2011 Annual Ecological Survey: Pacific Northwest National Laboratory Site (open access)

2011 Annual Ecological Survey: Pacific Northwest National Laboratory Site

The U.S. Department of Energy (DOE) Pacific Northwest Site Office (PNSO) oversees and manages the DOE contract for the Pacific Northwest National Laboratory (PNNL), a DOE Office of Science multi-program laboratory located in Richland, Washington. PNSO is responsible for ensuring that all activities conducted on the PNNL site comply with applicable laws, policies, and DOE Orders. The DOE Pacific Northwest Site Office Cultural and Biological Resources Management Plan (DOE/PNSO 2008) addresses the requirement for annual surveys and monitoring for species of concern and to identify and map invasive species. In addition to the requirement for an annual survey, proposed project activities must be reviewed to assess any potential environmental consequences of conducting the project. The assessment process requires a thorough understanding of the resources present, the potential impacts of a proposed action to those resources, and the ultimate consequences of those actions. The PNNL site is situated on the southeastern corner of the DOE Hanford Site, located at the north end of the city of Richland in south-central Washington. The site is bordered on the east by the Columbia River, on the west by Stevens Drive, and on the north by the Hanford Site 300 Area (Figure 1). The environmental …
Date: February 27, 2012
Creator: Becker, James M. & Chamness, Michele A.
Object Type: Report
System: The UNT Digital Library
2012 ELECTRONIC SPECTROSCOPY & DYNAMICS GORDON RESEARCH CONFERENCE, JULY 22-27, 2012 (open access)

2012 ELECTRONIC SPECTROSCOPY & DYNAMICS GORDON RESEARCH CONFERENCE, JULY 22-27, 2012

Topics covered in this GRC include high-resolution spectroscopy, coherent electronic energy transport in biology, excited state theory and dynamics, excitonics, electronic spectroscopy of cold and ultracold molecules, and the spectroscopy of nanostructures. Several sessions will highlight innovative techniques such as time-resolved x-ray spectroscopy, frequency combs, and liquid microjet photoelectron spectroscopy that have forged stimulating new connections between gas-phase and condensed-phase work.
Date: July 27, 2012
Creator: Kohler, Bern
Object Type: Article
System: The UNT Digital Library
2012 Emergency Response Capability BNA Compliance Assessment (open access)

2012 Emergency Response Capability BNA Compliance Assessment

None
Date: December 27, 2012
Creator: Sharry, J. A.
Object Type: Report
System: The UNT Digital Library
2012 THIN FILM AND SMALL SCALE MECHANICAL BEHAVIOR GRS/GRC, JULY 21-27, 2012 (open access)

2012 THIN FILM AND SMALL SCALE MECHANICAL BEHAVIOR GRS/GRC, JULY 21-27, 2012

The mechanical behavior of materials with small dimension(s) is of both fundamental scientific interest and technological relevance. The size effects and novel properties that arise from changes in deformation mechanism have important implications for modern technologies such as thin films for microelectronics and MEMS devices, thermal and tribological coatings, materials for energy production and advanced batteries, etc. The overarching goal of the 2012 Gordon Research Conference on "Thin Film and Small Scale Mechanical Behavior" is to discuss recent studies and future opportunities regarding elastic, plastic and time-dependent deformation, as well as degradation and failure mechanisms such as fatigue, fracture and wear. Specific topics of interest include, but are not limited to: fundamental studies of physical mechanisms governing small-scale mechanical behavior; advances in test techniques for materials at small length scales, such as nanotribology and high-temperature nanoindentation; in-situ mechanical testing and characterization; nanomechanics of battery materials, such as swelling-induced phenomena and chemomechanical behavior; flexible electronics; mechanical properties of graphene and carbon-based materials; mechanical behavior of small-scale biological structures and biomimetic materials. Both experimental and computational work will be included in the oral and poster presentations at this Conference.
Date: July 27, 2012
Creator: Balk, Thomas
Object Type: Article
System: The UNT Digital Library
Accelerated deployment of nanostructured hydrotreating catalysts. Final CRADA Report. (open access)

Accelerated deployment of nanostructured hydrotreating catalysts. Final CRADA Report.

