Trace Assessment for BWR ATWS Analysis (open access)

Trace Assessment for BWR ATWS Analysis

A TRACE/PARCS input model has been developed in order to be able to analyze anticipated transients without scram (ATWS) in a boiling water reactor. The model is based on one developed previously for the Browns Ferry reactor for doing loss-of-coolant accident analysis. This model was updated by adding the control systems needed for ATWS and a core model using PARCS. The control systems were based on models previously developed for the TRAC-B code. The PARCS model is based on information (e.g., exposure and moderator density (void) history distributions) obtained from General Electric Hitachi and cross sections for GE14 fuel obtained from an independent source. The model is able to calculate an ATWS, initiated by the closure of main steam isolation valves, with recirculation pump trip, water level control, injection of borated water from the standby liquid control system and actuation of the automatic depres-surization system. The model is not considered complete and recommendations are made on how it should be improved.
Date: April 22, 2010
Creator: Cheng, L. Y.; Diamond, D. & Arantxa Cuadra, Gilad Raitses, Arnold Aronson
Object Type: Report
System: The UNT Digital Library
MEASUREMENTS OF PAST 14C LEVELS AND 13C/12C RATIOS IN THE SURFACE WATERS OF THE WORLD'S SUBPOLAR OCEANS. (open access)

MEASUREMENTS OF PAST 14C LEVELS AND 13C/12C RATIOS IN THE SURFACE WATERS OF THE WORLD'S SUBPOLAR OCEANS.

Under this project we have developed methods that allow the reconstruction of past {sup 14}C levels of the surface waters of the subpolar North Pacific Ocean by measuring the {sup 14}C contents of archived salmon scales. The overall goal of this research was to reduce of the uncertainty in the uptake of fossil CO{sub 2} by the oceans and thereby improve the quantification of the global carbon cycle and to elucidate the fate of anthropogenic CO{sub 2}. Ocean General Circulation Models (OGCMs), with their three dimensional global spatial coverage and temporal modeling capabilities, provide the best route to accurately calculating the total uptake of CO{sub 2} by the oceans and, hence, to achieving the desired reduction in uncertainty. {sup 14}C has played, and continues to play, a central role in the validation of the OGCMs calculations, particularly with respect to those model components which govern the uptake of CO{sub 2} from the atmosphere and the transport of this carbon within the oceans. Under this project, we have developed time-series records of the {sup 14}C levels of the surface waters of three areas of the subpolar North Pacific Ocean. As the previously available data on the time-history of oceanic surface water …
Date: April 22, 2010
Creator: Brown, T A
Object Type: Report
System: The UNT Digital Library
On0Line Fuel Failure Monitor for Fuel Testing and Monitoring of Gas Cooled Very High Temperature Reactor (open access)

On0Line Fuel Failure Monitor for Fuel Testing and Monitoring of Gas Cooled Very High Temperature Reactor

IVery High Temperature Reactors (VHTR) utilize the TRISO microsphere as the fundamental fuel unit in the core. The TRISO microsphere (~ 1- mm diameter) is composed of a UO2 kernel surrounded by a porous pyrolytic graphite buffer, an inner pyrolytic graphite layer, a silicon carbide (SiC) coating, and an outer pyrolytic graphite layer. The U-235 enrichment of the fuel is expected to range from 4% – 10% (higher enrichments are also being considered). The layer/coating system that surrounds the UO2 kernel acts as the containment and main barrier against the environmental release of radioactivity. To understand better the behavior of this fuel under in-core conditions (e.g., high temperature, intense fast neutron flux, etc.), the US Department of Energy (DOE) is launching a fuel testing program that will take place at the Advanced Test Reactor (ATR) located at Idaho National Laboratory (INL). During this project North Carolina State University (NCSU) researchers will collaborate with INL staff for establishing an optimized system for fuel monitoring for the ATR tests. In addition, it is expected that the developed system and methods will be of general use for fuel failure monitoring in gas cooled VHTRs.
Date: April 22, 2010
Creator: Hawari, Ayman I. & Bourham, Mohamed A.
Object Type: Report
System: The UNT Digital Library
The Influence of Linker Geometry on Uranyl Complexation by Rigidly-Linked Bis(3-hydroxy-N-methyl-pyridin-2-one) (open access)

