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What product might a renewal of Heavy IonFusion development offerthat competes with methane microbes and hydrogen HTGRs

Description: In 1994 a Fusion Technology journal publication by Logan, Moir and Hoffman described how exploiting unusually-strong economy-of-scale for large (8 GWe-scale) multi-unit HIF plants sharing a driver and target factory among several low cost molten salt fusion chambers {at} < $40M per 2.4 GW fusion each (Fig. 1), could produce electricity below 3 cts/kWehr, even lower than similar multi-unit fission plants. The fusion electric plant could cost $12.5 B for 7.5 GWe and produce hydrogen fuel by electrolysis at prices competitive with gasoline-powered hybrids getting fuel from oil at $20$/bbl. At $60/bbl oil, the fusion plant can cost $35B and compete {at} 10% APR financing. Given massive and still-increasing world demand for transportation fuel even with oil climbing above $60/bbl, large HIF plants producing both low cost electricity and hydrogen could be more relevant to motivate new R&D funding for HIF development in the next few years. Three major challenges to get there: (1) NIF ignition in indirect drive geometry for liquid chambers, (2) a modular accelerator to enable a one-module IRE < $100 M, (3) compatible HIF target, driver and chamber allowing a small driver {at}< $500 M cost for a >100MWe net power DEMO. This scoping study, at a very preliminary conceptual level, attempts to identify how we might meet the last two great challenges taking advantage of several recent ideas and advances which motivate reconsideration of modular HIF drivers: >60X longitudinal compression of neutralized ion beams using a variable waveform induction module in NDCX down to 2 nanosecond bunches, the proof-of-principle demonstration of fast optical-gated solid state SiC switches by George Caporaso's group at LLNL (see George's RPIA06 paper), and recent work by Ed Lee, John Barnard and Hong Qin on methods for time-dependent correction of chromatic focusing errors in neutralized beams with up to 10 % ...
Date: April 19, 2006
Creator: Logan, Grant; Lee, Ed; Yu, Simon; Briggs, Dick; Barnard, John; Friedman, Alex et al.
Partner: UNT Libraries Government Documents Department

Pumpernickel Valley Geothermal Project Thermal Gradient Wells

Description: The Pumpernickel Valley geothermal project area is located near the eastern edge of the Sonoma Range and is positioned within the structurally complex Winnemucca fold and thrust belt of north-central Nevada. A series of approximately north-northeast-striking faults related to the Basin and Range tectonics are superimposed on the earlier structures within the project area, and are responsible for the final overall geometry and distribution of the pre-existing structural features on the property. Two of these faults, the Pumpernickel Valley fault and Edna Mountain fault, are range-bounding and display numerous characteristics typical of strike-slip fault systems. These characteristics, when combined with geophysical data from Shore (2005), indicate the presence of a pull-apart basin, formed within the releasing bend of the Pumpernickel Valley – Edna Mountain fault system. A substantial body of evidence exists, in the form of available geothermal, geological and geophysical information, to suggest that the property and the pull-apart basin host a structurally controlled, extensive geothermal field. The most evident manifestations of the geothermal activity in the valley are two areas with hot springs, seepages, and wet ground/vegetation anomalies near the Pumpernickel Valley fault, which indicate that the fault focuses the fluid up-flow. There has not been any geothermal production from the Pumpernickel Valley area, but it was the focus of a limited exploration effort by Magma Power Company. In 1974, the company drilled one exploration/temperature gradient borehole east of the Pumpernickel Valley fault and recorded a thermal gradient of 160oC/km. The 1982 temperature data from five unrelated mineral exploration holes to the north of the Magma well indicated geothermal gradients in a range from 66 to 249oC/km for wells west of the fault, and ~283oC/km in a well next to the fault. In 2005, Nevada Geothermal Power Company drilled four geothermal gradient wells, PVTG-1, -2, -3, and -4, ...
Date: January 1, 2006
Creator: Szybinski, Z. Adam
Partner: UNT Libraries Government Documents Department

