Development of novel copper-based sorbents for hot-gas cleanup. [Quarterly] technical report, September 1--November 30, 1993 (open access)

Development of novel copper-based sorbents for hot-gas cleanup. [Quarterly] technical report, September 1--November 30, 1993

The objective of this investigation is to evaluate two novel copper-based sorbents, namely copper-chromium and copper-cerium, for their effectiveness in removing hydrogen sulfide from fuel gas in the temperature range of 650{degree} to 850{degree}C. Such high temperatures will be required for the new generation of gas turbines (inlet >750{degree}C) in Integrated Gasification Combined Cycle (IGCC) systems. The effect of pre-reduction on the performance of the sorbents as well as the rate of different reactions occurring in cyclic sulfidation/regeneration, were studied in a thermogravimetric analyzer (TGA). Sulfidation was conducted with and without H{sub 2} and H{sub 2}O, and with and without pre-reduction in H{sub 2} or H{sub 2}/H{sub 2}O. The results of these tests indicate that reduction and regeneration of both sorbents occurs rapidly. Sulfidation of CuCr{sub 2}O{sub 4}, in H{sub 2}O-free and H{sub 2}-/H{sub 2}O-free gas indicates the possible sulfidation of both copper and chromium. Small quantities of SO{sub 2}, were released during sulfidation suggesting the possible oxidation of H{sub 2}S by the sorbent. Regeneration of the CuCr{sub 2}O{sub 4} was complete while regeneration of the CuO-CeO{sub 2} indicated possible limited sulfate formation.
Date: March 1, 1994
Creator: Abbasian, J.; Hill, A. H.; Flytzani-Stephanopoulos, M. & Li Li
Object Type: Report
System: The UNT Digital Library
Sulfur removal in advanced two-staged pressurized fluidized-bed combustion; [Quarterly] report, September 1--November 1993 (open access)

Sulfur removal in advanced two-staged pressurized fluidized-bed combustion; [Quarterly] report, September 1--November 1993

The objective of this study is to obtain data on the rates of reaction between hydrogen sulfide (H{sub 2}S) and uncalcined calcium-based sorbents under operating conditions relevant to first stage (carbonizer) of Advanced Two-Stage Pressurized Fluidized-Bed Combustors (PFBC). In these systems the CO{sub 2} partial pressure in the first stage generally exceeds the equilibrium value for calcium carbonate decomposition. Therefore, removal of sulfur compounds takes place through the reaction between H{sub 2}S and calcium carbonate. To achieve this objective, the rates of reaction between hydrogen sulfide and uncalcined calcium-based sorbents will be determined by conducting tests in pressurized thermogravimetric analyzer (TGA) and high-pressure/high-temperature fluidized-bed reactor (HPTR) units. The effects of sorbent type, sorbent particle size, reactor temperature and pressure, and CO{sub 2} and H{sub 2}S partial pressures on the sulfidation reaction rate will be determined. A pressurized TGA unit has been purchased by IGT for use in this project.
Date: March 1, 1994
Creator: Abbasian, Javad; Hill, Andy H.; Wangerow, James R. & Rue, David M.
Object Type: Report
System: The UNT Digital Library
Spent Fuel Background Report Volume I (open access)

Spent Fuel Background Report Volume I

This report is an overview of current spent nuclear fuel management in the DOE complex. Sources of information include published literature, internal DOE documents, interviews with site personnel, and information provided by individual sites. Much of the specific information on facilities and fuels was provided by the DOE sites in response to the questionnaire for data for spent fuels and facilities data bases. This information is as accurate as is currently available, but is subject to revision pending results of further data calls. Spent fuel is broadly classified into three categories: (a) production fuels, (b) special fuels, and (c) naval fuels. Production fuels, comprising about 80% of the total inventory, are those used at Hanford and Savannah River to produce nuclear materials for defense. Special fuels are those used in a wide variety of research, development, and testing activities. Special fuels include fuel from DOE and commercial reactors used in research activities at DOE sites. Naval fuels are those developed and used for nuclear-powered naval vessels and for related research and development. Given the recent DOE decision to curtail reprocessing, the topic of main concern in the management of spent fuel is its storage. Of the DOE sites that have …
Date: March 1, 1994
Creator: Abbott, D.
Object Type: Report
System: The UNT Digital Library
Spent Fuel Background Report Volume II (open access)