Nanomanufacturing offers an opportunity to create domestic jobs and facilitate economic growth. In response to this need, U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy issued a Research Call to develop nanomanufacturing capabilities at the National Laboratories. High performance catalysts represent a unique opportunity to deploy nanomanufacturing technologies. Re-refining of used lube oil offers an opportunity to create manufacturing jobs and decrease dependence on imported petroleum. Improved catalysts are required to produce a better quality product, decrease environmental impact, extend catalyst life, and improve overall economics of lube oil re-refining. Argonne National Laboratory (Argonne) in cooperation with Universal Lubricants, Inc. (ULI) and Chemical Engineering Partners (CEP) have carried out a Cooperative Research and Development Agreement (CRADA) to prepare nanostructured hydrotreating catalysts using atomic layer deposition (ALD) to exhibit superior performance for the re-refining of used lube oil. We investigated the upgrading of recycled lube oil by hydrogenation using commercial, synthetically-modified commercial catalysts, and synthesized catalysts. A down-flow (trickle bed) catalytic unit was used for the hydrogenation experiments. In addition to carrying out elemental analyses of the various feed and product fractions, characterization was undertaken using H{sup 1} and C{sup 13} NMR. Initially commercial were evaluated. Second these …
Date: August 27, 2012
Creator: Libera, J. A.; Snyder, S. W.; Mane, A.; Elam, J. W.; Cronauer, D. C.; Muntean, J. A. et al.
Object Type: Report
System: The UNT Digital Library
Adaptive Environmentally Contained Power and Cooling IT Infrastructure for the Data Center (open access)

Adaptive Environmentally Contained Power and Cooling IT Infrastructure for the Data Center

The objectives of this program were to research and develop a fully enclosed Information Technology (IT) rack system for 100 kilowatts (KW) of IT load that provides its own internal power and cooling with High Voltage Alternating Current (HVAC defined as 480 volt) and chilled water as the primary inputs into the system and accepts alternative energy power sources such as wind and solar. For maximum efficiency, internal power to the IT equipment uses distributed High Voltage Direct Current power (HVDC defined as 360-380 volt) from the power source to the IT loads. The management scheme aggressively controls energy use to insure the best utilization of available power and cooling resources. The solution incorporates internal active management controls that not only optimizes the system environment for the given dynamic IT loads and changing system conditions, but also interfaces with data center Building Management Systems (BMS) to provide a complete end-to-end view of power and cooling chain. This technology achieves the goal of a Power Usage Effectiveness (PUE) of 1.25, resulting in a 38% reduction in the total amount of energy needed to support a 100KW IT load compared to current data center designs.
Date: June 27, 2012
Creator: Mann, Ron & Chavez, Miguel, E.
Object Type: Report
System: The UNT Digital Library
Advanced Materials for RSOFC Dual Operation with Low Degradation (open access)

Advanced Materials for RSOFC Dual Operation with Low Degradation

Reversible solid oxide fuel cells (RSOFCs) are energy conversion devices. They are capable of operating in both power generation mode (SOFC) and electrolysis modes (SOEC). RSOFC can integrate renewable production of electricity and hydrogen when power generation and steam electrolysis are coupled in a system, which can turn intermittent solar and wind energy into "firm power." In this DOE EERE project, VPS continuously advanced RSOFC cell stack technology in the areas of endurance and performance. Over 20 types of RSOFC cells were developed in the project. Many of those exceeded performance (area specific resistance less than 300 mohmcm2) and endurance (degradation rate less than 4% per 1000 hours) targets in both fuel cell and electrolysis modes at 750C. One of those cells, RSOFC-7, further demonstrated the following: Steady-state electrolysis with a degradation rate of 1.5% per 1000 hours. Ultra high current electrolysis over 3 A/cm2 at 75% water electrolysis efficiency voltage of 1.67 V. Daily SOFC/SOEC cyclic test of over 600 days with a degradation rate of 1.5% per 1000 hours. Over 6000 SOFC/SOEC cycles in an accelerated 20-minute cycling with degradation less than 3% per 1000 cycles. In RSOFC stack development, a number of kW-class RSOFC stacks were developed …
Date: December 27, 2012
Creator: Tang, Eric; Wood, Tony; Benhaddad, Sofiane; Brown, Casey; He, Hongpeng; Nelson, Jeff et al.
Object Type: Report
System: The UNT Digital Library
An Advanced simulation Code for Modeling Inductive Output Tubes (open access)

