A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING (open access)

A METHODOLOGY FOR DETERMINING THE DOSE RATE FOR BOUNDING MASS LIMITS IN A 9977 PACKAGING

The Small Gram Quantity (SGQ) concept is based on the understanding that the hazards associated with the shipment of a radioactive material are directly proportional to its mass. This study describes a methodology that estimates the acceptable masses for several neutron and gamma emitting isotopes that can be shipped in a 9977 Package compliant with the Title 10 of the Code of Federal Regulations, Part 71 (10CFR71) external radiation level limits. 10CFR71.33 states that a shipping application identifies the radioactive and fissile materials at their maximum quantity and provides an evaluation demonstrating compliance with the external radiation standards. Since rather small amounts of some isotopes emit sufficiently strong radiation to produce a large external dose rate, quantifying of the dose rate for a proposed content is a challenging issue for the SGQ approach. It is essential to quantify external radiation levels from several common gamma and neutron sources that can be safely placed in a specific packaging, to ensure compliance with federal regulations. A methodology was established for determining the dose rate for bounding mass limits for a set of isotopes in the Model 9977 Shipping Package. Calculations were performed to estimate external radiation levels using the MCNP radiation transport …
Date: May 24, 2012
Creator: Abramczyk, G.; Bellamy, S.; Nathan, S. & Loftin, B.
Object Type: Article
System: The UNT Digital Library
LETTER REPORT. INDEPENDENT CONFIRMATORY SURVEY RESULTS OF SOILS ASSOCIATED WITH THE ARGYLE STREET SEWER LINE AT THE UNITED NUCLEAR CORPORATION NAVAL PRODUCTS SITE, NEW HAVEN, CONNECTICUT (open access)

LETTER REPORT. INDEPENDENT CONFIRMATORY SURVEY RESULTS OF SOILS ASSOCIATED WITH THE ARGYLE STREET SEWER LINE AT THE UNITED NUCLEAR CORPORATION NAVAL PRODUCTS SITE, NEW HAVEN, CONNECTICUT

Oak Ridge Institute for Science and Education (ORISE) personnel visited the United Nuclear Corporation (UNC) Naval Products site on three separate occasions during the months of October and November 2011. The purpose of these visits was to conduct confirmatory surveys of soils associated with the Argyle Street sewer line that was being removed. Soil samples were collected from six different, judgmentally determined locations in the Argyle Street sewer trench. In addition to the six soil samples collected by ORISE, four replicate soil samples were collected by Cabrera Services, Inc. (CSI) for analysis by the ORISE laboratory. Replicate samples S0010 and S0011 were final status survey (FSS) bias samples; S0012 was an FSS systematic sample; and S0015 was a waste characterization sample. Six soil samples were also collected for background determination. Uranium-235 and uranium-238 concentrations were determined via gamma spectroscopy; the spectra were also reviewed for other identifiable photopeaks. Radionuclide concentrations for these soil samples are provided. In addition to the replicate samples and the samples collected by ORISE, CSI submitted three soil samples for inter-laboratory comparison analyses. One sample was from the background reference area, one was from waste characterization efforts (material inside the sewer line), and one was a …
Date: January 24, 2012
Creator: Adams, Wade C.
Object Type: Report
System: The UNT Digital Library
TORUS: Theory of Reactions for Unstable iSotopes Annual Continuation and Progress Report Year-2: March 1, 2011 - February 29, 2012 (open access)

TORUS: Theory of Reactions for Unstable iSotopes Annual Continuation and Progress Report Year-2: March 1, 2011 - February 29, 2012

