Environmental management of assembled chemical weapons assessment program. (open access)

Environmental management of assembled chemical weapons assessment program.

Environmental planning and management was an integral part of the ACWA Program planning process. To ensure that environmental protection issues could be addressed expeditiously and not delay the demonstrations, the PMACWA scaled the technology demonstrations such that simplified regulatory processes and existing research and development facilities could be used. The use of enclosed facilities for the demonstrations prevents any uncontrolled discharges to the environment and made it possible to conduct environmental assessments relatively quickly. The PMACWA also arranged for public briefings to ease any community concerns over the operations with chemical weapons. These steps precluded regulatory and community resistance to the ACWA activities. The cooperation of the regulators and stakeholders has been a key element in enabling the ACWA Program to move with the speed that it has to date. Technology demonstrations are currently underway and are scheduled to be completed in late May 1999. The data collected during these demonstrations will be used to prepare and submit a summary report to Congress by August 1999. The challenge continues for the ACWA management to guide the demonstrations to completion and to plan for possible pilot testing. As the scale of the ACWA facilities increase in size, the ease of reduced …
Date: May 7, 1999
Creator: Frey, G.; Mohrman, G. & Templin, B. R.
System: The UNT Digital Library
Periscope Pop-in Beam Monitor. (open access)

Periscope Pop-in Beam Monitor.

We have built monitors for use as beam diagnostics in the narrow gap of an undulator for an FEL experiment. They utilize an intercepting screen of doped YAG scintillating crystal to make light that is imaged through a periscope by conventional video equipment. The absolute position can be ascertained by comparing the electron beam position with the position of a He:Ne laser that is observed by this pop-in monitor. The optical properties of the periscope and the mechanical arrangement of the system mean that beam can be spatially determined to the resolution of the camera, in this case approximately 10 micrometers. Our experience with these monitors suggests improvements for successor designs, which we also describe.
Date: May 7, 1998
Creator: Johnson, E. D.
System: The UNT Digital Library
Fourier mode analysis of slab-geometry transport iterations in spatially periodic media (open access)

Fourier mode analysis of slab-geometry transport iterations in spatially periodic media

We describe a Fourier analysis of the diffusion-synthetic acceleration (DSA) and transport-synthetic acceleration (TSA) iteration schemes for a spatially periodic, but otherwise arbitrarily heterogeneous, medium. Both DSA and TSA converge more slowly in a heterogeneous medium than in a homogeneous medium composed of the volume-averaged scattering ratio. In the limit of a homogeneous medium, our heterogeneous analysis contains eigenvalues of multiplicity two at ''resonant'' wave numbers. In the presence of material heterogeneities, error modes corresponding to these resonant wave numbers are ''excited'' more than other error modes. For DSA and TSA, the iteration spectral radius may occur at these resonant wave numbers, in which case the material heterogeneities most strongly affect iterative performance.
Date: May 7, 1999
Creator: Larsen, E W & Zika, M R
System: The UNT Digital Library
Comparisons of cloud cover estimates and cloud fraction profiles from ARM's cloud-detecting instruments and GOES-8 data (open access)

Comparisons of cloud cover estimates and cloud fraction profiles from ARM's cloud-detecting instruments and GOES-8 data

The DOE's Atmospheric Radiation Measurement (ARM) Program employs both upward- and downward-looking remote-sensing instruments to measure the horizontal and vertical distributions of clouds across its Southern Great Plains (SGP) site. No single instrument is capable of completely determining these distributions over the scales of interest to ARM's Single Column Modeling (SCM) and Instantaneous Radiative Flux (IRF) groups; these groups embody the primary strategies through which ARM expects to achieve its objectives of developing and testing cloud formation parameterizations (USDOE, 1996). Collectively, however, the data from ARM's cloud-detecting instruments offer the potential for such a three-dimensional characterization. Data intercomparisons, like the ones illustrated in this paper, are steps in this direction. Examples of some initial comparisons, involving satellite, millimeter cloud radar, whole sky imager and ceilometer data, are provided herein. that many of the lessons learned can later be adapted to cloud data at the Boundary and Extended Facilities. Principally, we are concerned about: (1) the accuracy of various estimates of cloud properties at a single point, or within a thin vertical column, above the CF over time, and (2) the accuracy of various estimates of cloud properties over the Cloud and Radiation Testbed (CART) site, which can then be reduced …
Date: May 7, 1999
Creator: Krueger, S K & Rodriguez, D
System: The UNT Digital Library
Arc View/Avenue: Coding styles and utility scripts for efficient development (open access)