The Influence of Linker Geometry on Uranyl Complexation by Rigidly-Linked Bis(3-hydroxy-N-methyl-pyridin-2-one)

A series of bis(3-hydroxy-N-methyl-pyridin-2-one) ligands was synthesized, and their respective uranyl complexes were characterized by single crystal X-ray diffraction analyses. These structures were inspected for high-energy conformations and evaluated using a series of metrics to measure co-planarity of chelating moieties with each other and the uranyl coordination plane, as well as to measure coordinative crowding about the uranyl dication. Both very short (ethyl, 3,4-thiophene and o-phenylene) and very long ({alpha},{alpha}{prime}-m-xylene and 1,8-fluorene) linkers provide optimal ligand geometries about the uranyl cation, resulting in planar, unstrained molecular arrangements. The planarity of the rigid linkers also suggests there is a degree of pre-organization for a planar coordination mode that is ideal for uranyl-selective ligand design. Comparison of intramolecular N{sub amide}-O{sub phenolate} distances and {sup 1}H NMR chemical shifts of amide protons supports earlier results that short linkers provide the optimal geometry for intramolecular hydrogen bonding.
Date: April 22, 2010
Creator: Szigethy, Geza & Raymond, Kenneth
Object Type: Article
System: The UNT Digital Library
Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers (open access)

Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers

A neutron source for neutron resonance spectroscopy (NRS) has been developed using high intensity, short pulse lasers. This measurement technique will allow for robust measurements of interior ion temperature of laser-shocked materials and provide insight into equation of state (EOS) measurements. The neutron generation technique uses protons accelerated by lasers off of Cu foils to create neutrons in LiF, through (p,n) reactions with {sup 7}Li and {sup 19}F. The distribution of the incident proton beam has been diagnosed using radiochromic film (RCF). This distribution is used as the input for a (p,n) neturon prediction code which is compared to experimentally measured neutron yields. From this calculation, a total fluence of 1.8 x 10{sup 9} neutrons is infered, which is shown to be a reasonable amount for NRS temperature measurement.
Date: April 22, 2010
Creator: Higginson, D. P.; McNaney, J. M.; Swift, D. C.; Bartal, T.; Hey, D. S.; Pape, S. L. et al.
Object Type: Article
System: The UNT Digital Library
Development of a Hydrodynamic and Transport model of Bellingham Bay in Support of Nearshore Habitat Restoration (open access)

Development of a Hydrodynamic and Transport model of Bellingham Bay in Support of Nearshore Habitat Restoration

In this study, a hydrodynamic model based on the unstructured-grid finite volume coastal ocean model (FVCOM) was developed for Bellingham Bay, Washington. The model simulates water surface elevation, velocity, temperature, and salinity in a three-dimensional domain that covers the entire Bellingham Bay and adjacent water bodies, including Lummi Bay, Samish Bay, Padilla Bay, and Rosario Strait. The model was developed using Pacific Northwest National Laboratory’s high-resolution Puget Sound and Northwest Straits circulation and transport model. A sub-model grid for Bellingham Bay and adjacent coastal waters was extracted from the Puget Sound model and refined in Bellingham Bay using bathymetric light detection and ranging (LIDAR) and river channel cross-section data. The model uses tides, river inflows, and meteorological inputs to predict water surface elevations, currents, salinity, and temperature. A tidal open boundary condition was specified using standard National Oceanic and Atmospheric Administration (NOAA) predictions. Temperature and salinity open boundary conditions were specified based on observed data. Meteorological forcing (wind, solar radiation, and net surface heat flux) was obtained from NOAA real observations and National Center for Environmental Prediction North American Regional Analysis outputs. The model was run in parallel with 48 cores using a time step of 2.5 seconds. It took …
Date: April 22, 2010
Creator: Wang, Taiping; Yang, Zhaoqing & Khangaonkar, Tarang
Object Type: Report
System: The UNT Digital Library
DOD-SBIR Structured Multi-Resolution PIC Code for Electromagnetic Plasma Simulations, Final Report (open access)

