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A MOBILE MELT-DILUTE MODULE FOR THE TREATMENT OF ALUMINUM RESEARCH REACTOR SPENT FUEL

Description: A mobile melt-dilute (MMD) module for the treatment of aluminum research reactor spent fuel is being developed jointly by the Savannah River National Laboratory and Argonne National Laboratory. The process uses a closed system approach to retain fission products/gases inside a sealed canister after treatment. The MMD process melts and dilutes spent fuel with depleted uranium to obtain an isotopic content of less than 20 percent. The final ingot is solidified inside the sealed canister and can be stored safely either wet or dry until final disposition or reprocessing. The MMD module can be staged at or near the research reactor fuel storage sites to facilitate the melt-dilute treatment of the spent fuel into a stable non-proliferable form.
Date: November 3, 2004
Creator: ADAMS, THAD
Partner: UNT Libraries Government Documents Department

IRIS Reactor a Suitable Option to Provide Energy and Water Desalination for the Mexican Northwest Region

Description: The Northwest region of Mexico has a deficit of potable water, along this necessity is the region growth, which requires of additional energy capacity. The IRIS reactor offers a very suitable source of energy given its modular size of 300 MWe and it can be coupled with a desalination plant to provide the potable water for human consumption, agriculture and industry. The present paper assess the water and energy requirements for the Northwest region of Mexico and how the deployment of the IRIS reactor can satisfy those necessities. The possible sites for deployment of Nuclear Reactors are considered given the seismic constraints and the closeness of the sea for external cooling. And in the other hand, the size of the desalination plant and the type of desalination process are assessed accordingly with the water deficit of the region.
Date: October 3, 2004
Creator: Alonso, G.; Ramirez, R.; Gomez, C. & Viais, J.
Partner: UNT Libraries Government Documents Department

Measurements of the optical constants of scandium in the 50-1300eV range.

Description: Scandium containing multilayers have been produced with very high reflectivity in the soft x-ray spectrum. Accurate optical constants are required in order to model the multilayer reflectivity. Since there are relatively few measurements of the optical constants of Scandium in the soft x-ray region we have performed measurements over the energy range of 50-1,300 eV. Thin films of Scandium were deposited by ion-assisted magnetron sputtering at Linkoping University and DC Magnetron sputtering at CXRO. Transmission measurements were performed at the Advanced Light Source beamline 6.3.2. The absorption coefficient was deduced from the measurements and the dispersive part of the index of refraction was obtained using the Kramers-Kronig relation. The measured optical constants are used to model the near-normal incidence reflectivity of Cr/Sc multilayers near the Sc L{sub 2,3} edge.
Date: October 3, 2004
Creator: Aquila, A.L.; Salmassi, F.; Gullikson, E.M; Eriksson, F. & Birch, J.
Partner: UNT Libraries Government Documents Department

Measurement of the beam longitudinal profile in a storage ring bynon-linear laser mixing

Description: We report on the development of a new technique for the measurement of the longitudinal beam profile in storage rings. This technique, which has been successfully demonstrated at the Advanced Light Source, mixes the synchrotron radiation with the light from a mode-locked solid state laser oscillator in a non-linear crystal. The up-converted radiation is then detected with a photomultiplier and processed to extract, store, and display the required information. The available choices of laser repetition frequency, pulse width, and phase modulation give a wide range of options for matching the bunch configuration of a particular storage ring. Besides the dynamic measurement of the longitudinal profile of each bunch, the instrument can monitor the evolution of the bunch tails, the presence of untrapped particles and their diffusion into nominally empty RF buckets (''ghostbunches'').
Date: May 3, 2004
Creator: Beche, J.-F.; Byrd, J.; De Santis, S.; Denes, P.; Placidi, M.; Turner, W. et al.
Partner: UNT Libraries Government Documents Department