Arc View/Avenue: Coding styles and utility scripts for efficient development

Effectiveness and efficiency of software development can be greatly increased by writing modularized code using informal (styles) and formal (standards) work approaches. Software development is about connecting pieces into a coherent whole. Thus consistent work approaches provide a structure that allows individuals and teams to minimize the time and thought put into making these connections. These investments in structure return even more benefits in the maintenance phase when old code has to be examined by new programmers, or after time has passed. We present some examples of coding style for Avenue: a simplified form of Hungarian notation (notationHungarian, stringCustomerName, etc.), script naming prefixes and suffixes, and options in script headers. We demonstrate several modular, object-like utility scripts that can be used alone or combined into other utilities. These include developer tools such as a System.Echo substitute for Windows, a Window inspector, and a script for detecting and dealing with multiple display resolutions.
Date: May 7, 1996
Creator: Ganter, J.
System: The UNT Digital Library
Imaging back scattered and near back scattered light in ignition scale plasmas (open access)

Imaging back scattered and near back scattered light in ignition scale plasmas

Diagnostics have been developed and fielded at the Nova laser facility that image scattered light in the vicinity of the final laser focusing lens. The absolute calibration of optical components exposed to the target debris have been achieved by a combination of routine in situ calibration and maintenance. The scattering observed from plasmas relevant to ignition experiments indicates that light scattered just outside the lens can be larger than that collected by the lens, and is a significant factor in the energy balance when the f number is high.
Date: May 7, 1996
Creator: Kirkwood, R. K.; Back, C. A.; Glenzer, S. H. & Moody, J. D.
System: The UNT Digital Library
Neutron source strength monitors for ITER (open access)

Neutron source strength monitors for ITER

There are several goals for the neutron source strength monitor system for the International Thermonuclear Experimental Reactor (ITER). Desired is a stable, reliable, time-dependent neutron detection system which exhibits a wide dynamic range and broad energy response to incident neutrons while being insensitive to gamma rays and having low noise characteristics in a harsh reactor environment. This system should be able to absolutely calibrated in-situ using various neutron sources. An array of proportional counters of varying sensitivities is proposed along with the most promising possible locations. One proposed location is in the pre-shields of the neutron camera collimators which would allow an integrated design of neutron systems with good detector access. As part of an ongoing conceptual design for this system, the detector-specific issues of dynamic range, performance monitoring, and sensitivity will be presented. The location options of the array will be discussed and most importantly, the calibration issues associated with a heavily shielded vessel will be presented.
Date: May 7, 1996
Creator: Barnes, C.W. & Roquemore, A.L.
System: The UNT Digital Library
Degradation of transuranic waste drums in underground storage at the Hanford Site (open access)

Degradation of transuranic waste drums in underground storage at the Hanford Site

In situ inspections were performed on tarp-covered 55-gallon drums of transuranic (TRU) waste stored underground at the Hanford Site. These inspections were part of a task to characterize TRU drums for extent of corrosion degradation and uncertainty in TRU designation (inaccuracy in earlier assay determinations may have led to drums that actually were low-level waste to be termed TRU), and to attempt to correlate accuracy of existing records with actual drum contents. Two separate storage trench sites were investigated; a total of 90 drums were inspected with ultrasonic techniques and 104 additional drums were visually inspected. A high-humidity environment in the underground storage trenches had been reported in earlier investigations and was expected to result in substantial corrosion degradation. However, corrosion was much less than expected. Only a small percentage of drums had significant corrosion (with one breach) and the maximum rate was estimated at 0.051 mm/yr (2 mils/yr). The corrosion time of underground exposure was 14 to 15 years. These inspection results should be applicable to other similar environments (this applicability should be restricted to arid climates such as the Hanford Site) where drums are stored underground but shielded from direct soil contact by a tarp or other means. …
Date: May 7, 1996
Creator: Duncan, D. R.
System: The UNT Digital Library
Novel transport-vehicle design for moving optic modules in the National Ignition Facility (open access)