Spent Fuel Background Report Volume II

This Volume II contains tables that describe DOE fuel storage facilities and the fuel contained in those facilities.
Date: March 1, 1994
Creator: Abbott, D.
Object Type: Report
System: The UNT Digital Library
Using the internet in middle schools: A model for success (open access)

Using the internet in middle schools: A model for success

Los Alamos National Laboratory (LANL) developed a model for school networking using Los Alamos Middle School as a testbed. The project was a collaborative effort between the school and the Laboratory. The school secured administrative funding for hardware and software; and LANL provided the network architecture, installation, consulting, and training. The model is characterized by a computer classroom linked with two GatorBoxes and a UNIX-based workstation server. Six additional computers have also been networked from a teacher learning center and the library. The model support infrastructure includes: local school system administrators/lead teachers, introductory and intermediate hands-on teacher learning, teacher incentives for involvement and use, opportunities for student training and use, and ongoing LANL consulting. Formative evaluation data reveals that students and teachers alike are finding the Internet to be a tool that crosses disciplines, allowing them to obtain more, timely information and to communicate with others more effectively and efficiently. A lead teacher`s enthusiastic comments indicate some of the value gained: ``We have just scratched the surface. Each day someone seems to find something new and interesting on the Internet. The possibilities seem endless.``
Date: March 1, 1994
Creator: Addessio, B.; Boorman, M.; Eker, P.; Fletcher, K.; Judd, B.; Trainor, M. et al.
Object Type: Article
System: The UNT Digital Library
Development of a cost effective environment compliance technology for stripper brine wells. [Annual] report, January 1, 1993--December 31, 1993 (open access)

Development of a cost effective environment compliance technology for stripper brine wells. [Annual] report, January 1, 1993--December 31, 1993

The specific objective of the research is to demonstrate that the characteristics of wastewater from stripper oil wells and marginal gas wells are sufficiently similar to be treated under a standardized treatment methodology, that the environmental impacts of the discharge of treated brines from both stripper oil and marginal gas wells can be adequately regulated, and that the inclusion of marginal gas wells in the same category as stripper oil wells is appropriate, especially for wells operating in the Appalachian Basin. The work accomplished during 1992 for both the field-scale and the laboratory-scale treatment facilities focused on iron removal from the field and synthetic brines. The laboratory work also included single-element kinetics studies to determine the effect of one metal on another with respect to the rates of the various reactions. The laboratory process studies investigated such parameters as the sand bed thickness, the temperature of the system, the angle of the aeration unit, and the presence of the retention tank. All of these laboratory parametric studies provided insight into how each component of the treatment process contributes to the removal of iron from the synthetic brine. Similar studies have begun for investigating copper removal effectiveness. As for the field …
Date: March 8, 1994
Creator: Adewumi, M. A.; Watson, R. W.; Tian, S.; Heckman, S.; Safargar, S. & Drielinger, I.
Object Type: Report
System: The UNT Digital Library
A tool for debugging internet multicast routing (open access)

A tool for debugging internet multicast routing

In this paper the authors describe a debugging tool that is an effective means of analyzing problems with multicast packet routing in a network. Multicast packet routing is a source-driven distributed calculation performed by the routers in a multicast network. The routes taken by multicast packets are difficult to predict manually due to the large number of variables that must be considered. The multicast route debugging tool allows off-line investigation of the route taken by a multicast packet and the effects of network modifications on that route. The tool has already proved useful in debugging the problems that have occurred in the experimental Internet Multicast Backbone. The multicast route debugging tool currently predicts multicast routes of packets using the distance-vector truncated-broadcast algorithm implemented for Internet multicast traffic. They will be upgrading the tool to allow the user to choose other multicast routing algorithms.
Date: March 1, 1994
Creator: Agarwal, D. & Floyd, S.
Object Type: Article
System: The UNT Digital Library
Spectral radiative heat transfer in coal furnaces using a hybrid technique (open access)