The TORUS collaboration derives its name from the research it focuses on, namely the Theory of Reactions for Unstable iSotopes. It is a Topical Collaboration in Nuclear Theory, and funded by the Nuclear Theory Division of the Office of Nuclear Physics in the Office of Science of the Department of Energy. The funding supports one postdoctoral researcher for the years 1 through 3. The collaboration brings together as Principal Investigators a large fraction of the nuclear reaction theorists currently active within the USA. The mission of the TORUS Topical Collaboration is to develop new methods that will advance nuclear reaction theory for unstable isotopes by using three-body techniques to improve direct-reaction calculations, and, by using a new partial-fusion theory, to integrate descriptions of direct and compound-nucleus reactions. This multi-institution collaborative effort is directly relevant to three areas of interest: the properties of nuclei far from stability; microscopic studies of nuclear input parameters for astrophysics, and microscopic nuclear reaction theory.
Date: February 24, 2012
Creator: Arbanas, Goran; Elster, Charlotte; Escher, Jutta; Mukhamedzanov, Akram; Nunes, Filomena & Thompson, Ian J.
Object Type: Report
System: The UNT Digital Library
Final Report (open access)

Final Report

This project combines outcrop-scale heterogeneity characterization, laboratory experiments, and numerical simulations. The study is designed to test whether established dispersion theory accurately predicts the behavior of solute transport through heterogeneous media and to investigate the relationship between heterogeneity and the parameters that populate these models. The dispersion theory tested by this work is based upon the fractional advection-dispersion equation (fADE) model. Unlike most dispersion studies that develop a solute transport model by fitting the solute transport breakthrough curve, this project will explore the nature of the heterogeneous media to better understand the connection between the model parameters and the aquifer heterogeneity. Our work at the Colorado School of Mines was focused on the following questions: 1) What are the effects of multi-scale geologic variability on transport of conservative and reactive solutes? 2) Can those transport effects be accounted for by classical methods, and if not, can the nonlocal fractional-order equations provide better predictions? 3) Can the fractional-order equations be parameterized through a link to some simple observable geologic features? 4) Are the classical equations of transport and reaction sufficient? 5) What is the effect of anomalous transport on chemical reaction in groundwater systems? The work is predicated on the observation …
Date: September 24, 2012
Creator: Benson, David A.
Object Type: Report
System: The UNT Digital Library
Final Report (open access)

Final Report

The overall objective is to create robust artificial protein modules as scaffolds to control both (a) the conformation of novel cofactors incorporated into the modules thereby making the modules possess a desired functionality and (b) the organization of these functional modules into ordered macroscopic ensembles, whose macroscopic materials properties derive from the designed microscopic function of the modules. We focus on two specific types of cofactors for imparting functionality in this project; primarily nonlinear optical (NLO) chromophores designed to exhibit extraordinary molecular hyperpolarizabilities, as well as donor-bridge-acceptor cofactors designed to exhibit highly efficient, 'through-bonds' light-induced electron transfer (LIET) over nano-scale distances. The ensembles range from 2-D to 3-D, designed to possess the degree of orientational and positional order necessary to optimize their macroscopic response, the latter ranging from liquid-crystalline or glass-like to long-range periodic. Computational techniques, firmly based in statistical thermodynamics, are utilized for the design the artificial protein modules, based on robust {alpha}-helical bundle motifs, necessarily incorporating the desired conformation, location, and environment of the cofactor. Importantly, this design approach also includes optimization of the interactions between the modules to promote their organization into ordered macroscopic ensembles in 2-D and 3-D via either directed-assembly or self-assembly. When long-range periodic …
Date: May 24, 2012
Creator: Blasie, J. K.; DeGrado, W.F.; Saven, J.G. & Therien, M.J.
Object Type: Report
System: The UNT Digital Library
Femtosecond Synchronization of Laser Systems for the LCLS (open access)

Femtosecond Synchronization of Laser Systems for the LCLS

The scientific potential of femtosecond x-ray pulses at linac-driven free-electron lasers such as the Linac Coherent Light Source is tremendous. Time-resolved pump-probe experiments require a measure of the relative arrival time of each x-ray pulse with respect to the experimental pump laser. An optical timing system based on stabilized fiber links has been developed for the LCLS to provide this synchronization. Preliminary results show synchronization of the installed stabilized links at the sub-20-femtosecond level. We present details of the implementation at LCLS and potential for future development.
Date: August 24, 2012
Creator: Byrd, John; Doolittle, Lawrence; Huang, Gang; Staples, John; Wilcox, Russell; Arthur, John et al.
Object Type: Article
System: The UNT Digital Library
Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction (open access)