Novel transport-vehicle design for moving optic modules in the National Ignition Facility

The National Ignition Facility, currently under design and construction at Lawrence Livermore National Laboratory, will be the world`s largest laser when complete. The NIF will use about 8,000 large optics of 26 different types to focus up to 192 laser beams on a dime-size target. Given the constraints of the NIF operating environment, the tasks associated with optics transport and handling require a novel, versatile transport system. The system will consist of a computer system containing guidance, traffic management and order entry functions, and four or more automated laser-guided vehicles. This transport system will transport optics enclosures that are essentially portable clean rooms and will lift, align, and position them as needed to contact and engage mating points on the laser support structure.
Date: May 7, 1998
Creator: Grasz, E. & Tiszauer, D.
System: The UNT Digital Library
Pthreads vs MPI Parallel Performance of Angular-Domain Decomposed S (open access)

Pthreads vs MPI Parallel Performance of Angular-Domain Decomposed S

Two programming models for parallelizing the Angular Domain Decomposition (ADD) of the discrete ordinates (S{sub n}) approximation of the neutron transport equation are examined. These are the shared memory model based on the POSIX threads (Pthreads) standard, and the message passing model based on the Message Passing Interface (MPI) standard. These standard libraries are available on most multiprocessor platforms thus making the resulting parallel codes widely portable. The question is: on a fixed platform, and for a particular code solving a given test problem, which of the two programming models delivers better parallel performance? Such comparison is possible on Symmetric Multi-Processors (SMP) architectures in which several CPUs physically share a common memory, and in addition are capable of emulating message passing functionality. Implementation of the two-dimensional,(S{sub n}), Arbitrarily High Order Transport (AHOT) code for solving neutron transport problems using these two parallelization models is described. Measured parallel performance of each model on the COMPAQ AlphaServer 8400 and the SGI Origin 2000 platforms is described, and comparison of the observed speedup for the two programming models is reported. For the case presented in this paper it appears that the MPI implementation scales better than the Pthreads implementation on both platforms.
Date: May 7, 2000
Creator: Azmy, Y. Y. & Barnett, D. A.
System: The UNT Digital Library
Syntheses and Structures of the Open-Framework Phases (CH(3)NH(3))(3).Zn(4)O(AsO(4))(3) and (CH(3)NH(3))(3).Zn(4)O(PO(4))(3) Related to the M(3)Zn(4)O(XO(4)(3).nH(2)O Family (open access)

Syntheses and Structures of the Open-Framework Phases (CH(3)NH(3))(3).Zn(4)O(AsO(4))(3) and (CH(3)NH(3))(3).Zn(4)O(PO(4))(3) Related to the M(3)Zn(4)O(XO(4)(3).nH(2)O Family

The solution-mediated syntheses and single crystal structures of (CH<sub>3</sub>NH<sub>3</sub>)<sub>3</sub>&middot;Zn<sub>4</sub>0(AsO<sub>4</sub>)<sub>3</sub> and (CH<sub>3</sub>NH<sub>3</sub>)<sub>3</sub>&middot;Zn<sub>4</sub>O(P0<sub>4</sub>)<sub>3</sub> are reported. These compounds are built up from vertex-sharing three-dimensional Zn0<sub>4</sub> + AsO<sub>4</sub>/P0<sub>4</sub> tetrahedral frameworks encapsulating methylammonium cations in three-dimensional channel systems. These phases are closely related to the zeolite- like M<sub>3</sub>Zn<sub>4</sub>O(XO<sub>4</sub>)<sub>3</sub>&middot;nH<sub>2</sub>O family of phases. Crystal data for (CH<sub>3</sub>NH<sub>3</sub>)<sub>3</sub>&middot;Zn<sub>4</sub>0(AsO<sub>4</sub>)<sub>3</sub>, M, = 790.47, monoclinic, space group P2<sub>1</sub> (No. 4), a = 7.814 (3)&Aring;, b = 15.498 (6)&Aring;, c = 7.815 (3) &Aring;, {beta} = 92.91 (2)0, V = 945.1 (9) &Aring;<sup>3</sup>, Z = 2, R(F) = 3.01%, R<sub>W</sub>(F) = 3.98% (2301 reflections, 236 parameters). Crystal data for (CH<sub>3</sub>NH<sub>3</sub>)<sub>3</sub>&middot;Zn<sub>4</sub>0(P0<sub>4</sub>)<sub>3</sub>: M, = 658.63, monoclinic, space group P2<sub>1</sub> (No. 4), a = 7.6569 (5) &Aring;, b = 15.241 (1)&Aring;, c= 7.6589 (5) &Aring;, {beta} = 92.740 (1)0, V= 892.7 (5) &Aring;<sup>3</sup>, Z = 2, R(F)= 8.07%, R<sub>W</sub>(F)= 9.60% (2694 reflections, 106 parameters).
Date: May 7, 1999
Creator: Chavez, Alejandra V.; Harrison, William T.A.; Nenoff, Tina M. & Phillips, Mark L.F.
System: The UNT Digital Library
Synthesis, Characterization and Ion Exchange of New Na/Nb/M(4+)/O/H(2)O(M=Ti,Zr) Phases (open access)