Spectral radiative heat transfer in coal furnaces using a hybrid technique

A hybrid technique has been developed to solve three-dimensional spectral radiation transport equations for absorbing, emitting and anisotropically scattering media. An optimal mix of computational speed and accuracy is obtained by combining the discrete ordinate method (S{sub 4}), modified differential approximation (MDA) and P{sub 1} approximation for use in different range of optical thicknesses. The technique is used in conjunction with a char burnout model and spectroscopic data for H{sub 2}O, CO{sub 2}, CO, char, soot and ash to determine the influence of ash composition, ash content and coal preparation on furnace heat absorption.
Date: March 1, 1994
Creator: Ahluwalia, R. K. & Im, K. H.
Object Type: Report
System: The UNT Digital Library
The ATLAS Positron Experiment -- APEX (open access)

The ATLAS Positron Experiment -- APEX

APEX -- the ATLAS Positron Experiment -- is designed to measure electrons and positrons emitted in heavy-ion collisions. Its scientific goal is to gain insight into the puzzling positron-line phenomena observed at the GSI Darmstadt. It is in operation at the ATLAS accelerator at Argonne National Lab. The assembly of the apparatus is finished and beginning 1993 the first positrons produced in heavy-ion collisions were observed. The first full scale experiment was carried out in December 1993, and the data are currently being analyzed. In this paper, the principles of operation are explained and a status report on the experiment is given.
Date: March 1, 1994
Creator: Ahmad, I.; Back, B. B.; Betts, R. R.; Dunford, R.; Kutschera, W.; Rhein, M. D. et al.
Object Type: Article
System: The UNT Digital Library
Westinghouse radiological containment guide (open access)

Westinghouse radiological containment guide

This document provides uniform guidance for Westinghouse contractors on the implementation of radiological containments. This document reflects standard industry practices and is provided as a guide. The guidance presented herein is consistent with the requirements of the DOE Radiological Control Manual (DOE N 5480.6). This guidance should further serve to enable and encourage the use of containments for contamination control and to accomplish the following: Minimize personnel contamination; Prevent the spread of contamination; Minimize the required use of protective clothing and personal protective equipment; Minimize the generation of waste.
Date: March 1, 1994
Creator: Aitken, S. B.; Brown, R. L.; Cantrell, J. R. & Wilcox, D. P.
Object Type: Report
System: The UNT Digital Library
TMI-2 nozzle examinations performed at the Idaho National Engineering Laboratory (open access)

TMI-2 nozzle examinations performed at the Idaho National Engineering Laboratory

As part of the Three Mile Island Unit 2 (TMI-2) Vessel Investigation Project, under the auspices of the Organization for Economic Cooperation and Development, examinations were performed at the Idaho National Engineering Laboratory on eight nozzles and one guide tube from the TMI-2 reactor vessel. This document describes the examination methodology, summarizes the examination results, and presents interpretations of the results as they relate to the damage to the reactor vessel and to the development of a core relocation scenario. Not all examinations originally proposed as part of this program were completed due to facility problems at the INEL. Consequently, only the results of completed aspects of the examination program are presented.
Date: March 1, 1994
Creator: Akers, D. W. & Schuetz, B. K.
Object Type: Report
System: The UNT Digital Library
Examination of relocated fuel debris adjacent to the lower head of the TMI-2 reactor vessel (open access)

Examination of relocated fuel debris adjacent to the lower head of the TMI-2 reactor vessel

