Access

Resource Type

Partner

Collection

Serial/Series Title

Degree Department

Degree Discipline

Degree Level

Country

States

Counties

Year

Month

Day

Language

400 Matching Results

Start Over Access Open Access Year 2011 Day 6th Language English

Results open in a new window/tab.

prev Results: 97 - 120 of 400 next

(open access)

SHIPMENT OF NON-TRADITIONAL CONTENTS IN THE 9977 TYPE B PACKAGE

The 9977 is a certified Type B Packaging authorized to ship uranium and plutonium in metal and oxide forms. These materials are typically confined within metallic containers designed for ease of handling and to prevent the spread of contamination. The Pacific Northwest National Laboratory (PNNL) uses Pu and U sources for the training of domestic and international customs agents in the identification and detection of radioactive materials (RAM). These materials are packed in polycarbonate containers which permit the trainees to view the RAM. The safety basis was made to authorize the use of these unusual containers. The inclusion of the PNNL Training Source Contents into the 9977 Packaging imposed unique conditions previously unanalyzed. The use of polycarbonate as a content container material, while different from any configuration previously considered, does not raise any safety issues with the package which continues to operate with a large safety margin for temperatures, pressures, containment, dose rates, and subcriticality.

Date: June 6, 2011

Creator: Abramczyk, G.; Loftin, B.; Bellamy, S. & Nathan, S.

Object Type: Article

System: The UNT Digital Library

(open access)

DETERMINATION OF HLW GLASS MELT RATE USING X-RAY COMPUTED TOMOGRAPHY

The purpose of the high-level waste (HLW) glass melt rate study is two-fold: (1) to gain a better understanding of the impact of feed chemistry on melt rate through bench-scale testing, and (2) to develop a predictive tool for melt rate in support of the on-going frit development efforts for the Defense Waste Processing Facility (DWPF). In particular, the focus is on predicting relative melt rates, not the absolute melt rates, of various HLW glass formulations solely based on feed chemistry, i.e., the chemistry of both waste and glass-forming frit for DWPF. Critical to the successful melt rate modeling is the accurate determination of the melting rates of various HLW glass formulations. The baseline procedure being used at the Savannah River National Laboratory (SRNL) is to; (1) heat a 4 inch-diameter stainless steel beaker containing a mixture of dried sludge and frit in a furnace for a preset period of time, (2) section the cooled beaker along its diameter, and (3) measure the average glass height across the sectioned face using a ruler. As illustrated in Figure 1-1, the glass height is measured for each of the 16 horizontal segments up to the red lines where relatively large-sized bubbles begin …

Date: October 6, 2011

Creator: Choi, A.; Miller, D. & Immel, D.

Object Type: Report

System: The UNT Digital Library

(open access)

9975 SHIPPING PACKAGE LIFE EXTENSION SURVEILLANCE PROGRAM RESULTS SUMMARY

Results from the 9975 Surveillance Program at the Savannah River Site (SRS) are summarized for justification to extend the life of the 9975 packages currently stored in the K-Area Materials Storage (KAMS) facility from 10 years to 15 years. This justification is established with the stipulation that surveillance activities will continue throughout this extended time to ensure the continued integrity of the 9975 materials of construction and to further understand the currently identified degradation mechanisms. The current 10 year storage life was developed prior to storage. A subsequent report was later used to extend the qualification of the 9975 shipping packages for 2 years for shipping plus 10 years for storage. However the qualification for the storage period was provided by the monitoring requirements of the Storage and Surveillance Program. This report summarizes efforts to determine a new safe storage limit for the 9975 shipping package based on the surveillance data collected since 2005 when the surveillance program began. KAMS is a zero-release facility that depends upon containment by the 9975 to meet design basis storage requirements. Therefore, to confirm the continued integrity of the 9975 packages while stored in KAMS, a 9975 Storage and Surveillance Program was implemented alongside …

Date: January 6, 2011

Creator: Daugherty, W.; Dunn, K.; Hackney, B.; Hoffman, E. & Skidmore, E.

Object Type: Report

System: The UNT Digital Library

(open access)

WATER ACTIVITY DATA ASSESSMENT TO BE USED IN HANFORD WASTE SOLUBILITY CALCULATIONS

The purpose of this report is to present and assess water activity versus ionic strength for six solutes:sodium nitrate, sodium nitrite, sodium chloride, sodium carbonate, sodium sulfate, and potassium nitrate. Water activity is given versus molality (e.g., ionic strength) and temperature. Water activity is used to estimate Hanford crystal hydrate solubility present in the waste.

