Aquifer Testing and Rebound Study in Support of the 100-H Deep Chromium Investigation (open access)

Aquifer Testing and Rebound Study in Support of the 100-H Deep Chromium Investigation

The 100-HR-3 Groundwater Operable Unit (OU) second Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) 5-year review (DOEIRL-2006-20, The Second CERCLA Five-Year Review Report for the Hanford Site) set a milestone to conduct an investigation of deep hexavalent chromium contamination in the sediments of the Ringold upper mud (RUM) unit, which underlies the unconfined aquifer in the 100-H Area. The 5-year review noted that groundwater samples from one deep well extending below the aquitard (i.e., RUM) exceeded both the groundwater standard of 48 parts per billion (ppb) (Ecology Publication 94-06, Model Toxics Control Act Cleanup Statute and Regulation) and the federal drinking water standard of 100 {mu}g/L for hexavalent chromium. The extent of hexavalent chromium contamination in this zone is not well understood. Action 12-1 from the 5-year review is to perform additional characterization of the aquifer below the initial aquitard. Field characterization and aquifer testing were performed in the Hanford Site's 100-H Area to address this milestone. The aquifer tests were conducted to gather data to answer several fundamental questions regarding the presence of the hexavalent chromium in the deep sediments of the RUM and to determine the extent and magnitude of deeper contamination. The pumping tests …
Date: November 5, 2010
Creator: Smoot, J. L.
Object Type: Report
System: The UNT Digital Library

Module Technology: Current Practice and Issues

PV modules must provide mechanical support for the cells, protect the world from the voltages inside, protect the cells, diodes and interconnects from the weather outside, couple as much light as possible into the PV cells and minimize the temperature increase of the cells. The package must continue to serve these functions for at least 25 years as that is the typical module warranty period today. Furthermore the package must do all this for as low a cost as possible since the key to large scale PV growth is a reduction in cost while retaining excellent module reliability and durability. This paper will review current module construction practices for both crystalline silicon and thin film PV with emphasis on explaining why the present designs and materials have been selected. Possible long term issues with today's designs and materials will be discussed. Several proposed solutions to these issues will be presented, highlighting the research efforts that will be necessary in order to verify that they can cost effectively solve the identified issues.
Date: October 5, 2010
Creator: Wohlgemuth, J.
Object Type: Presentation
System: The UNT Digital Library
Electron-cloud Build-up Simulations in the Proposed PS2: Status Report (open access)

Electron-cloud Build-up Simulations in the Proposed PS2: Status Report

A replacement for the PS storage ring is being considered, in the context of the future LHC accelerator complex upgrade, that would likely place the new machine (the PS2) in a regime where the electron-cloud (EC) effect might be significant. We report here our current estimate of the EC density ne in the bending magnets and the field-free regions at injection and extraction beam energy, for both proposed bunch spacings, tb = 25 and 50 ns. The primary model parameters exercised are the peak secondary emission yield (SEY) delta max, the electron-wall impact energy at which the SEY peaks, Emax, and the chamber radius a in the fieldfree regions. We present many of our results as a function of the bunch intensity Nb, and we provide a tentative explanation for the non-monotonic behavior of ne as a function of Nb.
Date: May 5, 2010
Creator: Furman, M. A.; De Maria, R.; Papaphilippou, Y. & Rumolo, G.
Object Type: Article
System: The UNT Digital Library
Terrestrial biogeochemical feedbacks in the climate system: from past to future (open access)

Terrestrial biogeochemical feedbacks in the climate system: from past to future

The terrestrial biosphere plays a major role in the regulation of atmospheric composition, and hence climate, through multiple interlinked biogeochemical cycles (BGC). Ice-core and other palaeoenvironmental records show a fast response of vegetation cover and exchanges with the atmosphere to past climate change, although the phasing of these responses reflects spatial patterning and complex interactions between individual biospheric feedbacks. Modern observations show a similar responsiveness of terrestrial biogeochemical cycles to anthropogenically-forced climate changes and air pollution, with equally complex feedbacks. For future conditions, although carbon cycle-climate interactions have been a major focus, other BGC feedbacks could be as important in modulating climate changes. The additional radiative forcing from terrestrial BGC feedbacks other than those conventionally attributed to the carbon cycle is in the range of 0.6 to 1.6 Wm{sup -2}; all taken together we estimate a possible maximum of around 3 Wm{sup -2} towards the end of the 21st century. There are large uncertainties associated with these estimates but, given that the majority of BGC feedbacks result in a positive forcing because of the fundamental link between metabolic stimulation and increasing temperature, improved quantification of these feedbacks and their incorporation in earth system models is necessary in order to develop …
Date: January 5, 2010
Creator: Arneth, A.; Harrison, S. P.; Zaehle, S.; Tsigaridis, K.; Menon, S.; Bartlein, P. J. et al.
Object Type: Article
System: The UNT Digital Library
Gene by Disease Interaction on Orbitofrontal Gray Matter in Cocaine Addiction (open access)