As part of the Three Mile Island Unit 2 (TMI-2) Vessel Investigation Project, funded by the Organization for Economic Cooperation and Development, physical, metallurgical, and radiochemical examinations were performed on samples of previously molten material that had relocated to the lower plenum of the TMI-2 reactor during the accident of 28 March 1979. This report presents the results of those examinations and some limited analysis of these results as required for the interpretation of the data. Principal conclusions of the examinations are that the bulk lower head debris is homogeneous and composed primarily of (U,Zr)O{sub 2}. This molten material reached temperatures greater than 2,600 C and probably reached the lower head as a liquid or slurry at temperatures below the peak temperature. A debris bed was formed, which was composed of particular debris above a monolithic melt that solidified on the lower head.
Date: March 1, 1994
Creator: Akers, D. W.; Jensen, S. M. & Schuetz, B. K.
Object Type: Report
System: The UNT Digital Library
Release of radionuclides and chelating agents from cement-solidified decontamination low-level radioactive waste collected from the Peach Bottom Atomic Power Station Unit 3 (open access)

Release of radionuclides and chelating agents from cement-solidified decontamination low-level radioactive waste collected from the Peach Bottom Atomic Power Station Unit 3

As part of a study being performed for the Nuclear Regulatory Commission (NRC), small-scale waste-form specimens were collected during a low oxidation-state transition-metal ion (LOMI)-nitric permanganate (NP)-LOMI solidification performed in October 1989 at the Peach Bottom Atomic Power Station Unit 3. The purpose of this program was to evaluate the performance of cement-solidified decontamination waste to meet the low-level waste stability requirements defined in the NRC`s ``Technical Position on Waste Form,`` Revision 1. The samples were acquired and tested because little data have been obtained on the physical stability of actual cement-solidified decontamination ion-exchange resin waste forms and on the leachability of radionuclides and chelating agents from those waste forms. The Peach Bottom waste-form specimens were subjected to compressive strength, immersion, and leach testing in accordance with the NRC`s ``Technical Position on Waste Form,`` Revision 1. Results of this study indicate that the specimens withstood the compression tests (>500 psi) before and after immersion testing and leaching, and that the leachability indexes for all radionuclides, including {sup 14}C, {sup 99}{Tc}, and {sup 129}I, are well above the leachability index requirement of 6.0, required by the NRC`s ``Technical Position on Waste Form,`` Revision 1.
Date: March 1, 1994
Creator: Akers, D. W.; Kraft, N. C. & Mandler, J. W.
Object Type: Report
System: The UNT Digital Library
Mitigation of Tank 241-SY-101 by pump mixing: Results of testing phases A and B (open access)

Mitigation of Tank 241-SY-101 by pump mixing: Results of testing phases A and B

A spare mixing pump from the Hanford Grout Program was installed in Hanford double-shell waste Tank 241-SY-101 on July 3, 1993, after being modified to take advantage of waste stratification. It was anticipated that pump mixing would prevent large episodic flammable gas releases that had been occurring about every 100-150 days. A cautious initial test plan, called Phase A, was run to find how the pump and tank would behave in response to very brief and gentle pump operation. No large gas releases were triggered, and the pump performed well except for two incidents of nozzle plugging. On October 21, 1993, the next test series, Phase B, began, and the pump was applied more aggressively to mix the tank contents and mitigate uncontrolled gas releases. Orienting the pump in new directions released large volumes of gas and reduced the waste level to a near-record low. Results of the entire period from pump installation to the end of Phase B on December 17, 1993, are presented in detail in this document. Though long-term effects require further evaluation, we conclude from these data that the jet mixer pump is an effective means of controlling flammable gas release and that it has met …
Date: March 1, 1994
Creator: Allemann, R. T.; Antoniak, Z. I.; Chvala, W. D.; Friley, J. R.; Gregory, W. B.; Hudson, J. D. et al.
Object Type: Report
System: The UNT Digital Library
Determining Uranium Speciation in Contaminated Soils by Molecular Spectroscopic Methods: Examples From the Uranium in Soils Integrated Demonstration (open access)

Determining Uranium Speciation in Contaminated Soils by Molecular Spectroscopic Methods: Examples From the Uranium in Soils Integrated Demonstration

