Geomorphology of plutonium in the Northern Rio Grande (open access)

Geomorphology of plutonium in the Northern Rio Grande

Nearly all of the plutonium in the natural environment of the Northern Rio Grande is associated with soils and sediment, and river processes account for most of the mobility of these materials. A composite regional budget for plutonium based on multi-decadal averages for sediment and plutonium movement shows that 90 percent of the plutonium moving into the system is from atmospheric fallout. The remaining 10 percent is from releases at Los Alamos. Annual variation in plutonium flux and storage exceeds 100 percent. The contribution to the plutonium budget from Los Alamos is associated with relatively coarse sediment which often behaves as bedload in the Rio Grande. Infusion of these materials into the main stream were largest in 1951, 1952, 1957, and 1968. Because of the schedule of delivery of plutonium to Los Alamos for experimentation and weapons manufacturing, the latter two years are probably the most important. Although the Los Alamos contribution to the entire plutonium budget was relatively small, in these four critical years it constituted 71--86 percent of the plutonium in bedload immediately downstream from Otowi.
Date: March 1, 1993
Creator: Graf, William L.
Object Type: Report
System: The UNT Digital Library
Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La{sub 2{minus}x}Sr{sub x}CuO{sub 4} (0 {le} x {le} 0.08) and electrochemically oxidized La{sub 2{minus}x}Sr{sub x}CuO{sub 4+{delta}} (0 {le} x {le} 0.33, 0 {le} {delta} {le} 0.12) (open access)

Synthesis, characterization, phase diagrams and superconducting and normal state magnetic properties of La{sub 2{minus}x}Sr{sub x}CuO{sub 4} (0 {le} x {le} 0.08) and electrochemically oxidized La{sub 2{minus}x}Sr{sub x}CuO{sub 4+{delta}} (0 {le} x {le} 0.33, 0 {le} {delta} {le} 0.12)

La{sub 2{minus}x}Sr{sub x}CuO{sub 4} (0 {le} x {le} 0.15) can all be intercalated with oxygen by a novel electrochemical oxidation method. Bulk superconductivity is found with an onset {Tc} {approx} 40 K for the whole range 0.01 {le} x {le} 0.15; for x = 0.25 and 0.33, the electrochemical oxidation did not improve the superconducting properties. The magnetic susceptibility {chi}(T = 50--320 K) data for La{sub 2}CuO{sub 4.11} and La{sub 1.92}Sr{sub 0.08}CuO{sub 4.07} are nearly identical with those of conventionally prepared La{sub 1.85}Sr{sub 0.15}CuO{sub 4}, indicating that the hole doping level (p) in the CuO{sub 2} planes of the three compounds is nearly the same. Combined thermogravimetric analysis and iodometric titration experiments indicate that part of the intercalated oxygen has a formal valence close to {minus}1. The maximum doped-hole concentration in the CuO{sub 2} planes that can be achieved from combined Sr-doping and electrochemical oxygen doping for 0 {le} x {le} 0.15 is p {approx} 0.16 holes/formula unit. Oxygen can also intercalate into single crystal La{sub 2}CuO{sub 4} through a slow electrochemical oxidation process. The required low current and long time for the charging process reflects that the oxygen intercalation for a single crystal is limited by its small specific …
Date: August 1, 1993
Creator: Chou, F.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
1993 RCRA Part B permit renewal application, Savannah River Site: Volume 10, Consolidated Incineration Facility, Section C, Revision 1 (open access)

1993 RCRA Part B permit renewal application, Savannah River Site: Volume 10, Consolidated Incineration Facility, Section C, Revision 1

This section describes the chemical and physical nature of the RCRA regulated hazardous wastes to be handled, stored, and incinerated at the Consolidated Incineration Facility (CIF) at the Savannah River Site. It is in accordance with requirements of South Carolina Hazardous Waste Management Regulations R.61-79.264.13(a) and(b), and 270.14(b)(2). This application is for permit to store and teat these hazardous wastes as required for the operation of CIF. The permit is to cover the storage of hazardous waste in containers and of waste in six hazardous waste storage tanks. Treatment processes include incineration, solidification of ash, and neutralization of scrubber blowdown.
Date: August 1, 1993
Creator: Molen, G.
Object Type: Report
System: The UNT Digital Library
Liquid abrasive grit blasting literature search and decontamination scoping tests report (open access)