Development of an abort gap monitor for high-energy proton rings

Description: The fill pattern in proton synchrotrons usually features an empty gap, longer than the abort kicker raise time, for machine protection. This gap is referred to as the ''abort gap'' and any particles, which may accumulate in it due to injection errors and diffusion between RF buckets, would be lost inside the ring, rather than in the beam dump, during the kicker firing. In large proton rings, due to the high energies involved, it is vital to monitor the build up of charges in the abort gap with a high sensitivity. We present a study of an abort gap monitor based on a photomultiplier with a gated microchannel plate, which would allow for detecting low charge densities by monitoring the synchrotron radiation emitted. We show results of beam test experiments at the Advanced Light Source using a Hamamatsu 5916U MCP-PMT and compare them to the specifications for the Large Hadron Collider
Date: May 3, 2004
Creator: Beche, Jean-Francois; Byrd, John; De Santis, Stefano; Denes, Peter; Placidi, Massimo; Turner, William et al.
Partner: UNT Libraries Government Documents Department

Fe XVII Emission from Hot, Collisional Plasmas

Description: The ratios of the Fe XVII 3s {yields} 2p transitions to that of the dominant 3d {yields} 2p transition measured in high-temperature tokamak plasmas are compared to solar and astrophysical observations. Good agreement is found, indicating that the collisional line formation processes active in opacity-free, low-density, high-temperature laboratory plasmas are a good description of those found in astrophysical plasmas.
Date: December 3, 2004
Creator: Beiersdorfer, P; Bitter, M; von Goeler, S & Hill, K W
Partner: UNT Libraries Government Documents Department

The Nuclear Energy Option for the U.S.--How Far Are We from Public Acceptance?

Description: The recent rise of oil and gasoline prices accompanied by reluctant acknowledgement that traditional sources of energy are limited has renewed public interest in renewable energy sources. This perspective on energy is focusing attention on and facilitating acceptance of alternative energy concepts, such as solar, wind, and biomass. The nuclear energy alternative, while clean with potentially abundant fuel supplies and associated with low costs, is burdened with the frequently negative public opinion reserved for things nuclear. Coincident with the heightened examination of alternative energy concepts, 2004 marks the 25-year anniversary of the Three Mile Island accident. Since this pivotal accident in 1979, no new reactor licenses have been granted in the U.S. The resolution of the issues of nuclear waste management and disposition are central to and may advance public discussions of the future use of nuclear energy. The U.S. Department of Energy (DOE) is currently preparing the licensing application for Yucca Mountain, which was designated in 2003 as the site for a high-level waste and spent nuclear fuel repository in the U.S. The DOE also has been operating a deep geologic repository for the permanent disposal of transuranic (TRU) waste since 1999. The operational status of the Waste Isolation Pilot Plant (WIPP) as a repository for TRU waste was successfully realized along with the lesson learned that stakeholder trust and acceptance are as critical to the success of a repository program as the resolution of technical issues and obtaining regulatory approvals. For the five years of its operation and for decades prior, the challenge of attaining public acceptance of the WIPP has persisted for reasons aligned with the opposition to nuclear energy. Due to this commonality, the nuclear waste approach to public acceptance, with its pros and cons, provides a baseline for the examination of an approach for the ...
Date: October 3, 2004
Creator: Biedscheid, J.A. & Devarakonda, M.
Partner: UNT Libraries Government Documents Department

Edge Localized Mode Dynamics and Transport in the Scrape-Off Layer of the DIII-D Tokamak