Geochemical and Strontium Isotope Characterization of Produced Waters from Marcellus Shale Natural Gas Extraction

Extraction of natural gas by hydraulic fracturing of the Middle Devonian Marcellus Shale, a major gas-bearing unit in the Appalachian Basin, results in significant quantities of produced water containing high total dissolved solids (TDS). We carried out a strontium (Sr) isotope investigation to determine the utility of Sr isotopes in identifying and quantifying the interaction of Marcellus Formation produced waters with other waters in the Appalachian Basin in the event of an accidental release, and to provide information about the source of the dissolved solids. Strontium isotopic ratios of Marcellus produced waters collected over a geographic range of ∼375 km from southwestern to northeastern Pennsylvania define a relatively narrow set of values (εSr SW = +13.8 to +41.6, where εSr SW is the deviation of the 87Sr/86Sr ratio from that of seawater in parts per 104); this isotopic range falls above that of Middle Devonian seawater, and is distinct from most western Pennsylvania acid mine drainage and Upper Devonian Venango Group oil and gas brines. The uniformity of the isotope ratios suggests a basin-wide source of dissolved solids with a component that is more radiogenic than seawater. Mixing models indicate that Sr isotope ratios can be used to sensitively differentiate …
Date: February 24, 2012
Creator: Chapman, Elizabeth C.; Capo, Rosemary. C.; Stewart, Brian W.; Kirby, Carl S.; Hammack, Richard W.; Schroeder, Karl T. et al.
Object Type: Article
System: The UNT Digital Library
Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques (open access)

Photonic Doppler Velocimetry Multiplexing Techniques: Evaluation of Photonic Techniques

This poster reports progress related to photonic technologies. Specifically, the authors developed diagnostic system architecture for a Multiplexed Photonic Doppler Velocimetry (MPDV) that incorporates frequency and time-division multiplexing into existing PDV methodology to provide increased channel count. Current MPDV design increases number of data records per digitizer channel 8x, and also operates as a laser-safe (Class 3a) system. Further, they applied heterodyne interferometry to allow for direction-of-travel determination and enable high-velocity measurements (>10 km/s) via optical downshifting. They also leveraged commercially available, inexpensive and robust components originally developed for telecom applications. Proposed MPDV architectures employ only commercially available, fiber-coupled hardware.
Date: May 24, 2012
Creator: Daykin, Edward
Object Type: Article
System: The UNT Digital Library
Modular control of fusion power heating applications (open access)

Modular control of fusion power heating applications

This work is motivated by the growing demand for auxiliary heating on small and large machines worldwide. Numerous present and planned RF experiments (EBW, Lower Hybrid, ICRF, and ECH) are increasingly complex systems. The operational challenges are indicative of a need for components of real-time control that can be implemented with a moderate amount of effort in a time- and cost-effective fashion. Such a system will improve experimental efficiency, enhance experimental quality, and expedite technological advancements. The modular architecture of this control-suite serves multiple purposes. It facilitates construction on various scales from single to multiple controller systems. It enables expandability of control from basic to complex via the addition of modules with varying functionalities. It simplifies the control implementation process by reducing layers of software and electronic development. While conceived with fusion applications in mind, this suite has the potential to serve a broad range of scientific and industrial applications. During the Phase-I research effort we established the overall feasibility of this modular control-suite concept. We developed the fundamental modules needed to implement open-loop active-control and demonstrated their use on a microwave power deposition experiment.
Date: August 24, 2012
Creator: Demers, D. R.
Object Type: Report
System: The UNT Digital Library
FINAL TECHNICAL REPORT (open access)

