TRANSPARENCY: Tracking Uranium under the U.S. / Russian HEU Purchase Agreement (open access)

TRANSPARENCY: Tracking Uranium under the U.S. / Russian HEU Purchase Agreement

By the end of August, 2005, the Russia Federation delivered to the United States (U.S.) more than 7,000 metric tons (MT) of low enriched uranium (LEU) containing approximately 46 million SWU and 75,000 MT of natural uranium. This uranium was blended down from weapons-grade (nominally enriched to 90% {sup 235}U) highly enriched uranium (HEU) under the 1993 HEU Purchase Agreement that provides for the blend down of 500 MT HEU into LEU for use as fuel in commercial nuclear reactors. The HEU Transparency Program, under the National Nuclear Security Administration (NNSA), monitored the conversion and blending of the more than 250 MT HEU used to produce this LEU. The HEU represents more than half of the 500 MT HEU scheduled to be blended down through the year 2013 and is equivalent to the elimination of more than 10,000 nuclear devices. The HEU Transparency Program has made considerable progress in its mission to develop and implement transparency measures necessary to assure that Russian HEU extracted from dismantled Russian nuclear weapons is blended down into LEU for delivery to the United States. U.S. monitor observations include the inventory of in process containers, observation of plant operations, nondestructive assay measurements to determine {sup …
Date: October 19, 2005
Creator: Benton, J B; Decman, D J & Leich, D A
Object Type: Article
System: The UNT Digital Library
Waste Package Corrosion Studies Using Small Mockup Experiments (open access)

Waste Package Corrosion Studies Using Small Mockup Experiments

The corrosion of spent nuclear fuel and subsequent mobilization of radionuclides is of great concern in a geologic repository, particularly if conditions are oxidizing. Corroding A516 steel may offset these transport processes within the proposed waste packages at the Yucca Mountain Repository (YMR) by retaining radionuclides, creating locally reducing conditions, and reducing porosity. Ferrous iron, Fe{sup 2+}, has been shown to reduce UO{sub 2}{sup 2+} to UO{sub 2(s)} [1], and some ferrous iron-bearing ion-exchange materials adsorb radionuclides and heavy metals [2]. Of particular interest is magnetite, a potential corrosion product that has been shown to remove TcO{sub 4}{sup -} from solution [3]. Furthermore, if Fe{sup 2+} minerals, rather than fully oxidized minerals such as goethite, are produced during corrosion, then locally reducing conditions may be present. High electron availability leads to the reduction and subsequent immobilization of problematic dissolved species such as TcO{sub 4}{sup -}, NpO{sub 2}{sup +}, and UO{sub 2}{sup 2+} and can also inhibit corrosion of spent nuclear fuel. Finally, because the molar volume of iron material increases during corrosion due to oxygen and water incorporation, pore space may be significantly reduced over long time periods. The more water is occluded, the bulkier the corrosion products, and the …
Date: October 19, 2005
Creator: Anderson, B. E.; Helean, K. B.; Bryan, C. R.; Brady, P. V. & Ewing, R. C.
Object Type: Report
System: The UNT Digital Library
Miniatuization of the flowing fluid electric conductivity loggingtec hnique (open access)

Miniatuization of the flowing fluid electric conductivity loggingtec hnique

An understanding of both the hydraulic properties of the aquifer and the depth distribution of salts is critical for evaluating the potential of groundwater for conjunctive water use and for maintaining suitable groundwater quality in agricultural regions where groundwater is used extensively for irrigation and drinking water. The electrical conductivity profiles recorded in a well using the flowing fluid electric conductivity logging (FEC logging) method can be analyzed to estimate interval specific hydraulic conductivity and estimates of the salinity concentration with depth. However, irrigation wells that are common in agricultural regions have limited access into them because these wells are still in operation, and the traditional equipment used for FEC logging cannot fit through the small access pipe intersecting the well. A modified, miniaturized FEC logging technique was developed such that this logging method could be used in wells with limited access. In addition, a new method for injecting water over the entire screened interval of the well was developed to reduce the time required to perform FEC logging. Results of FEC logging using the new methodology and miniaturized system in two irrigation wells are also summarized.
Date: October 19, 2005
Creator: Su, Grace W.; Quinn, Nigel W.T.; Cook, Paul J. & Shipp, William
Object Type: Article
System: The UNT Digital Library
Gyrokinetic Stability Studies of the Microtearing Mode in the National Spherical Torus Experiment H-mode (open access)

