AN INTEGRATED RELAP5-3D AND MUTLIPHASE CFD CODE SYSTEM UTILIZING A SEMI-implicit coupling technique (open access)

AN INTEGRATED RELAP5-3D AND MUTLIPHASE CFD CODE SYSTEM UTILIZING A SEMI-implicit coupling technique

An integrated code system consisting of RELAP5-3D and a multiphase CFD program has been created through the use of a generic semi-implicit coupling algorithm. Unlike previous CFD coupling work, this coupling scheme is numerically stable provided the material Courant limit is not violated in RELAP5-3D or at the coupling locations. The basis for the coupling scheme and details regarding the unique features associated with the application of this technique to a four-field CFD program are presented. Finally, the results of a verification problem are presented. The coupled code system is shown to yield accurate and numerically stable results.
Date: September 5, 2001
Creator: Aumiller, D.L., Tomlinson, E.T., and Weaver, W.L.
Object Type: Report
System: The UNT Digital Library
Use of Optically Stimulated Luminescence Imaging Plates and Reader for Arms Control Applications (open access)

Use of Optically Stimulated Luminescence Imaging Plates and Reader for Arms Control Applications

Optically Stimulated Luminescence (OSL) technology has been pioneered at the Pacific Northwest National Laboratory (PNNL) for applications in personnel radiation dosimetry and commercially has become highly successful in replacing older technologies such as Thermoluminescence Dosimeters (TLDs) and film. OSL phosphors are used to measure radiation exposure by illuminating them with light after ionizing radiation exposure and measuring the amount of light emitted by the OSL phosphor. By using a two-dimensional plate of OSL material and raster scanning a light beam across the OSL plate a radiation pattern or image can be measured. The Arms Control community requires an electrons-free medium to measure the attributes of extent and symmetry on Pu pits in storage containers. OSL technology, used in the two-dimensional imaging mode, provides a means to measure these attributes with exposure times on the order of an hour. A special OSL reader has been built by PNNL to measure OSL imaging plates with a size of 20 cm by 30 cm. The reader uses 10 light emitting diode clusters with 10 corresponding photomultiplier tubes to measure an OSL imaging plate in less than 5 minutes. The resolution of each of the 10 measurement assemblies is 1 square-centimeter. A collimator assembly …
Date: July 5, 2001
Creator: Miller, Steven D.; Tomeraasen, Paul L.; Burghard, Brion J. & Traub, Richard J.
Object Type: Report
System: The UNT Digital Library
NIF PEPC LRU Test Stand Safety Note Addendum (open access)

NIF PEPC LRU Test Stand Safety Note Addendum

It is necessary that the NIF PEPC LRU Test Stand be modified to accommodate a new experiment. This modification will involve boring two 1/2 inch holes in the Center Loaded Upper Beam of the stand. These holes will allow a small wire to pass through half of the length of one of the long sections of 80/20 part 3030. The holes could adversely effect the load-bearing capabilities of an important structural member of the stand so calculations must be done to assure a minimal risk of part failure.
Date: September 5, 2001
Creator: Mason, D
Object Type: Report
System: The UNT Digital Library
Signal and imaging sciences workshop 1999 proceedings (open access)

Signal and imaging sciences workshop 1999 proceedings

None
Date: January 5, 2001
Creator: Candy, J V
Object Type: Report
System: The UNT Digital Library
Theory Issues for Induced Plasma Convection Experiments in the Divertor of the MAST Spherical Tokamak (open access)

Theory Issues for Induced Plasma Convection Experiments in the Divertor of the MAST Spherical Tokamak