Gene by Disease Interaction on Orbitofrontal Gray Matter in Cocaine Addiction

Chronic cocaine use has been associated with structural deficits in brain regions having dopamine receptive neurons. However, the concomitant use of other drugs and common genetic variability in monoamine regulation present additional structural variability. We therefore examined variations in gray matter volume (GMV) as a function of lifetime drug use and the monoamine oxidase A (MAOA) genotype in cocaine use disorders (CUD) and healthy controls.
Date: December 5, 2010
Creator: Alia-Klein, N.; Alia-Klein, N.; Parvaz, M. A.; Woicik, P. A.; Konova, A.; Maloney, T. et al.
Object Type: Article
System: The UNT Digital Library
Identification of 300 Area Contaminants of Potential Concern for Soil (open access)

Identification of 300 Area Contaminants of Potential Concern for Soil

This report documents the process used to identify source area contaminants of potential concern (COPCs) in support of the 300 Area remedial investigation/feasibility study (RI/FS) work plan. This report also establishes the exclusion criteria applicable for 300 Area use and the analytical methods needed to analyze the COPCs.
Date: April 5, 2010
Creator: Ovink, R.W.
Object Type: Report
System: The UNT Digital Library
Calibration of the ERL cavity FPC and PU couplers (open access)

Calibration of the ERL cavity FPC and PU couplers

The performance parameters of a superconducting cavity, notably accelerating field and quality factor, are first obtained in a cryogenic vertical test Dewar, and again after the final assembly in its cryostat. The tests involve Network Analyzer (NA) measurements in which the cavity is excited through an input coupler and the properties are obtained from the reflected signal at the input and the transmitted signal from the output coupler. The interpretation of the scattering coefficients in terms of field strength requires the knowledge of the Fundamental Power Coupler (FPC) and Pick-Up (PU) coupler strength, as expressed by their 'external' and Q{sub FPC} Q{sub PU}. The coupler strength is independent of the field level or cavity losses and thus can be determined at low levels with the scattering coefficients S{sub 11} and S{sub 21}, assuming standard 50 {Omega} terminations in the network analyzer. Also needed is the intrinsic cavity parameter, R{sub a} /Q{sub 0} {triple_bond} {l_brace}R/Q{r_brace}, a quantity independent of field or losses which must be obtained from simulation programs, such as the Microwave Studio.
Date: April 5, 2010
Creator: Hahn, H.; Johnson, E. & Kayran, D.
Object Type: Report
System: The UNT Digital Library
Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol (open access)

Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol

A detailed understanding of the sources, transformations, and fates of organic species in the environment is crucial because of the central roles that organics play in human health, biogeochemical cycles, and Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state (OSC), a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of OSC , using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number (nC).
Date: November 5, 2010
Creator: Technology, Massachusetts Institute of; Kroll, Jesse H.; Donahue, Neil M.; Jimenez, Jose L.; Kessler, Sean H.; Canagaratna, Manjula R. et al.
Object Type: Article
System: The UNT Digital Library
Derivation and Solution of Multifrequency Radiation Diffusion Equations for Homogeneous Refractive Lossy Media (open access)

Derivation and Solution of Multifrequency Radiation Diffusion Equations for Homogeneous Refractive Lossy Media

Starting from the radiation transport equation for homogeneous, refractive lossy media, we derive the corresponding time-dependent multifrequency diffusion equations. Zeroth and first moments of the transport equation couple the energy density, flux and pressure tensor. The system is closed by neglecting the temporal derivative of the flux and replacing the pressure tensor by its diagonal analogue. The system is coupled to a diffusion equation for the matter temperature. We are interested in modeling annealing of silica (SiO{sub 2}). We derive boundary conditions at a planar air-silica interface taking account of reflectivities. The spectral dimension is discretized into a finite number of intervals leading to a system of multigroup diffusion equations. Three simulations are presented. One models cooling of a silica slab, initially at 2500 K, for 10 s. The other two are 1D and 2D simulations of irradiating silica with a CO{sub 2} laser, {lambda} = 10.59 {micro}m. In 2D, we anneal a disk (radius = 0.4, thickness = 0.4 cm) with a laser, Gaussian profile (r{sub 0} = 0.5 mm for 1/e decay).
Date: January 5, 2010
Creator: Shestakov, A I; Vignes, R M & Stolken, J S
Object Type: Article
System: The UNT Digital Library
Visualization and Analysis-Oriented Reconstruction of Material Interfaces (open access)