Description: High temporal and spatial resolution measurements in the boundary of the DIII-D tokamak show that edge localized modes (ELMs) are produced in the low field side, are poloidally localized and are composed of fast bursts ({approx}20 to 40 {micro}s long) of hot, dense plasma on a background of less dense, colder plasma ({approx}5 x 10{sup 18} m{sup {+-}3}, 50 eV) possibly created by the bursts themselves. The ELMs travel radially in the scrapeoff layer (SOL), starting at the separatrix at {approx}450 m/s, and slow down to {approx}150 m/s near the wall, convecting particles and energy to the SOL and walls. The temperature and density in the ELM plasma initially correspond to those at the top of the density pedestal but quickly decay with radius in the SOL. The temperature decay length ({approx}1.2 to 1.5 cm) is much shorter than the density decay length ({approx}3 to 8 cm), and the latter decreases with increasing pedestal (and SOL) density. The local particle and energy flux at the midplane wall during the bursts are 10% to 50% ({approx}1 to 2 x 10{sup 21} m{sup {+-}2} s{sup {+-}1}) and 1% to 2 % ({approx}20 to 30 kW/m{sup 2}) respectively of the LCFS average fluxes, indicating that particles are transported radially much more efficiently than heat. Evidence is presented suggesting toroidal rotation of the ELM plasma in the SOL. The ELM plasma density and temperature increase linearly with discharge/pedestal density up to a Greenwald fraction of {approx}0.6, and then decrease resulting in more benign (grassier) ELMs.
Date: December 3, 2004
Creator: Boedo, J A; Rudakov, D L; Hollmann, E; Gray, D S; Burrell, K H; Moyer, R A et al.
Partner: UNT Libraries Government Documents Department

Computer Simulation for Emergency Incident Management

Description: This report describes the findings and recommendations resulting from the Department of Homeland Security (DHS) Incident Management Simulation Workshop held by the DHS Advanced Scientific Computing Program in May 2004. This workshop brought senior representatives of the emergency response and incident-management communities together with modeling and simulation technologists from Department of Energy laboratories. The workshop provided an opportunity for incident responders to describe the nature and substance of the primary personnel roles in an incident response, to identify current and anticipated roles of modeling and simulation in support of incident response, and to begin a dialog between the incident response and simulation technology communities that will guide and inform planned modeling and simulation development for incident response. This report provides a summary of the discussions at the workshop as well as a summary of simulation capabilities that are relevant to incident-management training, and recommendations for the use of simulation in both incident management and in incident management training, based on the discussions at the workshop. In addition, the report discusses areas where further research and development will be required to support future needs in this area.
Date: December 3, 2004
Creator: Brown, D L
Partner: UNT Libraries Government Documents Department

Recent Developments of the IRIS Project of Interest for Latin America

Description: The IRIS (International Reactor Innovative and Secure) reactor design is being developed by an international consortium of 21 organizations from ten countries, including three members from Brazil and one from Mexico. This reflects the interest that Latin America has for a project which addresses the energy needs of the region. Presented here are some of the most recent developments in the IRIS project. The project's highest priority is the current pre-application licensing with the US NRC, which has required an investigation of the major accident sequences and a preliminary probabilistic risk assessment (PRA). The results of the accident analyses confirmed the outstanding inherent safety of the IRIS configuration and the PRA analyses indicated a core damage frequency due to internal events of the order of 2E-8. This not only highlights the enhanced safety characteristic of IRIS which should enhance its public acceptance, but it has also prompted IRIS to consider the possibility of being licensed without the need for off-site emergency response planning which would have a very positive economic implication. The modular IRIS, with each module rated at {approx} 335 MWe, is of course an ideal size for developing countries as it allows to easily introduce a moderate amount of power on limited electric grids. IRIS can be deployed in single modules in regions only requiring a few hundred MWs or in multiple modules deployed successively at time intervals in large urban areas requiring a larger amount of power increasing with time. IRIS is designed to operate ''hands-off'' as much as possible, with a small crew, having in mind deployment in areas with limited infrastructure. Thus IRIS has a 48-months maintenance interval, long refueling cycles in excess of three years, and is designed to increase as much as possible operational reliability. For example, the project has recently adopted internal ...
Date: October 3, 2004
Creator: Carelli, M. D. & Petrovic, B.
Partner: UNT Libraries Government Documents Department