TRADITIONAL AND DIGITAL AUTORADIOGRAPHY TECHNIQUES: A COMPARISON STUDY

Description: This report fulfills the FY 2006 Enhanced Surveillance Campaign Level 3 milestones for Task TSR 11.1 as defined in the execution plan [1, 2]. The purpose of this task is to reduce the cycle time necessary to complete analytical evaluations required for surveillance of reservoirs. The development of the digital autoradiography system supports this task. The digital autoradiography system is currently operational and ready for implementation in reservoir surveillance performed in the Materials Test Facility (MTF) at Savannah River Site (SRS). SRS requests design agency (Los Alamos National Laboratory and Sandia National Laboratory) concurrence for the implementation of this system and on the establishment, in conjunction with the Savannah River National Laboratory (SRNL), of the implementation requirements for this system. Stainless steel tritium reservoirs and pinch welded tubes, which have been exposed to tritium for a prolonged period, are destructively evaluated at the end of their service lives for a variety of reasons. One requirement of this evaluation is to assess the tritium diffusion into the reservoir material. The current method used to determine the geometry and depth of tritium penetration is autoradiography. This technique employs a photographic emulsion and has been effective for a number of years. The primary disadvantage of this technique is the time required to obtain results. The success of the traditional technique is dependent on many variables, such as the proficiency of the operators in conducting sample preparation, the geometry of the sample and the shelf life of the photographic chemicals. If results are not satisfactory, several repetitions are often required and usually add weeks to the total analysis time for the sample. Due to the extensive time required for the liquid emulsion autoradiography method, a new, faster technique was desired. Personnel from the Savannah River National Laboratory (SRNL) have been working on a system ...
Date: August 29, 2006
Creator: Gibbs, K & Carol Kestin, C
Partner: UNT Libraries Government Documents Department

Perrhenate and Pertechnetate Behavior on Iron and Sulfur-Bearing Compounds.

Description: Investigations on the behavior of the radioactive element technetium frequently use a stable isotope of rhenium as an analogue. This is justified by citing the elements similar radii and major oxidation states of +7 and +4. However, at least one study [1] has shown this analogy to be imperfect. Therefore, one goal of our study is to compare the adsorption behavior of perrhenate and pertechnetate (the major forms of Re and Tc in natural waters) on a number of different mineral surfaces. Quantum mechanical calculations were performed on the adsorption of these two anions on a series of iron oxides and sulfides. With these calculations, we gain insight into any differences between the anions adsorption behavior, including geometry, adsorption energies, and electronic structure such as density of states and orbital shapes and energies at the adsorption site. Differences between interactions on terraces and step edges, the effects of co-adsorbates such as Na{sup +} or H{sup +}, and possible reduction mechanisms are also explored. The influence of water was calculated using homogeneous dielectric fluids and explicit water molecules. As a complement to the calculations, batch sorption tests are in progress involving ReO{sub 4}{sup -}/TcO{sub 4}{sup -} solution in contact with Fe metal, 10% Fe-doped hydroxyapatite, goethite, hematite, magnetite, pyrite, galena, and sphalerite.
Date: September 15, 2006
Creator: Anderson, B. E.; Becker, U.; Helean, K. B. & Ewing, R. C.
Partner: UNT Libraries Government Documents Department

High Efficiency, Ultra-Low Emission, Integrated Process Heater System

Description: The team of TIAX LLC, ExxonMobil Research and Engineering Company, and Callidus Technologies, LLC conducted a six-year program to develop an ultra-low emission process heater burner and an advanced high efficiency heater design. This project addresses the critical need of process heater operators for reliable, economical emission reduction technologies to comply with stringent emission regulations, and for heater design alternatives that reduce process heater energy requirements without significant cost increase. The key project targets were NOx emissions of 10 ppm (@ 3% O2), and a heater thermal efficiency of 95 percent. The ultra low NOx burner was developed through a series of pilot-scale and field tests combined with computational fluid dynamic modeling to arrive at simultaneous low emissions and suitable flame shape and stability. Pilot scale tests were run at TIAX, at the 2 MMBtu/hr scale, and at Callidus at 8 MMBtu/hr. The full scale burner was installed on a 14 burner atmospheric pipestill furnace at an ExxonMobil refinery. A variety of burner configurations, gas tips and flame stabilizers were tested to determine the lowest emissions with acceptable flame shape and stability. The resulting NOx emissions were 22 ppm on average. Starting in 2001, Callidus commercialized the original ultra low NOx burner and made subsequent design improvements in a series of commercial burners evolving from the original concept and/or development. Emissions in the field with the ultra low-NOx burner over a broad spectrum of heater applications have varied from 5 ppm to 30 ppm depending on heater geometry, heater service, fuel and firing capacity. To date, 1550 of the original burners, and 2500 of subsequent generation burners have been sold by Callidus. The advanced heater design was developed by parametric evaluations of a variety of furnace and combustion air preheater configurations and technologies for enhancing convective and radiative heat transfer. ...
Date: June 19, 2006
Creator: Mason, Howard; Boral, Anindya; Chhotray, San & Martin, Matthew
Partner: UNT Libraries Government Documents Department