Visualization and Analysis-Oriented Reconstruction of Material Interfaces

Reconstructing boundaries along material interfaces from volume fractions is a difficult problem, especially because the under-resolved nature of the input data allows for many correct interpretations. Worse, algorithms widely accepted as appropriate for simulation are inappropriate for visualization. In this paper, we describe a new algorithm that is specifically intended for reconstructing material interfaces for visualization and analysis requirements. The algorithm performs well with respect to memory footprint and execution time, has desirable properties in various accuracy metrics, and also produces smooth surfaces with few artifacts, even when faced with more than two materials per cell.
Date: March 5, 2010
Creator: Childs, Henry R.
Object Type: Article
System: The UNT Digital Library
Full multiple scattering analysis of XANES at the Cd L3 and O K edges in CdO films combined with a soft-x-ray emission investigation (open access)

Full multiple scattering analysis of XANES at the Cd L3 and O K edges in CdO films combined with a soft-x-ray emission investigation

X-ray absorption near edge structure (XANES) at the cadmium L3 and oxygen K edges for CdO thin films grown by pulsed laser deposition method, is interpreted within the real-space multiple scattering formalism, FEFF code. The features in the experimental spectra are well reproduced by calculations for a cluster of about six and ten coordination shells around the absorber for L3 edge of Cd and K edge of O, respectively. The calculated projected electronic density of states is found to be in good agreement with unoccupied electronic states in experimental data and allows to conclude that the orbital character of the lowest energy of the conductive band is Cd-5s-O-2p. The charge transfer has been quantified and not purely ionic bonding has been found. Combined XANES and resonant inelastic x-ray scattering measurements allow us to determine the direct and indirect band gap of investigated CdO films to be {approx}2.4-eV and {approx}0.9-eV, respectively.
Date: July 5, 2010
Creator: Demchenko, I. N.; Denlinger, J. D.; Chernyshova, M.; Yu, K. M.; Speaks, D. T.; Olalde-Velasco, P. et al.
Object Type: Article
System: The UNT Digital Library
Dust-Plasma Interactions (open access)

Dust-Plasma Interactions

The objective of our theoretical research under this grant over the past 3 years was to develop new understanding in a range of topics in the physics of dust-plasma interactions, with application to space and the laboratory. We conducted studies related to the physical properties of dust, waves and instabilities in both weakly coupled and strongly coupled dusty plasmas, and innovative possible applications. A major consideration in our choice of topics was to compare theory with experiments or observations, and to motivate new experiments, which we believe is important for developing this relatively new field. Our research is summarized, with reference to our list of journal publications.
Date: January 5, 2010
Creator: Rosenberg, M.
Object Type: Report
System: The UNT Digital Library
Mechanisms underlying cellular responses of cells from haemopoietic tissue to low dose/low LET radiation (open access)

Mechanisms underlying cellular responses of cells from haemopoietic tissue to low dose/low LET radiation

To accurately define the risks associated with human exposure to relevant environmental doses of low LET ionizing radiation, it is necessary to completely understand the biological effects at very low doses (i.e., less than 0.1 Gy), including the lowest possible dose, that of a single electron track traversal. At such low doses, a range of studies have shown responses in biological systems which are not related to the direct interaction of radiation tracks with DNA. The role of these “non-targeted” responses in critical tissues is poorly understood and little is known regarding the underlying mechanisms. Although critical for dosimetry and risk assessment, the role of individual genetic susceptibility in radiation risk is not satisfactorily defined at present. The aim of the proposed grant is to critically evaluate radiation-induced genomic instability and bystander responses in key stem cell populations from haemopoietic tissue. Using stem cells from two mouse strains (CBA/H and C57BL/6J) known to differ in their susceptibility to radiation effects, we plan to carefully dissect the role of genetic predisposition on two non-targeted radiation responses in these models; the bystander effect and genomic instability, which we believe are closely related. We will specifically focus on the effects of low doses …
Date: March 5, 2010
Creator: Kadhim, Munira A
Object Type: Report
System: The UNT Digital Library
Heavy Water Components Test Reactor Decommissioning - Major Component Removal (open access)