Polarization measurement of Iron L-shell lines on EBIT-I

Description: We report measurements of the line polarization of Ne-like and F-like of iron n=3 to n=2 transitions in the x-ray region. We used the ''two-crystal technique'' developed in previous polarization measurements in our laboratory. Preliminary results from our measurements are presented together with the theoretical calculations using the Flexible Atomic Code (FAC). Our calculations show that contributions from cascades play an important role in the polarization calculations of most of the transitions. The uncertainties and difficulties of our experiments are also discussed.
Date: March 3, 2004
Creator: Chen, H; Beiersdorfer, P; Robbins, D; Smith, A J & Gu, M F
Partner: UNT Libraries Government Documents Department

U.S. Department of Energy Program of International Technical Cooperation for Research Reactor Utilization

Description: The U.S. Department of Energy, National Nuclear Security Administration (DOE/NNSA) has initiated collaborations with the national nuclear authorities of Egypt, Peru, and Romania for the purpose of advancing the commercial potential and utilization of their respective research reactors. Under its Office of International Safeguards ''Sister Laboratory'' program, DOE/NNSA has undertaken numerous technical collaborations over the past decade intended to promote peaceful applications of nuclear technology. Among these has been technical assistance in research reactor applications, such as neutron activation analysis, nuclear analysis, reactor physics, and medical radioisotope production. The current collaborations are intended to provide the subject countries with a methodology for greater commercialization of research reactor products and services. Our primary goal is the transfer of knowledge, both in administrative and technical issues, needed for the establishment of an effective business plan and utilization strategy for the continued operation of the countries' research reactors. Technical consultation, cooperation, and the information transfer provided are related to: identification, evaluation, and assessment of current research reactor capabilities for products and services; identification of opportunities for technical upgrades for new or expanded products and services; advice and consultation on research reactor upgrades and technical modifications; characterization of markets for reactor products and services; identification of competition and estimation of potential for market penetration; integration of technical constraints; estimation of cash flow streams; and case studies.
Date: October 3, 2004
Creator: Chong, D.; Manning, M.; Ellis, R.; Apt, K.; Flaim, S. & Sylvester, K.
Partner: UNT Libraries Government Documents Department

A cartesian grid embedded boundary method for hyperbolic conservation laws

Description: We present a second-order Godunov algorithm to solve time-dependent hyperbolic systems of conservation laws on irregular domains. Our approach is based on a formally consistent discretization of the conservation laws on a finite-volume grid obtained from intersecting the domain with a Cartesian grid. We address the small-cell stability problem associated with such methods by hybridizing our conservative discretization with a stable, nonconservative discretization at irregular control volumes, and redistributing the difference in the mass increments to nearby cells in a way that preserves stability and local conservation. The resulting method is second-order accurate in L{sup 1} for smooth problems, and is robust in the presence of large-amplitude discontinuities intersecting the irregular boundary.
Date: October 3, 2004
Creator: Colella, Phillip; Graves, Daniel T.; Keen, Benjamin J. & Modiano, David
Partner: UNT Libraries Government Documents Department

