Resource Type

Spin structures of Fe/Gd and Fe/Cr multilayers determined by polarized neutron reflectometry (open access)

Spin structures of Fe/Gd and Fe/Cr multilayers determined by polarized neutron reflectometry

Polarized neutron reflection was used to determine the magnetic structure of two different antiferromagnetically coupled multilayer systems, Fe/Gd and Fe/Cr. In Fe/Gd, the Fe and Gd moments are coupled antiparallel at the interface. At low temperatures a surface induced magnetic phase transition was found. In Fe/Cr, annealing at temperatures of up to 425{degrees}C, resulted in the degrading of antiferromagnetic coupling between Fe layers and in the formation of ferromagnetically coupled regions.
Date: August 1, 1992
Creator: Loewenhaupt, M.; Hahn, W. (Forschungszentrum Juelich GmbH (Germany). Inst. fuer Festkoerperforschung); Huang, Y. Y.; Felcher, G. P. (Argonne National Lab., IL (United States)) & Parkin, S. S. P. (IBM Research Div., San Jose, CA (United States). Almaden Research Center)
System: The UNT Digital Library
Containment and recovery system for fuel-reprocessing plants (open access)

Containment and recovery system for fuel-reprocessing plants

Tritium containment and removal problems in a fuel-reprocessing plant are identified and conceptual process designs for reducing emissions to the environment to below 1 Ci/day are studied. The conceptual design recommended would allow an air atmosphere in the reprocessing-plant hall and would use a continuous-catalytic-oxidizer/molecular-sieve-adsorber cleanup system to maintain a 40-..mu..Ci/m/sup 3/ tritium level (5 ..mu..Ci/m/sup 3/ HTO) against 180 Ci/day leakage from components and process piping.
Date: August 25, 1976
Creator: Galloway, T. R.
System: The UNT Digital Library
Resolution of safety issues associated with the storage of high-level radioactive waste at the Hanford Site (open access)

Resolution of safety issues associated with the storage of high-level radioactive waste at the Hanford Site

A number of high-level radioactive waste (HLW) safety issues have been identified at the Hanford Site in southeastern Washington State. Resolution of these issues is one of the Highest Priorities of the US Department of Energy. The most urgent issues are the potential for explosions in certain tanks (due to periodic venting of large quantities of flammable gases, or the presence of substantial quantities of ferrocyanide and/or organic compounds in combination with nitrates-nitrites). Other safety issues have been identified as well, such as the requirement for periodic water additions to one tank to control its temperature and the release of noxious vapors from a number of tanks. Substantial progress has been made toward safety issue resolution. Potential mechanisms have been identified for the generation, retention and periodic venting of flammable gas mixtures; potential methods for controlling the periodic release behavior have been identified and in-tank testing will be initiated in 1992. Research is being conducted to determine the initiation temperatures, energetics, reaction sequences and effects of catalysts and initiators on ferrocyanide-nitrate/nitrite reactions; waste characterization on a tank-by-tank basis will be required to identify whether ferrocyanide-containing wastes are safe to store as-is or will require further treatment to eliminate safety concerns. …
Date: August 1, 1992
Creator: Mellinger, G. B. (Pacific Northwest Lab., Richland, WA (United States)) & Tseng, J. C. (USDOE Assistant Secretary for Environmental Restoration and Waste Management, Washington, DC (United States))
System: The UNT Digital Library
Brookhaven superconducting cable test facility (open access)

Brookhaven superconducting cable test facility

Construction has started on an outdoor testing station for flexible ac superconducting power transmission cables. It is intended to serve as an intermediate step between laboratory-scale experiments and qualification testing of prototype-scale cables. The permanent equipment includes a 500 W supercritical helium refrigerator using a screw compressor and multistage turbine expanders. Helium storage for 250,000 cu ft of helium at 250 psi is provided. Initially, the cables will be tested in a horizontal cryostat some 250 ft long. High-voltage 60 Hz tests will be performed with the cable in a series resonant mode with a maximum line to ground capability of 240 kV, this is adequate for a 138 kV system design. Impulse testing up to about 650 kV is planned. The cable conductor will be energized by current transformers, initially at about 4 kA and later up to fault levels of 40 kA. The refrigerator is now at the site and testing on a dummy load will commence in the Fall of 1976. The cryostat will be installed in 1977 followed about a year later by the first cable tests.
Date: August 17, 1976
Creator: Forsyth, E. B. & Gibbs, R. J.
System: The UNT Digital Library
Ion exchange purification of bis(2-ethylhexyl)phosphoric acid (open access)