Heavy Water Components Test Reactor Decommissioning - Major Component Removal

The Heavy Water Components Test Reactor (HWCTR) facility (Figure 1) was built in 1961, operated from 1962 to 1964, and is located in the northwest quadrant of the Savannah River Site (SRS) approximately three miles from the site boundary. The HWCTR facility is on high, well-drained ground, about 30 meters above the water table. The HWCTR was a pressurized heavy water test reactor used to develop candidate fuel designs for heavy water power reactors. It was not a defense-related facility like the materials production reactors at SRS. The reactor was moderated with heavy water and was rated at 50 megawatts thermal power. In December of 1964, operations were terminated and the facility was placed in a standby condition as a result of the decision by the U.S. Atomic Energy Commission to redirect research and development work on heavy water power reactors to reactors cooled with organic materials. For about one year, site personnel maintained the facility in a standby status, and then retired the reactor in place. In 1965, fuel assemblies were removed, systems that contained heavy water were drained, fluid piping systems were drained, deenergized and disconnected and the spent fuel basin was drained and dried. The doors of …
Date: May 5, 2010
Creator: Austin, W. & Brinkley, D.
Object Type: Article
System: The UNT Digital Library
Alternative Enhanced Chemical Cleaning Basic Studies Results FY09 (open access)

Alternative Enhanced Chemical Cleaning Basic Studies Results FY09

This report is about an Alternative Enhanced Chemical Cleaning Basic Studies Results FY09
Date: May 5, 2010
Creator: Hay, M. & King, W.
Object Type: Report
System: The UNT Digital Library
Task 1.5 Genomic Shift and Drift Trends of Emerging Pathogens (open access)

Task 1.5 Genomic Shift and Drift Trends of Emerging Pathogens

The Lawrence Livermore National Laboratory (LLNL) Bioinformatics group has recently taken on a role in DTRA's Transformation Medical Technologies Initiative (TMTI). The high-level goal of TMTI is to accelerate the development of broad-spectrum countermeasures. To achieve those goals, TMTI has a near term need to conduct analyses of genomic shift and drift trends of emerging pathogens, with a focused eye on select agent pathogens, as well as antibiotic and virulence markers. Most emerging human pathogens are zoonotic viruses with a genome composed of RNA. The high mutation rate of the replication enzymes of RNA viruses contributes to sequence drift and provides one mechanism for these viruses to adapt to diverse hosts (interspecies transmission events) and cause new human and zoonotic diseases. Additionally, new viral pathogens frequently emerge due to genetic shift (recombination and segment reassortment) which allows for dramatic genotypic and phenotypic changes to occur rapidly. Bacterial pathogens also evolve via genetic drift and shift, although sequence drift generally occurs at a much slower rate for bacteria as compared to RNA viruses. However, genetic shift such as lateral gene transfer and inter- and intragenomic recombination enables bacteria to rapidly acquire new mechanisms of survival and antibiotic resistance. New technologies such …
Date: January 5, 2010
Creator: Borucki, M
Object Type: Report
System: The UNT Digital Library
High-Power Electrostatic Discharges in PETN: Threshold and Scaling Experiments (open access)

High-Power Electrostatic Discharges in PETN: Threshold and Scaling Experiments

There is a considerable set of data establishing the safety of PETN-based detonators that are insulted by electrostatic discharge (ESD) from a human body. However, the subject of ESD safety has garnered renewed interest because of the sparse data on high-power, low-impedance discharges that result when the source is a metallic object such as a tool. Experiments on as-built components, using pin-to-cap fault circuits through PETN-based detonators, showed significant evidence of a power dependence but with a very broad energy threshold and some uncertainty in the breakdown path. We have performed a series of experiments using a well-defined arc discharge path and a well-characterized source that is capable of independent variation of energy and power. Studies include threshold variation with power, arc length, powder surface area, and surface vs. bulk discharge paths. We find that an energy threshold variation with power does not appear to exist in the tested range of fractions to tens of MW, and that there are many subtleties to proper energy and power bookkeeping. We also present some test results for PBX 9407.
Date: March 5, 2010
Creator: Liou, W.; McCarrick, J. F.; Hodgin, R. L. & Phillips, D. F.
Object Type: Article
System: The UNT Digital Library
Laser Systems for Orbital Debris Removal (open access)