An Advanced simulation Code for Modeling Inductive Output Tubes

During the Phase I program, CCR completed several major building blocks for a 3D large signal, inductive output tube (IOT) code using modern computer language and programming techniques. These included a 3D, Helmholtz, time-harmonic, field solver with a fully functional graphical user interface (GUI), automeshing and adaptivity. Other building blocks included the improved electrostatic Poisson solver with temporal boundary conditions to provide temporal fields for the time-stepping particle pusher as well as the self electric field caused by time-varying space charge. The magnetostatic field solver was also updated to solve for the self magnetic field caused by time changing current density in the output cavity gap. The goal function to optimize an IOT cavity was also formulated, and the optimization methodologies were investigated.
Date: April 27, 2012
Creator: Bui, Thuc & Ives, R. Lawrence
Object Type: Report
System: The UNT Digital Library
Aleutian Pribilof Islands Wind Energy Feasibility Study (open access)

Aleutian Pribilof Islands Wind Energy Feasibility Study

Under this project, the Aleutian Pribilof Islands Association (APIA) conducted wind feasibility studies for Adak, False Pass, Nikolski, Sand Point and St. George. The DOE funds were also be used to continue APIA's role as project coordinator, to expand the communication network quality between all participants and with other wind interest groups in the state and to provide continued education and training opportunities for regional participants. This DOE project began 09/01/2005. We completed the economic and technical feasibility studies for Adak. These were funded by the Alaska Energy Authority. Both wind and hydro appear to be viable renewable energy options for Adak. In False Pass the wind resource is generally good but the site has high turbulence. This would require special care with turbine selection and operations. False Pass may be more suitable for a tidal project. APIA is funded to complete a False Pass tidal feasibility study in 2012. Nikolski has superb potential for wind power development with Class 7 wind power density, moderate wind shear, bi-directional winds and low turbulence. APIA secured nearly $1M from the United States Department of Agriculture Rural Utilities Service Assistance to Rural Communities with Extremely High Energy Costs to install a 65kW wind …
Date: March 27, 2012
Creator: Wright, Bruce A.
Object Type: Report
System: The UNT Digital Library
Analysis of 2011 Meteorological Data from the Knolls Atomic Power Laboratory and Kesselring Site Operations Facilities (open access)

Analysis of 2011 Meteorological Data from the Knolls Atomic Power Laboratory and Kesselring Site Operations Facilities

Both the Knolls Atomic Power Laboratory (KAPL) in Schenectady, NY and the Kesselring Site Operations (KSO) facility near Ballston Spa, NY are required to estimate the effects of hypothetical emissions of radiological material from their respective facilities by the US Environmental Protection Agency (EPA), which regulates these facilities. An atmospheric dispersion model known as CAP88, which was developed and approved by the EPA for such purposes, is used by KAPL and KSO to meet this requirement. CAP88 calculations over a given time period are based on statistical data on the meteorological conditions for that period. Both KAPL and KSO have on-site meteorological towers which take atmospheric measurements at a frequency ideal for EPA regulatory model input. However, an independent analysis and processing of the meteorological data from each tower is required to derive a data set appropriate for use in the CAP88 model. The National Atmospheric Release Advisory Center (NARAC) was contracted by KAPL to process the on-site data for the calendar year 2011. The purpose of this document is to: (1) summarize the procedures used in the preparation/analysis of the 2011 meteorological data; and (2) document adherence of these procedures to the guidance set forth in 'Meteorological Monitoring Guidance …
Date: February 27, 2012
Creator: Aluzzi, F J
Object Type: Report
System: The UNT Digital Library
Analysis of AGS E880 polarimeter data at Ggamma = 12.5 (open access)

