Nuclear Material Accountability Applications of a Continuous Energy and Direction Gamma Ray Detector (open access)

Nuclear Material Accountability Applications of a Continuous Energy and Direction Gamma Ray Detector

The Idaho National Laboratory has recently developed a detector system based on the principle of a Wilson cloud chamber that gives the original energy and direction to a gamma ray source. This detector has the properties that the energy resolution is continuous and the direction to the source can be resolved to desired fidelity. Furthermore, the detector has low power requirements, is durable, operates in widely varying environments, and is relatively cheap to produce. This detector is expected, however, to require significant time to perform measurements. To mitigate the significant time for measurements, the detector is expected to scale to very large sizes with a linear increase in cost. For example, the proof of principle detector is approximately 30,000 cm3. This work describes the technical results that lead to these assertions. Finally, the applications of this detector are described in the context of nuclear material accountability.
Date: July 1, 2010
Creator: Gerts, David; Bean, Robert & Paff, Marc
Object Type: Article
System: The UNT Digital Library
NREL Support for a Functional Genomics Approach to Investigate Regulation of Phenolic Glycoside: Cooperative Research and Development Final Report, CRADA number CRD-07-00218 (open access)

NREL Support for a Functional Genomics Approach to Investigate Regulation of Phenolic Glycoside: Cooperative Research and Development Final Report, CRADA number CRD-07-00218

NREL and MTU collaborated on a proposal 'A Functional Genomics Approach to Investigate Regulation of Phenolic Glycoside Metabolism in Populus' funded by the National Science Foundation.
Date: July 1, 2010
Creator: Davis, M.
Object Type: Report
System: The UNT Digital Library
Selected test results from the neosonic polymer Li-ion battery. (open access)

Selected test results from the neosonic polymer Li-ion battery.

The performance of the Neosonic polymer Li-ion battery was measured using a number of tests including capacity, capacity as a function of temperature, ohmic resistance, spectral impedance, hybrid pulsed power test, utility partial state of charge (PSOC) pulsed cycle test, and an over-charge/voltage abuse test. The goal of this work was to evaluate the performance of the polymer Li-ion battery technology for utility applications requiring frequent charges and discharges, such as voltage support, frequency regulation, wind farm energy smoothing, and solar photovoltaic energy smoothing. Test results have indicated that the Neosonic polymer Li-ion battery technology can provide power levels up to the 10C{sub 1} discharge rate with minimal energy loss compared to the 1 h (1C) discharge rate. Two of the three cells used in the utility PSOC pulsed cycle test completed about 12,000 cycles with only a gradual loss in capacity of 10 and 13%. The third cell experienced a 40% loss in capacity at about 11,000 cycles. The DC ohmic resistance and AC spectral impedance measurements also indicate that there were increases in impedance after cycling, especially for the third cell. Cell No.3 impedance Rs increased significantly along with extensive ballooning of the foil pouch. Finally, at a …
Date: July 1, 2010
Creator: Ingersoll, David T. & Hund, Thomas D.
Object Type: Report
System: The UNT Digital Library
Control of Toxic Chemicals in Puget Sound, Phase 3: Study of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound (open access)

Control of Toxic Chemicals in Puget Sound, Phase 3: Study of Atmospheric Deposition of Air Toxics to the Surface of Puget Sound

