[en] This report serves as a documentation for SIMREP 1.1, a discrete event computer simulation model of repository operations in the surface waste-handling facility. The logic for this model is provided by Fluor Technology, Inc., the Architect/Engineer of the salt repository. Part I of this report deals with simulation techniques and program design. Simulation methods and the use of the SIMSCRIPT II.5 simulation language are discussed. Repository operations modeled in SIMREP are briefly described. Detailed program logic is included in an appendix. Part II of this report is a guide for the use of SIMREP 1.1. Input data requirements, output file organization, and software and hardware specifications are described in detail. A sample problem is provided to illustrate the use of SIMREP 1.1. The required input data and the resulting output files for the sample problem are shown in appendices

[en] The magnetostriction of the RNi₂ compounds (R = Tb, Dy, Ho, Er and Tm) was measured as a function of applied field from T = 5⁰K to above the Curie temperatures. A direct comparison is made between these results and the huge magnetostriction observed at cryogenic temperatures in the RFe₂ and RCo₂ compounds. The largest magnetostriction in the RNi₂ series occurs in the TbNi₂. At T = 5⁰K the magnetostriction is fairly well saturated and results in a value of lambda/sub parallel to/-lambda/sub perpendicular to/lambda = 2270 x 10^-6 at H = 25kOe, while extrapolation to infinite field yields 2340 x 10^-6. DyNi₂ also displays a tendency to saturate at the higher fields at lower temperatures with lambda/sub parallel to/-lambda/sub perpendicular to/ = -765 x 10^-6 at 25 kOe and - 840 ppM at H = infinity. The compounds HoNi₂, ErNi₂ and TmNi₂ all exhibit large strains at T = 5⁰K although fail to saturate with available fields. At 25kOe the magnetostriction for these compounds was found to be -386 x 10^-6, - 415 x 10^-6 and - 552 x 10^-6 respectively

[en] Grain-oriented samples of highly magnetostrictive rare earth--iron compounds have successfully been prepared. These samples possess lower inhomogeneous strains than found in the random polycrystalline RFe₂ compounds, resulting in much higher values of relative permeability (μ/sub r/) and magnetomechanical coupling (K₃₃). A partiallly oriented Tb ₂₀Dy ₂₂Ho ₅₈Fe₁₉₅ sample was prepared using a pyrolytic Bridgman type boron nitride crucible. At a bias field of 100 Oe k₃₃ = .73, which is considerably larger than found in the random polycrystal of the same composition. A relative permeability of 36 occurs in this same sample when a low ac drive of 1.6 Oe rms is used. A second fabrication method using a horizontal zone technique with a supporting cold finger was employed to grow the ternary Tb ₂₇Dy ₇₃Fe₁₉₈. The low ac drive values of k₃₃ and μ/sub r/ were .74 and 19 respectively. The permeability at low bias was found to possess a sharp ac drive dependence. Near zero bias, when the drive was changed from 1.6 Oe rms to 13 Oe rms, μ/sub r/ in the quaternary increased from 36 to 98. In the ternary the values of μ/sub r/ near zero bias increased from 19 to 61. Magnetostriction measurements on both samples show a significant increase in dlambda/dH and lambda/sub s/ over the random polycrystals

[en] The National Nuclear Security Agency Global Threat Reduction Initiative (GTRI) is tasked with minimizing the use of high-enriched uranium (HEU) worldwide. A key component of that effort is the conversion of research reactors from HEU to low-enriched uranium (LEU) fuels. The GTRI Convert Fuel Development program, previously known as the Reduced Enrichment for Research and Test Reactors program was initiated in 1978 by the United States Department of Energy to develop the nuclear fuels necessary to enable these conversions. The program cooperates with the research reactors operators to achieve this goal of HEU to LEU conversion without reduction in reactor performance. The programmatic mandate is to complete the conversion of all civilian domestic research reactors by 2014. These reactors include the five domestic high-performance research reactors (HPRR), namely: the High Flux Isotope Reactor at the Oak Ridge National Laboratory, the Advanced Test Reactor at the Idaho National Laboratory, the National Bureau of Standards Reactor at the National Institute of Standards and Technology, the Missouri University Research Reactor at the University of Missouri-Columbia, and the MIT Reactor-II at the Massachusetts Institute of Technology. Characteristics for each of the HPRRs are given in Appendix A. The GTRI Convert Fuel Development program is currently engaged in the development of a novel nuclear fuel that will enable these conversions. The fuel design is based on a monolithic fuel meat (made from a uranium-molybdenum alloy) clad in Al-6061 that has shown excellent performance in irradiation testing. The unique aspects of the fuel design, however, necessitate the development and implementation of new fabrication techniques and, thus, establishment of the infrastructure to ensure adequate fuel fabrication capability. A conceptual fabrication process description and rough estimates of the total facility throughput are described in this document as a basis for establishing preconceptual fabrication facility designs

[en] Experimental studies of self-focused, high-current electron-beam propagation phenomena are compared with the results of computational modeling. The model includes the radial structure of the beam-plasma system, a full electromagnetic field description, primary and secondary gas ionization processes, and a linear theory of the hose-like distortions. Good agreement between the experimental results and the computations strengthens the premise that hose instability is the principal limitation to propagation at high pressure

No abstract available

[en] Numerous devices utilizing slow-wave structures have been developed for the purpose of generating microwaves. Examples are the so-called M- and O-type microwave tubes. Operation of such devices involves drifting an electron beam through a periodic structure capable of supporting slow electromagnetic waves. That is, waves having phase velocity less than the speed of light. The beam space charge excites, and subsequently interacts with, fundamental slow-wave modes associated with the structure. This interaction produces microwave energy at the expense of beam kinetic energy. These devices typically require externally applied d.c. fields to guide the beam. In addition, space charge considerations limit the amount of beam charge that can be transported through a slow-wave structure. One of the authors has proposed using a coaxial, self-insulated, crossed-field device for the purpose of generating microwaves. The device consists of a coaxial transmission line having a corrugated outer-conductor (slow-wave structure), and operates as a diode. In line-limited operation the inner and outer conductors are the cathode and anode, respectively; otherwise, the transmission line is terminated by a load. In the case of load-limited operation the microwave output can be tuned to a specific frequency

[en] The definitions of terms used in describing the phenomenology and measurement practices of practical superconductive materials are proposed. The definitions cover the subject categories of: (1) fundamental states and flux phenomena, (2) critical parameters, (3) fabrication, stabilization, and transient losses, and (4) Josephson phenomena. It is intended that these terms become the basis for the development of standard measurement practices and responses are invited. (author)

[en] A conceptual systems model is developed to provide a framework for the assessment and comparison of the impacts of various technologies for electricity generation and distribution. The model also shows the influence of social factors and political institutions on technology implementation. A case study is presented in which the model is used to assess a rural electrification project in the Dominican Republic using photovoltaic technology. It is shown that the technology is appropriate for most desired end-uses, and has many positive social, environmental, and economic characteristics. (Author)

[en] This paper is devoted to a microscopic study of the elementary excitations of a hard-sphere Fermi gas which are produced by a weakly interacting probe. The authors apply linear-response theory in a correlated basis and calculate the density-density response function II(q,ω) and corresponding dynamic structure factor S(q,ω), as functions of the transferred momentum hq and energy hω. Systems with single-particle level degeneracy v = 4 and v = 2 are considered, in correspondence with symmetrical nuclear matter and pure neutron matter. The results are referred to a hard-core radius of c = 0.4 fm/sup /minus/1/, again with nuclear systems in mind