65 Matching Results

Results open in a new window/tab.

Potential of pyroprocessing for partitioning purex wastes (open access)

Potential of pyroprocessing for partitioning purex wastes

The processes are extremely compact. The process reagents are highly resistant to radiation damage and, therefore, can be used to handle short-cooled, highly concentrated waste with negligible degradation. Most reagents can be recycled back through the process many times, thereby minimizing the generation of waste products, and also reducing the process cost. Fission-product wastes are discharged from the process as concentrated, solid wastes, typically in a metal matrix suitable for permanent disposal. Long cooling periods are not needed prior to conversion to a suitable waste form. The recovered actinides are obtained as metals and cen be easily stored or shipped. Pyrochemical processing of nuclear fuels should be considered as a second generation technology.
Date: July 23, 1980
Creator: Coops, M. S. & Sisson, D. H.
System: The UNT Digital Library
Personal extrapolation of CDF test beam use to the SSC (open access)

Personal extrapolation of CDF test beam use to the SSC

The author's personal experience in test beam usage at CDF is used to predict SSC needs at the point of turn-on. It is concluded that the test beam demand will reflect the scale of effort involved in SSC detectors rather than the total number of them. Provision for later expansion is recommended. It is also recommended that the test beam facilities, as well as detector electronics, should reflect the available dynamic range; particularly, a single high energy beam derived from the SSC could be shared by several groups. (LEW)
Date: June 23, 1986
Creator: Nodulman, L.
System: The UNT Digital Library
Photomultiplier characteristics considerations for the deep underwater muon and neutrino detection system (open access)

Photomultiplier characteristics considerations for the deep underwater muon and neutrino detection system

The results of an investigation of the characteristics of photomultipliers for the Deep Underwater Muon and Neutrino Detection (DUMAND) System are discussed. The pulse-height resolution, the afterpulsing phenomena and the gain sensitivity to the ambient magnetic field have been determined for large photocathode area photomultipliers. Furthermore, the transient time difference, the single photoelectron time spread, and the collection and photocathode quantum efficiency uniformity as a function of the position of the photocathode sensing area have been reviewed. Finally, an attempt has been made to estimate the photomultiplier reliability and its lifetime.
Date: February 23, 1980
Creator: Leskovar, B.
System: The UNT Digital Library
Cosmic ray events in Soudan 2 (open access)

Cosmic ray events in Soudan 2

The Soudan 2 detector is located at a depth of 2090 meters-water equivalent (mwe). About 2 million muon events have been recorded. Here we report on our plans to analyze them for comparison with expectations from atmospheric cosmic ray models. Plans and capabilities to analyze multiple muons and monopoles are also discussed. 3 refs., 5 figs.
Date: August 23, 1989
Creator: Allison, W. W. M.; Alner, G. J.; Ambats, I.; Ayres, D.; Balka, L.; Barr, G. D. et al.
System: The UNT Digital Library
Studies of. mu. prime s underground with the Soudan 2 Tracker (open access)

Studies of. mu. prime s underground with the Soudan 2 Tracker

During the period July 1987 through March 1988, a section of the Soudan 2 active shield known as the Tracker' recorded {approximately}250,000 muon tracks. The detector is located in the Tower-Soudan State Park in Soudan, Minnesota USA at a depth of 2090 meters-water equivalent. We have analysed the data collected and searched for time-dependent astronomical sources. Distributions in azimuthal and zenith angles as well as declination and right ascension are shown. 1 ref., 7 figs., 1 tab.
Date: August 23, 1989
Creator: Kochocki, J.; Benjamin, D.; Ewen, B.; Kafka, T.; Mann, A.; McMaster, L. et al.
System: The UNT Digital Library
Heat transfer in inertial confinement fusion reactor systems (open access)

Heat transfer in inertial confinement fusion reactor systems

The short time and deposition distance for the energy from inertial fusion products results in local peak power densities on the order of 10/sup 18/ watts/m/sup 3/. This paper presents an overview of the various inertial fusion reactor designs which attempt to reduce these peak power intensities and describes the heat transfer considerations for each design.
Date: April 23, 1980
Creator: Hovingh, J.
System: The UNT Digital Library
Tandem mirror reactors with thermal barriers (open access)