Date: January 6, 2011

Creator: Disselkamp, R. S.

Object Type: Report

System: The UNT Digital Library

(open access)

A Noisy 10GB Provenance Database

Provenance of scientific data is a key piece of the metadata record for the data's ongoing discovery and reuse. Provenance collection systems capture provenance on the fly, however, the protocol between application and provenance tool may not be reliable. Consequently, the provenance record can be partial, partitioned, and simply inaccurate. We use a workflow emulator that models faults to construct a large 10GB database of provenance that we know is noisy (that is, has errors). We discuss the process of generating the provenance database, and show early results on the kinds of provenance analysis enabled by the large provenance.

Date: June 6, 2011

Creator: Cheah, You-Wei; Plale, Beth; Kendall-Morwick, Joey; Leake, David & Ramakrishnan, Lavanya

Object Type: Article

System: The UNT Digital Library

(open access)

Status of EXO-200

EXO-200 is the first phase of the Enriched Xenon Observatory (EXO) experiment, which searches for neutrinoless double beta decay in {sup 136}Xe to measure the mass and probe the Majorana nature of the neutrino. EXO-200 consists of 200 kg of liquid Xe enriched to 80% in {sup 136}Xe in an ultra-low background TPC. Energy resolution is enhanced through the simultaneous collection of scintillation light using Large Area Avalanche Photodiodes (LAAPD's) and ionization charge. It is being installed at the WIPP site in New Mexico, which provides a 2000 meter water-equivalent overburden. EXO-200 will begin taking data in 2009, with the expected two-year sensitivity to the half-life for neutrinoless double beta decay of 6.4 x 10{sup 25} years. According to the most recent nuclear matrix element calculations, this corresponds to an effective Majorana neutrino mass of 0.13 to 0.19 eV. It will also measure the two neutrino mode for the first time in {sup 136}Xe.

Date: December 6, 2011

Creator: Ackerman, Nicole

Object Type: Article

System: The UNT Digital Library

(open access)

DEVELOPMENT OF A SENSOR NETWORK TEST BED FOR ISD MATERIALS AND STRUCUTRAL CONDITION MONITORING

The P Reactor at the Savannah River Site is one of the first reactor facilities in the US DOE complex that has been placed in its end state through in situ decommissioning (ISD). The ISD end state consists of a grout-filled concrete civil structure within the concrete frame of the original building. To evaluate the feasibility and utility of remote sensors to provide verification of ISD system conditions and performance characteristics, an ISD Sensor Network Test Bed has been designed and deployed at the Savannah River National Laboratory. The test bed addresses the DOE-EM Technology Need to develop a remote monitoring system to determine and verify ISD system performance. Commercial off-the-shelf sensors have been installed on concrete blocks taken from walls of the P Reactor Building. Deployment of this low-cost structural monitoring system provides hands-on experience with sensor networks. The initial sensor system consists of: (1) Groutable thermistors for temperature and moisture monitoring; (2) Strain gauges for crack growth monitoring; (3) Tiltmeters for settlement monitoring; and (4) A communication system for data collection. Preliminary baseline data and lessons learned from system design and installation and initial field testing will be utilized for future ISD sensor network development and deployment.

Date: July 6, 2011

Creator: Zeigler, K.; Ferguson, B.; Karapatakis, D.; Herbst, C. & Stripling, C.

Object Type: Report

System: The UNT Digital Library

(open access)

Commissioning: A Highly Cost-Effective Building Energy Management Strategy

Quality assurance and optimization are essential elements of any serious technological endeavor, including efforts to improve energy efficiency. Commissioning is an important tool in this respect. The aim of commissioning new buildings is to ensure that they deliver-if not exceed-the performance and energy savings promised by their design. When applied to existing buildings, one-time or repeated commissioning (often called retrocommissioning) identifies the almost inevitable drift in energy performance and puts the building back on course, often surpassing the original design intent. In both contexts, commissioning is a systematic, forensic approach to improving performance, rather than a discrete technology.