Gyrokinetic Stability Studies of the Microtearing Mode in the National Spherical Torus Experiment H-mode

Insight into plasma microturbulence and transport is being sought using linear simulations of drift waves on the National Spherical Torus Experiment (NSTX), following a study of drift wave modes on the Alcator C-Mod Tokamak. Microturbulence is likely generated by instabilities of drift waves, which cause transport of heat and particles. Understanding this transport is important because the containment of heat and particles is required for the achievement of practical nuclear fusion. Microtearing modes may cause high heat transport through high electron thermal conductivity. It is hoped that microtearing will be stable along with good electron transport in the proposed low collisionality International Thermonuclear Experimental Reactor (ITER). Stability of the microtearing mode is investigated for conditions at mid-radius in a high density NSTX high performance (H-mode) plasma, which is compared to the proposed ITER plasmas. The microtearing mode is driven by the electron temperature gradient, and believed to be mediated by ion collisions and magnetic shear. Calculations are based on input files produced by TRXPL following TRANSP (a time-dependent transport analysis code) analysis. The variability of unstable mode growth rates is examined as a function of ion and electron collisionalities using the parallel gyrokinetic computational code GS2. Results show the microtearing …
Date: October 19, 2005
Creator: Baumgaertel J.A., Redi M.H., Budny R.V., Rewoldt G., Dorland W.
Object Type: Report
System: The UNT Digital Library
Alpha Channeling in Mirror Machines (open access)

Alpha Channeling in Mirror Machines

Because of their engineering simplicity, high-β, and steady-state operation, mirror machines and related open-trap machines such as gas dynamic traps, are an attractive concept for achieving controlled nuclear fusion. In these open-trap machines, the confinement occurs by means of magnetic mirroring, without the magnetic field lines closing upon themselves within the region of particle confinement. Unfortunately, these concepts have not achieved to date very spectacular laboratory results, and their reactor prospects are dimmed by the prospect of a low Q-factor, the ratio of fusion power produced to auxiliary power. Nonetheless, because of its engineering promise, over the years numerous improvements have been proposed to enhance the reactor prospects of mirror fusion, such as tandem designs, end-plugging, and electric potential barriers.
Date: October 19, 2005
Creator: Fisch, N. J.
Object Type: Report
System: The UNT Digital Library
Compton Scattering X-Ray Sources Driven by Laser Wakefield Acceleration (open access)

Compton Scattering X-Ray Sources Driven by Laser Wakefield Acceleration

Recent laser wakefield acceleration experiments have demonstrated the generation of femtosecond, nano-Coulomb, low emittance, nearly monokinetic relativistic electron bunches of sufficient quality to produce bright, tunable, ultrafast x-rays via Compton scattering. Design parameters for a proof-of-concept experiment are presented using a three-dimensional Compton scattering code and a laser-plasma interaction particle-in-cell code modeling the wakefield acceleration process; x-ray fluxes exceeding 10{sup 22} s{sup -1} are predicted, with a peak brightness > 10{sup 20} photons/(mm{sup 2} x mrad{sup 2} x s x 0.1% bandwidth).
Date: October 19, 2005
Creator: Hartemann, F V; Gibson, D J; Brown, W J; Rousse, A; Phuoc, K T & Pukhov, A
Object Type: Article
System: The UNT Digital Library
Radiation Research Symposium: Chemistry and Biology of Radical-mediated Deoxyribose Oxidation in DNA (open access)

Radiation Research Symposium: Chemistry and Biology of Radical-mediated Deoxyribose Oxidation in DNA

The $3000 of funding provided by this grant supported a well-attended (150 people) symposium at the annual Radiation Research Society meeting in Denver, Colorado, on October 19, 2005. The symposium was entitled, ''Chemistry and Biology of Radical-mediated Deoxyribose Oxidation in DNA'', and it focused on the chemistry of damage to deoxyribose caused by radiation and other oxidants, and the role of this chemistry in the biological consequences and responses of cells to chemical and physical insults. The talks highlighted the emerging evidence for a major role for deoxyribose oxidation in the toxic effects of ionizing radiation.
Date: October 19, 2005
Creator: Dedon, Peter
Object Type: Report
System: The UNT Digital Library
Density Changes in Plutonium Observed from Accelerated Aging Using Pu-238 Enrichment (open access)