Tandem mirror reactors with thermal barriers

Preliminary calculations of Q and magnet designs are presented for three different versions of tandem mirror reactors (TMR) using thermal barriers to enhance plug potentials by auxiliary electron heating. These three versions, called A-cell-barrier TMR, axisymmetric-barrier TMR, and inside-barrier TMR, exhibit reduced plug density (n/sub p/ << 10/sup 19/ m/sup -3/) and less required magnetic mirror field (B/sub mirror approx. = 9 T) compared to TMR designs without thermal barriers. A-cell barrier TMR Q's range from 5 to 25 depending on the central-cell length (L/sub c/ = 100 to 200 m) and peak center-cell beta ..beta../sub c/ (0.3 to 0.7) allowed by MHD stability. Axisymmetric-barrier TMR Q's range from 14 at L/sub c/ = 100 m to 30 at L/sub c/ = 200 m, if peak ..beta../sub c/ = 1. From a global equilibrium model for the inside-barrier TMR, Q values greater than 15 are achieved for ..nu.. = 0.5 in the modified Boltzmann relation for the plug potential. Even higher Q's are obtained using ECRF heating in the barrier to create a hot, mirror-trapped electron population. TMR's burning D-D as a fuel have been analyzed with a modified version of the global equilibrium model and under the assumption of …
Date: May 23, 1980
Creator: Logan, B. G.; Arfin, B. & Barr, W. L.
System: The UNT Digital Library
Evaluation of low activation vanadium alloys for structural material in a fusion reactor (open access)

Evaluation of low activation vanadium alloys for structural material in a fusion reactor

The V-7.2Cr-14.5Ti, V-9.2Cr-4.9Ti, V-9.9Cr-9.2Ti, V-13.5Cr-5.2Ti, V-4.1Cr-4.3Ti, Vanstar-7, V-4.6Ti, V-17.7Ti, and V-3.1Ti-(0.5-1.0)Si alloys were evaluated for use as structural material in a fusion reactor. The alloys were evaluated on the basis of their yield strength, swelling resistance, resistance to hydrogen and irradiation embrittlement, and compatibility with a lithium reactor coolant. On the basis of these evaluations, the V-7.2Cr-14.5Ti, V-9.2Cr-4.9Ti, V-9.9Cr-9.2Ti, V-13.5Cr-5.2Ti, Vanstar-7, and V-3.1Ti-(0.5-1.0)Si alloys are considered unacceptable for structural material in a fusion reactor, whereas the V-4.1Cr-4.3Ti, V-4.6Ti, and V-17.7Ti alloys are recommended for more intensive evaluation. The V-7Cr-5Ti alloy may have the optimum combination of strength, DBTT, swelling rate, and lithium dissolution rate for a structural material in a fusion reactor. 4 refs., 6 figs., 4 tabs.
Date: October 23, 1989
Creator: Loomis, B. A.; Hull, A. B. & Smith, D. L.
System: The UNT Digital Library
Vacuum technology issues for the SSC (Superconducting Super Collider) (open access)

Vacuum technology issues for the SSC (Superconducting Super Collider)

The Superconducting Super Collider, to be built in Texas, will provide an energy of 40 TeV from colliding proton beams. This energy is twenty times higher than currently available from the only other cryogenic collider, the Fermilab Tevatron, and will allow experiments that can lead to a better understanding of the fundamental properties of matter. The energy scale and the size of the new machine pose intriguing challenges and opportunities for the its vacuum systems. The discussion will include the effects of synchrotron radiation on cryogenic beam tubes, cold adsorption pumps for hydrogen, methods of leak checking large cryogenic systems, the development of cold beam valves, and radiation damage to components, especially electronics. 9 figs., 1 tab.
Date: October 23, 1989
Creator: Joestlein, H.
System: The UNT Digital Library
Contained Events in Soudan 2 (open access)

Contained Events in Soudan 2

A search for contained events in the Soudan 2 nucleon decay detector has been made for the initial exposure of the first quarter of the 1.1 kiloton detector. This corresponds to an exposure of 0.083 kiloton years in the fiducial volume. We observe 5 {nu}{sub mu} candidate events and 5 {nu}{sub e} candidate events. Results of Monte Carlo simulations of neutrino events and proton decay events in Soudan 2 are compared. 6 refs., 3 figs.
Date: August 23, 1989
Creator: Allison, W. W. M.; Alner, G. J.; Ambats, I.; Balka, L.; Barr, G. D.; Benjamin, D. et al.
System: The UNT Digital Library
Characterizing W-2 SLSF experiment temperature oscillations using computer graphics. [Sodium Loop Safety Facility] (open access)