FINAL TECHNICAL REPORT

The United States has abundant wind resources, such that only about 3% of the resource would need to be developed to achieve the goal of producing 20% of electricity in the United States by 2030. Inappropriately sited wind development may result in conflicts with wildlife that can delay or derail development projects, increase projects costs, and may degrade important conservation values. The most cost-effective approach to reducing such conflicts is through landscape-scale siting early in project development. To support landscape scale siting that avoids sensitive areas for wildlife, we compiled a database on species distributions, wind resource, disturbed areas, and land ownership. This database can be viewed and obtained via http://wind.tnc.org/awwi. Wind project developers can use this web tool to identify potentially sensitive areas and areas that are already disturbed and are therefore likely to be less sensitive to additional impacts from wind development. The United States goal of producing 20% of its electricity from wind energy by the year 2030 would require 241 GW of terrestrial nameplate capacity. We analyzed whether this goal could be met by using lands that are already disturbed, which would minimize impacts to wildlife. Our research shows that over 14 times the DOE goal …
Date: February 24, 2012
Creator: Fargione, Joseph
Object Type: Report
System: The UNT Digital Library
Final Technical Report - Advanced Optical Sensors to Minimize Energy Consumption in Polymer Extrusion Processes (open access)

Final Technical Report - Advanced Optical Sensors to Minimize Energy Consumption in Polymer Extrusion Processes

Project Objective: The objectives of this study are to develop an accurate and stable on-line sensor system to monitor color and composition on-line in polymer melts, to develop a scheme for using the output to control extruders to eliminate the energy, material and operational costs of off-specification product, and to combine or eliminate some extrusion processes. Background: Polymer extrusion processes are difficult to control because the quality achieved in the final product is complexly affected by the properties of the extruder screw, speed of extrusion, temperature, polymer composition, strength and dispersion properties of additives, and feeder system properties. Extruder systems are engineered to be highly reproducible so that when the correct settings to produce a particular product are found, that product can be reliably produced time after time. However market conditions often require changes in the final product, different products or grades may be processed in the same equipment, and feed materials vary from lot to lot. All of these changes require empirical adjustment of extruder settings to produce a product meeting specifications. Optical sensor systems that can continuously monitor the composition and color of the extruded polymer could detect process upsets, drift, blending oscillations, and changes in dispersion of …
Date: July 24, 2012
Creator: Foulk, Susan J.
Object Type: Report
System: The UNT Digital Library
Solar-thermal Water Splitting Using the Sodium Manganese Oxide Process & Preliminary H2A Analysis (open access)

Solar-thermal Water Splitting Using the Sodium Manganese Oxide Process & Preliminary H2A Analysis

There are three primary reactions in the sodium manganese oxide high temperature water splitting cycle. In the first reaction, Mn2O3 is decomposed to MnO at 1,500°C and 50 psig. This reaction occurs in a high temperature solar reactor and has a heat of reaction of 173,212 J/mol. Hydrogen is produced in the next step of this cycle. This step occurs at 700°C and 1 atm in the presence of sodium hydroxide. Finally, water is added in the hydrolysis step, which removes NaOH and regenerates the original reactant, Mn2O3. The high temperature solar‐driven step for decomposing Mn2O3 to MnO can be carried out to high conversion without major complication in an inert environment. The second step to produce H2 in the presence of sodium hydroxide is also straightforward and can be completed. The third step, the low temperature step to recover the sodium hydroxide is the most difficult. The amount of energy required to essentially distill water to recover sodium hydroxide is prohibitive and too costly. Methods must be found for lower cost recovery. This report provides information on the use of ZnO as an additive to improve the recovery of sodium hydroxide.
Date: October 24, 2012
Creator: Francis, Todd M.; Lichty, Paul R.; Perkins, Christopher; Tucker, Melinda; Kreider, Peter B.; Funke, Hans H. et al.
Object Type: Report
System: The UNT Digital Library
The First Angstrom X-Ray Free-Electron Laser (open access)