CHANDRA AND XMM-NEWTON OBSERVATIONS OF RDCS1252.9-2927, A MASSIVE CLUSTER AT z = 1.24

Description: We present deep Chandra and XMM-Newton observations of the galaxy cluster RDCS1252.9-2927, which was selected from the ROSAT Deep Cluster Survey (RDCS) and confirmed by extensive spectroscopy with the VLT at redshift z = 1.237. With the Chandra data, the X-ray emission from the intra-cluster medium is well resolved and traced out to 500 kpc, thus allowing a measurement of the physical properties of the gas with unprecedented accuracy at this redshift. We detect a clear 6.7 keV Iron K line in the Chandra spectrum providing a redshift within 1% of the spectroscopic one. By augmenting our spectroscopic analysis with the XMM-Newton data (MOS detectors only), we significantly narrow down the 1{sigma} error bar to 10% for the temperature and 30% for the metallicity, with best fit values kT = 6.0{sup +0.7}{sub -0.5} keV, Z = 0.36{sup +0.12}{sup -0.10}Z{sub {circle_dot}}. In the likely hypothesis of hydrostatic equilibrium, we measure a total mass of M{sub 500} = (1.9{+-}0.3)10{sup 14}h{sup -1}{sub 70} M{sub {circle_dot}} within R{sub {Delta}=500} {approx} 536 kpc. Overall, these observations imply that RDCS1252.9-2927 is the most X-ray luminous and likely the most massive bona-fide cluster discovered to date at z > 1. When combined with current samples of distant clusters, these data lend further support to a mild evolution of the cluster scaling relations, as well the metallicity of the intra-cluster gas. Inspection of the cluster mass function in the current cosmological concordance model (h,{Omega}{sub m},{Omega}{sub {Lambda}}) = (0.7,0.3,0.7) and {sigma}{sub 8} = 0.7-0.8 shows that RDCS1252.9-2927 is an M* cluster at z = 1.24, in keeping with number density expectations in the RDCS survey volume.
Date: March 3, 2004
Creator: DEMARCO, R; ETTORI, S; TOZZI, P; BORGANI, S; MAINIERI, V; NONINO, M et al.
Partner: UNT Libraries Government Documents Department

Mechanisms of Strontium and Uranium Removal From Radioactive Waste Simulant Solutions by the Sorbent Monosodium Titanate

Description: High-Level Radioactive Waste (HLW) is the priority problem for the U.S. Dept. of Energy's Environmental Management Program. Current HLW treatment processes at the Savannah River Site (Aiken, SC) include the use of monosodium titanate (MST, similar to NaTi{sub 2}O{sub 5}xH{sub 2}O) to concentrate radioactive strontium (Sr) and actinides. Mechanistic information about radionuclide uptake will provide us with insight about the reliability of MST treatments. We characterized the morphology of MST and the chemistry of sorbed Sr{sup 2+} and uranium [U(VI)] on MST with x-ray based spectroscopic and electron microscopic techniques. Sorbed Sr{sup 2+} exhibited specific adsorption as partially-hydrated species, whereas sorbed U exhibited site-specific adsorption as monomeric and dimeric U(VI)-carbonate complexes. These differences in site specificity and mechanism may account for the difficulties associated with predicting MST loading and removal kinetics.
Date: December 3, 2004
Creator: DUFF, MARTINE
Partner: UNT Libraries Government Documents Department

Calculation of Np-237 and Am-241 Detector Calibration Constants from First Principles

Description: The Analytical Development Section of Savannah River Technology Center (SRTC) was requested to determine the holdup of enriched uranium in a facility as part of an overall deactivation project of the facility. The facility was used to fabricate enriched uranium fuel assemblies, lithium-aluminum target tubes, neptunium assemblies, and miscellaneous components for the production reactors. The results of the holdup assays are essential for determining compliance with the Waste Acceptance Criteria, Material Control and Accountability, and to meet criticality safety controls. This report covers calibration of the detectors in order to support holdup measurements in the out-gassing ovens. These ovens were used to remove gas entrained in billet assembly material prior to the billets being extruded into rods by the extrusion press. A portable high purity germanium detection system was used to determine highly enriched uranium (HEU) holdup and to determine holdup of U-235, Np-237, and Am-24 1 that were observed in these components. The detector system was run by an EG and G system that contains the high voltage power supply and signal processing electronics. A personal computer with Gamma-Vision software was used to control and provide space to store and manipulate multiple channel spectra. The measured Np-237 and Am-241 contents were especially important in these components because their presence is unusual and unexpected in the facility. It was important to obtain a measured value of these two components to disposition the out-gassing ovens and to determine whether a separate waste stream was necessary for release of these contaminated components to a solid waste vault. This report presents determination of the calibration constants from first principles for determination of Am-241 and Np-237 using this detection system and compares the values obtained for Np-237 with the calibration factors obtained with a subsequent measurement using a point source of radioactive equilibrium Np-237/Pa-233.
Date: May 3, 2004
Creator: Dewberry, R.A.
Partner: UNT Libraries Government Documents Department