Characterizing W-2 SLSF experiment temperature oscillations using computer graphics. [Sodium Loop Safety Facility]

The W-2 SLSF (Sodium Loop Safety Facility) experiment was an instrumented in-reactor test performed to characterize the failure response of full-length, preconditioned LMFBR prototypic fuel pins to slow transient overpower (TOP) conditions. Although the test results were expected to confirm analytical predictions of upper level failure and fuel expulsion, an axial midplane failure was experienced. Extensive post-test analyses were conducted to understand all of the unexpected behavior in the experiment. (1) The initial post-test effort focused on the temperature oscillations recorded by the 54 thermocouples used in the experiment. In order to synthesize the extensive data records and identify patterns of behavior in the data records, a computer-generated film was used to present the temperature data recorded during the experiment.
Date: June 23, 1983
Creator: Smith, D. E.
System: The UNT Digital Library
Value-impact analysis of regulations for the nuclear industry (open access)

Value-impact analysis of regulations for the nuclear industry

This paper summarizes a quantitative tool developed at Lawrence Livermore National Laboratory to aid the NRC in establishing Material Control and Accounting (MC and A) regulations for safeguarding Special Nuclear Material (SNM). Illustrative Value-Impact results of demonstrating the methodology at a facility handling SNM to evaluate alternative safeguards rules is given. The methodology developed also offers a useful framework for facility designers to choose safeguards measures that meet the NRC's criteria in a cost-effective manner. Furthermore, the methodology requires very modest computing capability and is straightforward to apply.
Date: June 23, 1980
Creator: Al-Ayat, R.; Judd, B. & Huntsman, J.
System: The UNT Digital Library
Mechanical properties of high-current multifilamentary Nb/sub 3/Sn conductors (open access)

Mechanical properties of high-current multifilamentary Nb/sub 3/Sn conductors

Nb/sub 3/Sn is a strain-sensitive superconductor which exhibits large changes in properties for strains of less than 1 percent. The critical current density at 12 T undergoes a reversible degradation of a factor of two for compressive strains of about 1 percent and undergoes an irreversible degradation for tensile strains on the Nb/sub 3/Sn greater than 0.2 percent. Consequently, the successful application of Nb/sub 3/Sn in large high-field magnets requires a complete understanding of the mechanical properties of the conductor. One conductor which is being used for many applications consists of filaments of Nb/sub 3/Sn in a bronze matrix, and much progress has been made in understanding the mechanical behavior of this composite. The Nb/sub 3/Sn filaments are placed in compression due to the differential thermal contraction between Nb/sub 3/Sn and bronze which occurs when the composite is cooled from the Nb/sub 3/Sn formation temperature (typically 700/sup 0/C) to the 4.2/sup 0/K operating temperature. The general behavior of the critical current when this conductor is subjected to a tensile stress is an increase to a maximum when the compressive strain on the Nb/sub 3/Sn is relieved, followed by a decrease as the Nb/sub 3/Sn filemants are placed in tension. The …
Date: May 23, 1980
Creator: Scanlan, R. M.; Hoard, R. W.; Cornish, D. N. & Zbasnik, J. P.
System: The UNT Digital Library
Developments in solid state detectors for personnel neutron dosimetry (open access)

Developments in solid state detectors for personnel neutron dosimetry

The personnel neutron exposure potential at the Lawrence Livermore National Laboratory is more diverse than at many other facilities, due to the wide range of neutron producing activities. Albedo energy response problems in the face of the diversity of sources, and a concern about possible photon interferences with the neutron albedo response, have prompted development of some additional dosimetry techniques to augment the personnel monitoring program. This work now consists of two programs - the dosimeter/spectrometer (DOSPEC) in which track etch detectors are added to the albedo badge to provide some energy evaluation and gamma insensitivity, and development of solid state thin film MOS detectors to provide a real time, gamma insensitive dosimeter.
Date: July 23, 1981
Creator: Griffith, R.V.; Davidson, K.J.; Miller, D.E. & Vindelov, K.E.
System: The UNT Digital Library
Materials considerations for the coupling of thermochemical hydrogen cycles to tandem mirror reactors (open access)

Materials considerations for the coupling of thermochemical hydrogen cycles to tandem mirror reactors