Analysis of AGS E880 polarimeter data at Ggamma = 12.5

Data were collected with the AGS internal (E880) polarimeter at G{gamma} = 12.5 during the FY04 polarized proton run. Measurements were made with forward scintillation counters in coincidence with recoil counter telescopes, permitting an absolute calibration of the polarimeter for both nylon and carbon targets. The results are summarized and they will also be useful for an absolute calibration of the AGS CNI polarimeter at G{gamma} = 12.5.
Date: January 27, 2012
Creator: Cadman, R. V.; Huang, H.; Krueger, K.; Spinka, H. & Underwood, D.
Object Type: Report
System: The UNT Digital Library
Analysis Of The Tank 5F Final Characterization Samples-2011 (open access)

Analysis Of The Tank 5F Final Characterization Samples-2011

The Savannah River National Laboratory (SRNL) was requested by SRR to provide sample preparation and analysis of the Tank 5F final characterization samples to determine the residual tank inventory prior to grouting. Two types of samples were collected and delivered to SRNL: floor samples across the tank and subsurface samples from mounds near risers 1 and 5 of Tank 5F. These samples were taken from Tank 5F between January and March 2011. These samples from individual locations in the tank (nine floor samples and six mound Tank 5F samples) were each homogenized and combined in a given proportion into 3 distinct composite samples to mimic the average composition in the entire tank. These Tank 5F composite samples were analyzed for radiological, chemical and elemental components. Additional measurements performed on the Tank 5F composite samples include bulk density and water leaching of the solids to account for water soluble species. With analyses for certain challenging radionuclides as the exception, all composite Tank 5F samples were analyzed and reported in triplicate. The target detection limits for isotopes analyzed were based on customer desired detection limits as specified in the technical task request documents. SRNL developed new methodologies to meet these target detection …
Date: September 27, 2012
Creator: Oji, L. N.; Diprete, D.; Coleman, C. J. & Hay, M. S.
Object Type: Report
System: The UNT Digital Library
Analysis Of The Tank 6F Final Characterization Samples-2012 (open access)

Analysis Of The Tank 6F Final Characterization Samples-2012

The Savannah River National Laboratory (SRNL) was requested by Savannah River Remediation (SRR) to provide sample preparation and analysis of the Tank 6F final characterization samples to determine the residual tank inventory prior to grouting. Fourteen residual Tank 6F solid samples from three areas on the floor of the tank were collected and delivered to SRNL between May and August 2011. These Tank 6F samples were homogenized and combined into three composite samples based on a proportion compositing scheme and the resulting composite samples were analyzed for radiological, chemical and elemental components. Additional measurements performed on the Tank 6F composite samples include bulk density and water leaching of the solids to account for water soluble components. The composite Tank 6F samples were analyzed and the data reported in triplicate. Sufficient quality assurance standards and blanks were utilized to demonstrate adequate characterization of the Tank 6F samples. The main evaluation criteria were target detection limits specified in the technical task request document. While many of the target detection limits were met for the species characterized for Tank 6F some were not met. In a few cases, the relatively high levels of radioactive species of the same element or a chemically similar …
Date: September 27, 2012
Creator: Oji, L. N.; Diprete, D. P.; Coleman, C. J.; Hay, M. S. & Shine, E. P.
Object Type: Report
System: The UNT Digital Library
ANALYSIS OF VENTING OF A RESIN SLURRY (open access)