Cost Effective Open Geometry HTS MRI System amended to BSCCO 2212 Wire for High Field Magnets

Description: The original goal of this Phase II Superconductivity Partnership Initiative project was to build and operate a prototype Magnetic Resonance Imaging (MRI) system using high temperature superconductor (HTS) coils wound from continuously processed dip-coated BSCCO 2212 tape conductor. Using dip-coated tape, the plan was for MRI magnet coils to be wound to fit an established commercial open geometry, 0.2 Tesla permanent magnet system. New electronics and imaging software for a prototype higher field superconducting system would have added significantly to the cost. However, the use of the 0.2 T platform would allow the technical feasibility and the cost issues for HTS systems to be fully established. Also it would establish the energy efficiency and savings of HTS open MRI compared with resistive and permanent magnet systems. The commercial goal was an open geometry HTS MRI running at 0.5 T and 20 K. This low field open magnet was using resistive normal metal conductor and its heat loss was rather high around 15 kolwatts. It was expected that an HTS magnet would dissipate around 1 watt, significantly reduce power consumption. The SPI team assembled to achieve this goal was led by Oxford Instruments, Superconducting Technology (OST), who developed the method of producing commercial dip coated tape. Superconductive Components Inc. (SCI), a leading US supplier of HTS powders, supported the conductor optimization through powder optimization, scaling, and cost reduction. Oxford Magnet Technology (OMT), a joint venture between Oxford Instruments and Siemens and the world’s leading supplier of MRI magnet systems, was involved to design and build the HTS MRI magnet and cryogenics. Siemens Magnetic Resonance Division, a leading developer and supplier of complete MRI imaging systems, was expected to integrate the final system and perform imaging trials. The original MRI demonstration project was ended in July 2004 by mutual consent of Oxford ...
Date: August 11, 2006
Creator: Marken, Kennth
Partner: UNT Libraries Government Documents Department

Fracture Dissolution of Carbonate Rock: An Innovative Process for Gas Storage

Description: The goal of the project is to develop and assess the feasibility and economic viability of an innovative concept that may lead to commercialization of new gas-storage capacity near major markets. The investigation involves a new approach to developing underground gas storage in carbonate rock, which is present near major markets in many areas of the United States. Because of the lack of conventional gas storage and the projected growth in demand for storage capacity, many of these areas are likely to experience shortfalls in gas deliverability. Since depleted gas reservoirs and salt formations are nearly non-existent in many areas, alternatives to conventional methods of gas storage are required. The need for improved methods of gas storage, particularly for ways to meet peak demand, is increasing. Gas-market conditions are driving the need for higher deliverability and more flexibility in injection/withdrawal cycling. In order to meet these needs, the project involves an innovative approach to developing underground storage capacity by creating caverns in carbonate rock formations by acid dissolution. The basic concept of the acid-dissolution method is to drill to depth, fracture the carbonate rock layer as needed, and then create a cavern using an aqueous acid to dissolve the carbonate rock. Assessing feasibility of the acid-dissolution method included a regional geologic investigation. Data were compiled and analyzed from carbonate formations in six states: Indiana, Ohio, Kentucky, West Virginia, Pennsylvania, and New York. To analyze the requirements for creating storage volume, the following aspects of the dissolution process were examined: weight and volume of rock to be dissolved; gas storage pressure, temperature, and volume at depth; rock solubility; and acid costs. Hydrochloric acid was determined to be the best acid to use because of low cost, high acid solubility, fast reaction rates with carbonate rock, and highly soluble products (calcium chloride) ...
Date: October 31, 2006
Creator: Castle, James W.; Falta, Ronald W.; Bruce, David; Murdoch, Larry; Brame, Scott E. & Brooks, Donald
Partner: UNT Libraries Government Documents Department

Black Hole Attractors and Pure Spinors

Description: We construct black hole attractor solutions for a wide class of N = 2 compactifications. The analysis is carried out in ten dimensions and makes crucial use of pure spinor techniques. This formalism can accommodate non-Kaehler manifolds as well as compactifications with flux, in addition to the usual Calabi-Yau case. At the attractor point, the charges fix the moduli according to {Sigma}f{sub k} = Im(C{Phi}), where {Phi} is a pure spinor of odd (even) chirality in IIB (A). For IIB on a Calabi-Yau, {Phi} = {Omega} and the equation reduces to the usual one. Methods in generalized complex geometry can be used to study solutions to the attractor equation.
Date: February 21, 2006
Creator: Hsu, Jonathan P.; Maloney, Alexander & Tomasiello, Alessandro
Partner: UNT Libraries Government Documents Department