Density Changes in Plutonium Observed from Accelerated Aging Using Pu-238 Enrichment

In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 atomic percentage of {sup 238}Pu is underway using dilatometry at 35, 50, and 65 C and immersion density measurements of material stored at 50 C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After twenty-five equivalent years of aging, the dilatometry data shows that the alloys at 35 C have expanded in volume by 0.11% to 0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-to-vacancy ratio from tested specimens was determined to be around 2.3. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35 C. The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.
Date: October 19, 2005
Creator: Chung, B. W.; Thompson, S. R.; Woods, C. H.; Hopkins, D. J.; Gourdin, W. H. & Ebbinghaus, B. B.
Object Type: Article
System: The UNT Digital Library
Geomechanical/Geochemical Modeling Studies Conducted within theInternational DECOVALEX Project (open access)

Geomechanical/Geochemical Modeling Studies Conducted within theInternational DECOVALEX Project

The DECOVALEX project is an international cooperative project initiated by SKI, the Swedish Nuclear Power Inspectorate, with participation of about 10 international organizations. The general goal of this project is to encourage multidisciplinary interactive and cooperative research on modeling coupled thermo-hydro-mechanical-chemical (THMC) processes in geologic formations in support of the performance assessment for underground storage of radioactive waste. One of the research tasks, initiated in 2004 by the U.S. Department of Energy (DOE), addresses the long-term impact of geomechanical and geochemical processes on the flow conditions near waste emplacement tunnels. Within this task, four international research teams conduct predictive analysis of the coupled processes in two generic repositories, using multiple approaches and different computer codes. Below, we give an overview of the research task and report its current status.
Date: October 19, 2005
Creator: Birkholzer, J.T.; Rutqvist, J.; Sonnenthal, E.L.; Barr, D.; Chijimatsu, M.; Kolditz, O. et al.
Object Type: Article
System: The UNT Digital Library
PSTD Simulations of Multiple Light Scattering in 3-D Macrocsopic Random Media (open access)

PSTD Simulations of Multiple Light Scattering in 3-D Macrocsopic Random Media

We report a full-vector, three-dimensional, numerical solution of Maxwell's equations for optical propagation within, and scattering by, a random medium of macroscopic dimensions. The total scattering cross-section is determined using the pseudospectral time-domain technique. Specific results reported in this Paper indicate that multiply scattered light also contains information that can be extracted by the proposed cross-correlation analysis. On a broader perspective, our results demonstrate the feasibility of accurately determining the optical characteristics of arbitrary, macroscopic random media, including geometries with continuous variations of refractive index. Specifically, our results point toward the new possibilities of tissue optics--by numerically solving Maxwell's equations, the optical properties of tissue structures can be determined unambiguously.
Date: October 19, 2005
Creator: Tseng, S H; Taflove, A; Maitland, D & Backman, V
Object Type: Article
System: The UNT Digital Library
Adaptive Perturbation Theory I: Quantum Mechanics (open access)

Adaptive Perturbation Theory I: Quantum Mechanics

Adaptive perturbation is a new method for perturbatively computing the eigenvalues and eigenstates of quantum mechanical Hamiltonians that heretofore were not believed to be treatable by such methods. The novel feature of adaptive perturbation theory is that it decomposes a given Hamiltonian, H, into an unperturbed part and a perturbation in a way which extracts the leading non-perturbative behavior of the problem exactly. This paper introduces the method in the context of the pure anharmonic oscillator and then goes on to apply it to the case of tunneling between both symmetric and asymmetric minima. It concludes with an introduction to the extension of these methods to the discussion of a quantum field theory. A more complete discussion of this issue will be given in the second paper in this series, and it will show how to use the method of adaptive perturbation theory to non-perturbatively extract the structure of mass, wavefunction and coupling constant renormalization.
Date: October 19, 2005
Creator: Weinstein, Marvin
Object Type: Report
System: The UNT Digital Library
Search for Pentaquarks at BABAR (open access)