Synthesis, Characterization and Ion Exchange of New Na/Nb/M(4+)/O/H(2)O(M=Ti,Zr) Phases

Due to the vast diversity of chemical media in which metal separations are executed, a wide range of ion separation materials are employed. This results in an ongoing effort to discover new phases with novel ion exchange properties. We present here the synthesis of a novel class of thermally and chemically stable microporous, niobate-based materials. Ion exchange studies show these new phases are highly selective for Sr<sup>2+</sup> and other bivalent metals.
Date: May 7, 1999
Creator: Nenoff, Tina M. & Nyman, May
System: The UNT Digital Library
VVER-1000 weapons-grade MOX computational benchmark analysis (open access)

VVER-1000 weapons-grade MOX computational benchmark analysis

Calculations of computational benchmark problems for the disposition of weapons-grade plutonium fuel in VVER-1000 reactors have been performed under the Joint US/Russian Fissile Material Disposition Program. The benchmarks cover pin cell, single fuel assembly, and multi-assembly structures with several different fuel types, moderator densities, and boron content for operational and off-normal conditions. Fuel depletion is performed to a burnup of 60 MWd/kgHM. The results of the analysis of the benchmarks with US and Russian code systems have been compared and indicated good agreement among the different methods and data.
Date: May 7, 2000
Creator: Kalugin, M. A.; Lazarenko, A. P.; Kalahnikov, A. G. & Gehin, J. C.
System: The UNT Digital Library
"A Novel Synthesis of Zeolite W..." (open access)

"A Novel Synthesis of Zeolite W..."

Zeolite W has been synthesized using organometallic silicon and aluminum precursors in two hydrothermal systems: organocation containing and organocation-free. The reaction using the organocation yielded a fully crystalline, relatively uniform crystal size product, with no organic molecules occluded in the pores. In contrast, the product obtained from an identical reaction, except for the absence of the organocation, contained amorphous as well as crystalline material and the crystalline phase showed a large diversity of both crystal size and morphology. The use of organometallic precursors, either with or without an organocation, allows for the crystallization of the MER framework at much lower 0H/Si02 and (K+ Na - Al)/Si ratios than is typical of inorganic systems. The reaction products were characterized by XRD, SEM, EDS, and thermal analyses.
Date: May 7, 1999
Creator: Nenoff, Tina M. & Thoma, Steven G.
System: The UNT Digital Library
Electronic excitation in transmission of relativistic H{sup {minus}} ions through thin foils (open access)

Electronic excitation in transmission of relativistic H{sup {minus}} ions through thin foils

The authors describe a theoretical model to study the transmission of relativistic H{sup {minus}} ions through thin carbon foils. The approach is based on a Monte Carlo solution of the Langevin equation describing electronic excitations of the atoms during the transport through the foil. Calculations for the subshell populations of outgoing hydrogen atoms are found to be in good agreement with recent experimental data on an absolute scale and show that there exists a propensity for populating extreme Stark states.
Date: May 7, 1998
Creator: Reinhold, C.O.; Kuerpick, P.; Burgdoerfer, J.; Yoshida, S. & Gervais, B.
System: The UNT Digital Library
Production of bacterial cellulose from alternate feedstocks (open access)