The First Angstrom X-Ray Free-Electron Laser

The Linac Coherent Light Source produced its first x-ray laser beam on 10 April 2009. Today it is routinely producing x-ray pulses with energy >2 mJ across the operating range from 820-8,200 eV. The facility has begun operating for atomic/molecular/optical science experiments. Performance of the facility in its first user run (1 October - 21 December) and current machine development activities will be presented. Early results from the preparations for the start of the second user run is also reported.
Date: August 24, 2012
Creator: Galayda, John
Object Type: Article
System: The UNT Digital Library
Status Update of the Power Conditioning System in the National Ignition Facility (open access)

Status Update of the Power Conditioning System in the National Ignition Facility

None
Date: May 24, 2012
Creator: Galloudec, B. L.; Arnold, P.; James, G.; Pendleton, D.; Petersen, D.; Arellano-Womack, G. et al.
Object Type: Article
System: The UNT Digital Library
Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants (open access)

Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants

The Hanford Site has 28 double-shell tanks (DSTs) and 149 single-shell tanks (SSTs) containing radioactive wastes that are complex mixes of radioactive and chemical products. The mission of the Department of Energy's River Protection Project is to retrieve and treat the Hanford tank waste for disposal and close the tank farms. A key aspect of the mission is to retrieve and transfer waste from the SSTs, which are at greater risk for leaking, into DSTs for interim storage until the waste is transferred to and treated in the Waste Treatment and Immobilization Plant. There is, however, limited space in the existing DSTs to accept waste transfers from the SSTs, and approaches to overcoming the limited DST space will benefit the overall mission. The purpose of this study is to summarize and analyze the key previous experiment that forms the basis for the relaxed controls and to summarize progress and results on new experiments focused on understanding the conditions that result in low gas retention. The previous large-scale test used about 50 m3 of sediment, which would be unwieldy for doing multiple parametric experiments. Accordingly, experiments began with smaller-scale tests to determine whether the desired mechanisms can be studied without the …
Date: February 24, 2012
Creator: Gauglitz, Phillip A.; Buchmiller, William C.; Probert, Samuel G.; Owen, Antionette T. & Brockman, Fred J.
Object Type: Report
System: The UNT Digital Library
Simulant Development for Hanford Double-Shell Tank Mixing and Waste Feed Delivery Testing (open access)

Simulant Development for Hanford Double-Shell Tank Mixing and Waste Feed Delivery Testing

The U.S. Department of Energy Office of River Projection manages the River Protection Project, which has the mission to retrieve and treat the Hanford tank waste for disposal and close the tank farms (Certa et al. 2011). Washington River Protection Solutions, LLC (WRPS) is responsible for a primary objective of this mission which is to retrieve and transfer tank waste to the Hanford Waste Treatment and Immobilization Plant (WTP). A mixing and sampling program with four separate demonstrations is currently being conducted to support this objective and also to support activities in a plan for addressing safety concerns identified by the Defense Nuclear Facilities Safety Board related to the ability of the WTP to mix, sample, and transfer fast settling particles. Previous studies have documented the objectives, criteria, and selection of non-radioactive simulants for these four demonstrations. The identified simulants include Newtonian suspending liquids with densities and viscosities that span the range expected in waste feed tanks. The identified simulants also include non-Newtonian slurries with Bingham yield stress values that span a range that is expected to bound the Bingham yield stress in the feed delivery tanks. The previous studies identified candidate materials for the Newtonian and non-Newtonian suspending fluids, …
Date: September 24, 2012
Creator: Gauglitz, Phillip A.; Tran, Diana N. & Buchmiller, William C.
Object Type: Report
System: The UNT Digital Library
A study of plasmonic enhanced transmission effects in nano-optics (open access)