Liquid abrasive grit blasting literature search and decontamination scoping tests report

Past decontamination and solvent recovery activities at the Idaho Chemical Processing Plant (ICPP) have resulted in the accumulation of 1.5 million gallons of radioactively contaminated sodium-bearing liquid waste. Future decontamination activities at the ICPP could result in the production of 5 million gallons or more of sodium-bearing waste using the current decontamination techniques of chemical/water flushes and steam jet cleaning. With the curtailment of reprocessing at the ICPP, the focus of decontamination is shifting from maintenance for continued operation of the facilities to decommissioning. As decommissioning plans are developed, new decontamination methods must be used which result in higher decontamination factors and generate lower amounts of sodium-bearing secondary waste. The primary initiative of the WINCO Decontamination Development Program is the development of methods to eliminate/minimize the use of sodium-bearing decontamination chemicals. One method that was chosen for cold scoping studies during FY-93 was abrasive grit blasting. Abrasive grit blasting has been used in many industries and a vast amount of research and development has already been conducted. However, new grits, process improvements and ICPP applicability was investigated. This evaluation report is a summary of the research efforts and scoping tests using the liquid abrasive grit blasting decontamination technique. The purpose …
Date: October 1, 1993
Creator: Ferguson, R.L.
Object Type: Report
System: The UNT Digital Library
Analysis of releases due to drilling at the potential Yucca Mountain repository (open access)

Analysis of releases due to drilling at the potential Yucca Mountain repository

Human Instrusion into the potential repository at Yucca Mountain, Nevada, was modeled in the Total-System Performance Assessment (``TSPA-91``) recently completed for the Yucca Mountain Site Characterization Project Office of the DOE. The scenario model assumed that the repository would be penetrated at random locations by a number of boreholes drilled using twentieth-century rotary drilling techniques.
Date: July 1, 1993
Creator: Barnard, R.W.
Object Type: Article
System: The UNT Digital Library
Streamflow and selected precipitation data for Yucca Mountain and vicinity, Nye County, Nevada, water years 1983--85 (open access)

Streamflow and selected precipitation data for Yucca Mountain and vicinity, Nye County, Nevada, water years 1983--85

Streamflow and precipitation data collected at and near Yucca Mountain, Nevada, during water years 1983--85, are presented in this report. The data were collected and compiled as part of the studies the US Geological Survey is making, in cooperation with the US Department of Energy, to characterize surface-water hydrology in the Yucca Mountain area. Streamflow data include daily mean discharges and peak discharges at 4 complete-record gaging stations and peak discharges at 10 crest-stage, partial-record stations and 12 miscellaneous sites. Precipitation data include cumulative totals at 12 stations maintained by the US Geological Survey and daily totals at 17 stations maintained by the Weather Service Nuclear Support Office, National Oceanic and Atmospheric Administration.
Date: January 1, 1993
Creator: Pabst, M. E.; Beck, D. A.; Glancy, P. A. & Johnson, J. A.
Object Type: Report
System: The UNT Digital Library
Enhanced thermal capacity aerogels summary report for FY 1993 (open access)

Enhanced thermal capacity aerogels summary report for FY 1993

In a continuation of work done previously, the authors have fabricated a set of silica aerogels and then chemically modified their internal surfaces for the purpose of inhibiting the effects of sintering at high temperatures. They performed surface nitridation of silica aerogels, i.e., the replacement of surface oxygen atoms with nitrogen atoms, by reacting ammonia gas with the silica surfaces at elevated temperatures. After pre-oxidizing the aerogels, they exposed three sets of samples to anhydrous ammonia gas under different processing conditions. Each set contained silica aerogels of three different densities, 0.07 g/cc, 0.16 g/cc, and 0.29 g/cc. The treated samples, together with companion untreated reference samples, were sent to NASA Ames Research Laboratory for high temperature testing. They also fabricated two carbon aerogel cylinders, 7 cm diameter x 1.5 cm thick. These samples were also delivered to NASA Ames Research Laboratory for high temperature tests.
Date: December 1, 1993
Creator: Hrubesh, L. W.; Coronado, P. R. & Poco, J. F.
Object Type: Report
System: The UNT Digital Library
Characterization and modification of phage T7 DNA polymerase for use in DNA sequencing; Progress report, June 1, 1990--May 31, 1993 (open access)