Ion exchange purification of bis(2-ethylhexyl)phosphoric acid

Bis(2-ethylhexyl)phosphoric acid (HDEHP) may be purified by absorption on a macroreticular, strong base anion exchange resin. Properties of ion exchange purified HDEHP are in excellent agreement with literature values.
Date: August 1, 1976
Creator: Honaker, C. B. & Schulz, W. W.
System: The UNT Digital Library
Stochastic Cooling at Fermilab (open access)

Stochastic Cooling at Fermilab

The topics discussed are the stochastic cooling systems in use at Fermilab and some of the techniques that have been employed to meet the particular requirements of the anti-proton source. Stochastic cooling at Fermilab became of paramount importance about 5 years ago when the anti-proton source group at Fermilab abandoned the electron cooling ring in favor of a high flux anti-proton source which relied solely on stochastic cooling to achieve the phase space densities necessary for colliding proton and anti-proton beams. The Fermilab systems have constituted a substantial advance in the techniques of cooling including: large pickup arrays operating at microwave frequencies, extensive use of cryogenic techniques to reduce thermal noise, super-conducting notch filters, and the development of tools for controlling and for accurately phasing the system.
Date: August 1986
Creator: Marriner, John
System: The UNT Digital Library
SU(4) breaking and the new particles: some applications (open access)

SU(4) breaking and the new particles: some applications

The applications for SU(4) breaking for new particles considered are an expression of the vector and axial vector weak charges of charmed hadrons and a relativistic mass formula for vector mesons. Wave functions defined in momentum space are considered. Quantum numbers of various meson resonances are found. (JFP)
Date: August 1, 1976
Creator: Sorba, P.
System: The UNT Digital Library
ERDA--DGE/LBL geothermal reservoir engineering management program (open access)

ERDA--DGE/LBL geothermal reservoir engineering management program

The management program is outlined and the objectives are discussed. The development procedure and implementation of the plan are described. (MHR)
Date: August 1977
Creator: Howard, J. H.
System: The UNT Digital Library
GAPCON-3: a computer code to analyze the path-dependent thermal and mechanical performance of nuclear fuel rods. [BWR and PWR] (open access)

GAPCON-3: a computer code to analyze the path-dependent thermal and mechanical performance of nuclear fuel rods. [BWR and PWR]

GAPCON-3 provides an integrated thermal and mechanical analysis of a reactor fuel pin in terms of its path-dependent power history. It is designed to handle the axial and radial variations in power, temperature, and fuel cladding mechanical interaction, normally encountered in LWR fuel. It provides detailed information regarding temperatures, stresses, and strains depending upon the mesh size selected and the needs of the user. The code uses a finite element formulation for the mechanical analysis and includes the effects of creep, plasticity, and anisotropy. The steady state thermal calculations are based upon the method of weighted residuals (MWR) and use a finite difference formulation for treating the transient thermal dependence. The fuel behavior models incorporate relocation, swelling, and densification as well as power history-dependent local fission gas release. The code is structured to operate efficiently and to allow its use in both parametric as well as detailed analysis applications. A typical problem on a CDC-6600 computer will require 8 to 10 seconds per time step for solution.
Date: August 1, 1976
Creator: Mohr, C L; Lanning, D D; Panisko, F E & Stewart, K B
System: The UNT Digital Library
Dissociation of NH/sub 3/ and NH/sub 2/D by high power CO/sub 2/ laser radiation (open access)

Dissociation of NH/sub 3/ and NH/sub 2/D by high power CO/sub 2/ laser radiation

Multiquantum dissociation of polyatomics using intense CO/sub 2/ lasers resulting in isotopic enrichment has been demonstrated for several molecules. In this presentation, the possibility of selective dissociation of NH/sub 3/ and NH/sub 2/D by high power laser radiation at 10 ..mu..m will be considered. Relevant work performed at the Lawrence Livermore Laboratory and elsewhere will be summarized. In this review, attention will be given to four distinct mechanisms that can play varying degrees of importance in such investigations. Discussion will deal with the usefulness of two-resonant-frequency molecular excitation, the role of buffer gases, and the need to monitor the yields into the ground and excited electronic states of the dissociated fragments.
Date: August 1, 1976
Creator: Jacobs, R. R.
System: The UNT Digital Library
Frontiers of accelerator instrumentation (open access)