The US Department of Energy`s former uranium production facility located at Fernald, OH (18 mi NW of Cincinnati) is the host site for an Integrated Demonstration for remediation of uranium-contaminated soils. A wide variety of source terms for uranium contamination have been identified reflecting the diversity of operations at the facility. Most of the uranium contamination is contained in the top {approximately}1/2 m of soil, but uranium has been found in perched waters indicating substantial migration. In support of the development of remediation technologies and risk assessment, we are conducting uranium speciation studies on untreated and treated soils using molecular spectroscopies. Untreated soils from five discrete sites have been analyzed. We have found that {approximately}80--90% of the uranium exists as hexavalent UO{sub 2}{sup 2+} species even though many source terms consisted of tetravalent uranium species such as UO{sub 2}. Much of the uranium exists as microcrystalline precipitates (secondary minerals). There is also clear evidence for variations in uranium species from the microscopic to the macroscopic scale. However, similarities in speciation at sites having different source terms suggest that soil and groundwater chemistry may be as important as source term in defining the uranium speciation in these soils. Characterization of treated …
Date: March 1, 1994
Creator: Allen, P. G.; Berg, J. M.; Chisholm-Brause, C. J.; Conradson, S. D.; Donohoe, R. J.; Morris, D. E. et al.
Object Type: Article
System: The UNT Digital Library
The computation of cloud base height from paired whole-sky imaging cameras (open access)

The computation of cloud base height from paired whole-sky imaging cameras

A major goal for global change studies is to improve the accuracy of general circulation models (GCMs) capable of predicting the timing and magnitude of greenhouse gas-induced global warming. Research has shown that cloud radiative feedback is the single most important effect determining the magnitude of possible climate responses to human activity. Of particular value to reducing the uncertainties associated with cloud-radiation interactions is the measurement of cloud base height (CBH), both because it is a dominant factor in determining the infrared radiative properties of clouds with respect to the earth`s surface and lower atmosphere and because CBHs are essential to measuring cloud cover fraction. We have developed a novel approach to the extraction of cloud base height from pairs of whole sky imaging (WSI) cameras. The core problem is to spatially register cloud fields from widely separated WSI cameras; this complete, triangulation provides the CBH measurements. The wide camera separation (necessary to cover the desired observation area) and the self-similarity of clouds defeats all standard matching algorithms when applied to static views of the sky. To address this, our approach is based on optical flow methods that exploit the fact that modern WSIs provide sequences of images. We will …
Date: March 1, 1994
Creator: Allmen, M. C. & Kegelmeyer, W. P. Jr.
Object Type: Report
System: The UNT Digital Library
Fluorescence detection of single molecules using pulsed near-field optical excitation and time correlated photon counting (open access)

Fluorescence detection of single molecules using pulsed near-field optical excitation and time correlated photon counting

Pulsed excitation, time correlated single photon counting and time gated detection are used in near-field optical microscopy to enhance fluorescence images and measure the fluorescence lifetimes of single molecules of Rhodamine 6G on silica surfaces. Time gated detection is used to reject prompt scattered background and to improve the image signal to noise ratio. The excited state lifetime of a single Rhodamine 6G molecule is found to depend on the position of the near-field probe. We attribute the lifetime variations to spontaneous emission rate alterations by the fluorescence reflected from and quenching by the aluminum coated probe.
Date: March 1, 1994
Creator: Ambrose, W. P.; Goodwin, P. M.; Martin, J. C. & Keller, R. A.
Object Type: Article
System: The UNT Digital Library
Redeployment as an alternative to decommissioning. Conversion of a US Department of Energy facility to fish rearing (open access)

Redeployment as an alternative to decommissioning. Conversion of a US Department of Energy facility to fish rearing

The Hanford Site and the Tri-Cities community have before them an unprecedented opportunity to create an economic renaissance based on the unparalleled environmental cleanup mission. The nation and the world await the emergence of the post-Cold War economy and conversion of the national defense complex into new national economic thrusts. The legacy of the Hanford Site national defense mission must not end up simply with the Site being cleaned up and land being restored to near-original conditions. There also needs to be a future economic legacy of a dynamic Tri-Cities community resulting from the cumulative current activities that will have a positive impact for years to come. In anticipation of the eventual completion of the Hanford Site cleanup mission, the US Department of Energy (DOE) has established the Office of Economic Transition to identify and implement policies and actions that will support the cleanup mission of the Site and the long-term economic development of the Tri-Cities area. In the future, it is envisioned that one phase of a vibrant regional economy with a diversified economic job base will be the capability to compete in national and international environmental services markets. Recently, it was realized that the K Area water treatments …
Date: March 1, 1994
Creator: Anderson, B. N. & Herborn, D. I.
Object Type: Article
System: The UNT Digital Library
Preparation and combustion of Yugoslavian lignite-water fuel, Task 7.35. Topical report, July 1991--December 1993 (open access)