Laser Systems for Orbital Debris Removal

The use of a ground based laser for space debris cleaning was investigated by the ORION project in 1996. Since that study the greatest technological advance in the development of high energy pulsed laser systems has taken place within the NIF project at LLNL. The proposed next laser system to follow the NIF at LLNL will be a high rep rate version of the NIF based on diode-pumping rather than flashlamp excitation; the so called 'LIFE' laser system. Because a single 'LIFE' beamline could be built up in a few year time frame, and has performance characteristics relevant to the space debris clearing problem, such a beamline could enable a near term demonstration of space debris cleaning. Moreover, the specifics of debris cleaning make it possible to simplify the LIFE laser beyond what is required for a fusion drive laser, and so substantially reduce its cost. Starting with the requirements for laser intensity on the target, and then considering beam delivery, we will flow back the laser requirements needed for space debris cleaning. Using these derived requirements we will then optimize the pulse duration, the operational regime, and the output pulse energy of the laser with a focus of simplifying …
Date: February 5, 2010
Creator: Rubenchik, A M; Barty, C P; Beach, R J; Erlandson, A C & Caird, J A
Object Type: Article
System: The UNT Digital Library
Evaluation of Sludge Batch 5 Qualification with ISDP Salt Batch 1 Compliance to DWPF Waste Acceptance Criteria (open access)

Evaluation of Sludge Batch 5 Qualification with ISDP Salt Batch 1 Compliance to DWPF Waste Acceptance Criteria

The purpose of this report is to document the acceptability of Sludge Batch 5 with the initial macrobatch operation of the Interim Salt Disposition Project (ISDP) waste to the Defense Waste Processing Facility (DWPF). This report was prepared to comply with the requirements listed in the Waste Acceptance Criteria for Sludge, Actinide Removal Process (ARP), and Modular Caustic Side Solvent Extraction Unit (MCU) Process Transfers to 512-S and DWPF. The requirements for transfers to 512-S were evaluated during ISDP Salt Batch 1 qualification. The calculations of sludge concentrations are based entirely on the Tank 51 sample processed at SRNL. This is conservative because Tank 51 is blended with the dilute feed in the DWPF Feed Tank (Tank 40). This report documents the acceptability of sludge only as well as Sludge Batch 5 sludge slurry combined with ARP/MCU products for feed to DWPF. All criteria were met for unblended Tank 51 material.
Date: May 5, 2010
Creator: Shafer, A.
Object Type: Report
System: The UNT Digital Library
Applying Human Factors during the SIS Life Cycle (open access)

Applying Human Factors during the SIS Life Cycle

Safety Instrumented Systems (SIS) are widely used in U.S. Department of Energy's (DOE) nonreactor nuclear facilities for safety-critical applications. Although use of the SIS technology and computer-based digital controls, can improve performance and safety, it potentially introduces additional complexities, such as failure modes that are not readily detectable. Either automated actions or manual (operator) actions may be required to complete the safety instrumented function to place the process in a safe state or mitigate a hazard in response to an alarm or indication. DOE will issue a new standard, Application of Safety Instrumented Systems Used at DOE Nonreactor Nuclear Facilities, to provide guidance for the design, procurement, installation, testing, maintenance, operation, and quality assurance of SIS used in safety significant functions at DOE nonreactor nuclear facilities. The DOE standard focuses on utilizing the process industry consensus standard, American National Standards Institute/ International Society of Automation (ANSI/ISA) 84.00.01, Functional Safety: Safety Instrumented Systems for the Process Industry Sector, to support reliable SIS design throughout the DOE complex. SIS design must take into account human-machine interfaces and their limitations and follow good human factors engineering (HFE) practices. HFE encompasses many diverse areas (e.g., information display, user-system interaction, alarm management, operator response, control …
Date: May 5, 2010
Creator: Avery, K.
Object Type: Article
System: The UNT Digital Library
Alternative Enhanced Chemical Cleaning Basic Studies Results FY09 (open access)