Frontiers of accelerator instrumentation

New technology has permitted significant performance improvements of established instrumentation techniques including beam position and profile monitoring. Fundamentally new profile monitor strategies are required for the next generation of accelerators, especially linear colliders (LC). Beams in these machines may be three orders of magnitude smaller than typical beams in present colliders. In this paper we review both the present performance levels achieved by conventional systems and present some new ideas for future colliders.
Date: August 1, 1992
Creator: Ross, M.
System: The UNT Digital Library
Theory of mesonic and dibaryonic excitations in. pi. NN systems (open access)

Theory of mesonic and dibaryonic excitations in. pi. NN systems

Progress made in developing a ..pi..NN model for describing all NN and ..pi..d reactions up to intermediate energy regions is reported. An accurate ..pi..NN model is the starting point of developing a microscopic description of nuclear phenomena up to the energy region where pion production can occur. The model can be used to carry out many-nucleon calculations, such as the calculations of pion absorption and electroproduction of ..delta.. on nuclei. It reduces to existing nuclear theory in the low energy region. 5 refs., 6 figs.
Date: August 1, 1986
Creator: Lee, T. S. H.
System: The UNT Digital Library
Well, hydrology, and geochemistry problems encountered in ATES systems and their solutions (open access)

Well, hydrology, and geochemistry problems encountered in ATES systems and their solutions

In aquifer thermal energy storage (ATES) systems, wells provide the interface between the energy storage and use. Efficient operational wells are, therefore, essential for the system to run at maximum (design) efficiency. Adequate test drilling to accurately predict aquifer properties is essential in the design phase; proper construction and development are crucial; and proper monitoring of performance is necessary to identify the early stages of clogging and to evaluate the adequacy of well rehabilitation. Problems related to hydrology, well, and aquifer properties include: loss of permeability resulting from gas exsolution, chemical precipitation, and dispersion and movement of fine-grained particles; loss of recoverable heat caused by excessive regional ground-water gradient, hydrodynamic mixing of injected and native ground water, buoyancy flow and heat conduction through the cap and base of the storage zone; leakage up along the well casing; and fracturing'' of a shallow upper aquiclude as a result of an injection pressure greater than the hydrostatic pressure on the aquiclude. The predominant geochemical problems encountered are precipitation of carbonates in some areas and iron plus manganese oxides in others. These precipitation problems can be anticipated, and thus avoided, via geochemical calculations. The likelihood of iron carbonate precipitation is less certain because …
Date: August 1, 1992
Creator: Jenne, E. A. (Pacific Northwest Lab., Richland, WA (United States)); Andersson, O. (VBB VIAK AB, Malmo (Sweden)) & Willemsen, A. (IF Technology, Arnhem, (Netherlands))
System: The UNT Digital Library
Optical engineering problems associated with construction of the Shiva Laser Fusion Facility (open access)

Optical engineering problems associated with construction of the Shiva Laser Fusion Facility

The Shiva laser system is part of a new 20 terawatt laser facility at Lawrence Livermore Laboratory. The system contains more than $5,000,000 worth of optics. This paper discusses the various optical components, typical component quantities and specification, and the problem of laser damage to components.
Date: August 24, 1977
Creator: Godwin, R. O.; Bliss, E. S.; Glaze, J. A.; O'Neal, W. C.; Patton, H. G.; Summers, M. A. et al.
System: The UNT Digital Library
Finite amplitude thermal convection in porous media with uniform heat source (open access)

Finite amplitude thermal convection in porous media with uniform heat source

An unbounded horizontal fluid layer in a porous medium with an internal heat source and uniformly heated from below was studied. The layer is in the gravitational field. Linear theory predicts that the disturbances of infinitesimal amplitude will start to grow when the Rayleigh number exceeds its critical value. These disturbances do not grow without limit; but by advecting heat and momentum, the distrurbances alter their forms to achieve a finite amplitude. Just like infinitesimal amplitude disturbances the degenercies of possible solutions persist for finite amplitude solutions. This study evaluates the stability of these various forms of solutions. The small parameter method of Poincare is used to treat the problem in successive order.
Date: August 11, 1976
Creator: Hwang, I. T.
System: The UNT Digital Library
Structure for the decomposition of safeguards responsibilities (open access)