Production of bacterial cellulose from alternate feedstocks

Production of bacterial cellulose by Acetobacter xylinum ATCC 10821 and 23770 in static cultures was tested from unamended food process effluents. Effluents included low- and high-solids potato effluents (LS and HS), cheese whey permeate (CW), and sugar beet raffinate (CSB). Strain 23770 produced 10% less cellulose from glucose than did 10821, and diverted more glucose to gluconate. Unamended HS, CW, and CSB were unsuitable for cellulose production by either strain, while LS was unsuitable for production by 10821. However, 23770 produced 17% more cellulose from LS than from glucose, indicating unamended LS could serve as a feedstock for bacterial cellulose.
Date: May 7, 2000
Creator: Thompson, D. N. & Hamilton, M. A.
System: The UNT Digital Library
Formation of Mesostructured Nanoparticles through Self-Assembly and Aerosol Process (open access)

Formation of Mesostructured Nanoparticles through Self-Assembly and Aerosol Process

Silica nanoparticles exhibiting hexagonal, cubic, and vesicular mesostructures have been prepared using aerosol assisted, self-assembled process. This process begins with homogennous aerosol droplets containing silica source, water, ethanol, and surfactant, in which surfactant concentration is far below the critical micelle concentration (cmc). Solvent evaporation enriches silica and surfactant inducing interfacial self-assembly confined to a spherical aerosol droplet and results in formation of completely solid, ordered spherical particles with stable hexagonal, cubic, or vesicular mesostructures.
Date: May 7, 1999
Creator: Brinker, C. Jeffrey; Fan, Hongyou; Lu, Yunfeng; Rieker, Thomas; Stump, Arron & Ward, Timothy L.
System: The UNT Digital Library
The effect of pretreatments on surfactin production from potato process effluent by Bacillus subtilis (open access)

The effect of pretreatments on surfactin production from potato process effluent by Bacillus subtilis

Pretreatment of low-solids (LS) potato process effluent was tested for potential to increase surfactin yield. Pretreatments included heat, removal of starch particulates, and acid hydrolysis. Elimination of contaminating vegetative cells was necessary for surfactin production. After autoclaving, 0.40 g/L of surfactin was produced from the effluent in 72 h, versus 0.24 g/L in the purified potato starch control. However, surfactin yields per carbon consumed were 76% lower from process effluent. Removal of starch particulates had little effect on the culture. Acid hydrolysis decreased growth and surfactant production, except 0.5 wt% acid, which increased the yield by 25% over untreated effluent.
Date: May 7, 2000
Creator: Thompson, D. N.; Fox, S. L. & Bala, G. A.
System: The UNT Digital Library
Tetrahedral-Network Organo-Zincophosphates: Syntheses and Structures of (N(2)C(6)H(14)).Zn(HPO(4))(2).H(2)O, H(3)N(CH(2))(3)NH(3).Zn(2)(HPO(4))(3) and (N(2)C(6)H(14)).Zn(3)(HPO(4))(4) (open access)

Tetrahedral-Network Organo-Zincophosphates: Syntheses and Structures of (N(2)C(6)H(14)).Zn(HPO(4))(2).H(2)O, H(3)N(CH(2))(3)NH(3).Zn(2)(HPO(4))(3) and (N(2)C(6)H(14)).Zn(3)(HPO(4))(4)

