used to remove radioactive waste from the tank. To validate VRF dose predictions, comparison was made with reported values for tank C-106, which showed agreement to within 0.5%. Graphical information is presented regarding the 3D dose rate variation inside the tank. Cumulative dose predictions were …
Date:
December 31, 1995
Creator:
Knight, T. W.
Object Type:
Report
System:
The UNT Digital Library
Virtual reality visualization of parallel molecular dynamics simulation
When performing communications mapping experiments for massively parallel processors, it is important to be able to visualize the mappings and resulting communications. In a molecular dynamics model, visualization of the atom to atom interaction and the processor mappings provides insight into the effectiveness of the communications algorithms. The basic quantities available for visualization in a model of this type are the number of molecules per unit volume, the mass, and velocity of each molecule. The computational information available for visualization is the atom to atom interaction within each time step, the atom to processor mapping, and the energy resealing events. We use the CAVE (CAVE Automatic Virtual Environment) to provide interactive, immersive visualization experiences.
Date:
December 31, 1995
Creator:
Disz, T.; Papka, M.; Stevens, R.; Pellegrino, M. & Taylor, V.
Object Type:
Article
System:
The UNT Digital Library
Vitrification of hazardous and radioactive wastes
Vitrification offers many attractive waste stabilization options. Versatility of waste compositions, as well as the inherent durability of a glass waste form, have made vitrification the treatment of choice for high-level radioactive wastes. Adapting the technology to other hazardous and radioactive waste streams will provide an environmentally acceptable solution to many of the waste challenges that face the public today. This document reviews various types and technologies involved in vitrification.
Date:
December 31, 1995
Creator:
Bickford, D. F. & Schumacher, R.
Object Type:
Article
System:
The UNT Digital Library
Vitrification of ion-exchange (IEX) resins: Advantages and technical challenges
Technologies are being developed by the US Department of Energy`s (DOE) Savannah River Site (SRS) in conjunction with the Electric Power Research Institute (EPRI) and the commercial sector to convert low-level radioactive ion exchange (IEX) resin wastes from the nuclear utilities to solid stabilized waste forms for permanent disposal. One of the alternative waste stabilization technologies is vitrification of the resin into glass. Wastes can be vitrified at elevated temperatures by thermal treatment. One alternative thermal treatment is conventional Joule heated melting. Vitrification of wastes into glass is an attractive option because it atomistically bonds both hazardous and radioactive species in the glass structure, and volume reduces the wastes by 70-80%. The large volume reductions allow for large associated savings in disposal and/or long term storage costs.
Date:
December 31, 1995
Creator:
Jantzen, Carol M.; Peeler, D. K. & Cicero, C. A.
Object Type:
Article
System:
The UNT Digital Library
Vitrification of Rocky Flats ash followed by encapsulation in the Defense Waste Processing Facility
Approximately 10 to 20 metric tons of plutonium in the US is in the form of scrap, residues, oxides, ash, metal, sludge, compounds, etc. This paper describes a relatively simple concept of stabilizing most of this type of plutonium by converting it into encapsulated glass. A full-scale hot demonstration of the concept is proposed, in which Rocky Flats ash would be vitrified and sealed in small cans, followed by encapsulation of the cans in Defense Waste Processing Facility (DWPF) canisters with high-level waste glass. The proposal described in this paper offers an integrated national approach for early stabilization and disposition of the nation`s plutonium-bearing residues.
Date:
December 31, 1995
Creator:
McKibben, J.M.; Land, B.; Strachan, D.M. & Perez, J.M.
Object Type:
Article
System:
The UNT Digital Library
Voltage-probe-position dependence and magnetic-flux contribution to the measured voltage in ac transport measurements: which measuring circuit determines the real losses?
The voltage V{sub ab} measured between two voltage taps a and b during magnetic flux transport in a type-II superconductor carrying current I is the sum of two contributions, the line integral from a to b of the electric field along an arbitrary path C{sub s} through the superconductor and a term proportional to the time rate of change of magnetic flux through the area bounded by the path C{sub s} and the measuring circuit leads. When the current I(t) is oscillating with time t, the apparent ac loss (the time average of the product IV{sub ab}) depends upon the measuring circuit used. Only when the measuring-circuit leads are brought out far from the surface does the apparent power dissipation approach the real (or true) ac loss associated with the length of sample probed. Calculations showing comparisons between the apparent and real ac losses in a flat strip of rectangular cross section will be presented, showing the behavior as a function of the measuring-circuit dimensions. Corresponding calculations also are presented for a sample of elliptical cross section.
Date:
December 31, 1995
Creator:
Pe, T.; McDonald, J. & Clem, J.R.