Date: January 6, 2011

Creator: Mills, Evan

Object Type: Article

System: The UNT Digital Library

(open access)

Optically Detected Magnetic Resonance Studies on π-conjugated semiconductor systems

Optically Detected Magnetic Resonance (ODMR) techniques were used to investigate the dynamics of excitons and charge carriers in π-conjugated organic semiconductors. Degradation behavior of the negative spin-1/2 electroluminescence-detected magnetic resonance (ELDMR) was observed in Alq3 devices. The increase in the resonance amplitude implies an increasing bipolaron formation during degradation, which might be the result of growth of charge traps in the device. The same behavior of the negative spin-1/2 ELDMR was observed in 2wt% Rubrene doped Tris(8-hydroxyquinolinato)aluminium (Alq3) devices. However, with increasing injection current, a positive spin-1/2 ELDMR, together with positive spin 1 triplet powder patterns at {delta}m{sub S}={+-}1 and {delta}m{sub S}={+-}2, emerges. Due to the similarities in the frequency dependences of single and double modulated ELDMR and the photoluminescence-detected magnetic resonance (PLDMR) results in poly[2-methoxy-5-(2 -ethyl-hexyloxy)-1,4-phenyl ene vinylene] (MEH-PPV) films, the mechanism for this positive spin-1/2 ELDMR was assigned to enhanced triplet-polaron quenching under resonance conditions. The ELDMR in rubrene doped Alq3 devices provides a path to investigate charge distribution in the device under operational conditions. Combining the results of several devices with different carrier blocking properties and the results from transient EL, it was concluded trions not only exist near buffer layer but also exist in the electron …

Date: December 6, 2011

Creator: Chen, Ying

Object Type: Thesis or Dissertation

System: The UNT Digital Library

(open access)

MARIANE: MApReduce Implementation Adapted for HPC Environments

MapReduce is increasingly becoming a popular framework, and a potent programming model. The most popular open source implementation of MapReduce, Hadoop, is based on the Hadoop Distributed File System (HDFS). However, as HDFS is not POSIX compliant, it cannot be fully leveraged by applications running on a majority of existing HPC environments such as Teragrid and NERSC. These HPC environments typicallysupport globally shared file systems such as NFS and GPFS. On such resourceful HPC infrastructures, the use of Hadoop not only creates compatibility issues, but also affects overall performance due to the added overhead of the HDFS. This paper not only presents a MapReduce implementation directly suitable for HPC environments, but also exposes the design choices for better performance gains in those settings. By leveraging inherent distributed file systems' functions, and abstracting them away from its MapReduce framework, MARIANE (MApReduce Implementation Adapted for HPC Environments) not only allows for the use of the model in an expanding number of HPCenvironments, but also allows for better performance in such settings. This paper shows the applicability and high performance of the MapReduce paradigm through MARIANE, an implementation designed for clustered and shared-disk file systems and as such not dedicated to a specific …

Date: July 6, 2011

Creator: Fadika, Zacharia; Dede, Elif; Govindaraju, Madhusudhan & Ramakrishnan, Lavanya

Object Type: Article

System: The UNT Digital Library

(open access)

Strength Measurements of Archive K Basin Sludge Using a Soil Penetrometer

Spent fuel radioactive sludge present in the K East and K West spent nuclear fuel storage basins now resides in the KW Basin in six large underwater engineered containers. The sludge will be dispositioned in two phases under the Sludge Treatment Project: (1) hydraulic retrieval into sludge transport and storage containers (STSCs) and transport to interim storage in Central Plateau and (2) retrieval from the STSCs, treatment, and packaging for shipment to the Waste Isolation Pilot Plant. In the years the STSCs are stored, sludge strength is expected to increase through chemical reaction, intergrowth of sludge crystals, and compaction and dewatering by settling. Increased sludge strength can impact the type and operation of the retrieval equipment needed prior to final sludge treatment and packaging. It is important to determine whether water jetting, planned for sludge retrieval from STSCs, will be effective. Shear strength is a property known to correlate with the effectiveness of water jetting. Accordingly, the unconfined compressive strengths (UCS) of archive K Basin sludge samples and sludge blends were measured using a pocket penetrometer modified for hot cell use. Based on known correlations, UCS values can be converted to shear strengths. Twenty-six sludge samples, stored in hot cells …

Date: December 6, 2011

Creator: Delegard, Calvin H.; Schmidt, Andrew J. & Chenault, Jeffrey W.

Object Type: Report

System: The UNT Digital Library

(open access)