Characterization and modification of phage T7 DNA polymerase for use in DNA sequencing; Progress report, June 1, 1990--May 31, 1993

This project focuses on the DNA polymerase (gene 5 protein) of phage T7 for use in DNA sequence analysis. Gene 5 protein interacts with accessory proteins to acquire properties essential for DNA replication. One goal is to understand these interactions in order to modify the proteins for use in DNA sequencing. E. coli thioredoxin, binds to gene 5 protein and clamps it to a primer-template. They have analyzed the binding of gene 5 protein-thioredoxin to primer-templates and have defined the optimal conditions to form an extremely stable complex with a dNTP in the polymerase catalytic site. The spatial proximity of these components has been determined using fluorescence emission anisotropy. The T7 DNA binding protein, the gene 2.5 protein, interacts with gene 5 protein and gene 4 protein to increase processivity and primer synthesis, respectively. Mutant gene 2.5 proteins have been isolated that do not interact with T7 DNA polymerase and can not support T7 growth. The nucleotide binding site of the T7 helicase has been identified and mutations affecting the site provide information on how the hydrolysis of NTPs fuel its unidirectional translocation. The sequence, GTC, has been shown to be necessary and sufficient for recognition by the T7 primase. …
Date: December 31, 1993
Creator: Richardson, C.C.
Object Type: Report
System: The UNT Digital Library
Auxiliary analyses in support of performance assessment of a hypothetical low-level waste disposal facility: Application of an infiltration evaluation methodology. Volume 1 (open access)

Auxiliary analyses in support of performance assessment of a hypothetical low-level waste disposal facility: Application of an infiltration evaluation methodology. Volume 1

This report provides an analysis of infiltration and percolation at a hypothetical low-level waste (LLW) disposal facility was carried out. The analysis was intended to illustrate general issues of concern in assessing the performance of LLW disposal facilities. Among the processes considered in the analysis were precipitation, runoff, information, evaporation, transpiration, and redistribution. The hypothetical facility was located in a humid environment characterized by frequent and often intense precipitation events. The facility consisted of a series of concrete vaults topped by a multilayer cover. Cover features included a sloping soil surface to promote runoff, plant growth to minimize erosion and promote transportation, a sloping clay layer, and a sloping capillary barrier. The analysis within the root zone was carried out using a one-dimensional, transient simulation of water flow. Below the root zone, the analysis was primarily two-dimensional and steady-state.
Date: December 1, 1993
Creator: Meyer, P.D.
Object Type: Report
System: The UNT Digital Library
Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff; Yucca Mountain Site Characterization Project (open access)

Initial field testing definition of subsurface sealing and backfilling tests in unsaturated tuff; Yucca Mountain Site Characterization Project

This report contains an initial definition of the field tests proposed for the Yucca Mountain Project repository sealing program. The tests are intended to resolve various performance and emplacement concerns. Examples of concerns to be addressed include achieving selected hydrologic and structural requirements for seals, removing portions of the shaft liner, excavating keyways, emplacing cementitious and earthen seals, reducing the impact of fines on the hydraulic conductivity of fractures, efficient grouting of fracture zones, sealing of exploratory boreholes, and controlling the flow of water by using engineered designs. Ten discrete tests are proposed to address these and other concerns. These tests are divided into two groups: Seal component tests and performance confirmation tests. The seal component tests are thorough small-scale in situ tests, the intermediate-scale borehole seal tests, the fracture grouting tests, the surface backfill tests, and the grouted rock mass tests. The seal system tests are the seepage control tests, the backfill tests, the bulkhead test in the Calico Hills unit, the large-scale shaft seal and shaft fill tests, and the remote borehole sealing tests. The tests are proposed to be performed in six discrete areas, including welded and non-welded environments, primarily located outside the potential repository area. The …
Date: May 1, 1993
Creator: Fernandez, J. A.; Case, J. B. & Tyburski, J. R.
Object Type: Report
System: The UNT Digital Library
Code development incorporating environmental, safety and economic aspects of fusion reactors; Annual progress report (open access)