A study of plasmonic enhanced transmission effects in nano-optics

This project was a numerical study of the behavior of surface plasmons in nano-systems, focusing on the interaction between plasmons, light, and nano-scale structures such as nano-scale metallic wires and quantum wires/dots. The primary results of the project included: a) the demonstration of the use of surface plasmons to modify the spatial coherence of a light wave, b) the demonstration of a feasible plasmonic superresolved readout system, and c) the demonstration of a “Plasmonic Zeno effect”, in which the attenuation of a light wave in metal is suppressed by breaking up the metal into a collection of structured layers. The integration of quantum wire/dot effects with the plasmonic simulations proved to be harder than expected, in large part due to the lack of accurate and simple quantum dot models.
Date: January 24, 2012
Creator: Gbur, Greg
Object Type: Report
System: The UNT Digital Library
Prompt Neutron Lifetime for the NBSR Reactor (open access)

Prompt Neutron Lifetime for the NBSR Reactor

In preparation for the proposed conversion of the National Institute of Standards and Technology (NIST) research reactor (NBSR) from high-enriched uranium (HEU) to low-enriched uranium (LEU) fuel, certain point kinetics parameters must be calculated. We report here values of the prompt neutron lifetime that have been calculated using three independent methods. All three sets of calculations demonstrate that the prompt neutron lifetime is shorter for the LEU fuel when compared to the HEU fuel and longer for the equilibrium end-of-cycle (EOC) condition when compared to the equilibrium startup (SU) condition for both the HEU and LEU fuels.
Date: June 24, 2012
Creator: Hanson, A. L. & Diamond, D.
Object Type: Article
System: The UNT Digital Library
Resolving Lifshitz Horizons (open access)

Resolving Lifshitz Horizons

Via the AdS/CFT correspondence, ground states of field theories at finite charge density are mapped to extremal black brane solutions. Studies of simple gravity + matter systems in this context have uncovered wide new classes of extremal geometries. The Lifshitz metrics characterizing field theories with non-trivial dynamical critical exponent z {ne} 1 emerge as one common endpoint in doped holographic toy models. However, the Lifshitz horizon exhibits mildly singular behaviour - while curvature invariants are finite, there are diverging tidal forces. Here we show that in some of the simplest contexts where Lifshitz metrics emerge, Einstein-Maxwell-dilaton theories, generic corrections lead to a replacement of the Lifshitz metric, in the deep infrared, by a re-emergent AdS{sub 2} x R{sup 2} geometry. Thus, at least in these cases, the Lifshitz scaling characterizes the physics over a wide range of energy scales, but the mild singularity is cured by quantum or stringy effects.
Date: April 24, 2012
Creator: Harrison, Sarah; Kachru, Shamit; Wang, Huajia & /Stanford U., ITP /Stanford U., Phys. Dept. /SLAC
Object Type: Report
System: The UNT Digital Library
Final Report on Development of Thermoanaerobacterium saccharolyticum for the conversion of lignocellulose to ethanol (open access)

Final Report on Development of Thermoanaerobacterium saccharolyticum for the conversion of lignocellulose to ethanol

This project addressed the need for economical technology for the conversion of lignocellulosic biomass to fuels, specifically the conversion of pretreated hardwood to ethanol. The technology developed is a set of strains of the bacterium Thermoanaerobacterium saccharolyticum and an associated fermentation process for pretreated hardwood. Tools for genetic engineering and analysis of the organism were developed, including a markerless mutation method, a complete genome sequence and a set of gene expression profiles that show the activity of its genes under a variety of conditions relevant to lignocellulose conversion. Improved strains were generated by selection and genetic engineering to be able to produce higher amounts of ethanol (up to 70 g/L) and to be able to better tolerate inhibitory compounds from pretreated hardwood. Analysis of these strains has generated useful insight into the genetic basis for desired properties of biofuel producing organisms. Fermentation conditions were tested and optimized to achieve ethanol production targets established in the original project proposal. The approach proposed was to add cellulase enzymes to the fermentation, a method called Simultaneous Saccharification and Fermentation (SSF). We had reason to think SSF would be an efficient approach because the optimal temperature and pH for the enzymes and bacterium are …
Date: January 24, 2012
Creator: Herring, Christopher D.; Kenealy, William R.; Shaw, A. Joe; Raman, Babu; Tschaplinski, Timothy J.; Brown, Steven D. et al.
Object Type: Report
System: The UNT Digital Library
Dielectric-Lined High-Gradient Accelerator Structure (open access)