ANALYSIS OF VENTING OF A RESIN SLURRY

A resin slurry venting analysis was conducted to address safety issues associated with overpressurization of ion exchange columns used in the Purex process at the Savannah River Site (SRS). If flow to these columns were inadvertently interrupted, an exothermic runaway reaction could occur between the ion exchange resin and the nitric acid used in the feed stream. The nitric acid-resin reaction generates significant quantities of noncondensable gases, which would pressurize the column. To prevent the column from rupturing during such events, rupture disks are installed on the column vent lines. The venting analysis models accelerating rate calorimeter (ARC) tests and data from tests that were performed in a vented test vessel with a rupture disk. The tests showed that the pressure inside the test vessel continued to increase after the rupture disk opened, though at a slower rate than prior to the rupture. Calculated maximum discharge rates for the resin venting tests exceeded the measured rates of gas generation, so the vent size was sufficient to relieve the pressure in the test vessel if the vent flow rate was constant. The increase in the vessel pressure is modeled as a transient phenomenon associated with expansion of the resin slurry/gas mixture …
Date: March 27, 2012
Creator: Laurinat, J. & Hensel, S.
Object Type: Article
System: The UNT Digital Library
California GAMA Special Study: Stable Isotopic Composition of Boron in Groundwater - San Diego County Domestic Well Data (open access)

California GAMA Special Study: Stable Isotopic Composition of Boron in Groundwater - San Diego County Domestic Well Data

None
Date: February 27, 2012
Creator: Eppich, G. R.; Wimpenny, J. B.; Yin, Q. Z. & Esser, B. K.
Object Type: Report
System: The UNT Digital Library
Closure Report for Corrective Action Unit 548: Areas 9, 10, 18, 19, and 20 Housekeeping Sites, Nevada National Security Site, Nevada (open access)

Closure Report for Corrective Action Unit 548: Areas 9, 10, 18, 19, and 20 Housekeeping Sites, Nevada National Security Site, Nevada

This Closure Report (CR) documents closure activities for Corrective Action Unit (CAU) 548, Areas 9, 10, 18, 19, and 20 Housekeeping Sites, and complies with the Federal Facility Agreement and Consent Order (FFACO) that was agreed to by the State of Nevada; the U.S. Department of Energy (DOE), Environmental Management; the U.S. Department of Defense; and DOE, Legacy Management (FFACO, 1996 as amended). CAU 548 consists of the following Corrective Action Sites (CASs), located in Areas 9, 10, 12, 18, 19, and 20 of the Nevada National Security Site: · CAS 09-99-02, Material Piles (2) · CAS 09-99-04, Wax, Paraffin · CAS 09-99-05, Asbestos, Vermiculite · CAS 09-99-07, Tar Spill · CAS 10-22-02, Drums · CAS 10-22-05, Gas Block · CAS 10-22-07, Gas Block · CAS 10-22-34, Drum · CAS 10-22-38, Drum; Cable · CAS 12-99-04, Epoxy Tar Spill · CAS 12-99-08, Cement Spill · CAS 18-14-01, Transformers (3) · CAS 19-22-01, Drums · CAS 19-22-11, Gas Block (2) · CAS 19-44-01, Fuel Spill · CAS 20-22-07, Drums (2) · CAS 20-22-09, Drums (3) · CAS 20-22-14, Drums (2) · CAS 20-22-16, Drums (2) · CAS 20-24-09, Battery Closure activities began in July 2011 and were completed in December 2011 …
Date: August 27, 2012
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Collisionless coupling of ion and electron temperatures in counter-streaming plasma flows (open access)

Collisionless coupling of ion and electron temperatures in counter-streaming plasma flows

None
Date: December 27, 2012
Creator: Ross, J. S.; Park, H. S.; Berger, D.; Divol, L.; Kugland, N. L.; Rozmus, W. et al.
Object Type: Article
System: The UNT Digital Library
Comparison of Gas Puff Imaging Data in NSTX with the DEGAS 2 Simulation (open access)

Comparison of Gas Puff Imaging Data in NSTX with the DEGAS 2 Simulation

Gas-Puff-Imaging (GPI) is a two dimensional diagnostic which measures the edge Dα light emission from a neutral D2 gas puff nears the outer mid-plane of NSTX. DEGAS 2 is a 3-D Monte Carlo code used to model neutral transport and atomic physics in tokamak plasmas. In this paper we compare measurements of the Dα light emission obtained by GPI on NSTX with DEGAS 2 simulations of Dα light emission for specific experiments. Both the simulated spatial distribution and absolute intensity of the Dα light emission agree well with the experimental data obtained between ELMs in H-mode.
Date: October 27, 2012
Creator: Cao, B.; Stotler, D. P.; Zweben, S. J.; Bell, M.; Diallo, A. & Leblanc, B.
Object Type: Report
System: The UNT Digital Library
Comparison of Options for a Pilot Plant Fusion Nuclear Mission (open access)