The results of the Phase 1 Toxics Loading study suggested that runoff from the land surface and atmospheric deposition directly to marine waters have resulted in considerable loads of contaminants to Puget Sound (Hart Crowser et al. 2007). The limited data available for atmospheric deposition fluxes throughout Puget Sound was recognized as a significant data gap. Therefore, this study provided more recent or first reported atmospheric deposition fluxes of PAHs, PBDEs, and select trace elements for Puget Sound. Samples representing bulk atmospheric deposition were collected during 2008 and 2009 at seven stations around Puget Sound spanning from Padilla Bay south to Nisqually River including Hood Canal and the Straits of Juan de Fuca. Revised annual loading estimates for atmospheric deposition to the waters of Puget Sound were calculated for each of the toxics and demonstrated an overall decrease in the atmospheric loading estimates except for polybrominated diphenyl ethers (PBDEs) and total mercury (THg). The median atmospheric deposition flux of total PBDE (7.0 ng/m2/d) was higher than that of the Hart Crowser (2007) Phase 1 estimate (2.0 ng/m2/d). The THg was not significantly different from the original estimates. The median atmospheric deposition flux for pyrogenic PAHs (34.2 ng/m2/d; without TCB) shows …
Date: July 5, 2010
Creator: Brandenberger, Jill M.; Louchouarn, Patrick; Kuo, Li-Jung; Crecelius, Eric A.; Cullinan, Valerie I.; Gill, Gary A. et al.
Object Type: Report
System: The UNT Digital Library
Field Testing: Independent, Accredited Testing and Validation for the Wind Industry (Fact Sheet) (open access)

Field Testing: Independent, Accredited Testing and Validation for the Wind Industry (Fact Sheet)

This fact sheet describes field testing at the National Wind Technology Center.
Date: July 1, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Using Nuclear Resonance Fluorescence for Nondestructive Isotopic Analysis (open access)

Using Nuclear Resonance Fluorescence for Nondestructive Isotopic Analysis

Nuclear resonance fluorescence (NRF) has been studied as one of the nondestructive analysis (NDA) techniques currently being investigated by a multi-laboratory collaboration for the determination of Pu mass in spent fuel. In NRF measurements specific isotopes are identified by their characteristic lines in recorded gamma spectra. The concentration of an isotope in a material can be determined from measured NRF signal intensities if NRF cross sections and assay geometries are known. The potential of NRF to quantify isotopic content and Pu mass in spent fuel has been studied. The addition of NRF data to MCNPX and an improved treatment of the elastic photon scattering at backward angles has enabled us to more accurately simulate NRF measurements on spent fuel assemblies. Using assembly models from the spent fuel assembly library generated at LANL, NRF measurements are simulated to find the best measurement configurations, and to determine measurement sensitivities and times, and photon source and gamma detector requirements. A first proof-of-principal measurement on a mock-up assembly with a bremsstrahlung photon source demonstrated isotopic sensitivity to approximately 1% limited by counting statistics. Data collection rates are likely a limiting factor of NRF-based measurements of fuel assemblies but new technological advances may lead to …
Date: July 14, 2010
Creator: Ludewigt, Bernhard A.; Mozin, Vladimir; Haefner, Andrew & Quiter, Brian
Object Type: Article
System: The UNT Digital Library
Identified high-pT spectra in Cu+Cu collisions at sqrt sNN=200 GeV (open access)

Identified high-pT spectra in Cu+Cu collisions at sqrt sNN=200 GeV

We report new results on identified (anti)proton and charged pion spectra at large transverse momenta (3 < p{sub T} < 10 GeV/c) from Cu+Cu collisions at {radical}s{sub NN} = 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider (RHIC). This study explores the system size dependence of two novel features observed at RHIC with heavy ions: the hadron suppression at high-p{sub T} and the anomalous baryon to meson enhancement at intermediate transverse momenta. Both phenomena could be attributed to the creation of a new form of QCD matter. The results presented here bridge the system size gap between the available pp and Au+Au data, and allow the detailed exploration for the on-set of the novel features. Comparative analysis of all available 200 GeV data indicates that the system size is a major factor determining both the magnitude of the hadron spectra suppression at large transverse momenta and the relative baryon to meson enhancement.
Date: July 5, 2010
Creator: STAR Collaboration
Object Type: Article
System: The UNT Digital Library
Hydrogen-peroxide-induced oxidative stress responses in Desulfovibrio vulgaris Hildenborough (open access)

Hydrogen-peroxide-induced oxidative stress responses in Desulfovibrio vulgaris Hildenborough