Search for Pentaquarks at BABAR

The results of searches for the strange pentaquark states, {Theta}{sub 5}(1540){sup +}, {Xi}{sub 5}(1860){sup --} and {Xi}{sub 5}(1860){sup 0} in data recorded by the BABAR experiment are presented. We search for these three states inclusively in 123.4 fb{sup -1} of e{sup +}e{sup -} annihilation data produced at the PEP-II asymmetric storage rings; we find no evidence for their production in any physics process, and set limits on their production rates that are well below the measured rates for conventional baryons. We also search for {Theta}{sub 5}(1540){sup +} produced in interactions of electrons or hadrons in the material of the inner part of the detector. No evidence for this state is found in a sample with much higher statistics than similar electroproduction experiments that claim a signal.
Date: October 19, 2005
Creator: Gotzen, K. & /Ruhr U., Bochum
Object Type: Article
System: The UNT Digital Library
Adaptive Perturbation Theory: Quantum Mechanics and Field Theory (open access)

Adaptive Perturbation Theory: Quantum Mechanics and Field Theory

Adaptive perturbation is a new method for perturbatively computing the eigenvalues and eigenstates of quantum mechanical Hamiltonians that are widely believed not to be solvable by such methods. The novel feature of adaptive perturbation theory is that it decomposes a given Hamiltonian, H, into an unperturbed part and a perturbation in a way which extracts the leading non-perturbative behavior of the problem exactly. In this talk I will introduce the method in the context of the pure anharmonic oscillator and then apply it to the case of tunneling between symmetric minima. After that, I will show how this method can be applied to field theory. In that discussion I will show how one can non-perturbatively extract the structure of mass, wavefunction and coupling constant renormalization.
Date: October 19, 2005
Creator: Weinstein, Marvin
Object Type: Article
System: The UNT Digital Library
Charmless Quasi-Two-Body Modes at BaBar (open access)

Charmless Quasi-Two-Body Modes at BaBar

We present results for measurements of B{sup 0} meson decays to charmless final states {eta}K{sup 0}, {eta}{omega}, a{sub 1}{sup +}(1260){pi}{sup -} with a{sub 1}{sup +}(1260) {yields} {pi}{sup +}{pi}{sup +}{pi}{sup -}, {rho}{sup 0}K{sub S}{sup 0}, K{sub S}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0}, and of B{sup +} to {eta}{rho}{sup +} and {eta}{prime}{pi}{sup +}. Analyses are based on data taken with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC.
Date: October 19, 2005
Creator: Palombo, F. & /INFN, Milan
Object Type: Article
System: The UNT Digital Library
Influence of Specimen Size on the SCC Growth Rate of Ni-Alloys Exposed to High Temperature Water (open access)

Influence of Specimen Size on the SCC Growth Rate of Ni-Alloys Exposed to High Temperature Water

Tests were conducted on a single heat of Alloy 600 using compact tension specimens ranging from 50.80 mm (2 inches) in gross thickness (2T) to 10.16 mm (0.4 inches, 0.4T) in gross thickness. Results indicated that at stress intensity factor (K) levels above 55 MPa{radical}m, the growth rate is affected by specimen size in deaerated primary water. The growth rate can be significantly faster in 0.4T and 0.6T (15.24 mm = 0.6 inches in gross thickness) specimens at these elevated K levels compared to 2T specimens. Stress corrosion crack (SCC) growth rates > 6 x 10{sup -7} mm/s were observed at 338 C and 40 cc/kg H{sub 2} in 0.6T and 0.4T specimens at these elevated K levels, although the fracture mode was not significantly affected by the specimen size. The SCC growth rate of 2T specimens under comparable test conditions was {approx}6 x 10{sup -8} mm/s. All of the specimens examined that were tested at K > 55 MPa{radical}m exhibited intergranular failure, although ductile dimples and cracked grains were observed in the 0.4T specimens loaded to the elevated K levels. The effect of specimen size on the crack growth behavior indicated by electric potential drop (EPD) monitoring at K …
Date: October 19, 2005
Creator: Richey, E; Morton, D & Moshier, W
Object Type: Article
System: The UNT Digital Library
The Effect of Load-Line Displacement Rate on the SCC Growth Rate of Nickel Alloys and Mechanistic Implications (open access)

The Effect of Load-Line Displacement Rate on the SCC Growth Rate of Nickel Alloys and Mechanistic Implications