Code development incorporating environmental, safety and economic aspects of fusion reactors; Annual progress report

This document is a proposal to continue the authors work on the Environmental, Safety and Economic (ESE) aspects of fusion reactors under DOE contract DE-FR03-89ER52514. The grant objectives continue those from the previous grant: (1) completion of first-generation Environmental, Safety and Economic (ESE) computer modules suitable as integral components of tokamak systems codes. (2) continuation of work on special topics, in support of the above and in response to OFE requests. The proposal also highlights progress on the contract in the twelve months since April, 1992. This has included work with the ARIES and ITER design teams, work on tritium management, studies on materials activation, and calculation of radioactive inventories in fusion reactors.
Date: December 31, 1993
Creator: Fowler, T.K.; Greenspan, E. & Holdren, J.P.
Object Type: Report
System: The UNT Digital Library
Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly report No. 7, October 1, 1992--December 31, 1992 (open access)

Development of a catalyst for conversion of syngas-derived materials to isobutylene. Quarterly report No. 7, October 1, 1992--December 31, 1992

The main goal of this contract is to develop a catalyst and technology that will produce iC{sub 4}= directly from coal-derived syngas and that is capable of utilizing a lower (0.5 to 1.0) H{sub 2}:CO ratio. The research will identify and optimize the key catalyst and process characteristics that give improved performance for CO conversion by a non-Fischer-Tropsch process. This report, which is the seventh quarterly report covers the testing of various ZrO{sub 2}-based catalyst systems designed to examine the effects of catalyst preparation and process variables, especially low calcination temperature and mild reaction conditions (low temperatures, low pressure and low space velocity). Testing of solvent-extracted sol-gel ZrO{sub 2} catalysts indicate a decrease in isobutene yield. Lowering the reaction temperature, pressure and space velocity resulted in a small improvement in isobutene yield. Three extended runs demonstrated reasonable catalyst stability. In view of the generally poor isobutene yields, the emphasis in this project will shift to isoalcohol production.
Date: September 8, 1993
Creator: Gajda, G.J.
Object Type: Report
System: The UNT Digital Library
The use of solid-state NMR techniques for the analysis of water in coal and the effect of different coal drying techniques on the structure and reactivity of coal; Quarterly report, September 1--November 30, 1993 (open access)

The use of solid-state NMR techniques for the analysis of water in coal and the effect of different coal drying techniques on the structure and reactivity of coal; Quarterly report, September 1--November 30, 1993

For the research program reported here, different methods of drying are being investigated to determine if drying can be accomplished without destroying coal reactivity toward liquefaction. In an effort to understand the mechanism of water for enhancing coal liquefaction yield, the reactions of D{sub 2}O with the molecular constituents of coal during coal liquefaction are being investigated. This study involves the use of solution-state deuterium NMR, as well as, conventional solution-state {sup 1}H and {sup 13}C NMR analyses of the coal, and the coal liquids and residue from a coal liquefaction process. These D{sub 2}O transfer reactions will be conducted on coals which have been dried by various methods and rehydrated using D{sub 2}O and by successive exchange of H{sub 2}O associated with the coals with D{sub 2}O. The drying methods include thermal, microwave, and chemical dehydration of the coal. The overall objectives of this study are to develop a nuclear magnetic resonance (NMR) method for measuring the water in coal, to measure the changes in coal structure that occur during coal drying, to determine what effect water has on retrograde/condensation reactions, to determine the mechanism by which water may impact coal reactivity toward liquefaction, and to conduct D{sub 2}O …
Date: December 31, 1993
Creator: Netzel, D.A.
Object Type: Report
System: The UNT Digital Library
Transport of neptunium through Yucca Mountain tuffs (open access)

Transport of neptunium through Yucca Mountain tuffs

Neptunium has a high solubility in groundwaters from Yucca Mountain [1]. Uranium in nuclear reactors produces {sup 237}Np which has a half-life of 2.1 4 {times} 10{sup 6} years. Consequently, the transport of {sup 237}Np through tuffs is of major importance in assessing the performance of a high-level nuclear waste repository at Yucca Mountain. The objective of this work is to determine the amount of Np retardation that is provided by the minerals in Yucca Mountain tuffs as a function of groundwater chemistry.
Date: February 1, 1993
Creator: Triay, I. R.; Robinson, B. A.; Mitchell, A. J.; Overly, C. M. & Lopez, R. M.
Object Type: Article
System: The UNT Digital Library
A process for determining radiohalogens (open access)