To understand how sulphate-reducing bacteria respond to oxidative stresses, the responses of Desulfovibrio vulgaris Hildenborough to H{sub 2}O{sub 2}-induced stresses were investigated with transcriptomic, proteomic and genetic approaches. H{sub 2}O{sub 2} and induced chemical species (e.g. polysulfide, ROS) and redox potential shift increased the expressions of the genes involved in detoxification, thioredoxin-dependent reduction system, protein and DNA repair, and decreased those involved in sulfate reduction, lactate oxidation and protein synthesis. A gene coexpression network analysis revealed complicated network interactions among differentially expressed genes, and suggested possible importance of several hypothetical genes in H{sub 2}O{sub 2} stress. Also, most of the genes in PerR and Fur regulons were highly induced, and the abundance of a Fur regulon protein increased. Mutant analysis suggested that PerR and Fur are functionally overlapped in response to stresses induced by H{sub 2}O{sub 2} and reaction products, and the upregulation of thioredoxin-dependent reduction genes was independent of PerR or Fur. It appears that induction of those stress response genes could contribute to the increased resistance of deletion mutants to H{sub 2}O{sub 2}-induced stresses. In addition, a conceptual cellular model of D. vulgaris responses to H{sub 2}O{sub 2} stress was constructed to illustrate that this bacterium may employ …
Date: July 1, 2010
Creator: Zhou, Aifen; He, Zhili; Redding-Johanson, Alyssa M.; Mukhopadhyay, Aindrila; Hemme, Christopher L.; Joachimiak, Marcin P. et al.
Object Type: Article
System: The UNT Digital Library
CARES: Carbonaceous Aerosol and Radiative Effects Study Operations Plan (open access)

CARES: Carbonaceous Aerosol and Radiative Effects Study Operations Plan

The CARES field campaign is motivated by the scientific issues described in the CARES Science Plan. The primary objectives of this field campaign are to investigate the evolution and aging of carbonaceous aerosols and their climate-affecting properties in the urban plume of Sacramento, California, a mid-size, mid-latitude city that is located upwind of a biogenic volatile organic compound (VOC) emission region. Our basic observational strategy is to make comprehensive gas, aerosol, and meteorological measurements upwind, within, and downwind of the urban area with the DOE G-1 aircraft and at strategically located ground sites so as to study the evolution of urban aerosols as they age and mix with biogenic SOA precursors. The NASA B-200 aircraft, equipped with the High Spectral Resolution Lidar (HSRL), digital camera, and the Research Scanning Polarimeter (RSP), will be flown in coordination with the G-1 to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties, and to provide the vertical context for the G-1 and ground in situ measurements.
Date: July 12, 2010
Creator: Zaveri, R. A.; Shaw, W. J. & Cziczo, D. J.
Object Type: Report
System: The UNT Digital Library
The Ring of Fire - an internal illumination system for detector sensitivity and filter bandpass characterization (open access)

The Ring of Fire - an internal illumination system for detector sensitivity and filter bandpass characterization

We describe a prototype of an illumination system, the Ring of Fire (ROF), which is used as part of an internal calibration system for large focal plane detector arrays in TMA (Three Mirror Anastigmat) telescope designs. Such designs have been proposed for the SNAP (SuperNova Acceleration Probe) version of a Joint Dark Energy Mission (JDEM). The ROF system illuminates the focal plane with a light beam the closely matches that of the telescope and is used for creating high spatial frequency flat fields and monitoring filter bandpasses for experiments that demand a highly accurate characterization of the detectors. We present measurements of a mockup of this prototype ROF design including studies in variations in illumination across a large focal plane.
Date: July 1, 2010
Creator: Scarpine, Victor E.; Kent, Stephen M.; Deustua, Susana E.; Sholl, Michael J.; Mufson, Stuart L.; Ott, Melanie N. et al.
Object Type: Article
System: The UNT Digital Library
CRUSH TESTING OF 9977 GENERAL PURPOSE FISSILE PACKAGINGS (open access)