Alternative Enhanced Chemical Cleaning Basic Studies Results FY09

Due to the need to close waste storage tanks, chemical cleaning methods are needed for the effective removal of the heels. Oxalic acid is the preferred cleaning reagent for sludge heel dissolution, particularly for iron-based sludge, due to the strong complexing strength of the oxalate. However, the large quantity of oxalate added to the tank farm from oxalic acid based chemical cleaning has significant downstream impacts. Optimization of the oxalic acid cleaning process can potentially reduce the downstream impacts from chemical cleaning. To optimize oxalic acid usage, a detailed understanding of the chemistry of oxalic acid based sludge dissolution is required. Additionally, other acid systems may be required for specific waste components with low solubility in oxalic acid and as a means to reduce oxalic acid usage in general. Solubility tests were conducted using non-radioactive, pure metal phases known to be the primary phases present in High Level Waste sludge. The metal phases studied included the aluminum phases gibbsite and boehmite and the iron phases magnetite and hematite. Hematite and boehmite are expected to be the most difficult iron and aluminum phases to dissolve. These mineral phases have been identified in both SRS and Hanford High Level Waste sludge. Acids …
Date: May 5, 2010
Creator: Hay, M. & King, W.
Object Type: Report
System: The UNT Digital Library
Evaluation of ISDP Batch 2 Qualification Compliance to 512-S, DWPF, Tank Farm, and Saltstone Waste Acceptance Criteria (open access)

Evaluation of ISDP Batch 2 Qualification Compliance to 512-S, DWPF, Tank Farm, and Saltstone Waste Acceptance Criteria

The purpose of this report is to document the acceptability of the second macrobatch (Salt Batch 2) of Tank 49H waste to H Tank Farm, DWPF, and Saltstone for operation of the Interim Salt Disposition Project (ISDP). Tank 49 feed meets the Waste Acceptance Criteria (WAC) requirements specified by References 11, 12, and 13. Salt Batch 2 material is qualified and ready to be processed through ARP/MCU to the final disposal facilities.
Date: May 5, 2010
Creator: Shafer, A.
Object Type: Report
System: The UNT Digital Library
NEUTRON MULTIPLICITY AND ACTIVE WELL NEUTRON COINCIDENCE VERIFICATION MEASUREMENTS PERFORMED FOR MARCH 2009 SEMI-ANNUAL DOE INVENTORY (open access)

NEUTRON MULTIPLICITY AND ACTIVE WELL NEUTRON COINCIDENCE VERIFICATION MEASUREMENTS PERFORMED FOR MARCH 2009 SEMI-ANNUAL DOE INVENTORY

The Analytical Development (AD) Section field nuclear measurement group performed six 'best available technique' verification measurements to satisfy a DOE requirement instituted for the March 2009 semi-annual inventory. The requirement of (1) yielded the need for SRNL Research Operations Department Material Control & Accountability (MC&A) group to measure the Pu content of five items and the highly enrich uranium (HEU) content of two. No 14Q-qualified measurement equipment was available to satisfy the requirement. The AD field nuclear group has routinely performed the required Confirmatory Measurements for the semi-annual inventories for fifteen years using sodium iodide and high purity germanium (HpGe) {gamma}-ray pulse height analysis nondestructive assay (NDA) instruments. With appropriate {gamma}-ray acquisition modeling, the HpGe spectrometers can be used to perform verification-type quantitative assay for Pu-isotopics and HEU content. The AD nuclear NDA group is widely experienced with this type of measurement and reports content for these species in requested process control, MC&A booking, and holdup measurements assays Site-wide. However none of the AD HpGe {gamma}-ray spectrometers have been 14Q-qualified, and the requirement of reference 1 specifically excluded a {gamma}-ray PHA measurement from those it would accept for the required verification measurements. The requirement of reference 1 was a new …
Date: February 5, 2010
Creator: Dewberry, R.; Ayers, J.; Tietze, F. & Klapper, K.
Object Type: Article
System: The UNT Digital Library
POST-FIRE REVEGETATION AT HANFORD (open access)

POST-FIRE REVEGETATION AT HANFORD

Range fires on the Hanford Site can have a long lasting effect on native plant communities. Wind erosion following removal of protective vegetation from fragile soils compound the damaging effect of fires. Dust storms caused by erosion create health and safety hazards to personnel, and damage facilities and equipment. The Integrated Biological Control Program (IBC) revegetates burned areas to control erosion and consequent dust. Use of native, perennial vegetation in revegetation moves the resulting plant community away from fire-prone annual weeds, and toward the native shrub-steppe that is much less likely to burn in the future. Over the past 10 years, IBC has revegetated major fire areas with good success. IBC staff is monitoring the success of these efforts, and using lessons learned to improve future efforts.
Date: January 5, 2010
Creator: Roos, R. C.; Johnson, A. R.; Caudill, J. G.; Rodriguez, J. M. & Wilde, J. W.
Object Type: Article
System: The UNT Digital Library