ALE3D Rolling Simulations

Description: Hot rolling is a problem involving large deformations during the process of turning an ingot into a thin sheet. As a result of the large deformations inherent in the process, significant amounts of energy are put into the ingot mechanically, most of which results in heat generation. Therefore, in order to predict the results of rolling both the mechanical and the thermal factors must accurately represent the real conditions. The factors which must be properly tuned include interface friction, mass scaling to decrease computation times, heat transfer at the interface, convective heat transfer from the ingot, and convective heat transfer from the roll. Since these parameters are generally not measurable the correct values must be derived by tuning the parameters so that solutions match some other measurable result. The interface friction will be tuned using an ALE3D input deck which has been set up to output the torque applied to the roll during the pass. The friction coefficient will be adjusted so that the computed torque matches the measured value. The various heat transfer coefficients are dependent on each other, and are tuned based on measured roll surface temperatures, ingot exit temperatures, and the energy input through the mechanical deformation of the ingot. The heat transfer coefficient at the interface has been found to be approximately 1.25 x 10{sup 5} W/m{sup 2}K, based on estimates of how much heat can be taken from the roll surface by coolant and matching a roll surface temperature. The convection coefficient on the ingot surface has been assumed to be 100 W/m{sup 2}K, on the high end for convection to air. However, this convection coefficient is low enough that the ingot should cool uniformly through its thickness as it would with a lower convection coefficient. Also necessary in accurate modeling is a good description ...
Date: July 27, 2006
Creator: Riordan, T
Partner: UNT Libraries Government Documents Department

Calculation of Critical Experiments involving U(37)O2F2 Solution

Description: Critical experiments were conducted at the Oak Ridge Critical Experiment Facility (ORCEF) to determine the critical concentration for an unreflected 69.2-cm-diameter sphere of UO{sub 2}F{sub 2}, at an enrichment of {approx}37 percent U{sup 235}, by weight. These experiments were a continuation of previous efforts to determine critical dimensions for fissile materials in simple geometry. Some of the earlier experiments in this vessel have been published as part of the OECD handbook. The reports concerning these experiments have only recently become available. Until August 2005, Refs. 2 and 3 were still classified. These documents, along with experimental logbooks and unclassified papers available on the experimental campaign and facility are being used to generate a computer model for this critical experiment.
Date: March 3, 2006
Creator: Goluoglu, K.L.
Partner: UNT Libraries Government Documents Department

Analysis Strategy of Powder Diffraction Data with 2-D Detector

Description: To gain a clearer understanding of orientation and grain deformation of crystalline materials, x-ray powder diffraction has played an integral role in extracting three-dimensional structural information from one-dimensional diffraction patterns. Powder diffraction models identical geometry to the intersection of a normal right cone with a plane. The purpose of this paper is to develop a general expression defining the conic sections based on the geometry of a powder diffraction experiment. Applying the derived formulation of a diffraction arc to experimental data will give insight to the molecular and structural properties of the sample in question. Instead of using complex three-dimensional Euclidian geometry, we define the problem solving technique with a simpler two-dimensional transformation approach to arrive at the final equation describing the conic sections. Using the diffraction geometry parameters, we can use this equation to calibrate the diffractometer from the diffraction pattern of a known reference material, or to determine the crystalline lattice structure of the compound.
Date: January 25, 2006
Creator: Kumar, Abhik & /SLAC, SSRL
Partner: UNT Libraries Government Documents Department