Preparation and combustion of Yugoslavian lignite-water fuel, Task 7.35. Topical report, July 1991--December 1993

Yugoslavia`s interest in lignite-water fuel (LWF) stems from its involvement in an unusual power project at Kovin in northern Serbia. In the early 1980s, Electric Power of Serbia (EPS) proposed constructing a 600-MW power plant that would be fueled by lignite found in deposits along and under the Danube River. Trial underwater mining at Kovin proved that the dredging operation is feasible. The dredging method produces a coal slurry containing 85% to 90% water. Plans included draining the water from the coal, drying it, and then burning it in the pulverized coal plant. In looking for alternative ways to utilize the ``wet coal`` in a more efficient and economical way, a consortium of Yugoslavian companies agreed to assess the conversion of dredged lignite into a LWF using hot-water-drying (HWD) technology. HWD is a high-temperature, nonevaporative drying technique carried out under high pressure in water that permanently alters the structure of low-rank coals. Changes effected by the drying process include irreversible removal of moisture, micropore sealing by tar, and enhancement of heating value by removal of oxygen, thus, enhancement of the slurry ability of the coal with water. Physical cleaning results indicated a 51 wt % reduction in ash content with …
Date: March 1, 1994
Creator: Anderson, C. M.; DeWall, R. A.; Ljubicic, B. R.; Musich, M. A. & Richter, J. J.
Object Type: Report
System: The UNT Digital Library
Measurement of air quality within storage domes in technical area 54, areas G and L (open access)

Measurement of air quality within storage domes in technical area 54, areas G and L

The concentrations of volatile organic compounds (VOCs) and tritium inside of storage domes at TA-54 were measured to assess worker exposure and support the Area G site characterization, including the Radioactive Air Emissions Management (RAEM) program. Samples were collected at 2-3 locations within Domes 48, 49, and 153 on up to six days during the summer of 1994. Samples were collected to evaluate three scenarios: (1) normal working activities with the domes open; (2) after domes were closed overnight; and (3) after domes were closed for three days. Eight-hour integrated samples were collected and analyzed in Radian`s Austin laboratories. Tritium activities from 17.1 to 69,900 pCi/m{sup 3} were measured. About two dozen individual VOCs were identified in each sample, but most of the concentration levels were very low (e.g.; < 1 to 10 ppbv). The highest concentrations measured were bromomethane (56.5 ppbv), 1, 1,1-trichloroethane (75.4 ppbv), propane (958 ppbv), methylene chloride (1,450 ppbv), and toluene (22.8). The measured VOC concentrations were well below the action levels developed by the New Mexico Environment Department and the measured tritium concentrations were well below the DOE`s derived air concentration (DAC). The variability in concentration within a dome during a single sampling episode was …
Date: March 15, 1994
Creator: Anderson, E.
Object Type: Report
System: The UNT Digital Library
Secondary oil recovery from selected Carter sandstone oilfields, Black Warrior basin, Alabama. [Annual] yearly report, December 1, 1992--November 30, 1993 (open access)

Secondary oil recovery from selected Carter sandstone oilfields, Black Warrior basin, Alabama. [Annual] yearly report, December 1, 1992--November 30, 1993

In this Class I PON, Anderman/Smith Operating Company is targeting three Carter sandstone oilfields (Black Warrior basin) for secondary recovery. Waterfloods are underway in two of the areas -- Central Bluff and North Fairview units. For the third area, South Bluff, negotiations are underway to unitize the field. Once South Bluff is unitized, waterflooding will commence.
Date: March 1, 1994
Creator: Anderson, J. C.
Object Type: Report
System: The UNT Digital Library
Investigation of exposure to Extremely Low Frequency (ELF) magnetic and electric fields: Ongoing animal studies (open access)