DEVELOPMENT OF A KINETIC MODEL OF BOEHMITE DISSOLUTION IN CAUSTIC SOLUTIONS APPLIED TO OPTIMIZE HANFORD WASTE PROCESSING

Boehmite (e.g., aluminum oxyhydroxide) is a major non-radioactive component in Hanford and Savannah River nuclear tank waste sludge. Boehmite dissolution from sludge using caustic at elevated temperatures is being planned at Hanford to minimize the mass of material disposed of as high-level waste (HLW) during operation of the Waste Treatment Plant (WTP). To more thoroughly understand the chemistry of this dissolution process, we have developed an empirical kinetic model for aluminate production due to boehmite dissolution. Application of this model to Hanford tank wastes would allow predictability and optimization of the caustic leaching of aluminum solids, potentially yielding significant improvements to overall processing time, disposal cost, and schedule. This report presents an empirical kinetic model that can be used to estimate the aluminate production from the leaching of boehmite in Hanford waste as a function of the following parameters: (1) hydroxide concentration; (2) temperature; (3) specific surface area of boehmite; (4) initial soluble aluminate plus gibbsite present in waste; (5) concentration of boehmite in the waste; and (6) (pre-fit) Arrhenius kinetic parameters. The model was fit to laboratory, non-radioactive (e.g. 'simulant boehmite') leaching results, providing best-fit values of the Arrhenius A-factor, A, and apparent activation energy, E{sub A}, of A …

Date: January 6, 2011

Creator: RS, DISSELKAMP

Object Type: Report

System: The UNT Digital Library

(open access)

Predictions of Alpha Heating in ITER L-mode and H-mode Plasmas

Predictions of alpha heating in L-mode and H-mode DT plasmas in ITER are generated using the PTRANSP code. The baseline toroidal field of 5.3 T, plasma current ramped to 15 MA and a flat electron density profile ramped to Greenwald fraction 0.85 are assumed. Various combinations of external heating by negative ion neutral beam injection, ion cyclotron resonance, and electron cyclotron resonance are assumed to start half-way up the density ramp. The time evolution of plasma temperatures and, for some cases, toroidal rotation are predicted assuming GLF23 and boundary parameters. Significant toroidal rotation and flow-shearing rates are predicted by GLF23 even in the L-mode phase with low boundary temperatures, and the alpha heating power is predicted to be significant if the power threshold for the transition to H-mode is higher than the planned total heating power. The alpha heating is predicted to be 8-76 MW in L-mode at full density. External heating mixes with higher beam injection power have higher alpha heating power. Alternatively if the toroidal rotation is predicted assuming that the ratio of the momentum to thermal ion energy conductivity is 0.5, the flow-shearing rate is predicted to have insignificant effects on the GLF23- predicted temperatures, and alpha …

Date: January 6, 2011

Creator: Budny, R. V.

Object Type: Report

System: The UNT Digital Library

(open access)

Optical modeling of Fresnel zoneplate microscopes

Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5 nm wavelength. Arguably the most cost-effective and rapid path to proliferating this capability is through the development of Fresnel zoneplate-based microscopes. Given the relative obscurity of such systems, however, modeling tools are not necessarily optimized to deal with them and their imaging properties are poorly understood. Here we present a modeling methodology to analyze zoneplate microscopes based on commercially available optical modeling software and use the technique to investigate the imaging performance of an off-axis EUV microscope design. The modeling predicts that superior performance can be achieved by tilting the zoneplate, making it perpendicular to the chief ray at the center of the field, while designing the zoneplate to explicitly work in that tilted plane. Although the examples presented here are in the realm of EUV mask inspection, the methods described and analysis results are broadly applicable to zoneplate microscopes in general, including full-field soft-x-ray microscopes rou tinely used in the synchrotron community.

Date: April 6, 2011

Creator: Naulleau, Patrick; Mochi, Iacopo & Goldberg, Kenneth A.

Object Type: Article

System: The UNT Digital Library

(open access)

A Lattice for a Hybrid Fast-Ramping Muon Accelerator to 750 GeV

We describe a lattice for accelerating muons from 375 GeV to 750 GeV. The lattice is a fast-ramping synchrotron with a mixture of fixed-field superconducting dipoles and warm dipoles, so as to have a high average bending field while still being able to rapidly change the average bending field as the beam momentum increases. For a 1.5 TeV center of mass muon collider, muons must be rapidly accelerated to 750 GeV. To accomplish this efficiently, we wish to make as many passes through the RF cavities as possible, while keeping the average RF gradients sufficiently high to avoid excess muon decays. A synchrotron where the magnets are very rapidly ramped has been envisioned as one option to accomplish this. The entire acceleration cycle takes place in less than 1 ms, presenting a technological challenge for the magnets. Clearly superconducting magnets cannot be ramped on this time scale, so instead room-temperature magnets will be ramped. To keep losses low, dipoles can use grain-oriented silicon steel, but quadrupoles will probably need to use more conventional steel, giving a lower maximum field for these high ramping rates. If we want to have a large average RF gradient and simultaneously make a large number …

Date: September 6, 2011

Creator: Garren, A.A. & Berg, J.

Object Type: Report

System: The UNT Digital Library