This paper surveys theory issues associated with inducing convective cells through divertor tile biasing in a tokamak to broaden the scrape-off layer (SOL). The theory is applied to the Mega-Ampere Spherical Tokamak (MAST), where such experiments are planned in the near future. Criteria are presented for achieving strong broadening and for exciting shear-flow turbulence in the SOL; these criteria are shown to be attainable in practice. It is also shown that the magnetic shear present in the vicinity of the X-point is likely to confine the potential perturbations to the divertor region below the X-point, leaving the part of the SOL that is in direct contact with the core plasma intact. The current created by the biasing and the associated heating power are found to be modest.
Date: September 5, 2001
Creator: Cohen, R. H.; Fielding, S.; Helander, P. & Ryutov, D. D.
Object Type: Article
System: The UNT Digital Library
Development of Components for Wavelength Division Multiplexing Over Parallel Optical Interconnects (open access)

Development of Components for Wavelength Division Multiplexing Over Parallel Optical Interconnects

Parallel optical interconnects based on multimode fiber ribbon cables are emerging as a robust, high-performance data link technology that enhances throughput by using parallel arrays of fibers. While this technology has primarily been implemented as single wavelength point-to-point links, it can be significantly enhanced by wavelength division multiplexing (WDM). WDM enables both increased point-to-point bandwidth as well as more complex interconnect topologies and routing approaches that are particularly attractive for massively parallel processing (MPP) systems. Exploiting the advantages of WDM interconnects requires multi-wavelength sources, a low loss routing fabric, and small footprint wavelength selective filter modules. The Lambda-connect project ({gamma}- Connect) at Lawrence Livermore National Laboratory is a technology development and proof-of-principle demonstration of the enabling hardware for WDM parallel optical interconnects for use in massively parallel processing systems and other high-performance data link applications. This dissertation demonstrates several key system components and technologies for {gamma}-Connect.
Date: July 5, 2001
Creator: Patel, R
Object Type: Report
System: The UNT Digital Library
NIF Power Conditioning System Testing at LLNL (open access)

NIF Power Conditioning System Testing at LLNL

The National Ignition Facility (NIF) is now under construction at the Lawrence Livermore National Laboratory (LLNL). The Power Conditioning System (PCS) for NIF, when completed will consist of a 192 nearly identical 2 megajoule capacitor storage banks driving 7680 two meter long flashlamps. A fully integrated single-module test facility was completed in August of 2000 at LLNL. The purpose to the Test Facility is to conduct Reliability and Maintainability (RAM) testing of a true ''First Article'' system (built to the final drawing package as opposed to a prototype). The test facility can be fired once every ten minutes with a total peak output current of 580kA with a pulse width of 400us. To date over 4000 full power shots have been conducted at this facility.
Date: June 5, 2001
Creator: Fulkerson, E S; Newton, M; Hulsey, s; Hammon, J & Moore, W
Object Type: Article
System: The UNT Digital Library
Technical Advances in the Continuous Melting of Phosphate Laser Glass (open access)

Technical Advances in the Continuous Melting of Phosphate Laser Glass

Continuous melting of phosphate laser glass is now being used for the first time to prepare meter-scale amplifier optics for megajoule lasers. The scale-up to continuous melting from the previous one-at-a-time ''discontinuous'' batch process has allowed for the production of glass at rates more than 20 times faster, 5 times cheaper, and with 2-3 times better optical quality. Almost 8000 slabs of laser glass will be used in high-energy, high-peak-power laser systems that are being designed and built for fusion energy research. The success of this new continuous melting process, which is a result of a six year joint R&D program between government and industry, stems from numerous technical advances which include (1) dehydroxylating the glass to concentrations less than {approx}100 ppm OH; (2) minimizing damage-causing Pt-inclusions; (3) preventing glass fracture; (4) minimizing impurities such as Cu and Fe to <20 ppm; (5) improving forming methods to get high optical homogeneity glass; and (6) developing large aperture quality assurance tools to verify properties of the glass.
Date: September 5, 2001
Creator: Suratwala, T.; Thorsness, C.; Campbell, J.; Takeuchi, K.; Suzuki, K.; Yamamoto, K. et al.
Object Type: Article
System: The UNT Digital Library
Immobilization of uranium and plutonium into borobasalt, pyroxene and andradite mineral-like compositions (open access)