Contact Interface Verification for DYNA3D Scenario 2: Multi-Surface Contact

Description: A suite of test problems has been developed to examine contact behavior within the nonlinear, three-dimensional, explicit finite element analysis (FEA) code DYNA3D (Lin, 2005). The test problems use multiple interfaces and a combination of enforcement methods to assess the basic functionality of the contact algorithms. The results from the DYNA3D analyses are compared to closed form solutions to verify the contact behavior. This work was performed as part of the Verification and Validation efforts of LLNL W Program within the NNSA's Advanced Simulation and Computing (ASC) Program. DYNA3D models the transient dynamic response of solids and structures including the interactions between disjoint bodies (parts). A wide variety of contact surfaces are available to represent the diverse interactions possible during an analysis, including relative motion (sliding), separation and gap closure (voids), and fixed relative position (tied). The problem geometry may be defined using a combination of element formulations, including one-dimensional beam and truss elements, two-dimensional shell elements, and three-dimensional solid elements. Consequently, it is necessary to consider various element interactions during contact. This report and associated test problems examine the scenario where multiple bodies interact with each other via multiple interfaces. The test problems focus on whether any ordering issues exist in the contact logic by using a combination of interface types, contact enforcement options (i.e., penalty, Lagrange, and kinematic), and element interactions within each problem. The influence of rigid materials on interface behavior is also examined. The companion report (McMichael, 2006) and associated test problems address the basic contact scenario where one contact surface exists between two disjoint bodies. The test problems are analyzed using version 5.2 (compiled on 12/22/2005) of DYNA3D. The analytical results are used to form baseline solutions for subsequent regression testing. In section 2, the test problems are presented, and the static solution is developed ...
Date: May 10, 2006
Creator: McMichael, L D
Partner: UNT Libraries Government Documents Department

Contact Interface Verification for DYNA3D Scenario 1: Basic Contact

Description: A suite of test problems has been developed to examine contact behavior within the nonlinear, three-dimensional, explicit finite element analysis (FEA) code DYNA3D (Lin, 2005). The test problems address the basic functionality of the contact algorithms, including the behavior of various kinematic, penalty, and Lagrangian enforcement formulations. The results from the DYNA3D analyses are compared to closed form solutions to verify the contact behavior. This work was performed as part of the Verification and Validation efforts of LLNL W Program within the NNSA's Advanced Simulation and Computing (ASC) Program. DYNA3D models the transient dynamic response of solids and structures including the interactions between disjoint bodies (parts). A wide variety of contact surfaces are available to represent the diverse interactions possible during an analysis, including relative motion (sliding), separation and gap closure (voids), and fixed relative position (tied). The problem geometry may be defined using a combination of element formulations, including one-dimensional beam and truss elements, two-dimensional shell elements, and three-dimensional solid elements. Consequently, it is necessary to consider various element interactions for each contact algorithm being verified. Most of the contact algorithms currently available in DYNA3D are examined; the exceptions are the Type 4--Single Surface Contact and Type 11--SAND algorithms. It is likely that these algorithms will be removed since their functionality is embodied in other, more robust, contact algorithms. The automatic contact algorithm is evaluated using the Type 12 interface. Two other variations of automatic contact, Type 13 and Type 14, offer additional means to adapt the interface domain, but share the same search and restoration algorithms as Type 12. The contact algorithms are summarized in Table 1. This report and associated test problems examine the scenario where one contact surface exists between two disjoint bodies. These test problems focus on whether a particular contact algorithm properly represents the ...
Date: May 10, 2006
Creator: McMichael, L D
Partner: UNT Libraries Government Documents Department

POTENTIAL SCALE DEPENDENCE OF EFFECTIVE MATRIX DIFFUSION COEFFICIENT

Description: It is well known that matrix diffusion (mass transfer between fractures and the rock matrix through molecular diffusion) can significantly retard solute transport processes in fractured rock, and therefore is important for analyzing a variety of problems, including geological disposal of nuclear waste. Matrix-diffusion-coefficient values measured from small rock samples in the laboratory are generally used for modeling field-scale solute transport in fractured rock. However, by compiling results from a number of field tracer tests corresponding to different geological settings, this study demonstrates that the effective matrix diffusion coefficient at field scale is generally larger than that at lab scale and tends to increase with testing scale. Preliminary interpretations of this observation are also investigated. We found that this interesting scale dependence may be related to the complexity of flow-path geometry in fractured rock.
Date: March 13, 2006
Creator: Liu, H.; Zhou, Q. & Zhang, Y.
Partner: UNT Libraries Government Documents Department

The Non-BPS Black Hole Attractor Equation

Description: We study the attractor mechanism for extremal non-BPS black holes with an infinite throat near horizon geometry, developing, as we do so, a physical argument as to why such a mechanism does not exist in non-extremal cases. We present a detailed derivation of the non-supersymmetric attractor equation. This equation defines the stabilization of moduli near the black hole horizon: the fixed moduli take values specified by electric and magnetic charges corresponding to the fluxes in a Calabi Yau compactification of string theory. They also define the so-called double-extremal solutions. In some examples, studied previously by Tripathy and Trivedi, we solve the equation and show that the moduli are fixed at values which may also be derived from the critical points of the black hole potential.
Date: February 8, 2006
Creator: Kollosh, R
Partner: UNT Libraries Government Documents Department

Status report on high fidelity reactor simulation.

