8 Matching Results

Results open in a new window/tab.

Finite element method for solving neutron transport problems (open access)

Finite element method for solving neutron transport problems

A finite element method is introduced for solving the neutron transport equations. Our method falls into the category of Petrov-Galerkin solution, since the trial space differs from the test space. The close relationship between this method and the discrete ordinate method is discussed, and the methods are compared for simple test problems.
Date: March 21, 1984
Creator: Ferguson, J.M. & Greenbaum, A.
System: The UNT Digital Library
LLNL nuclear data libraries used for fusion calculations (open access)

LLNL nuclear data libraries used for fusion calculations

The Physical Data Group of the Computational Physics Division of the Lawrence Livermore National Laboratory has as its principal responsibility the development and maintenance of those data that are related to nuclear reaction processes and are needed for Laboratory programs. Among these are the Magnetic Fusion Energy and the Inertial Confinement Fusion programs. To this end, we have developed and maintain a collection of data files or libraries. These include: files of experimental data of neutron induced reactions; an annotated bibliography of literature related to charged particle induced reactions with light nuclei; and four main libraries of evaluated data. We also maintain files of calculational constants developed from the evaluated libraries for use by Laboratory computer codes. The data used for fusion calculations are usually these calculational constants, but since they are derived by prescribed manipulation of evaluated data this discussion will describe the evaluated libraries.
Date: May 21, 1984
Creator: Howerton, R. J.
System: The UNT Digital Library
Thermal effects in radiation processing (open access)

Thermal effects in radiation processing

The balance of ionizing radiation energy incident on an object being processed is discussed in terms of energy losses, influencing the amount really absorbed. To obtain the amount of heat produced, the absorbed energy is corrected for the change in internal energy of the system and for the heat effect of secondary reactions developing after the initiation. The temperature of a processed object results from the heat evolved and from the specific heat of the material comprising the object. The specific heat of most materials is usually much lower than that of aqueous systems and therefore temperatures after irradiation are higher. The role of low specific heat in radiation processing at cryogenic conditions is stressed. Adiabatic conditions of accelerator irradiation are contrasted with the steady state thermal conditions prevailing in large gamma sources. Among specific questions discussed in the last part of the paper are: intermediate and final temperature of composite materials, measurement of real thermal effects in situ, neutralization of undesired warming experienced during radiation processing, processing at temperatures other than ambient and administration of very high doses of radiation.
Date: October 21, 1984
Creator: Zagorski, Z.P.
System: The UNT Digital Library
General CP properties of neutrino mass eigenstates (open access)

General CP properties of neutrino mass eigenstates

We show that the mass eigenvectors of the neutrino mass matrix have definite CP quantum numbers whether or not CP is conserved, and we examine the conditions under which a mixture of even and odd CP eigenstates will occur.
Date: January 21, 1984
Creator: Rosen, S. P.
System: The UNT Digital Library
International Waste Glass Study - Composition and Leachability Correlations (open access)

International Waste Glass Study - Composition and Leachability Correlations

As part of an effort to assess and understand the performance and chemical durability of Savannah River Plant (SRP) waste glass, an International Glass Study was undertaken. That study found important similarities, based on correlations of composition and leaching performance, among many difference defense and commercial waste glass compositions being studied world-wide. In addition, the beneficial effect of waste on glass performance was confirmed for the systems evaluated. This paper discusses those results.
Date: November 21, 1984
Creator: Wicks, G. G.
System: The UNT Digital Library
Improved Uranium Recovery from the Process Streams in an Electroplating Facility (open access)

Improved Uranium Recovery from the Process Streams in an Electroplating Facility

This report discusses results of testing to improve uranium recovery from the process streams in an electroplating facility. Cylindrical uranium slugs are used as irradiation targets in the production reactors at the Savannah River Plant. These slugs are first chemically etched, nickel plated, encased in aluminum, inspected, and individually pressure tested. An improved process was developed to recover the uranium from the acidic etching streams for controlling pH and the PO4 to U ratio so that the precipitation of the uranium as hydrogen uranyl phosphate was maximized.
Date: November 21, 1984
Creator: Pickett, J.B.
System: The UNT Digital Library
Evaluation of Materials Performance in a Large-Scale Glass Melter after Two Years of Vitrifying Simulated SRP Defense Waste (open access)

Evaluation of Materials Performance in a Large-Scale Glass Melter after Two Years of Vitrifying Simulated SRP Defense Waste

The Large Slurry Fed Melter (LSFM) at the Department of Energy's Savannah River Plant recently completed two years of service and was shut down for evaluation. This paper reviews the melter operating history and describes the condition of the refractories and metal components. The excellent condition of the LSFM verifies the expected performance of the materials of construction and indicates that a two year melter life is achievable in the Defense Waste Processing Facility (DWPF).
Date: November 21, 1984
Creator: Iverson, D.C.
System: The UNT Digital Library
Leaching of Saltstone (open access)

Leaching of Saltstone

A modified IAEA leach test was used to evaluate the relative performance of potential saltstone formulations. The effects of sample size and leach rates for specific ions were determined. Nitrite, nitrate, sodium, and sulfate are listed in order of decreasing leach rates and effective diffusivities for saturated leaching of saltstone. This paper discusses the results of the testing.
Date: November 21, 1984
Creator: Langston, C.A.
System: The UNT Digital Library