Immobilization of uranium and plutonium into borobasalt, pyroxene and andradite mineral-like compositions

The immobilization of plutonium-containing wastes into stable solid compositions is one of the problems to be solved in the disposal of radioactive wastes. Research efforts on the selection, preparation with the use of the cold crucible induction melter (CCIM) technology, and investigation of materials that are most suitable for immobilizing plutonium-containing wastes of different origin have been carried out at the All-Russian Scientific Research Institute of Inorganic Materials (VNIINM) and the Institute of the Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences within the framework of agreements with Lawrence Livermore National Laboratory (LLNL, USA) regarding material and technical support. This paper presents the data on the synthesis of cerium-, uranium-, and plutonium-containing materials based on borobasalt, pyroxene, and andradite compositions in the muffle furnace and by the CCIM method. Compositions containing up to 15-18 wt% cerium oxide, 8-11 wt% uranium oxide, and 4.6-5.7 wt% plutonium oxide were obtained in laboratory facilities installed in glove boxes. Comparison studies of the materials synthesized in the muffle furnace and CCIM demonstrate the advantages of using the CCIM method. The distribution of components in the materials.
Date: February 5, 2001
Creator: Matyunin, Y I; Jardine, L J & Yudintsev, S V
Object Type: Article
System: The UNT Digital Library
Automated Test System for NIF Flashlamps (open access)

Automated Test System for NIF Flashlamps

This paper describes design and operation of the flashlamp test system, used to evaluate the primary laser flashlamps on the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory (LLNL) in Livermore, California. The tester delivers repetitive high voltage pulses to a series pair of flashlamps at levels closely simulating those encountered in normal operation. Each lamp pair is subjected to a pre-ionization and main pulse shot sequence, with two minute intervals between shots. This capability allows the manufacturer to test and evaluate the flashlamps for infant mortality and longevity before delivery to NIF. All operations are under computer control with fully automated test and data acquisition capabilities requiring minimal operator input. The system is designed to operate continuously. Typical pre-ionization and main pulse outputs are: (1) Pre-ionization Pulse--V{sub chg} = 27kV, I{sub peak} = 3kA, E = 2.4kJ; Pulse Width--(10%-90%) - 200us; Main Pulse--V{sub chg} = 23kV, I{sub peak} - 24kA, E - 78.6kJ; and Pulse Width--(10%-90%) - 350us.
Date: June 5, 2001
Creator: da Silva, T; Creely, P; Hammon, J; Shaw, R; Boyle, R T & Fulkerson, E S
Object Type: Article
System: The UNT Digital Library
Status of Optical Coatings for the National Ignition Facility (open access)

Status of Optical Coatings for the National Ignition Facility

Optical coatings are a crucial part of the pulse trapping and extraction in the NIF multipass amplifiers. Coatings also steer the 192 beams from four linear arrays to four converging cones entering the target chamber. There are a total of 1600 physical vapor deposited coatings on NIF consisting of 576 mirrors within the multipass cavity, 192 polarizers that work in tandem with a Pockels cell to create an optical switch, and 832 transport mirrors. These optics are of sufficient size so that they are not aperture-limiting for the 40-cm x 40 cm beams over an incident range of 0 to 56.4 degrees. These coatings must withstand laser fluences up to 25 J/cm{sup 2} at 1053 nm (1 {omega}) and 3-ns pulse length and are the 1{omega} fluence-limiting component on NIF. The coatings must have a minimal impact on the beam wavefront and phase to maintain beam focusability, minimize scattered loss, and minimize nonlinear damage mechanisms. This is achieved by specifications ranging from <50 MPa coating stress, <1% coating nonuniformity, <4{angstrom} RMS surface roughness, and a PSD specification to control the amplitude of periodic spatial frequencies. Finally, the primary mission of optical coatings is efficient beam steering so reflection and transmission …
Date: March 5, 2001
Creator: Stolz, C. J.; Weinzapfel, C.; Rogowski, G. T.; Smith, D.; Rigatti, A.; Oliver, J. et al.
Object Type: Article
System: The UNT Digital Library
Deterrence and National Security in the Face of an Amorphous Threat (open access)