Structure for the decomposition of safeguards responsibilities

A major mission of safeguards is to protect against the use of nuclear materials by adversaries to harm society. A hierarchical structure of safeguards responsibilities and activities to assist in this mission is defined. The structure begins with the definition of international or multi-national safeguards and continues through domestic, regional, and facility safeguards. The facility safeguards is decomposed into physical protection and material control responsibilities. In addition, in-transit safeguards systems are considered. An approach to the definition of performance measures for a set of Generic Adversary Action Sequence Segments (GAASS) is illustrated. These GAASS's begin outside facility boundaries and terminate at some adversary objective which could lead to eventual safeguards risks and societal harm. Societal harm is primarily the result of an adversary who is successful in the theft of special nuclear material or in the sabotage of vital systems which results in the release of material in situ. With the facility safeguards system, GAASS's are defined in terms of authorized and unauthorized adversary access to materials and components, acquisition of material, unauthorized removal of material, and the compromise of vital components. Each GAASS defines a set of ''paths'' (ordered set of physical protection components) and each component provides one …
Date: August 1, 1977
Creator: Dugan, V. L. & Chapman, L. D.
System: The UNT Digital Library
Interpretation of recent laser-plasma experiments (open access)

Interpretation of recent laser-plasma experiments

This review of laser implosion research contains discussions on the efficiency of light absorption, processes of absorption, and the energy spectra of heated electrons. Diagrams are given showing the various processes and stages of a laser imploded target. Some calculational results using the LASNEX code are described. (MOW)
Date: August 1, 1975
Creator: Shay, H. D.
System: The UNT Digital Library
Designing reliability into accelerators (open access)

Designing reliability into accelerators

For the next generation of high performance, high average luminosity colliders, the factories,'' reliability engineering must be introduced right at the inception of the project and maintained as a central theme throughout the project. There are several aspects which will be addressed separately: Concept; design; motivation; management techniques; and fault diagnosis.
Date: August 1, 1992
Creator: Hutton, A.
System: The UNT Digital Library
In situ experiments related to waste repository design (open access)

In situ experiments related to waste repository design

The Office of Waste Isolation of Union Carbide Corporation-Nuclear Division has been charged by the U. S. Energy Research and Development Administration with the responsibility to provide deep, land-based repositories in geologic formations for nuclear waste from the commercial fuel cycle. Design and construction of waste repositories require information relative to the behavior of rock under high-temperature and -pressure conditions for long periods of time. Experience has shown that although laboratory data characterizing rock properties are both necessary and useful for preliminary design studies, the behavior of the rock mass ultimately must be determined by in situ tests, preferably carried out at about the same depth and in the same formation horizon as would be used for the waste repository. This paper describes types of relevant in-situ tests.
Date: August 1, 1977
Creator: Fairchild, P. D. & Russell, J. E.
System: The UNT Digital Library
Design of the Nb[sub 3]Sn dipole D20 (open access)

Design of the Nb[sub 3]Sn dipole D20

The design of a 50 mm bore superconducting Nb[sub 3]Sn dipole with a short sample field of 13 T at 4.3 K and a current of 5500 A/turn is presented. The magnet is composed by two double pancake layers. The inner cable has 37 strands with a strand diameter of 0.75 mm and a Cu/Sc ratio of 0.4; the outer cable has 47 strands with a diameter of 0.48 mm and a Cu/Sc ratio of 1.15. In order to obtain a high transfer function and low saturation effects on the multipoles, the stainless steel collar is elliptical and the iron yoke is close-in.'' The thin collar itself provides only a minimum prestress and the full prestress of 100 MPa is given by a 25 mm welded stainless steel shell or by winding a wire around the yoke. Aluminum spacers are used as assembly tools and as a means to control the gap size in the vertically split iron yoke. This paper presents the magnetic design and the calculated stress and strain distribution in structure and coils. A 1 m model called D20 is to be built and tested at LBL.
Date: August 1, 1992
Creator: Dell'Orco, D.; Scanlan, R. & Taylor, C. E.
System: The UNT Digital Library
Analysis of BWR pressure suppression pool dynamics (open access)