Impact of Nuclear Energy Futures on Advanced Fuel Cycle Options

Description: The Nuclear Waste Policy Act requires the Secretary of Energy to inform Congress before 2010 on the need for a second geologic repository for spent nuclear fuel. By that time, the spent fuel discharged from current commercial reactors will exceed the statutory limit of the first repository. There are several approaches to eliminate the need for another repository in this century. This paper presents a high-level analysis of these spent fuel management options in the context of a full range of possible nuclear energy futures. The analysis indicates the best option to implement varies depending on the nuclear energy future selected.
Date: October 3, 2004
Creator: Dixon, B.W. & Piet, S.J.
Partner: UNT Libraries Government Documents Department

Picosecond x-ray laser photoelectron spectroscopy of room temperature and heated materials

Description: An 84.5 eV Ni-like Pd ion 4d - 4p x-ray laser source generated by the LLNL Compact Multipulse Terawatt (COMET) tabletop system has been used to probe the electronic structure of various metals and semiconductors. In addition to the {approx}4 - 5 ps time resolution, the probe provides the necessary high photon flux (>10{sup 12}/pulse), narrow line width ({Delta}E/E{approx}2 x 10{sup -5}) and coherence for studying valence band and shallow core electronic structure levels in a single shot. We show some preliminary results of room temperature and heated thin foil samples consisting of 50 nm Cu coated on a 20 nm C substrate. A 527 nm wavelength 400 fs laser pulse containing 0.1 - 2.5 mJ laser energy is focused in a large 500 x 700 {micro}m{sup 2} (FWHM) spot to create heated conditions of 0.07 - 1.8 x 1012 W cm{sup -2} intensity.
Date: August 3, 2004
Creator: Dunn, J; Nelson, A J; van Buuren, T & Hunter, J R
Partner: UNT Libraries Government Documents Department

Pulse duration measurements of a picosecond laser-pumped 14.7 nm x-ray laser

Description: The temporal dependence of the 14.7 nm Ni-like Pd ion x-ray laser is measured as a function of the laser drive conditions with a fast sub-picosecond x-ray streak camera. The chirped pulse amplification laser beam that pumps the inversion process is varied from 0.5 - 27 ps (FWHM) to determine the effect on the x-ray laser pulse duration. The average x-ray laser pulse duration varies by a relatively small factor of 2.5 times from 3.6 ps to 8.1 ps with traveling wave (TW) irradiation conditions. Slightly shorter pulse durations approaching 2 ps are observed with the x-ray laser operating below saturation. The x-ray laser is found to be 4 - 5 times transform-limited for 6 - 13 ps laser pumping conditions.
Date: August 3, 2004
Creator: Dunn, J; Smith, R F; Shepherd, R; Booth, R; Nilsen, J; Hunter, J R et al.
Partner: UNT Libraries Government Documents Department

An Application of the Coda Methodology for Moment-Rate Spectra Using Broadband Stations in Turkey