A process for determining radiohalogens

Techniques for the separation and potential determination of chlorine-36 and iodine-129 were examined. Separation was based upon addition to the carbon-carbon double bond in 1-hexene. These specific organic halides formed an acceptable liquid scintillation counting cocktail with chlorine but not with iodine. The miscibility of 1,2-dichlorohexane should allow a larger mass of sample in a scintillation cocktail, lowering the detection limit of the determination of chlorine-36. Organic halides are also expected to be more receptive to waste treatment than metals such as silver. These techniques offer the potential for determination of chlorine-36 in groundwater samples while producing less mixed waste than current analytical techniques.
Date: December 1, 1993
Creator: Washington, W.J. & Hohorst, F.A.
Object Type: Report
System: The UNT Digital Library
CMPO purity tests in the TRUEX solvent using americium-241 (open access)

CMPO purity tests in the TRUEX solvent using americium-241

The Transuranic Extraction (TRUEX) Process was developed by E.P. Horwitz and coworkers at Argonne National Laboratory (ANL) to separate the +4, +6, and +3 actinides from acidic aqueous solutions of nuclear wastes. Octyl (phenyl)-N-N-diisobutyl-carbamoylmethylphosphine oxide (CMPO) is the active actinide complexant used in the TRUEX solvent. CMPO is combined with tributyl phosphate (TBP) in an organic diluent, typically n-dodecane, to form the TRUEX solvent. Small quantities of impurities in the CMPO resulting from: (1) synthesis, (2) acid hydrolysis, or (3) radiolysis can result in actinide stripping problems from the solvent. The impurity, octylphenylphosphinic acid (POPPA), ia a powerful extractant at low acid concentrations which may be formed during CMPO synthesis. Consequently, commercial CMPO may contain sufficient quantities of POPPA to significantly impact the stripping of actinides from the TRUEX solvent. The purpose of these tests was to (1) determine if commercially available CMPO is sufficiently pure to alleviate actinide stripping problems from the TRUEX process and (2) to determine if solvent cleanup methods are sufficient to purify the commercially purchased CMPO. Extraction and solvent cleanup methodologies used by Horwitz and coworkers at ANL were used to determine CMPO purity with {sup 241}Am. The improvement of the americium distribution coefficient in …
Date: December 1, 1993
Creator: Brewer, K. N.; Herbst, R. S.; Tranter, T. J. & Todd, T. A.
Object Type: Report
System: The UNT Digital Library
The cost of ethanol production from lignocellulosic biomass -- A comparison of selected alternative processes. Final report (open access)

The cost of ethanol production from lignocellulosic biomass -- A comparison of selected alternative processes. Final report

The purpose of this report is to compare the cost of selected alternative processes for the conversion of lignocellulosic biomass to ethanol. In turn, this information will be used by the ARS/USDA to guide the management of research and development programs in biomass conversion. The report will identify where the cost leverages are for the selected alternatives and what performance parameters need to be achieved to improve the economics. The process alternatives considered here are not exhaustive, but are selected on the basis of having a reasonable potential in improving the economics of producing ethanol from biomass. When other alternatives come under consideration, they should be evaluated by the same methodology used in this report to give fair comparisons of opportunities. A generic plant design is developed for an annual production of 25 million gallons of anhydrous ethanol using corn stover as the model substrate at $30/dry ton. Standard chemical engineering techniques are used to give first order estimates of the capital and operating costs. Following the format of the corn to ethanol plant, there are nine sections to the plant; feed preparation, pretreatment, hydrolysis, fermentation, distillation and dehydration, stillage evaporation, storage and denaturation, utilities, and enzyme production. There are …
Date: April 30, 1993
Creator: Grethlein, H.E. & Dill, T.
Object Type: Report
System: The UNT Digital Library
The Si(100)-Sb 2{times}1 and Ge(100) 2{times}1 surfaces: A multi-technique study (open access)