Candidate materials are discussed and initial choices made for the critical elements in a liquid Li-Na Cauldron Tandem Mirror blanket and the General Atomic Sulfur-Iodine Cycle for thermochemical hydrogen production. V and Ti alloys provide low neutron activation, good radiation damage resistance, and good chemical compatibility for the Cauldron design. Aluminide coated In-800H and siliconized SiC are materials choices for heat exchanger components in the thermochemical cycle interface.
Date: May 23, 1980
Creator: Krikorian, O.H.
System: The UNT Digital Library
Focal spot size predictions for beam transport through a gas-filled reactor (open access)

Focal spot size predictions for beam transport through a gas-filled reactor

Results from calculations of focal spot size for beam transport through a gas-filled reactor are summarized. In the converging beam mode, we find an enlargement of the focal spot due to multiple scattering and zeroth order self-field effects. This enlargement can be minimized by maintaining small reactors together with a careful choice of the gaseous medium. The self-focused mode, on the other hand, is relatively insensitive to the reactor environment, but is critically dependent upon initial beam quality. This requirement on beam quality can be significantly eased by the injection of an electron beam of modest current from the opposite wall.
Date: January 23, 1980
Creator: Yu, S. S.; Lee, E. P. & Buchanan, H. L.
System: The UNT Digital Library
Applications of holographic interferometry to cryogenic ICF target characterization (open access)

Applications of holographic interferometry to cryogenic ICF target characterization

Uniformity of condensed layers of DT fuel in cryogenic ICF targets is a crucial parameter in their design. Measurements by classical interferometry lacks resolution to determine DT layer uniformity for targets with thick glass shells and/or thick ablative polymer coatings. We have developed holographic interferometry as an alternative tool for layer uniformity determination. This method is sensitive only to the fuel layer itself. We describe the technique and interference pattern analysis, and present preliminary results.
Date: September 23, 1981
Creator: Bernat, T. P.; Darling, D. H. & Sanchez, J. J.
System: The UNT Digital Library
NOVANET: communications network for a control system (open access)

NOVANET: communications network for a control system

NOVANET is a control system oriented fiber optic local area network that was designed to meet the unique and often conflicting requirements of the Nova laser control system which will begin operation in 1984. The computers and data acquisition devices that form the distributed control system for a large laser fusion research facility need reliable, high speed communications. Both control/status messages and experimental data must be handled. A subset of NOVANET is currently operating on the two beam Novette laser system.
Date: May 23, 1983
Creator: Hill, J.R.; Severyn, J.R. & VanArsdall, P.J.
System: The UNT Digital Library
Progress in Diamond Cell Experiments: Pressures Above Three Megabars (open access)

Progress in Diamond Cell Experiments: Pressures Above Three Megabars

Diamond cell experiments at pressures above 2 megabars have many important applications with respect to planetary interiors (e.g., metallization of hydrogen). To make possible acquisition of data at extreme pressures on materials of planetary interest, we have been exploring both numerically and experimentally several aspects of diamond cell design and methodology. We have conducted detailed finite element analyses of the diamond cell to explore how bevelled anvils and material properties of the gasket affect diamond cell performance (1). These calculations include nonlinear equations of state, gasket plasticity, and diamond-gasket interfacial friction. Gasket plasticity has a dramatic effect on the stress field and thus must be included in any physically realistic analysis of the diamond cell; purely elastic calculations, therefore, cannot model adequately the behavior of a diamond cell. Gasket yield strengh is very important in facilitating generation of extreme pressures in a diamond cell. Increasing gasket yield strength allows a higher radial pressure gradient to be supported at a given gasket thickness, which means that failure of an experiment by deformation of the anvils to allow anvil-anvil contact occurs at higher pressures than would occur with a lower yield strength gasket. Furthermore, the finite element analyses indicate that increasing gasket …
Date: January 23, 1986
Creator: Goettel, K. A.; Reichlin, R.; Moss, W. C. & Martin, S.
System: The UNT Digital Library
Shock anomaly and s-d transition in high-pressure lanthanum (open access)

Shock anomaly and s-d transition in high-pressure lanthanum

Linear-muffin-tin orbital calculations of the band structure and pressure-volume isotherms for fcc La, both at zero and finite temperatures. The calculated bulk modulus shows a rapid stiffening in the range from 40 to 50% compression, due to termination of the 6s to 5d electronic transition. When combined with a simple Slater model analysis, these results yield a temperature dependent peak in the lattice Grueneisen parameter. Experimental confirmation of this peak is found in an anomalous stiffening seen in the shock compression data for La, and it may also have some bearing on the observed saturation of the superconducting transition temperature in La around 200 kbar.
Date: July 23, 1981
Creator: McMahan, A.K.; Skriver, H.L. & Johansson, B.
System: The UNT Digital Library
Liquid-drop technique for generation of organic glass and metal shells (open access)