CRUSH TESTING OF 9977 GENERAL PURPOSE FISSILE PACKAGINGS

The 9977 General Purpose Fissile Package (GPFP) was designed in response to the adoption of the crush test requirement in the US regulations for packages for radioactive materials (10 CFR 71). This presentation on crush testing of the 9977 GPFP Reviews origins of Crush Test Requirements and implementation of crush test requirements in 10 CFR 71. SANDIA testing performed to support the rule making is reviewed. The differences in practice, on the part of the US Department of Energy from those required by the NRC for commercial purposes, are explained. The design features incorporated into the 9977 GPFP to enable it to withstand the crush test and the crush tests performed on the 9977 are described. Lessons learned from crush testing of GPFP packagings are given.
Date: July 28, 2010
Creator: Smith, A.
Object Type: Article
System: The UNT Digital Library
Enrichment Zoning Options for the Small Nuclear Rocket Engine (SNRE) (open access)

Enrichment Zoning Options for the Small Nuclear Rocket Engine (SNRE)

Advancement of U.S. scientific, security, and economic interests through a robust space exploration program requires high performance propulsion systems to support a variety of robotic and crewed missions beyond low Earth orbit. In NASA’s recent Mars Design Reference Architecture (DRA) 5.0 study (NASA-SP-2009-566, July 2009), nuclear thermal propulsion (NTP) was again selected over chemical propulsion as the preferred in-space transportation system option because of its high thrust and high specific impulse (-900 s) capability, increased tolerance to payload mass growth and architecture changes, and lower total initial mass in low Earth orbit. An extensive nuclear thermal rocket technology development effort was conducted from 1955-1973 under the Rover/NERVA Program. The Small Nuclear Rocket Engine (SNRE) was the last engine design studied by the Los Alamos National Laboratory during the program. At the time, this engine was a state-of-the-art design incorporating lessons learned from the very successful technology development program. Past activities at the NASA Glenn Research Center have included development of highly detailed MCNP Monte Carlo transport models of the SNRE and other small engine designs. Preliminary core configurations typically employ fuel elements with fixed fuel composition and fissile material enrichment. Uniform fuel loadings result in undesirable radial power and temperature …
Date: July 1, 2010
Creator: Schnitzler, Bruce G. & Borowski, Stanley K.
Object Type: Article
System: The UNT Digital Library
Air and Radon Pathway Modeling for the F Area Tank Farm (open access)

Air and Radon Pathway Modeling for the F Area Tank Farm

An air and radon pathways analysis was conducted for the F-Area Tank Farm (FTF) to estimate the flux of volatile radionuclides and radon at the ground surface due to residual waste remaining in the tanks following closure. This analysis was used as the basis to estimate the dose to the maximally exposed individual (MEI) for the air pathway per Curie (Ci) of each radionuclide remaining in the combined FTF waste tanks. For the air pathway analysis, several gaseous radionuclides were considered. These included carbon-14 (C-14), chlorine-36 (Cl-36), iodine-129 (I-129), selenium-79 (Se-79), antimony-125 (Sb-125), tin-126 (Sn-126), tritium (H-3), and technetium-99 (Tc-99). The dose to the MEI was estimated at the SRS Boundary during the 100 year institutional control period. For the 10,000 year post closure compliance period, the dose to the MEI was estimated at the 100 m compliance point. Additionally, the dose to the MEI was estimated at a seepage outcrop located 1600 m from the facility. For the radon pathway analysis, five parent radionuclides and their progeny were analyzed. These parent radionuclides included uranium-238 (U-238), plutonium-238 (Pu-238), uranium-234 (U-234), thorium-230 (Th-230), and radium-226 (Ra-226). The peak flux of radon-222 due to each parent radionuclide was estimated for the simulation …
Date: July 30, 2010
Creator: Dixon, K. & Phifer, M.
Object Type: Report
System: The UNT Digital Library

Blade Testing at NREL's National Wind Technology Center (NWTC)

Presentation of Blade Testing at NREL's National Wind Technology Center for the 2010 Sandia National Laboratories Blade Testing Workshop.
Date: July 20, 2010
Creator: Hughes, S.
Object Type: Presentation
System: The UNT Digital Library
Results of the Simulation of the HTR-Proteus Core 4.2 Using PEBBED-COMBINE: FY10 Report (open access)

