Microscopic Calculations of 240Pu Fission (open access)

Microscopic Calculations of 240Pu Fission

Hartree-Fock-Bogoliubov calculations have been performed with the Gogny finite-range effective interaction for {sup 240}Pu out to scission, using a new code developed at LLNL. A first set of calculations was performed with constrained quadrupole moment along the path of most probable fission, assuming axial symmetry but allowing for the spontaneous breaking of reflection symmetry of the nucleus. At a quadrupole moment of 345 b, the nucleus was found to spontaneously scission into two fragments. A second set of calculations, with all nuclear moments up to hexadecapole constrained, was performed to approach the scission configuration in a controlled manner. Calculated energies, moments, and representative plots of the total nuclear density are shown. The present calculations serve as a proof-of-principle, a blueprint, and starting-point solutions for a planned series of more comprehensive calculations to map out a large set of scission configurations, and the associated fission-fragment properties.
Date: September 11, 2007
Creator: Younes, W & Gogny, D
Object Type: Report
System: The UNT Digital Library
Uncertainty Detection for NIF Normal Pointing Images (open access)

Uncertainty Detection for NIF Normal Pointing Images

The National Ignition Facility at the Lawrence Livermore National Laboratory when completed in 2009, will deliver 192-beams aligned precisely at the center of the target chamber producing extreme energy densities and pressures. Video images of laser beams along the beam path are used by automatic alignment algorithms to determine the position of the beams for alignment purposes. However, noise and other optical effects may affect the accuracy of the calculated beam location. Realistic estimation of the uncertainty is necessary to assure that the beam is monitored within the clear optical path. When the uncertainty is above a certain threshold the automated alignment operation is suspended and control of the beam is transferred to a human operator. This work describes our effort to quantify the uncertainty of measurement of the most common alignment beam.
Date: September 11, 2007
Creator: Awwal, Abdul A.S.; Law, Clement & Ferguson, S. Walter
Object Type: Article
System: The UNT Digital Library
Status of the National Ignition Facility Integrated Computer Control System (ICCS) on the Path to Ignition (open access)

Status of the National Ignition Facility Integrated Computer Control System (ICCS) on the Path to Ignition

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a stadium-sized facility under construction that will contain a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter diameter target chamber with room for multiple experimental diagnostics. NIF is the world's largest and most energetic laser experimental system, providing a scientific center to study inertial confinement fusion (ICF) and matter at extreme energy densities and pressures. NIF's laser beams are designed to compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. NIF is comprised of 24 independent bundles of 8 beams each using laser hardware that is modularized into more than 6,000 line replaceable units such as optical assemblies, laser amplifiers, and multifunction sensor packages containing 60,000 control and diagnostic points. NIF is operated by the large-scale Integrated Computer Control System (ICCS) in an architecture partitioned by bundle and distributed among over 800 front-end processors and 50 supervisory servers. NIF's automated control subsystems are built from a common object-oriented software framework based on CORBA distribution that deploys the software across the computer network and achieves interoperation between different languages and target architectures. A shot automation framework has …
Date: September 11, 2007
Creator: Lagin, L. J.; Bettenhauasen, R. C.; Bowers, G. A.; Carey, R. W.; Edwards, O. D.; Estes, C. M. et al.
Object Type: Article
System: The UNT Digital Library
Technical and Political Assessment of Peaceful Nuclear Power Program Prospects in North Africa and the Middle East (open access)

Technical and Political Assessment of Peaceful Nuclear Power Program Prospects in North Africa and the Middle East

An exceptional number of Middle Eastern and North African nations have recently expressed interest in developing nuclear energy for peaceful purposes. Many of these countries have explored nuclear research in limited ways in the past, but the current focused interest and application of resources towards developing nuclear-generated electricity and nuclear-powered desalination plants is unprecedented. Consequently, questions arise in response to this emerging trend: What instigated this interest? To what end(s) will a nuclear program be applied? Does the country have adequate technical, political, legislative, nonproliferation, and safety infrastructure required for the capability desired? If so, what are the next steps for a country in preparation for a future nuclear program? And if not, what collaboration efforts are possible with the United States or others? This report provides information on the capabilities and interests of 13 countries in the region in nuclear energy programs in light of safety, nonproliferation and security concerns. It also provides information useful for determining potential for offering technical collaboration, financial aid, and/or political support.
Date: September 11, 2007
Creator: Windsor, Lindsay K. & Kessler, Carol E.
Object Type: Report
System: The UNT Digital Library

Process Systems Engineering R&D for Advanced Fossil Energy Systems

This presentation will examine process systems engineering R&D needs for application to advanced fossil energy (FE) systems and highlight ongoing research activities at the National Energy Technology Laboratory (NETL) under the auspices of a recently launched Collaboratory for Process & Dynamic Systems Research. The three current technology focus areas include: 1) High-fidelity systems with NETL's award-winning Advanced Process Engineering Co-Simulator (APECS) technology for integrating process simulation with computational fluid dynamics (CFD) and virtual engineering concepts, 2) Dynamic systems with R&D on plant-wide IGCC dynamic simulation, control, and real-time training applications, and 3) Systems optimization including large-scale process optimization, stochastic simulation for risk/uncertainty analysis, and cost estimation. Continued R&D aimed at these and other key process systems engineering models, methods, and tools will accelerate the development of advanced gasification-based FE systems and produce increasingly valuable outcomes for DOE and the Nation.
Date: September 11, 2007
Creator: Zitney, S. E.
Object Type: Presentation
System: The UNT Digital Library

Analysis of Buoyancy-Driven Ventilation of Hydrogen from Buildings

The scope of work for this project includes safe building design, vehicle leak in residential garage, continual slow leak, passive, buoyancy-driven ventilation (versus mechanical), and steady-state concentration of hydrogen versus vent size.
Date: September 11, 2007
Creator: Barley, C. D.; Gawlik, K.; Ohi, J. & Hewett, R.
Object Type: Presentation
System: The UNT Digital Library
First Principals and Classical Molecular Dynamics Simulations of Solvated Benzene (open access)

First Principals and Classical Molecular Dynamics Simulations of Solvated Benzene

We have performed extensive ab initio and classical MD simulations of benzene in water in order to examine the unique solvation structures that are formed. Qualitative differences between classical and ab initio MD simulations are found and the importance of various technical simulation parameters is examined. Our comparison indicates that non-polarizable classical models are not capable of describing the solute-water interface correctly if local interactions become energetically comparable to water hydrogen bonds. In addition, a comparison is made between a rigid water model and fully flexible water within ab initio MD simulations which shows that both models agree qualitatively for this challenging system.
Date: September 11, 2007
Creator: Allesch, M; Lightstone, F; Schwegler, E & Galli, G
Object Type: Article
System: The UNT Digital Library