Comparison of Options for a Pilot Plant Fusion Nuclear Mission

A fusion pilot plant study was initiated to clarify the development needs in moving from ITER to a first of a kind fusion power plant, following a path similar to the approach adopted for the commercialization of fission. The pilot plant mission encompassed component test and fusion nuclear science missions plus the requirement to produce net electricity with high availability in a device designed to be prototypical of the commercial device. Three magnetic configuration options were developed around this mission: the advanced tokamak (AT), spherical tokamak (ST) and compact stellarator (CS). With the completion of the study and separate documentation of each design option a question can now be posed; how do the different designs compare with each other as candidates for meeting the pilot plant mission? In a pro/con format this paper will examine the key arguments for and against the AT, ST and CS magnetic configurations. Key topics addressed include: plasma parameters, device configurations, size and weight comparisons, diagnostic issues, maintenance schemes, availability influences and possible test cell arrangement schemes.
Date: August 27, 2012
Creator: Brown, T.; Goldston, R. J.; El-Guebaly, L.; Kessel, C.; Neilson, G. H.; Malang, S. et al.
Object Type: Article
System: The UNT Digital Library
Corrosion Control Measures For Liquid Radioactive Waste Storage Tanks At The Savannah River Site (open access)

Corrosion Control Measures For Liquid Radioactive Waste Storage Tanks At The Savannah River Site

The Savannah River Site has stored radioactive wastes in large, underground, carbon steel tanks for approximately 60 years. An assessment of potential degradation mechanisms determined that the tanks may be vulnerable to nitrate- induced pitting corrosion and stress corrosion cracking. Controls on the solution chemistry and temperature of the wastes are in place to mitigate these mechanisms. These controls are based upon a series of experiments performed using simulated solutions on materials used for construction of the tanks. The technical bases and evolution of these controls is presented in this paper.
Date: November 27, 2012
Creator: Wiersma, B. J. & Subramanian, K. H.
Object Type: Article
System: The UNT Digital Library
Data Quality Objectives Supporting Radiological Air Emissions Monitoring for the Marine Sciences Laboratory, Sequim Site (open access)

Data Quality Objectives Supporting Radiological Air Emissions Monitoring for the Marine Sciences Laboratory, Sequim Site

This document of Data Quality Objectives (DQOs) was prepared based on the U.S. Environmental Protection Agency (EPA) Guidance on Systematic Planning Using the Data Quality Objectives Process, EPA, QA/G4, 2/2006 (EPA 2006), as well as several other published DQOs. The intent of this report is to determine the necessary steps required to ensure that radioactive emissions to the air from the Marine Sciences Laboratory (MSL) headquartered at the Pacific Northwest National Laboratory’s Sequim Marine Research Operations (Sequim Site) on Washington State’s Olympic Peninsula are managed in accordance with regulatory requirements and best practices. The Sequim Site was transitioned in October 2012 from private operation under Battelle Memorial Institute to an exclusive use contract with the U.S. Department of Energy, Office of Science, Pacific Northwest Site Office.
Date: December 27, 2012
Creator: Barnett, J. M.; Meier, Kirsten M.; Snyder, Sandra F.; Antonio, Ernest J.; Fritz, Brad G. & Poston, Theodore M.
Object Type: Report
System: The UNT Digital Library
DECONTAMINATION FACTORS AND FILTRATION FLUX IMPACT TO ARP AT REDUCED MST CONCENTRATION (open access)