Investigation of exposure to Extremely Low Frequency (ELF) magnetic and electric fields: Ongoing animal studies

There is now convincing evidence from a large number of laboratories, that exposure to extremely low frequency (ELF) magnetic and electric fields produces biological responses in animals. Many of the observed effects appear to be directly or indirectly associated with the neural or neuroendocrine systems. Such effects include increased neuronal excitability, chemical and hormonal changes in the nervous system, altered behavioral responses, some of which are related to sensing the presence of the field, and changes in endogenous biological rhythms. Additional indices of general physiological status appear relatively unaffected by exposure, although effects have occasionally been described in bone growth and fracture repair, reproduction and development, and immune system function. A major current emphasis in laboratory research is to determine whether or not the reported epidemiological studies that suggest an association between EMF exposure and risk of cancer are supported in studies using animal models. Three major challenges exist for ongoing research: (1) knowledge about the mechanisms underlying observed bioeffects is incomplete, (2) researchers do not as yet understand what physical aspects of exposure produce biological responses, and (3) health consequences resulting from ELF exposure are unknown. Although no animal studies clearly demonstrate deleterious effects of ELF fields, several are …
Date: March 1, 1994
Creator: Anderson, L. E.
Object Type: Article
System: The UNT Digital Library
Using virtual objects to aid underground storage tank teleoperation (open access)

Using virtual objects to aid underground storage tank teleoperation

In this paper we describe an algorithm by which obstructions and surface features in an underground storage tank can be modeled and used to generate virtual barrier function for a real-time telerobotic system, which provides an aid to the operator for both real-time obstacle avoidance and for surface tracking. The algorithm requires that the slave`s tool and every object in the waste storage tank be decomposed into convex polyhedral primitives, with the waste surface modeled by triangular prisms. Intrusion distance and extraction vectors are then derived at every time step by applying Gilbert`s polyhedra distance algorithm, which has been adapted for the task. This information is then used to determine the compression and location of nonlinear virtual spring-dampers whose total force is summed and applied to the manipulator/teleoperator system. Experimental results using a PUMA 560 and a simulated waste surface validate the approach, showing that it is possible to compute the algorithm and generate smooth, realistic pseudo forces for the teleoperator system using standard VME bus hardware.
Date: March 1, 1994
Creator: Anderson, R. J. & Davies, B.
Object Type: Article
System: The UNT Digital Library
Total System Performance Assessment, 1993: An evaluation of the potential Yucca Mountain repository, B00000000-01717-2200-00099, Rev. 01 (open access)

Total System Performance Assessment, 1993: An evaluation of the potential Yucca Mountain repository, B00000000-01717-2200-00099, Rev. 01

Total System Performance Assessments are an important component in the evaluation of the suitability of Yucca Mountain, Nevada as a potential site for a mined geologic repository for the permanent disposal of high-level radioactive wastes in the United States. The Total System Performance Assessments are conducted iteratively during the site characterization to identify issues which should be addressed by the characterization and design activities as well as providing input to regulatory/licensing and programmatic decisions. During fiscal years 1991 and 1992, the first iteration of Total System Performance Assessment (hereafter referred to as TSPA 1991) was completed by Sandia National Laboratories and Pacific Northwest Laboratory. Beginning in fiscal year 1993, the Civilian Radioactive Waste Management System Management and Operating Contractor was assigned the responsibility to plan, coordinate, and contribute to the second iteration of Total System Performance Assessment (hereafter referred to as TSPA 1993). This document presents the objectives, approach, assumptions, input, results, conclusions, and recommendations associated with the Management and Operating Contractor contribution to TSPA 1993. A parallel effort was conducted by Sandia National Laboratories and is reported in Wilson et al. (1994, in press).
Date: March 1, 1994
Creator: Andrews, R. W.; Dale, T. F. & McNeish, J. A.
Object Type: Report
System: The UNT Digital Library