Deterrence and National Security in the Face of an Amorphous Threat

The National Security threats that we face today and, in turn, the National Security . requirements, are more diverse and complex than they were during the Cold-War from 1945-1990. During that period, and bolstered by the experiences of World Wars I and II, US National Security policy was focused on the stabilization of post WW II country boundaries and containment of the Soviet block and China. The result was the bipolar world in which the nuclear and conventional forces of the United States, the Soviet Union, and their respective allies ensured a measure of political stability through a military stalemate of world wide proportions. The practical result was that large scale changes in national borders were unlikely, but internal conflict within countries, and local conflicts between neighboring countries could still occur, albeit with participation from one or both of the Superpower camps. US National Security Policy was designed primarily for stabilization of the bipolar world on the military front and for competition with the Soviet Union and China on economic and political fronts. The collapse of the Soviet Union changed the global picture. The bipolar world and its military stalemate appear to be gone for the moment and the threat …
Date: January 5, 2001
Creator: Werne, R
Object Type: Report
System: The UNT Digital Library
Progress in Infrared Pyrometry Measurements of Shocked Solids (open access)

Progress in Infrared Pyrometry Measurements of Shocked Solids

Temperature measurement is one of the grand challenges still facing experimental shock physics. A shock experiment fundamentally measures E({sigma}{sub x}, {var_epsilon}{sub 11}) which is an incomplete equation of state since temperature (or entropy) remains unspecified. Ideally, one would like to experimentally determine a free energy F(T, {var_epsilon}{sub ij}) from which all other thermo-mechanical properties might be derived. In practice, temperature measurement would allow direct comparison with theory/simulation since T and {var_epsilon}{sub 11} are in most theories the underlying variables. Temperature is a sensitive measure of energy partitioning, knowledge of which would increase our understanding phase boundaries and thermally activated processes (such as chemical reactivity (including dissociation and ionization)). Temperature measurement would also allow a thermodynamically consistent coupling of hydrodynamic equations of state to the material's constitutive (deformation) behavior. The measurement of the temperature of a material that has undergone severe strains at small time-scales is extremely difficult, and we are developing a method using infrared reflectance and pyrometry. The emitted power from a warm surface is measured over a range of wavelengths using a multi-channel IR detector with a response time of {approx}0.1 {micro}s. Each channel of the detector passes the radiation from a selected wavelength interval into a detector. …
Date: November 5, 2001
Creator: Cazamias, J U; Hare, D E & Poulsen, P
Object Type: Article
System: The UNT Digital Library
Intermittent Turbulence in the Very Stable Ekman Layer (open access)

Intermittent Turbulence in the Very Stable Ekman Layer

INTERMITTENT TURBULENCE IN THE VERY STABLE EKMAN LAYER This study describes a Direct Numerical Simulation (DNS) of a very stable Ekman layer in which a constant downward heat flux is applied at the lower boundary, thus cooling the fluid above. Numerical experiments were performed in which the strength of the imposed heat flux was varied. For downward heat fluxes above a certain critical value the turbulence becomes intermittent and, as the heat flux increases beyond this value, the flow tends to relaminarize because of the very strong ambient stratification. We adopt Mahrt?s (1999) definition of the very stable boundary layer as a boundary layer in which intermittent, rather than continuous turbulence, is observed. Numerical experiments were used to test various hypothesis of where in ?stability parameter space? the very stable boundary layer is found. These experiments support the findings of Howell and Sun (1999) that the boundary layer will exhibit intermittency and therefore be categorized as ?very stable?, when the stability parameter, z/L, exceeds unity. Another marker for the very stable boundary layer, Derbyshire?s (1990) maximum heat flux criterion, was also examined. Using a case study drawn from the simulations where turbulence intermittency was observed, the mechanism that causes the …
Date: January 5, 2001
Creator: Barnard, James C.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Selection of Sampling Pumps Used for Groundwater Monitoring at the Hanford Site (open access)