The Si(100)-Sb 2{times}1 and Ge(100) 2{times}1 surfaces: A multi-technique study

The electronic and geometric structures of the clean and Sb terminated Si(100)2{times}1 and Ge(100)-2{times}1 surfaces have been investigated using a multi-technique approach. Low energy electron diffraction (LEED), scanning tunneling microscopy (STM), surface extended X-ray absorption fine structure (SEXAFS) spectroscopy and angle-integrated core-level photoemission electron spectroscopy (PES) were employed to measure the surface symmetry, defect structure, relevant bond lengths, atomic coordination and electronic structure. By employing a multi-technique approach, it is possible to correlate changes in the geometric structure to specific features of the core-level lineshape of the substrate. This allows for the assignment of components of the core-level lineshape to be assigned to specific surface and near-surface atoms.
Date: August 1, 1993
Creator: Richter, M.
Object Type: Report
System: The UNT Digital Library
Evaluation and compilation of DOE waste package test data; Volume 8: Biannual report, August 1989--January 1990 (open access)

Evaluation and compilation of DOE waste package test data; Volume 8: Biannual report, August 1989--January 1990

This report summarizes evaluations by the National Institute of Standards and Technology (NIST) of some of the Department of Energy (DOE) activities on waste packages designed for containment of radioactive high-level nuclear waste (HLW) for the six-month period, August 1989--January 1990. This includes reviews of related materials research and plans, information on the Yucca Mountain, Nevada disposal site activities, and other information regarding supporting research and special assistance. Short discussions are given relating to the publications reviewed and complete reviews and evaluations are included. Reports of other work are included in the Appendices.
Date: June 1, 1993
Creator: Interrante, C. G.; Fraker, A. C. & Escalante, E.
Object Type: Report
System: The UNT Digital Library
Evaluation of severe accident risks: Methodology for the containment, source term, consequence, and risk integration analyses; Volume 1, Revision 1 (open access)

Evaluation of severe accident risks: Methodology for the containment, source term, consequence, and risk integration analyses; Volume 1, Revision 1

NUREG-1150 examines the risk to the public from five nuclear power plants. The NUREG-1150 plant studies are Level III probabilistic risk assessments (PRAs) and, as such, they consist of four analysis components: accident frequency analysis, accident progression analysis, source term analysis, and consequence analysis. This volume summarizes the methods utilized in performing the last three components and the assembly of these analyses into an overall risk assessment. The NUREG-1150 analysis approach is based on the following ideas: (1) general and relatively fast-running models for the individual analysis components, (2) well-defined interfaces between the individual analysis components, (3) use of Monte Carlo techniques together with an efficient sampling procedure to propagate uncertainties, (4) use of expert panels to develop distributions for important phenomenological issues, and (5) automation of the overall analysis. Many features of the new analysis procedures were adopted to facilitate a comprehensive treatment of uncertainty in the complete risk analysis. Uncertainties in the accident frequency, accident progression and source term analyses were included in the overall uncertainty assessment. The uncertainties in the consequence analysis were not included in this assessment. A large effort was devoted to the development of procedures for obtaining expert opinion and the execution of these …
Date: December 1, 1993
Creator: Gorham, E. D.; Breeding, R. J.; Brown, T. D.; Harper, F. T.; Helton, J. C.; Murfin, W. B. et al.
Object Type: Report
System: The UNT Digital Library
Single fracture aperture patterns: Characterization by slit-island fractal analysis (open access)

Single fracture aperture patterns: Characterization by slit-island fractal analysis

Single fracture measurements are difficult to obtain, but they are the only means we have to observe and study natural fracture morphology. The character of the fracture openings (apertures) is often one of the primary factors controlling fluid flow in the fracture. In particular, the shape, distribution, and connectivity of contact areas and flow channels can affect the relative permeability of wetting and non-wetting fluid phases in unsaturated systems. In this paper we use three methods of fractal analysis (the slit-island, the divider, and the variogram) as well as statistical and geostatistical analysis to characterize the geometry of measured fracture apertures obtained from two different fractured rock specimens from the field. One of these is a granitic fracture (crack) of homogeneous lithology and no displacement, the other is a fracture (fault) obtained from a highly altered fault zone, containing striations and slickensides. We discuss the fractal and geostatistical analysis of these two fractures in the context of what information is most helpful for making predictions about fluid flow in single fractures.
Date: January 1, 1993
Creator: Cox, B.L. & Wang, J.S.Y.
Object Type: Article
System: The UNT Digital Library
Waste glass corrosion modeling: Comparison with experimental results (open access)