Results of the Simulation of the HTR-Proteus Core 4.2 Using PEBBED-COMBINE: FY10 Report

ABSTRACT The Idaho National Laboratory’s deterministic neutronics analysis codes and methods were applied to the computation of the core multiplication factor of the HTR-Proteus pebble bed reactor critical facility. This report is a follow-on to INL/EXT-09-16620 in which the same calculation was performed but using earlier versions of the codes and less developed methods. In that report, results indicated that the cross sections generated using COMBINE-7.0 did not yield satisfactory estimates of keff. It was concluded in the report that the modeling of control rods was not satisfactory. In the past year, improvements to the homogenization capability in COMBINE have enabled the explicit modeling of TRIS particles, pebbles, and heterogeneous core zones including control rod regions using a new multi-scale version of COMBINE in which the 1-dimensional discrete ordinate transport code ANISN has been integrated. The new COMBINE is shown to yield benchmark quality results for pebble unit cell models, the first step in preparing few-group diffusion parameters for core simulations. In this report, the full critical core is modeled once again but with cross sections generated using the capabilities and physics of the improved COMBINE code. The new PEBBED-COMBINE model enables the exact modeling of the pebbles and control …
Date: July 1, 2010
Creator: Gougar, Hans
Object Type: Report
System: The UNT Digital Library
Streamlined Approach for Environmental Restoration (SAFER) Plan for Corrective Action Unit 544:  Cellars, Mud Pits, and Oil Spills, Nevada Test Site, Nevada, Revision 0 (open access)

Streamlined Approach for Environmental Restoration (SAFER) Plan for Corrective Action Unit 544: Cellars, Mud Pits, and Oil Spills, Nevada Test Site, Nevada, Revision 0

This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the actions needed to achieve closure for Corrective Action Unit (CAU) 544, Cellars, Mud Pits, and Oil Spills, identified in the Federal Facility Agreement and Consent Order (FFACO). Corrective Action Unit 544 comprises the following 20 corrective action sites (CASs) located in Areas 2, 7, 9, 10, 12, 19, and 20 of the Nevada Test Site (NTS): • 02-37-08, Cellar & Mud Pit • 02-37-09, Cellar & Mud Pit • 07-09-01, Mud Pit • 09-09-46, U-9itsx20 PS #1A Mud Pit • 10-09-01, Mud Pit • 12-09-03, Mud Pit • 19-09-01, Mud Pits (2) • 19-09-03, Mud Pit • 19-09-04, Mud Pit • 19-25-01, Oil Spill • 19-99-06, Waste Spill • 20-09-01, Mud Pits (2) • 20-09-02, Mud Pit • 20-09-03, Mud Pit • 20-09-04, Mud Pits (2) • 20-09-06, Mud Pit • 20-09-07, Mud Pit • 20-09-10, Mud Pit • 20-25-04, Oil Spills • 20-25-05, Oil Spills This plan provides the methodology for field activities needed to gather the necessary information for closing each CAS. There is sufficient information and process knowledge from historical documentation and investigations of similar sites regarding the expected nature and extent of potential contaminants to recommend …
Date: July 1, 2010
Creator: Krauss, Mark
Object Type: Report
System: The UNT Digital Library
RADBALL TECHNOLOGY TESTING IN THE SAVANNAH RIVER SITE HEALTH PHYSICS INSTRUMENT CALIBRATION LABORATORY (open access)