Analysis of BWR pressure suppression pool dynamics

The design basis loss of coolant accident (LOCA) for light water nuclear reactors postulates a major break in a coolant line. Both the response of the reactor vessel and its mechanical system as well as the response of the pressure suppression containment system exterior to the pressure vessel are of primary interest following such an event. The ability to determine system response and the suitability of particular mechanical and structural design features in both cases is predicted on the completeness with which the dynamic environment created in the various compartments is treated. In January of 1976, the Lawrence Livermore Laboratory (LLL) began a program for the NRC (RSR) to provide a sample problem solution activity which treats by numerical analysis the air-steam-water system flow implied by a LOCA. As a basis and focal point for modeling, the program addressed itself to the pressure suppression pool dynamics representative of the Mark I BWR. Program activities to date are described.
Date: August 30, 1976
Creator: McCauley, E. W.; Martin, R. W. & Sutton, S. B.
System: The UNT Digital Library
Tritium control in a mirror-fusion central power station (open access)

Tritium control in a mirror-fusion central power station

Tritium-containment systems for the blanket and power systems of a mirror-fusion reactor are described. These systems are designed to reduce emissions to below 1 Ci/d. The overall conceptual design uses air as the reactor-hall atmosphere. A continuous catalytic oxidizer-molecular sieve adsorber cleanup system would be used to control a 180-Ci/d leakage from reactor components, energy recovery systems, and process piping. Such a system would maintain a 40 ..mu..Ci/m/sup 3/ tritium level (5 ..mu..Ci/m/sup 3/ HTO) in the hall. The blanket considered contains submodules with Li/sub 2/Be/sub 2/O/sub 3/-Be for tritium breeding. This canned breeding material is scavenged with a lithium-vapor-doped helium gas stream. The container consists of molybdenum alloy (TZM) tubes and tube sheets with the breeding material packed and sintered in the shell surrounding the tubes. Potassium vapor coolant (also lithium-doped) passes through these tubes to recover the heat at 950/sup 0/C. Leakage following an intermediate TZM exchanger would result in a loss of 0.7 Ci/d into the steam through the Haynes-25 alloy boiler (potassium boiling). A moving getter bed is used to recover the tritium from the LiT and Li/sub 2/T scavengers in both the helium blanket scavenging flow and the potassium vapor coolant.
Date: August 25, 1976
Creator: Galloway, T. R.
System: The UNT Digital Library
Energy losses in mixed matrix superconducting wires under fast pulsed conditions (open access)

Energy losses in mixed matrix superconducting wires under fast pulsed conditions

Energy losses have been measured on a set of mixed matrix (CuNi, Cu, NbTi) superconducting wires at B's up to 1.5 x 10/sup 7/ G/s. The losses have been measured as a function of wire diameter, twist pitch, maximum applied field, and B. Both static and dynamic losses were measured for a field applied perpendicularly to the wire axis. The dynamic losses were measured by slowly applying an external field to a sample and then causing the field to decay exponentially in roughly 1 ms to 10 ms. Under low B (9 kG) and B (10/sup 6/ G/s) conditions the hysteretic loss dominated. At high B (21 kG) and B (1.5 x 10/sup 7/ G/s) the matrix losses became dominant. The systematic variation of the losses with the mentioned parameters will be presented and will be compared to theoretical predictions.
Date: August 17, 1976
Creator: Wollan, J. J.
System: The UNT Digital Library
Intense beams at the micron level for the Next Linear Collider (open access)

Intense beams at the micron level for the Next Linear Collider

High brightness beams with sub-micron dimensions are needed to produce a high luminosity for electron-positron collisions in the Next Linear Collider (NLC). To generate these small beam sizes, a large number of issues dealing with intense beams have to be resolved. Over the past few years many have been successfully addressed but most need experimental verification. Some of these issues are beam dynamics, emittance control, instrumentation, collimation, and beam-beam interactions. Recently, the Stanford Linear Collider (SLC) has proven the viability of linear collider technology and is an excellent test facility for future linear collider studies.
Date: August 1, 1991
Creator: Seeman, J. T.
System: The UNT Digital Library