DECONTAMINATION FACTORS AND FILTRATION FLUX IMPACT TO ARP AT REDUCED MST CONCENTRATION

Tank Farm and Closure Engineering is evaluating changes to the Actinide Removal Process facility operations to decrease the MST concentration from 0.4 g/L to 0.2 g/L and the contact time from 12 hours to between 6 and 8 hours. For this evaluation, SRNL reviewed previous datasets investigating the performance of MST at 0.2 g/L in salt solutions ranging from 4.5 to 7.5 M in sodium concentration. In general, reducing the MST concentration from 0.4 to 0.2 g/L and increasing the ionic strength from 4.5 to 7.5 M in sodium concentration will decrease the measured decontamination factors for plutonium, neptunium, uranium and strontium. The decontamination factors as well as single standard deviation values for each sorbate are reported. These values are applicable within the sorbate and sodium concentrations used in the experimental measurements. Decreasing the MST concentration in the ARP from 0.4 g/L to 0.2 g/L will produce an increase in the filter flux, and could lead to longer operating times between filter cleaning. The increase in flux is a function of a number of operating parameters, and is difficult to quantify. However, it is estimated that the reduction in MST could result in a reduction of filtration time of up …
Date: June 27, 2012
Creator: Hobbs, D.
Object Type: Report
System: The UNT Digital Library
The Dependence of H-mode Energy Confinement and Transport on Collisionality in NSTX (open access)

The Dependence of H-mode Energy Confinement and Transport on Collisionality in NSTX

Understanding the dependence of confi nement on collisionality in tokamaks is important for the design of next-step devices, which will operate at collisionalities at least one order of magnitude lower than in present generation. A wide range of collisionality has been obtained in the National Spherical Torus Experiment (NSTX) by employing two different wall conditioning techniques, one with boronization and between-shot helium glow discharge conditioning (HeGDC+B), and one using lithium evaporation (Li EVAP). Previous studies of HeGDC+B plasmas indicated a strong and favorable dependence of normalized con nement on collisionality. Discharges with lithium conditioning discussed in the present study gen- erally achieved lower collisionality, extending the accessible range of collisionality by almost an order of unity. While the confinement dependences on dimensional, engineering variables of the HeGDC+B and Li EVAP datasets differed, collisionality was found to unify the trends, with the lower collisionality lithium conditioned discharges extending the trend of increasing normalized confi nement time with decreasing collisionality when other dimension less variables were held as fi xed as possible. This increase of confi nement with decreasing collisionality was driven by a large reduction in electron transport in the outer region of the plasma. This result is consistent with gyrokinetic …
Date: November 27, 2012
Creator: S.M.. Kaye, S. Gerhardt, W. Guttenfelder, R. Maingi, R.E. Bell, A. Diallo, B.P. LeBlanc and M. Podesta
Object Type: Report
System: The UNT Digital Library
A Description of the Full Particle Orbit Following SPIRAL Code for Simulating Fast-ion Experiments in Tokamaks (open access)

A Description of the Full Particle Orbit Following SPIRAL Code for Simulating Fast-ion Experiments in Tokamaks

The numerical methods used in the full particle-orbit following SPIRAL code are described and a number of physics studies performed with the code are presented to illustrate its capabilities. The SPIRAL code is a test-particle code and is a powerful numerical tool to interpret and plan fast-ion experiments in Tokamaks. Gyro-orbit effects are important for fast ions in low-field machines such as NSTX and to a lesser extent in DIII-D. A number of physics studies are interlaced between the description of the code to illustrate its capabilities. Results on heat loads generated by a localized error-field on the DIII-D wall are compared to measurements. The enhanced Triton losses caused by the same localized error-field are calculated and compared to measured neutron signals. MHD activity such as tearing modes and Toroidicity-induced Alfven Eigenmodes (TAEs) have a profound effect on the fast-ion content of Tokamak plasmas and SPIRAL can calculate the effects of MHD activity on the confined and lost fast-ion population as illustrated for a burst of TAE activity in NSTX. The interaction between Ion Cyclotron Range of Frequency (ICRF) heating and fast ions depends solely on the gyro-motion of the fast ions and is captured exactly in the SPIRAL code. …
Date: July 27, 2012
Creator: Kramer, G. J.; Budny, R. V.; Bortolon, A.; Fredrickson, E. D.; Fu, G. Y.; Heidbrink, W. W. et al.
Object Type: Report
System: The UNT Digital Library