RADBALL TECHNOLOGY TESTING IN THE SAVANNAH RIVER SITE HEALTH PHYSICS INSTRUMENT CALIBRATION LABORATORY

The United Kingdom's National Nuclear Laboratory (NNL) has developed a radiation-mapping device that can locate and quantify radioactive hazards within contaminated areas of the nuclear industry. The device, known as RadBall{trademark}, consists of a colander-like outer collimator that houses a radiation-sensitive polymer sphere. The collimator has over two hundred small holes; thus, specific areas of the polymer sphere are exposed to radiation becoming increasingly more opaque in proportion to the absorbed dose. The polymer sphere is imaged in an optical-CT scanner that produces a high resolution 3D map of optical attenuation coefficients. Subsequent analysis of the optical attenuation data provides information on the spatial distribution of sources in a given area forming a 3D characterization of the area of interest. The RadBallTM technology has been deployed in a number of technology trials in nuclear waste reprocessing plants at Sellafield in the United Kingdom and facilities of the Savannah River National Laboratory (SRNL). This paper summarizes the tests completed at SRNL Health Physics Instrument Calibration Laboratory (HPICL).
Date: July 8, 2010
Creator: Farfan, E.
Object Type: Article
System: The UNT Digital Library
Papers from U.S. Department of Energy Science Undergraduate Laboratory Internship Program (SULI) 2009 (open access)

Papers from U.S. Department of Energy Science Undergraduate Laboratory Internship Program (SULI) 2009

None
Date: July 22, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Optimization Studies for Radiation Shielding of a Superconducting RF Cavity Test Facility (open access)

Optimization Studies for Radiation Shielding of a Superconducting RF Cavity Test Facility

Test facilities for high-gradient superconducting RF cavities must be shielded for particle radiation, which is generated by field emitted electrons in the cavities. A major challenge for the shielding design is associated with uncertainty in modeling the field emission. In this work, a semi-empirical method that allows us to predict the intensity of the generated field emission is described. Spatial, angular and energy distributions of the generated radiation are calculated with the FISHPACT code. The Monte Carlo code MARS15 is used for modeling the radiation transport in matter. The detailed distributions of the generated field emission are used for studies with 9-cell 1.3 GHz superconducting RF cavities in the Fermilab Vertical Cavity Test Facility. This approach allows us to minimize the amount of shielding inside cryostat which is an essential operational feature.
Date: July 9, 2010
Creator: Ginsburg, Camille M. & Rakhno, Igor
Object Type: Article
System: The UNT Digital Library
Carrier hopping in disordered semiconducting polymers: How accurate is the Miller-Abrahams model? (open access)

Carrier hopping in disordered semiconducting polymers: How accurate is the Miller-Abrahams model?

We performed direct calculations of carrier hopping rates in strongly disordered conjugated polymers based on the atomic structure of the system, the corresponding electronic states and their coupling to all phonon modes. We found that the dependence of hopping rates on distance and the dependence of the mobility on temperature are significantly different than the ones stemming from the simple Miller-Abrahams model, regardless of the choice of the parameters in the model. A model that satisfactorily describes the hopping rates in the system and avoids the explicit calculation of electron-phonon coupling constants was then proposed and verified. Our results indicate that, in addition to electronic density of states, the phonon density of states and the spatial overlap of the wavefunctions are the quantities necessary to properly describe carrier hopping in disordered conjugated polymers.
Date: July 30, 2010
Creator: Vukmirovic, Nenad & Wang, Lin-Wang
Object Type: Article
System: The UNT Digital Library
Observation of pi+pi-pi+pi- photoproduction in ultraperipheral heavy-ion collisions at sqrt sNN = 200 GeV at the STAR detector (open access)

Observation of pi+pi-pi+pi- photoproduction in ultraperipheral heavy-ion collisions at sqrt sNN = 200 GeV at the STAR detector

We present a measurement of {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} photonuclear production in ultra-peripheral Au-Au collisions at {radical}s{sub NN} = 200 GeV from the STAR experiment. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} invariant mass spectrum of the coherent events exhibits a broad peak around 1540 {+-} 40 MeV/c{sup 2} with a width of 570 {+-} 60 MeV/c{sup 2}, in agreement with the photoproduction data for the {rho}{sup 0}(1700). We do not observe a corresponding peak in the {pi}{sup +}{pi}{sup -} final state and measure an upper limit for the ratio of the branching fractions of the {rho}{sup 0}(1700) to {pi}{sup +}{pi}{sup -} and {pi}{sup +}{pi}{sup -}{pi}{sup +}{pi}{sup -} of 2.5% at 90% confidence level. The ratio of {rho}{sup 0}(1700) and {rho}{sup 0}(770) coherent production cross sections is measured to be 13.4 {+-} 0.8{sub stat.} {+-} 4.4{sub syst.}%.
Date: July 5, 2010
Creator: STAR Collaboration
Object Type: Article
System: The UNT Digital Library
MANAGEMENT OF RESEARCH AND TEST REACTOR ALUMINUM SPENT NUCLEAR FUEL - A TECHNOLOGY ASSESSMENT (open access)