Description: This report presents the effort under way at Argonne National Laboratory toward a comprehensive, integrated computational tool intended mainly for the high-fidelity simulation of sodium-cooled fast reactors. The main activities carried out involved neutronics, thermal hydraulics, coupling strategies, software architecture, and high-performance computing. A new neutronics code, UNIC, is being developed. The first phase involves the application of a spherical harmonics method to a general, unstructured three-dimensional mesh. The method also has been interfaced with a method of characteristics. The spherical harmonics equations were implemented in a stand-alone code that was then used to solve several benchmark problems. For thermal hydraulics, a computational fluid dynamics code called Nek5000, developed in the Mathematics and Computer Science Division for coupled hydrodynamics and heat transfer, has been applied to a single-pin, periodic cell in the wire-wrap geometry typical of advanced burner reactors. Numerical strategies for multiphysics coupling have been considered and higher-accuracy efficient methods proposed to finely simulate coupled neutronic/thermal-hydraulic reactor transients. Initial steps have been taken in order to couple UNIC and Nek5000, and simplified problems have been defined and solved for testing. Furthermore, we have begun developing a lightweight computational framework, based in part on carefully selected open source tools, to nonobtrusively and efficiently integrate the individual physics modules into a unified simulation tool.
Date: December 11, 2006
Creator: Palmiotti, G.; Smith, M.; Rabiti, C.; Lewis, E.; Yang, W.; Leclere,M. et al.
Partner: UNT Libraries Government Documents Department

GBL-2D Version 1.0: a 2D geometry boolean library.

Description: This report describes version 1.0 of GBL-2D, a geometric Boolean library for 2D objects. The library is written in C++ and consists of a set of classes and routines. The classes primarily represent geometric data and relationships. Classes are provided for 2D points, lines, arcs, edge uses, loops, surfaces and mask sets. The routines contain algorithms for geometric Boolean operations and utility functions. Routines are provided that incorporate the Boolean operations: Union(OR), XOR, Intersection and Difference. A variety of additional analytical geometry routines and routines for importing and exporting the data in various file formats are also provided. The GBL-2D library was originally developed as a geometric modeling engine for use with a separate software tool, called SummitView [1], that manipulates the 2D mask sets created by designers of Micro-Electro-Mechanical Systems (MEMS). However, many other practical applications for this type of software can be envisioned because the need to perform 2D Boolean operations can arise in many contexts.
Date: November 1, 2006
Creator: McBride, Cory L. (Elemental Technologies, American Fort, UT); Schmidt, Rodney Cannon; Yarberry, Victor R. & Meyers, Ray J. (Elemental Technologies, American Fort, UT)
Partner: UNT Libraries Government Documents Department

FY05 LDRD Final ReportNanomaterials for Radiation Detection

Description: We have demonstrated that it is possible to enhance current radiation detection capability by manipulating the materials at the nano level. Fabrication of three-dimensional (3-D) nanomaterial composite for radiation detection has great potential benefits over current semiconductor- and scintillation-based technologies because of the precise control of material-radiation interaction and modulation of signal output. It is also a significant leap beyond current 2-D nanotechnology. Moreover, since we are building the materials using a combination of top-down and bottom-up approaches, this strategy to make radiation detection materials can provide significant improvement to radiation-detection technologies, which are currently based on difficult-to-control bulk crystal growth techniques. We are applying this strategy to tackle two important areas in radiation detection: gamma-rays and neutrons. In gamma-ray detection, our first goal is to employ nanomaterials in the form of quantum-dot-based mixed matrices or nanoporous semiconductors to achieve scintillation output several times over that from NaI(Tl) crystals. In neutron detection, we are constructing a 3-D structure using a doped nanowire ''forest'' supported by a boron matrix and evaluating the detection efficiency of different device geometry with simulation.
Date: February 6, 2006
Creator: Wang, T F; Letant, S E; Nikolic, R J & Chueng, C L
Partner: UNT Libraries Government Documents Department