The solution-mediated syntheses and single crystal structures of (N<sub>2</sub>C<sub>6</sub>H<sub>14</sub>)&middot;Zn(HPO<sub>4</sub>)<sub>2</sub>&middot;H<sub>2</sub>O (I), H<sub>3</sub>N(CH<sub>2</sub>)<sub>3</sub>NH<sub>3</sub>&middot;Zn<sub>2</sub>(HPO<sub>4</sub>)<sub>3</sub> (II), and (N<sub>2</sub>C<sub>6</sub>H<sub>14</sub>)&middot;Zn<sub>3</sub>(HPO<sub>4</sub>)<sub>4</sub> (III) are described. These phases contain vertex-sharing Zn0<sub>4</sub> and HP0<sub>4</sub> tetrahedra, accompanied by doubly- protonated organic cations. Despite their formal chemical relationship, as members of the series of t&middot;Zn<sub>n</sub>(HP0<sub>4</sub>)<sub>n+1</sub> (t= template, n = 1-3), these phases adopt fimdamentally different crystal structures, as one-dimensional, two-dimensional, and three-dimensional Zn0<sub>4</sub>/HP0<sub>4</sub> networks, for I, II, and III respectively. Similarities and differences to some other zinc phosphates are briefly discussed. Crystal data: (N<sub>2</sub>C<sub>6</sub>H<sub>14</sub>)&middot;Zn(HP0<sub>4</sub>)<sub>2</sub>&middot;H<sub>2</sub>0, M<sub>r</sub> = 389.54, monoclinic, space group P2<sub>1</sub>/n (No. 14), a = 9.864 (4) &Aring;, b = 8.679 (4) &Aring;, c = 15.780 (3) &Aring;, &beta; = 106.86 (2)&deg;, V= 1294.2 (8) &Aring;<sup>3</sup>, Z = 4, R(F) = 4.58%, R<sub>W</sub>(F) = 5.28% [1055 reflections with I >3&sigma;(I)]. H<sub>3</sub>N(CH<sub>2</sub>)<sub>3</sub>NH<sub>3</sub>&middot;Zn<sub>2</sub>(HP0<sub>4</sub>)<sub>3</sub>, M<sub>r</sub> = 494.84, monoclinic, space group P2<sub>1</sub>/c (No. 14), a= 8.593 (2)&Aring;, b= 9.602 (2)&Aring;, c= 17.001 (3)&Aring;, &beta;= 93.571 (8)&deg;, V = 1400.0 (5) &Aring;<sup>3</sup>, Z = 4, R(F) = 4.09%, R<sub>W</sub>(F) = 4.81% [2794 reflections with I > 3&sigma; (I)]. (N<sub>2</sub>C<sub>6</sub>H<sub>14</sub>)&middot;Zn<sub>3</sub>(HP0<sub>4</sub>)<sub>4</sub>, M<sub>r</sub>= 694.25, monoclinic, space group P2<sub>1</sub>/n (No. 14), a = 9.535 (2) &Aring;, b = 23.246 (4)&Aring;, c= 9.587 (2)&Aring;, &beta;= 117.74 (2)&deg;, V= 1880.8 (8) &Aring;<sup>3</sup>, Z …
Date: May 7, 1999
Creator: Chavez, Alejandra V.; Hannooman, Lakshitha; Harrison, William T.A. & Nenoff, Tina M.
System: The UNT Digital Library
Analysis of Rod Removal Transient Experiments in VVER Reactors at Zero Power (open access)

Analysis of Rod Removal Transient Experiments in VVER Reactors at Zero Power

Within the context of the Fissile Materials Disposition Program of the U.S. Department of Energy we analyzed rod removal transient experiments performed at the Kurchatov Institute in a full-scale mockup of VVER reactors, The transients were started (via water inlet) in slightly (few cents) supercritical configurations with all the control rods withdrawn. After a few minutes, control rods banks or individual control rods were f and t inserted and later withdrawn (returning to the initial state). Available experimental data include the relative time profiles of nine incore and excore detectors. Because of the mild nature of the transients (very low power and no more than 2 $ reactivities) we decided to use a quasistatic approach. The time-dependent flux is factorized into two terms: a function of phase space, given by the solution of the static equation with parametric excitation; and a function of time, given by the solution of the point kinetic equations with time-dependent kinetics para meters. Due to the nature of the experiment, cold conditions, control rods withdrawn and critical state with water level, the power distributions, measured and calculated, are quite unusual, with the inner part of the core heavily shielded. Measured power levels at the center …
Date: May 7, 2000
Creator: Difillippo, F.C.
System: The UNT Digital Library
PU Disposition in Russian VVERs: Physics Studies of Lead Test Assembly Design (open access)