MANAGEMENT OF RESEARCH AND TEST REACTOR ALUMINUM SPENT NUCLEAR FUEL - A TECHNOLOGY ASSESSMENT

The Department of Energy's Environmental Management (DOE-EM) Program is responsible for the receipt and storage of aluminum research reactor spent nuclear fuel or used fuel until ultimate disposition. Aluminum research reactor used fuel is currently being stored or is anticipated to be returned to the U.S. and stored at DOE-EM storage facilities at the Savannah River Site and the Idaho Nuclear Technology and Engineering Center. This paper assesses the technologies and the options for safe transportation/receipt and interim storage of aluminum research reactor spent fuel and reviews the comprehensive strategy for its management. The U.S. Department of Energy uses the Appendix A, Spent Nuclear Fuel Acceptance Criteria, to identify the physical, chemical, and isotopic characteristics of spent nuclear fuel to be returned to the United States under the Foreign Research Reactor Spent Nuclear Fuel Acceptance Program. The fuel is further evaluated for acceptance through assessments of the fuel at the foreign sites that include corrosion damage and handleability. Transport involves use of commercial shipping casks with defined leakage rates that can provide containment of the fuel, some of which are breached. Options for safe storage include wet storage and dry storage. Both options must fully address potential degradation of the …
Date: July 11, 2010
Creator: Vinson, D.
Object Type: Article
System: The UNT Digital Library
Long range rapidity correlations and jet production in high energy nuclear collisions (open access)

Long range rapidity correlations and jet production in high energy nuclear collisions

The STAR Collaboration at RHIC presents a systematic study of high transverse momentum charged di-hadron correlations at small azimuthal pair separation {Delta}{phi}, in d+Au and central Au+Au collisions at {radical}s{sub NN} = 200 GeV. Significant correlated yield for pairs with large longitudinal separation {Delta}{eta} is observed in central Au+Au, in contrast to d+Au collisions. The associated yield distribution in {Delta}{eta} x {delta}{phi} can be decomposed into a narrow jet-like peak at small angular separation which has a similar shape to that found in d+Au collisions, and a component which is narrow in {Delta}{phi} and depends only weakly on {Delta}{eta}, the 'ridge'. Using two systematically independent analyses, finite ridge yield is found to persist for trigger p{sub t} > 6 GeV/c, indicating that it is correlated with jet production. The transverse momentum spectrum of hadrons comprising the ridge is found to be similar to that of bulk particle production in the measured range (2 < p{sub t} < 4 GeV/c).
Date: July 5, 2010
Creator: STAR Collaboration
Object Type: Article
System: The UNT Digital Library
WIMP search with the final year of CDMS II data (open access)

WIMP search with the final year of CDMS II data

The Cryogenic Dark Matter Search (CDMS) has pioneered the use of ionization and athermal phonon signals to discriminate between candidate (nuclear recoil) and background (electron recoil) events in Ge crystals cooled to {approx}50 mK. The yield and timing information allows for the maximization of discovery potential by adjusting the expected background in the signal region to less than one event. A blind analysis on 612 kg-days of raw exposure from the CDMS II experiment was performed. Two events with an expected background of {approx}0.9 events were observed. No statistically significant evidence for WIMP interactions is reported. Combining this data with previously analyzed CDMS II data sets an upper limit on the WIMP-nucleon spin-independent cross-section of 3.8 x 10{sup -44} cm{sup 2} for a WIMP of mass 70 GeV/c{sup 2}.
Date: July 1, 2010
Creator: Hsu, L.
Object Type: Article
System: The UNT Digital Library