Object Type:
Article
System:
The UNT Digital Library
Waste disposal in underground mines -- A technology partnership to protect the environment
Environmentally compatible disposal sites must be found despite all efforts to avoid and reduce the generation of dangerous waste. Deep geologic disposal provides the logical solution as ever more categories of waste are barred from long-term disposal in near-surface sites through regulation and litigation. Past mining in the US has left in its wake large volumes of suitable underground space. EPA studies and foreign practice have demonstrated deep geologic disposal in mines to be rational and viable. In the US, where much of the mined underground space is located on public lands, disposal in mines would also serve the goal of multiple use. It is only logical to return the residues of materials mined from the underground to their origin. Therefore, disposal of dangerous wastes in mined underground openings constitutes a perfect match between mining and the protection and enhancement of the environment.
Date:
December 31, 1995
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Waste minimization value engineering workshop for the Los Alamos National Laboratory Omega West Reactor Decommissioning Project
The Los Alamos National Laboratory Pollution Prevention Program Office sponsored a Value Engineering (VE) Workshop to evaluate recycling options and other pollution prevention and waste minimization (PP/WMin) practices to incorporate into the decommissioning of the Omega West Reactor (OWR) at the laboratory. The VE process is an organized, systematic approach for evaluating a process or design to identify cost saving opportunities, or in this application, waste reduction opportunities. This VE Workshop was a facilitated process that included a team of specialists in the areas of decontamination, decommissioning, PP/WMin, cost estimating, construction, waste management, recycling, Department of Energy representatives, and others. The uniqueness of this VE Workshop was that it used an interdisciplinary approach to focus on PP/WMin practices that could be included in the OWR Decommissioning Project Plans and specifications to provide waste reduction. This report discusses the VE workshop objectives, summarizes the OWR decommissioning project, and describes the VE workshop activities, results, and lessons learned.
Date:
December 31, 1995
Creator:
Hartnett, S.; Seguin, N. & Burns, M.
Object Type:
Article
System:
The UNT Digital Library
Western Area Power Administration combined power system financial statements, 30 September 1995 and 1994
The attached report presents the results of the independent certified public accountant`s audit of the Department of Energy`s Western Area Power Administration`s (Western) combined financial statements as of September 30, 1995. The auditors have expressed an unqualified opinion on Western`s 1995 statements. Their reports on Western`s internal control structure and on compliance with laws and regulations are also provided.
Date:
December 31, 1995
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Westinghouse thermal barrier coatings development
Westinghouse, in conjunction with the Department of Energy and Oak Ridge National Laboratory, has embarked upon a program for the development of advanced thermal barrier coatings for industrial gas turbines. Development of thermal barrier coatings (TBC`s) for industrial gas turbines has relied heavily on the transfer of technology from the aerospace industry. Significant differences in the time/temperature/stress duty cycles exist between these two coating applications. Coating systems which perform well in aerospace applications may not been optimized to meet power generation performance requirements. This program will focus on development of TBC`s to meet the specific needs of power generation applications.
Date:
December 31, 1995
Creator:
Goedjen, J.G. & Wagner, G.
Object Type:
Article
System:
The UNT Digital Library
What can we learn from off-specular neutron reflection?
Specular reflection of neutrons or x rays has been developed recently as a tool to probe density variations in the neighborhood of flat interfaces. The techniques have been applied to a variety of materials problems ranging from polymer adsorption to hydrogenation of carbon films and the structure of magnetic multilayers. In addition to the specular scattering, diffuse scattering is often observed, sometimes in strikingly beautiful patterns. This scattering is caused by imperfections such as interfacial roughness or density fluctuations within a layer. As a general rule, the diffuse, off-specular scattering measures the density-density correlation function within and between the interfaces responsible for the specular scattering. Interpretation of diffuse x-ray and neutron scattering from surfaces and interfaces is in its infancy using theoretical schemes that are still being developed. In this talk the author shows examples of diffuse scattering patterns and offers some guidelines for their interpretation.
Date:
December 31, 1995
Creator:
Pynn, R.
Object Type:
Article
System:
The UNT Digital Library
What have we learned about the solar interior from solar oscillations?
After a brief review of the discovery and properties of solar oscillations, I summarize the significant advances in our knowledge of the Sun`s interior structure achieved by using solar oscillation frequency data. I discuss the surprising solar interior rotation profile; the precise determination of the convection zone depth; the convection zone helium abundance; evidence for diffusive settling of helium during the Sun`s 4.5 billion year lifetime; and the Sun`s central structure and implications for the solar neutrino problem.
Date:
December 31, 1995
Creator:
Guzik, J.A.
Object Type:
Article
System:
The UNT Digital Library