Selection of Sampling Pumps Used for Groundwater Monitoring at the Hanford Site

The variable frequency drive centrifugal submersible pump, Redi-Flo2a made by Grundfosa, was selected for universal application for Hanford Site groundwater monitoring. Specifications for the selected pump and five other pumps were evaluated against current and future Hanford groundwater monitoring performance requirements, and the Redi-Flo2 was selected as the most versatile and applicable for the range of monitoring conditions. The Redi-Flo2 pump distinguished itself from the other pumps considered because of its wide range in output flow rate and its comparatively moderate maintenance and low capital costs. The Redi-Flo2 pump is able to purge a well at a high flow rate and then supply water for sampling at a low flow rate. Groundwater sampling using a low-volume-purging technique (e.g., low flow, minimal purge, no purge, or micropurgea) is planned in the future, eliminating the need for the pump to supply a high-output flow rate. Under those conditions, the Well Wizard bladder pump, manufactured by QED Environmental Systems, Inc., may be the preferred pump because of the lower capital cost.
Date: November 5, 2001
Creator: Schalla, Ronald; Webber, William D. & Smith, Ronald M.
Object Type: Report
System: The UNT Digital Library
Magnet options for sensors for the pulp and paper industry (open access)

Magnet options for sensors for the pulp and paper industry

The Lawrence Berkeley National Laboratory (LBNL) has been developing sensors for the pulp and paper industry that uses a magnetic field. The applications for magnetic sensors that have studied include (1) sensors for the measurement of the water and ice content of wood chips entering the pulping mill, (2) sensors for measuring the water content and other constituents of the black liquor leaving the paper digester, and (3) sensors for measuring paper thickness and water content as the paper is being processed. These tasks can be done using nuclear magnetic resonance (NMR). The magnetic field used for doing the NMR can come from either permanent magnets or superconducting magnets. The choice of the magnet is dependent on a number of factors, which include the size of the sample and field strength needed to do the sensing task at hand. This paper describes some superconducting magnet options that can be used in the pulp and paper industry.
Date: May 5, 2001
Creator: Green, M. A.; Barale, P. J.; Fong, C. G.; Luft, P. A.; Reimer, J. A. & Yahnke, M. S.
Object Type: Article
System: The UNT Digital Library
Reanalysis of the Schwertmannite structure and the incorporationof SO42- groups: An IR, XAS, WAXS and simulation study (open access)

Reanalysis of the Schwertmannite structure and the incorporationof SO42- groups: An IR, XAS, WAXS and simulation study

Schwertmannite is a poorly crystallized iron oxyhydroxidewith essential structural sulfate that can be a major component in acidmine drainage environments. Original characterization work concluded thatthe sulfate was largely contained within tunnels of an orderedakaganeite-like structure based on powder XRD, analysis of IR spectra,and sulfate extraction procedures [1]. Since the original description,problems have emerged with the nature of the tunnel sulfate, and with theinterpretation of the IR spectra. Other related work has shown that it isnow possible to determine sulfate-iron oxide inner sphere bindingunambiguously from the S K-edge XANES spectrum. Hence a reassessment ofthe evidence for the original schwertmannite structure was deemednecessary and timely.
Date: May 5, 2001
Creator: Waychunas, G.A.; Myneni, S.C.B.; Traina, S.J.; Bigham, J.M.; Fuller, C.C. & Davis, J.A.
Object Type: Article
System: The UNT Digital Library
Fuzzy systems modeling of in situ bioremediation of chlorinatedsolve n ts (open access)