A key set of SCC growth experiments was designed to test the hypothesis that deformation/creep is the rate controlling step in LPSCC. These tests were performed on Alloy X-750 AH compact tension specimens at a various constant displacement rates. The deformation/creep rate within the crack tip zone is proportional to the test displacement rate. If crack growth rates were observed to increase with the load-line displacement rate, then this would indicate that deformation/creep is a critical SCC mechanism process. However, results obtained from the load-line displacement tests did not find X-750 AH SCC growth rate to be dependent on the position rate and therefore do not support the assumption that deformation/creep is the rate controlling process in LPSCC. The similarities between the SCC response of X-750, Alloy 600 and EN82H suggests that it is likely that the same SCC process is occurring for all these alloys (i.e., the same rate controlling step) and that deformation based models are also inappropriate for Alloy 600 and EN82H. The strong temperature and coolant hydrogen dependencies exhibited by these alloys make it more likely that nickel alloy LPSCC is controlled by an environmental or corrosion driven process.
Date: October 19, 2005
Creator: Morton, D
Object Type: Article
System: The UNT Digital Library
Searches for Pentaquark Baryons at BaBar (open access)

Searches for Pentaquark Baryons at BaBar

This paper presents the results of inclusive searches for the strange pentaquark states {Theta}{sup +}(1540), {Xi}{sub 5}{sup --}(1860) and {Xi}{sub 5}(1860){sup 0} as well as the anti-charm pentaquark state {Theta}{sub c}(3099){sup 0} in a dataset of 123.4 fb{sup -1} collected on and 40MeV below the {Upsilon}(4S) resonance by the BABAR detector at the e{sup +}e{sup -} PEP-II storage rings. No evidence for the pentaquark states is found and upper limits on the rate of {Theta}{sup +}(1540) and {Xi}{sub 5}{sup --}(1860) production in e{sup +}e{sup -} annihilation are obtained.
Date: October 19, 2005
Creator: Berger-Hryn'ova, Tetiana
Object Type: Article
System: The UNT Digital Library
Studies of $e^+e^-$ Collisions with a Hard Initial-State Photon at BaBar (open access)

Studies of $e^+e^-$ Collisions with a Hard Initial-State Photon at BaBar

The authors present preliminary BaBar measurements of hadronic cross sections in e{sup +}e{sup -} annihilation using the radiative return technique. The cross sections for e{sup +}e{sup -} {yields} p{bar p}, 3({pi}{sup +}{pi}{sup -}), 2({pi}{sup +}{pi}{sup -})2{pi}{sup 0}, and K{sup +}K{sup -}2({pi}{sup +}{pi}{sup -}) are measured. Measurements of the proton form factor and of the ratio G{sub E}/G{sub M} are also shown.
Date: October 19, 2005
Creator: Berger, Nicolas
Object Type: Article
System: The UNT Digital Library
Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities (open access)

Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities

Field leachate samples are being collected from coal combustion product (CCP) management sites from several geographic locations in the United States to provide broad characterization of major and trace constituents in the leachate. In addition, speciation of arsenic, selenium, chromium, and mercury in the leachates is being determined. Through 2003, 35 samples were collected at 14 sites representing a variety of CCP types, management approaches, and source coals. Samples have been collected from leachate wells, leachate collection systems, drive-point piezometers, lysimeters, the ash/water interface at impoundments, impoundment outfalls and inlets, and seeps. Additional sampling at 23 sites has been conducted in 2004 or is planned for 2005. First-year results suggest distinct differences in the chemical composition of leachate from landfills and impoundments, and from bituminous and subbituminous coals. Concentrations of most constituents were generally higher in landfill leachate than in impoundment leachate. Sulfate, sodium, aluminum, molybdenum, vanadium, cadmium, mercury and selenium concentrations were higher in leachates for ash from subbituminous source coal. Calcium, boron, lithium, strontium, arsenic, antimony, and nickel were higher for ash from bituminous source coal. These variations will be explored in more detail when additional data from the 2004 and 2005 samples become available.
Date: October 19, 2005
Creator: Ladwig, K.; Hensel, B.; Wallschlager, D.; Lee, L. & Murarka, I
Object Type: Report
System: The UNT Digital Library
The Effect of Ionizing Radiation U6+ Phases (open access)

The Effect of Ionizing Radiation U6+ Phases

None
Date: October 19, 2005
Creator: Utsunomiya, S. & Ewing, R. C.
Object Type: Article
System: The UNT Digital Library