Liquid-drop technique for generation of organic glass and metal shells

We have for several years utilized the technique of capillary wave synchronization of the break-up of single and multiple component jets to produce uniform sized liquid drops and solid particles, and hollow liquid and solid shells. The technique has also been used to encapsulate a number of liquids in impermeable spherical shells. Highly uniform glass shells have been made by generating uniform drops of glass forming materials in an aqueous solution, subsequently evaporating the water, and then fusing and blowing the remaining solids in a high temperature vertical tube furnace. Experimental results will be presented and the critical problems in further research in this field will be discussed.
Date: December 23, 1981
Creator: Hendricks, C.D.
System: The UNT Digital Library
Perceived and calculated health risks: do the impacts differ (open access)

Perceived and calculated health risks: do the impacts differ

In many cases of radioactive and hazardous waste management, some members of the general public perceive that human health risks associated with the wastes are higher than the calculated risks. Calculated risks are projections that have been derived from models, and it is these risks that are usually used as the basis for waste management. However, for various reasons, the calculated risks are often considered by the public as too low or inappropriate. The reasons that calculated risks are not perceived as accurate and the factors that affect these perceptions are explored in this paper. Also discussed are the impacts related to the perceived and calculated health risks: what they are, and if and how they differ. The kinds of potential impacts examined are health effects, land value changes, and social, transportation, and economic effects. The paper concludes with a discussion of the implications of incorporating these different risk perspectives in decisions on waste management.
Date: January 23, 1986
Creator: Payne, B.A. & Williams, R.G.
System: The UNT Digital Library
Development of nitronic 50 fusion welding techniques for 4 K service (open access)

Development of nitronic 50 fusion welding techniques for 4 K service

The Mirror Fusion Test Facility (MFTF-B) is a large magnetic fusion energy experiment in the tandem mirror configuration. The requirement that each pair of Yin-Yang magnets, one pair at each end of the experiment, not undergo excessive lateral motion during seismic events was found to require excessively thick (> 12.7 mm) walled tubing in the support-struts, which accelerated the flow of heat inward to the 4 K magnet case from the nearby 300 K wall of the rector vessel, when any of the Cr-Ni austenite stainless steels, such as Type 304 with a 300 K yield-strength (sigma y) of 307 mpa (min.) was considered. Since the cold end of the lateral restraining strut was to be at or near 4 K, the additional constraints of good austenite stability and resistance to brittle fracture at 4 K existed. After consideration of these constraints against available information on Cr-Ni and Cr-Mn-Ni-N/sub 2/ austenitic stainless steels, grade XM-19 (Fe-22 Cr-12 Ni-5 Mn-.04 C-.02 N/sub 2/ was chosen. The mechanical properties of these welds were studied. (MOW)
Date: September 23, 1981
Creator: Dalder, E.N.C. & Juhas, M.C.
System: The UNT Digital Library
Simulation of multi-frequency ECRH (open access)

Simulation of multi-frequency ECRH

We use a test particle simulation code to investigate electron cyclotron heating in a magnetic mirror well. A comparison is made between heating with one frequency and heating with two closely spaced frequencies. The code follows electron orbits in the presence of one or two monochromatic ECRH waves using guiding center equations and an equation for the electron gyrophase. Coulomb collisions with electrons and ions are simulated as a Monte Carlo scattering process. We find for the parameters of SM-1 that at the fundamental resonance the heating rate, or velocity rf diffusion coefficient, begins to decrease significantly from the quasilinear value for epsilon/sub e/ greater than or equal to 10 keV due to superadiabatic effects. As suggested by Howard et al., using multiple frequencies pushes the superadiabatic boundary to higher energies. For a given energy, the optimum frequency separations for two frequencies are those which cause the axial bounce resonances to interlace; i.e., odd multiples of the bounce frequency, ..omega../sub b/. This interlacing increases the chance of resonance overlap and thus stochasticity. If the frequency difference is equal to an even multiple of ..omega../sub b/, the diffusion coefficient returns to near its one frequency value. More generally, for more than …
Date: November 23, 1981
Creator: Rognlien, T.D.
System: The UNT Digital Library