Fuzzy systems modeling of in situ bioremediation of chlorinatedsolve n ts

A large-scale vadose zone-groundwater bioremediationdemonstration was conducted at the Savannah River Site (SRS) by injectingseveral types of gases (ambient air, methane, and nitrous oxide andtriethyl phosphate mixtures) through a horizontal well in the groundwaterat a 175 ft depth. Simultaneously, soil gas was extracted through aparallel horizontal well in the vadose zone at a 80 ft depth Monitoringrevealed a wide range of spatial and temporal variations ofconcentrations of VOCs, enzymes, and biomass in groundwater and vadosezone monitoring boreholes over the field site. One of the powerful modernapproaches to analyze uncertain and imprecise data chemical data is basedon the use of methods of fuzzy systems modeling. Using fuzzy modeling weanalyzed the spatio-temporal TCE and PCE concentrations and methanotrophdensities in groundwater to assess the effectiveness of differentcampaigns of air stripping and bioremediation, and to determine the fuzzyrelationship between these compounds. Our analysis revealed some detailsabout the processes involved in remediation, which were not identified inthe previous studies of the SRS demonstration. We also identified somefuture directions for using fuzzy systems modeling, such as theevaluation of the mass balance of the vadose zone - groundwater system,and the development of fuzzy-ruled methods for optimization of managingremediation activities, predictions, and risk assessment.
Date: September 5, 2001
Creator: Faybishenko, Boris & Hazen, Terry C.
Object Type: Article
System: The UNT Digital Library
Technology Opportunities to Reduce U.S. Greenhouse Gas Emissions (open access)

Technology Opportunities to Reduce U.S. Greenhouse Gas Emissions

The rise in greenhouse gas emissions from fossil fuel combustion and industrial and agricultural activities has aroused international concern about the possible impacts of these emissions on climate. Greenhouse gases--mostly carbon dioxide, some methane, nitrous oxide and other trace gases--are emitted to the atmosphere, enhancing an effect in which heat reflected from the earth's surface is kept from escaping into space, as in a greenhouse. Thus, there is concern that the earth's surface temperature may rise enough to cause global climate change. Approximately 90% of U.S. greenhouse gas emissions from anthropogenic sources come from energy production and use, most of which are a byproduct of the combustion of fossil fuels. On a per capita basis, the United States is one of the world's largest sources of greenhouse gas emissions, comprising 4% of the world's population, yet emitting 23% of the world's greenhouse gases. Emissions in the United States are increasing at around 1.2% annually, and the Energy Information Administration forecasts that emissions levels will continue to increase at this rate in the years ahead if we proceed down the business-as-usual path. President Clinton has presented a two-part challenge for the United States: reduce greenhouse gas emissions and grow the economy. …
Date: April 5, 2001
Creator: National Lab Directors, . .
Object Type: Report
System: The UNT Digital Library
BPM Signal Level Calculation (open access)

BPM Signal Level Calculation

This note is a short summary of the calculation of the induced signal on a transmission line type BPM pickup plate.
Date: February 5, 2001
Creator: McGinnis, Dave
Object Type: Report
System: The UNT Digital Library
Quadrupole Focussing and Quadrupole Steering Tolerances for the 8 GeV AP3-P1 Lattice (open access)

Quadrupole Focussing and Quadrupole Steering Tolerances for the 8 GeV AP3-P1 Lattice

This note will outline the sensitivity to emittance blowup of antiproton transfers due to quadrupole focussing and quadrupole steering errors in the 8 GeV AP3-P1 transfer line. It will be shown that these tolerances are much larger than the dipole steering tolerances discussed in PBAR Note 649. This note will use the lattice discussed in PBAR Note 648.
Date: February 5, 2001
Creator: McGinnis, Dave
Object Type: Report
System: The UNT Digital Library
Algorithms for deriving crystallographic space-group information. II: Treatment of special positions (open access)