Finite Cosmology and a CMB Cold Spot

Description: The standard cosmological model posits a spatially flat universe of infinite extent. However, no observation, even in principle, could verify that the matter extends to infinity. In this work we model the universe as a finite spherical ball of dust and dark energy, and obtain a lower limit estimate of its mass and present size: the mass is at least 5 x 10{sup 23}M{sub {circle_dot}} and the present radius is at least 50 Gly. If we are not too far from the dust-ball edge we might expect to see a cold spot in the cosmic microwave background, and there might be suppression of the low multipoles in the angular power spectrum. Thus the model may be testable, at least in principle. We also obtain and discuss the geometry exterior to the dust ball; it is Schwarzschild-de Sitter with a naked singularity, and provides an interesting picture of cosmogenesis. Finally we briefly sketch how radiation and inflation eras may be incorporated into the model.
Date: March 20, 2006
Creator: Adler, R.J.; /Stanford U., HEPL; Bjorken, J.D.; /SLAC; Overduin, J.M. & /Stanford U., HEPL
Partner: UNT Libraries Government Documents Department

Geologic technical assessment of the Richton salt dome, Mississippi, for potential expansion of the U.S. strategic petroleum reserve.

Description: Technical assessment and remodeling of existing data indicates that the Richton salt dome, located in southeastern Mississippi, appears to be a suitable site for expansion of the U.S. Strategic Petroleum Reserve. The maximum area of salt is approximately 7 square miles, at a subsurface elevation of about -2000 ft, near the top of the salt stock. Approximately 5.8 square miles of this appears suitable for cavern development, because of restrictions imposed by modeled shallow salt overhang along several sides of the dome. The detailed geometry of the overhang currently is only poorly understood. However, the large areal extent of the Richton salt mass suggests that significant design flexibility exists for a 160-million-barrel storage facility consisting of 16 ten-million-barrel caverns. The dome itself is prominently elongated from northwest to southeast. The salt stock appears to consist of two major spine features, separated by a likely boundary shear zone trending from southwest to northeast. The dome decreases in areal extent with depth, because of salt flanks that appear to dip inward at 70-80 degrees. Caprock is present at depths as shallow as 274 ft, and the shallowest salt is documented at -425 ft. A large number of existing two-dimensional seismic profiles have been acquired crossing, and in the vicinity of, the Richton salt dome. At least selected seismic profiles should be acquired, examined, potentially reprocessed, and interpreted in an effort to understand the limitations imposed by the apparent salt overhang, should the Richton site be selected for actual expansion of the Reserve.
Date: January 1, 2006
Creator: Snider, Anna C.; Rautman, Christopher Arthur & Looff, Karl M. (Geologic Consultant)
Partner: UNT Libraries Government Documents Department

Geologic technical assessment of the Stratton Ridge salt dome, Texas, for potential expansion of the U.S. strategic petroleum reserve.

Description: The Stratton Ridge salt dome is a large salt diapir located only some ten miles from the currently active Strategic Petroleum Reserve Site at Bryan Mound, Texas. The dome is approximately 15 miles south-southwest of Houston. The Stratton Ridge salt dome has been intensively developed, in the desirable central portions, with caverns for both brine production and product storage. This geologic technical assessment indicates that the Stratton Ridge salt dome may be considered a viable, if less-than-desirable, candidate site for potential expansion of the Strategic Petroleum Reserve (SPR). Past development of underground caverns significantly limits the potential options for use by the SPR. The current conceptual design layout of proposed caverns for such an expansion facility is based upon a decades-old model of salt geometry, and it is unacceptable, according to this reinterpretation of salt dome geology. The easternmost set of conceptual caverns are located within a 300-ft buffer zone of a very major boundary shear zone, fault, or other structural feature of indeterminate origin. This structure transects the salt stock and subdivides it into an shallow western part and a deeper eastern part. In places, the distance from this structural boundary to the design-basis caverns is as little as 150 ft. A 300-ft distance from this boundary is likely to be the minimum acceptable stand-off, from both a geologic and a regulatory perspective. Repositioning of the proposed cavern field is possible, as sufficient currently undeveloped salt acreage appears to be available. However, such reconfiguration would be subject to limitations related to land-parcel boundaries and other existing infrastructure and topographic constraints. More broadly speaking, the past history of cavern operations at the Stratton Ridge salt dome indicates that operation of potential SPR expansion caverns at this site may be difficult, and correspondingly expensive. Although detailed information is difficult to come ...
Date: November 1, 2006
Creator: Rautman, Christopher Arthur; Snider, Anna C. & Looff, Karl M. (Geologic Consultant, Lovelady, TX)
Partner: UNT Libraries Government Documents Department

LENS repair and modification of metal NW components:materials and applications guide.