PU Disposition in Russian VVERs: Physics Studies of Lead Test Assembly Design

As part of Fissile Materials Disposition Program (FMDP) physics support was given to the design of a MOX lead test assembly (LTA) for use in Russian VVER nuclear reactors. This paper discusses some of the pertinent findings and assessments for two distinct LTA designs for weapons-grade (WG) Pu dispositioning in Russian VVER-1000 nuclear reactors. The two assessed MOX LTA designs are the graded-zone full MOX LTA and the Island LTA (2 central zones of MOX pins surrounded by UO{sub 2} pins). The process of optimizing the graded Pu-content by zone in the fuel assembly is discussed. Eigenvalue and power peaking comparisons are made as a function of fuel burnup. Zero-power reactivity effects were calculated for the different LTA options. For the ORNL results, the n,{gamma}-transport lattice physics code HELIOS-1.4 was used with nuclear data libraries (based on ENDF/B-VI) in 89 and 190 neutron energy groups. Some comparisons are made between the ORNL HELIOS results and corresponding Russian LTA calculations by the RRC-KI (Kurchatov Institute) using the code TVS-M. Also in this paper, pertinent results are discussed from a study of void reactivity effects for LEU, RG MOX and WG MOX fuels in PWR and VVER-1000 nuclear reactors. These void reactivity …
Date: May 7, 2000
Creator: Ellis, R. J.
System: The UNT Digital Library
GRAVE: An Interactive Geometry Construction and Visualization Software System for the TORT Nuclear Radiation Transport Code (open access)

GRAVE: An Interactive Geometry Construction and Visualization Software System for the TORT Nuclear Radiation Transport Code

A software system, GRAVE (Geometry Rendering and Visual Editor), has been developed at the Oak Ridge National Laboratory (ORNL) to perform interactive visualization and development of models used as input to the TORT three-dimensional discrete ordinates radiation transport code. Three-dimensional and two-dimensional visualization displays are included. Display capabilities include image rotation, zoom, translation, wire-frame and translucent display, geometry cuts and slices, and display of individual component bodies and material zones. The geometry can be interactively edited and saved in TORT input file format. This system is an advancement over the current, non-interactive, two-dimensional display software. GRAVE is programmed in the Java programming language and can be implemented on a variety of computer platforms. Three- dimensional visualization is enabled through the Visualization Toolkit (VTK), a free-ware C++ software library developed for geometric and data visual display. Future plans include an extension of the system to read inputs using binary zone maps and combinatorial geometry models containing curved surfaces, such as those used for Monte Carlo code inputs. Also GRAVE will be extended to geometry visualization/editing for the DORT two-dimensional transport code and will be integrated into a single GUI-based system for all of the ORNL discrete ordinates transport codes.
Date: May 7, 2000
Creator: Blakeman, E.D.
System: The UNT Digital Library
Time Evolution of Beam in the Recycler Ring (open access)

Time Evolution of Beam in the Recycler Ring

We study the time evolution of the beam current in the Fermilab Recycler Ring due to abrupt physical processes (single coulomb scattering, nuclear scattering) that cause sudden loss of beam, and diffusive processes (multiple coulomb scattering, lattice dependence, etc.) which cause emittance growth. This emittance growth combined with finite aperture of the beam pipe will lead to eventual loss of most beam. We develop a fitting technique to the time evolution of beam current to estimate emittance growth. Finally we compare the directly measured growth with the fitted value.
Date: May 7, 2003
Creator: Krish Gounder, John Marriner and Shekhar Mishra
System: The UNT Digital Library
Observation of high energy atmospheric neutrinos with antarctic muon and neutrino detector array (open access)

Observation of high energy atmospheric neutrinos with antarctic muon and neutrino detector array

The Antarctic Muon and Neutrino Detector Array (AMANDA) began collecting data with ten strings in 1997. Results from the first year of operation are presented. Neutrinos coming through the Earth from the Northern Hemisphere are identified by secondary muons moving upward through the array. Cosmic rays in the atmosphere generate a background of downward moving muons, which are about 10{sup 6} times more abundant than the upward moving muons. Over 130 days of exposure, we observed a total of about 300 neutrino events. In the same period, a background of 1.05 x 10{sup 9} cosmic ray muon events was recorded. The observed neutrino flux is consistent with atmospheric neutrino predictions. Monte Carlo simulations indicate that 90 percent of these events lie in the energy range 66 GeV to 3.4 TeV. The observation of atmospheric neutrinos consistent with expectations establishes AMANDA-B10 as a working neutrino telescope.
Date: May 7, 2002
Creator: Ahrens, J.; Andres, E.; Bai, X.; Barouch, G.; Barwick, S. W.; Bay, R. C. et al.
System: The UNT Digital Library