Description: A recently developed coda magnitude methodology was applied to selected broadband stations in Turkey for the purpose of testing the coda method in a large, laterally complex region. As found in other, albeit smaller regions, coda envelope amplitude measurements are significantly less variable than distance-corrected direct wave measurements (i.e., L{sub g} and surface waves) by roughly a factor 3-to-4. Despite strong lateral crustal heterogeneity in Turkey, we found that the region could be adequately modeled assuming a simple 1-D, radially symmetric path correction for 10 narrow frequency bands ranging between 0.02 to 2.0 Hz. For higher frequencies however, 2-D path corrections will be necessary and will be the subject of a future study. After calibrating the stations ISP, ISKB, and MALT for local and regional distances, single-station moment-magnitude estimates (M{sub w}) derived from the coda spectra were in excellent agreement with those determined from multi-station waveform modeling inversions of long-period data, exhibiting a data standard deviation of 0.17. Though the calibration was validated using large events, the results of the calibration will extend M{sub w} estimates to significantly smaller events which could not otherwise be waveform modeled due to poor signal-to-noise ratio at long periods and sparse station coverage. The successful application of the method is remarkable considering the significant lateral complexity in Turkey and the simple assumptions used in the coda method.
Date: February 3, 2004
Creator: Eken, T; Mayeda, K; Hofstetter, A; Gok, R; Orgulu, G & Turkelli, N
Partner: UNT Libraries Government Documents Department

PROGRESS IN DESIGNING A MUON COOLING RING WITH LITHIUM LENSES.

Description: We discuss particle tracking simulations in a storage ring with lithium lens inserts designed for the six-dimensional phase space cooling of muons by the ionization cooling. The ring design contains one or more lithium lens absorbers for transverse cooling that transmit the beam with very small beta-function values, in addition to liquid-hydrogen wedge-shaped absorbers in dispersive locations for longitudinal cooling. Such a ring could comprise the final component of a cooling system for use in a muon collider. The beam matching between dipole-quadrupole lattices and the lithium lenses is of particular interest.
Date: March 3, 2004
Creator: FUKUI,Y. CLINE,D. B. GARREN,A. A. KIRK,H. G.
Partner: UNT Libraries Government Documents Department

Mid infrared observations of Van Maanen 2: no substellar companion.

Description: The results of a comprehensive infrared imaging search for the putative 0.06 M{sub {circle_dot}} astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 {micro}m reveal a diffraction limited core of 0.09 inch and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50 M{sub J} brown dwarf would be only 1 magnitude fainter than van Maanen 2 at this wavelength and the astrometric analysis suggested a separation of 0.2 inch. In the case of a chance alignment along the line of sight, a 0.4 mag excess should be measured. An independent photometric observation at the same wavelength reveals no excess. In addition, there exist published ISO observations of van Maanen 2 at 6.8 {micro}m and 15.0 {micro}m which are consistent with photospheric flux of a 6750 K white dwarf. If recent brown dwarf models are correct, there is no substellar companion with T{sub eff} {approx}> 500 K.
Date: November 3, 2004
Creator: Farihi, J; Becklin, E & Macintosh, B
Partner: UNT Libraries Government Documents Department

Radionuclide Inventory Management at the New 100 MeV Isotope Production Facility at LANL

Description: The Isotope Production Facility (IPF) at Los Alamos is operated on the authorization basis of a radiological facility with an inventory limit of a Category 3 Nuclear Facility. For the commissioning of IPF, a ''dummy'' target stack containing Zn, Nb and Al disks, and a ''prototype'' stack were irradiated with a proton beam. The ''prototype'' stack contained two pressed RbCl disks, encapsulated in stainless steel, and a Ga metal target. Typical ''prototype'' stack beam parameters were 88.9 {micro}A, 101.3 h. Operation procedures require the projection of all generated radionuclide activities. This is mandatory in order to determine both maximum beam current and maximum beam exposure time. The Monte Carlo code MCNPX and the burn-up code CINDER90 were used to determine maximum beam parameters prior to irradiation. After irradiation, activity estimates were calculated assuming actual average beam parameters. They were entered into an online inventory database, and were later, after chemical separation and radioactive assays, replaced by experimental values. A comparison of ''prototype'' stack experimental yield data to Monte Carlo calculation results showed that the computer codes provide realistic, conservative estimates.
Date: October 3, 2004
Creator: Fassbender, M.E.; Phillips, D.R.; Nortier, F.M.; Trellue, H.R.; Hamilton, V.T.; Heaton, R.C. et al.
Partner: UNT Libraries Government Documents Department