Algorithms for deriving crystallographic space-group information. II: Treatment of special positions

Algorithms for the treatment of special positions in 3-dimensional crystallographic space groups are presented. These include an algorithm for the determination of the site-symmetry group given the coordinates of a point, an algorithm for the determination of the exact location of the nearest special position, an algorithm for the assignment of a Wyckoff letter given the site-symmetry group, and an alternative algorithm for the assignment of a Wyckoff letter given the coordinates of a point directly. All algorithms are implemented in ISO C++ and are integrated into the Computational Crystallography Toolbox. The source code is freely available.
Date: October 5, 2001
Creator: Grosse-Kunstleve, Ralf W. & Adams, Paul D.
Object Type: Article
System: The UNT Digital Library
THE EFFECTS OF BIODIESEL BLENDS AND ARCO EC-DIESEL ON EMISSIONS from LIGHT HEAVY-DUTY DIESEL VEHICLES (open access)

THE EFFECTS OF BIODIESEL BLENDS AND ARCO EC-DIESEL ON EMISSIONS from LIGHT HEAVY-DUTY DIESEL VEHICLES

Chassis dynamometer tests were performed on 7 light heavy-duty diesel trucks comparing the emissions of a California diesel fuel with emissions from 4 other fuels: ARCO EC-diesel (EC-D) and three 20% biodiesel blends (1 yellow grease and 2 soy-based). The EC-D and the yellow grease biodiesel blend both showed significant reductions in THC and CO emissions over the test vehicle fleet. EC-D also showed reductions in PM emission rates. NOx emissions were comparable for the different fuel types over the range of vehicles tested. The soy-based biodiesel blends did not show significant or consistent emissions differences over all test vehicles. Total carbon accounted for more than 70% of the PM mass for 4 of the 5 sampled vehicles. Elemental and organic carbon ratios varied significantly from vehicle-to-vehicle but showed very little fuel dependence. Inorganic species represented a smaller portion of the composite total, ranging from 0.2 to 3.3% of the total PM. Total PAH emissions ranged from approximately 1.8 mg/mi to 67.8 mg/mi over the different vehicle/fuel combinations representing between 1.6 and 3.8% of the total PM mass.
Date: August 5, 2001
Creator: Durbin, Thomas
Object Type: Article
System: The UNT Digital Library
Secondary Uranium-Phase Paragenesis and Incorporation of Radionuclides into Secondary Phase (open access)

Secondary Uranium-Phase Paragenesis and Incorporation of Radionuclides into Secondary Phase

The purpose of this analysis/model report (AMR) is to assess the potential for uranium (U) (VI) compounds, formed during the oxidative corrosion of spent uranium-oxide (UO{sub 2}) fuels, to sequester certain radionuclides and, thereby, limit their release. The ''unsaturated drip tests'' being conducted at Argonne National Laboratory (ANL) provide the basis of this AMR (Table 1). The ANL drip tests on spent fuel are the only experiments on fuel corrosion from which solids have been analyzed for trace levels of radionuclides. Brief summaries are provided of the results from other selected corrosion and dissolution experiments on spent UO{sub 2} fuels, specifically those conducted under nominally oxidizing conditions. Discussions of the current understanding of thermodynamic and kinetic properties of U(VI) compounds is provided in order to outline the scientific basis for modeling precipitation and dissolution of potential radionuclide-bearing phases under repository-relevant conditions. Attachment I provides additional information on corrosion mechanisms and behaviors of radionuclides in the tests at ANL. Attachment II reviews occurrence, formation, and alteration (collectively known as paragenesis) of naturally occurring U(VI) minerals because natural mineral occurrences can be used to assess the possible long-term behaviors of U(VI) compounds formed in short-term laboratory experiments and to extrapolate experimental results …
Date: June 5, 2001
Creator: Finch, R.
Object Type: Report
System: The UNT Digital Library