Dielectric-Lined High-Gradient Accelerator Structure

Rectangular particle accelerator structures with internal planar dielectric elements have been studied, with a view towards devising structures with lower surface fields for a given accelerating field, as compared with structures without dielectrics. Success with this concept is expected to allow operation at higher accelerating gradients than otherwise on account of reduced breakdown probabilities. The project involves studies of RF breakdown on amorphous dielectrics in test cavities that could enable high-gradient structures to be built for a future multi-TeV collider. The aim is to determine what the limits are for RF fields at the surfaces of selected dielectrics, and the resulting acceleration gradient that could be achieved in a working structure. The dielectric of principal interest in this study is artificial CVD diamond, on account of its advertised high breakdown field ({approx}2 GV/m for dc), low loss tangent, and high thermal conductivity. Experimental studies at mm-wavelengths on materials and structures for achieving high acceleration gradient were based on the availability of the 34.3 GHz third-harmonic magnicon amplifier developed by Omega-P, and installed at the Yale University Beam Physics Laboratory. Peak power from the magnicon was measured to be about 20 MW in 0.5 {micro}s pulses, with a gain of 54 …
Date: April 24, 2012
Creator: Hirshfield, Jay L.
Object Type: Report
System: The UNT Digital Library
FORM AND AGING OF PLUTONIUM IN SAVANNAH RIVER SITE WASTE TANK 18 (open access)

FORM AND AGING OF PLUTONIUM IN SAVANNAH RIVER SITE WASTE TANK 18

This report provides a summary of the effects of aging on and the expected forms of plutonium in Tank 18 waste residues. The findings are based on available information on the operational history of Tank 18, reported analytical results for samples taken from Tank 18, and the available scientific literature for plutonium under alkaline conditions. These findings should apply in general to residues in other waste tanks. However, the operational history of other waste tanks should be evaluated for specific conditions and unique operations (e.g., acid cleaning with oxalic acid) that could alter the form of plutonium in heel residues. Based on the operational history of other tanks, characterization of samples from the heel residues in those tanks would be appropriate to confirm the form of plutonium. During the operational period and continuing with the residual heel removal periods, Pu(IV) is the dominant oxidation state of the plutonium. Small fractions of Pu(V) and Pu(VI) could be present as the result of the presence of water and the result of reactions with oxygen in air and products from the radiolysis of water. However, the presence of Pu(V) would be transitory as it is not stable at the dilute alkaline conditions that …
Date: February 24, 2012
Creator: Hobbs, D.
Object Type: Report
System: The UNT Digital Library
Radioactive Waste Management Basis (open access)

Radioactive Waste Management Basis

None
Date: September 24, 2012
Creator: Hollister, R K
Object Type: Report
System: The UNT Digital Library
High Multiplicity Searches at the LHC Using Jet Masses (open access)

High Multiplicity Searches at the LHC Using Jet Masses

This article introduces a new class of searches for physics beyond the Standard Model that improves the sensitivity to signals with high jet multiplicity. The proposed searches gain access to high multiplicity signals by reclustering events into large-radius, or 'fat', jets and by requiring that each event has multiple massive jets. This technique is applied to supersymmetric scenarios in which gluinos are pair-produced and then subsequently decay to final states with either moderate quantities of missing energy or final states without missing energy. In each of these scenarios, the use of jet mass improves the estimated reach in gluino mass by 20% to 50% over current LHC searches.
Date: April 24, 2012
Creator: Hook, Anson; /SLAC /Stanford U., Appl. Phys. Dept.; Izaguirre, Eder; /SLAC /Stanford U., Phys. Dept.; Lisanti, Mariangela; U., /Princeton et al.
Object Type: Article
System: The UNT Digital Library