DOD-SBIR Structured Multi-Resolution PIC Code for Electromagnetic Plasma Simulations, Final Report

A novel electromagnetic solver with mesh refinement capability was implemented in Warp. The solver allows for calculations in 2-1/2 and 3 dimensions, includes the standard Yee stencil, and the Cole-Karkkainen stencil for lower numerical dispersion along the principal axes. Warp implementation of the Cole-Karkkainen stencil includes an extension to perfectly matched layers (PML) for absorption of waves, and is preserving the conservation property of charge conserving current deposition schemes, like the Buneman-Villanesor and Esirkepov methods. Warp's mesh refinement framework (originally developed for electrostatic calculations) was augmented to allow for electromagnetic capability, following the methodology presented in [1] extended to an arbitrary number of refinement levels. Other developments include a generalized particle injection method, internal conductors using stair-cased approximation, and subcycling of particle pushing. The solver runs in parallel using MPI message passing, with a choice at runtime of 1D, 2D and 3D domain decomposition, and is shown to scale linearly on a test problem up-to 32,768 CPUs. The novel solver was tested on the modeling of filamentation instability, fast ignition, ion beam induced plasma wake, and laser plasma acceleration.
Date: April 22, 2010
Creator: Vay, J. L.; Grote, D. P. & Friedman, A.
Object Type: Report
System: The UNT Digital Library
Aluminum-Catalyzed Intramolecular Hydroamination of Aminoalkenes (open access)

Aluminum-Catalyzed Intramolecular Hydroamination of Aminoalkenes

A new aluminium complex bearing a dianionic phenylene-diamine based ligand has been synthesized and shown to catalyze the intramolecular hydroamination of various aminoalkenes.
Date: April 22, 2010
Creator: Koller, Juergen & Bergman, Robert
Object Type: Article
System: The UNT Digital Library
Observation of high soft x-ray drive in large-scale hohlraums at the National Ignition Facility (open access)

Observation of high soft x-ray drive in large-scale hohlraums at the National Ignition Facility

None
Date: April 22, 2010
Creator: Kline, J. L.; Glenzer, S. H.; Olson, R. E.; Suter, L. J.; Widmann, K.; Callahan, D. A. et al.
Object Type: Article
System: The UNT Digital Library
Near-ultraviolet luminescence of N2 irradiated by short x-ray pulses (open access)

Near-ultraviolet luminescence of N2 irradiated by short x-ray pulses

None
Date: April 22, 2010
Creator: Hau-Riege, S.; Bionta, R.; Ryutov, D.; London, R.; Ables, E.; Kishiyama, K. et al.
Object Type: Article
System: The UNT Digital Library
The Cyber Science and Security Institute (open access)

The Cyber Science and Security Institute

None
Date: April 22, 2010
Creator: Brase, J M & Spain, C W
Object Type: Report
System: The UNT Digital Library
Advanced Simulation and Computing Fiscal Year 2011-2012 Implementation Plan, Revision 0 (open access)

Advanced Simulation and Computing Fiscal Year 2011-2012 Implementation Plan, Revision 0

The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the surety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future non-nuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering (D&E) programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC) is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear weapons design and manufacturing processes, to analyze accident scenarios and weapons aging, and to provide the tools to enable stockpile Life Extension Programs (LEPs) and the resolution of Significant Finding Investigations (SFIs). This requires a balanced resource, including technical staff, hardware, simulation software, and computer science solutions. In its first decade, the ASC strategy focused on demonstrating simulation capabilities of unprecedented scale in three spatial dimensions. In its second decade, ASC is …
Date: April 22, 2010
Creator: McCoy, M.; Phillips, J.; Hpson, J. & Meisner, R.
Object Type: Report
System: The UNT Digital Library