Description: Laser Engineered Net Shaping{trademark} (LENS{reg_sign}) is a unique, layer additive, metal manufacturing technique that offers the ability to create fully dense metal features and components directly from a computer solid model. LENS offers opportunities to repair and modify components by adding features to existing geometry, refilling holes, repairing weld lips, and many other potential applications. The material deposited has good mechanical properties with strengths typically slightly higher that wrought material due to grain refinement from a quickly cooling weld pool. The result is a material with properties similar to cold worked material, but without the loss in ductility traditionally seen with such treatments. Furthermore, 304L LENS material exhibits good corrosion resistance and hydrogen compatibility. This report gives a background of the LENS process including materials analysis addressing the requirements of a number of different applications. Suggestions are given to aid both the product engineer and the process engineer in the successful utilization of LENS for their applications. The results of testing on interface strength, machinability, weldability, corrosion resistance, geometric effects, heat treatment, and repair strategy testing are all included. Finally, the qualification of the LENS process is briefly discussed to give the user confidence in selecting LENS as the process of choice for high rigor applications. The testing showed LENS components to have capability in repair/modification applications requiring complex castings (W80-3 D-Bottle bracket), thin wall parts requiring metal to be rebuilt onto the part (W87 Firing Set Housing and Y-12 Test Rings), the filling of counterbores for use in reservoir reclamation welding (SRNL hydrogen compatibility study) and the repair of surface defects on pressure vessels (SRNL gas bottle repair). The material is machinable, as testing has shown that LENS deposited material machines similar to that of welded metal. Tool wear is slightly higher in LENS material than in wrought material, ...
Date: November 1, 2006
Creator: Smugeresky, John E. (Sandia National Laboratories, Livermore, CA); Gill, David Dennis; Oberhaus, Jason (BWXT Y-12); Adams, Thad (Savannah River National Laboratory) & VanCamp, Chad (Kansas City Plant)
Partner: UNT Libraries Government Documents Department

MERCURY vs. TART Comparisons to Verify Thermal Scattering

Description: Recently the results from many Monte Carlo codes were compared for a series of theoretical pin-cells; the results are documented in ref. [3]; details are also provided here in Appendix A and B. The purpose of this earlier code comparison was primarily to determine how accurately our codes model both bound and free atom neutron thermal scattering. Prior to this study many people assumed that our Monte Carlo transport codes were all now so accurate that they would all produce more or less the same answers, say for example K-eff to within 0.1%. The results demonstrated that in reality we see a rather large spread in the results for even simple scalar parameters, such as K-eff, where we found differences in excess of 2%, far exceeding many people's expectations. The differences between code results were traced to four major factors, (1) Differences between the sets of nuclear data used. (2) The accuracy of nuclear data processing codes. (3) The accuracy of the models used in our Monte Carlo transport codes. (4) Code user selected input options. Naturally at Livermore we would like to insure that we minimize the effects of these factors. In this report we compare the results using two of our Monte Carlo transport codes: MERCURY [2] and TART [2], with the following constraints designed to address the four points listed above, (1) Both codes used exactly the same nuclear data, namely the TART 2005 data. (2) Each code used its own nuclear data processing code. Even though these two data processing codes are independent, they have been extensively tested to insure the processed output results closely agree. (3) Both used the same nuclear physics models. This required that some physics be turned off in each code, namely, (a) Unresolved resonance energy region self-shielding was turned off in ...
Date: March 30, 2006
Creator: Cullen, D E; McKinley, S & Hagmann, C
Partner: UNT Libraries Government Documents Department

Modeling the Effects of Crevice Former, Partculates, and the Evolving Surface Profile in Crevice Corrsion

Description: Crevice corrosion is an important mode of localized corrosion to be evaluated for the long-term performance of corrosion resistant alloys in high temperature, aqueous environments. This work focuses on the evolution of corrosion damage of Ni-Cr-Mo alloys in hot brines. For the initiation of crevice corrosion, a critical crevice chemistry must develop within the crevice to break down the passive film. The geometry of the crevice and particularly the height of the crevice gap is an important parameter, with tighter crevices being more aggressive. Crevice corrosion models mostly define a smooth walled crevice of uniform gap and do not account for the changing profile after crevice corrosion has initiated. As a complement to the earlier models of the cathodic region, they focus here on the crevice (anodic) region and apply current and potential distribution models to examine the effects of the perturbed surface topography. The analysis focuses on three related issues: (1) the effects surface roughness of the metal and the crevice former, (2) the effects of particulate within the crevice, and (3) the evolution of the crevice profile in the active, anodic region.
Date: June 9, 2006
Creator: Landau, U.; Agarwal, A.S.; Shan, X. & Payer, J.H.
Partner: UNT Libraries Government Documents Department