Waste glass corrosion modeling: Comparison with experimental results

A chemical model of glass corrosion will be used to predict the rates of release of radionuclides from borosilicate glass waste forms in high-level waste repositories. The model will be used both to calculate the rate of degradation of the glass, and also to predict the effects of chemical interactions between the glass and repository materials such as spent fuel, canister and container materials, backfill, cements, grouts, and others. Coupling between the degradation processes affecting all these materials is expected. Models for borosilicate glass dissolution must account for the processes of (1) kinetically-controlled network dissolution, (2) precipitation of secondary phases, (3) ion exchange, (4) rate-limiting diffusive transport of silica through a hydrous surface reaction layer, and (5) specific glass surface interactions with dissolved cations and anions. Current long-term corrosion models for borosilicate glass employ a rate equation consistent with transition state theory embodied in a geochemical reaction-path modeling program that calculates aqueous phase speciation and mineral precipitation/dissolution. These models are currently under development. Future experimental and modeling work to better quantify the rate-controlling processes and validate these models are necessary before the models can be used in repository performance assessment calculations.
Date: November 1, 1993
Creator: Bourcier, W. L.
Object Type: Report
System: The UNT Digital Library
Target rapidity baryon distributions in {sup 28}Si + {sup 197}Au and {sup 197}Au + {sup 197}Au collisions at 14.6 and 11.7 A{center_dot}GeV/c (open access)

Target rapidity baryon distributions in {sup 28}Si + {sup 197}Au and {sup 197}Au + {sup 197}Au collisions at 14.6 and 11.7 A{center_dot}GeV/c

Proton and deuteron kinetic energy spectra have been measured at target rapidities for both minimum bias and central collisions of 14.6 A{center_dot}GeV/c {sup 28}Si and 11.7 A{center_dot}GeV/c {sup 197}Au beams with a {sup 197}Au target. The spectra were measured from a low energy threshold of approximately E{sub kin}=35 MeV to well over 200 MeV for laboratory angles of 50{degree} to 130{degree} ({vert_bar}{eta}{vert_bar} {le}0.76). The acceptance-corrected spectra have been fit over a limited range of kinetic energies using a Boltzmann distribution. The integrated yields and the inverse slope parameters are presented as a function of centrality for the {sup 28}Si + {sup 197}Au reaction and as a function of trigger for the {sup 197}Au + {sup 197}Au reaction. These quantities are also compared with the proton spectra generated using both the ARC and RQMD codes.
Date: February 25, 1993
Creator: Sangster, T.C.; Costales, J.B.; Namboodiri, M.N. & Collaboration, E802
Object Type: Article
System: The UNT Digital Library
Natural gas recovery, storage, and utilization SBIR program (open access)

Natural gas recovery, storage, and utilization SBIR program

A Fossil Energy natural-gas topic has been a part of the DOE Small Business Innovation Research (SBIR) program since 1988. To date, 50 Phase SBIR natural-gas applications have been funded. Of these 50, 24 were successful in obtaining Phase II SBIR funding. The current Phase II natural-gas research projects awarded under the SBIR program and managed by METC are presented by award year. The presented information on these 2-year projects includes project title, awardee, and a project summary. The 1992 Phase II projects are: landfill gas recovery for vehicular natural gas and food grade carbon dioxide; brine disposal process for coalbed gas production; spontaneous natural as oxidative dimerization across mixed conducting ceramic membranes; low-cost offshore drilling system for natural gas hydrates; motorless directional drill for oil and gas wells; and development of a multiple fracture creation process for stimulation of horizontally drilled wells.The 1993 Phase II projects include: process for sweetening sour gas by direct thermolysis of hydrogen sulfide; remote leak survey capability for natural gas transport storage and distribution systems; reinterpretation of existing wellbore log data using neural-based patter recognition processes; and advanced liquid membrane system for natural gas purification.
Date: December 31, 1993
Creator: Shoemaker, H.D.
Object Type: Article
System: The UNT Digital Library