States

In situ determination of desorbable methane content by use of three different decay functions (open access)

In situ determination of desorbable methane content by use of three different decay functions

The desorptive properties of methane in selected western coal seams were studied through actual field measurements using a manual bubble desorbometer and later verified through laboratory modeling. Data were reduced using a power decay function, a quadratic function, and an exponential function. Methane desorption characteristics from individual coal seams were shown theoretically to be a good estimator of a seams total methane content to within {plus minus}20%. A laboratory was set up and equipped to properly analyze and reduce field data, in addition to providing a controlled model for studying methane adsorption properties on coal. The results of the field tests indicate that all three theoretical desorption functions provide a satisfactory model of the desorption process based on estimated and actual gas contents, and on superior coefficient of regression. The estimated gas content for four western coal mines are presented based on computer reduction of data obtained from field and laboratory tests. One of the investigated coal seams is located in Colorado (B seam of the Dutch Creek Mine in Carbondale) and three are located in Central Utah (Rock Canyon seam of the Soldier Creek Mine), Lower Sunnyside (Sunnyside Coal Mines) and Sub 3 (Castle Gate Mine) seam. Their average …
Date: October 1, 1990
Creator: Plaizier, R.R. (Westech Engineering, Inc., Salem, OR (USA)) & Hucka, V.J. (Utah Univ., Salt Lake City, UT (USA). Dept. of Mining Engineering)
Object Type: Article
System: The UNT Digital Library
Janus Upgrade using brewster angle disk amplifier technology. [Janus laser system] (open access)

Janus Upgrade using brewster angle disk amplifier technology. [Janus laser system]

The Nuclear Test and Experimental Science Program (NTES) has requested that the Laser Program design and price an upgrade to the Janus laser system (JANUS UPGRADE) capable of reliably delivering in excess of 200 joules per beamline in a range of pulse forms to three experiment areas. The facility is to have the following characteristics: three experiment areas, two high energy beams, each with 200--400 joule/1 ns at a wavelength of 1.053 or 1.064 microns, and 125--250 J/1 ns when frequency doubled, one probe beam (0.1 J rated at 30 ps) to be used for interferometry, and reliable operation. The proposed facility would occupy approximately 5600 ft{sup 2} and be located in the Bldg. 174 complex. A block diagram of the entire facility is shown in Fig. 1. The facility is further defined by the Work Breakdown Structure (also shown in Fig. 1). The main elements of the WBS are the conventional facility and modifications thereof (WBS 1), special equipment (WBS 2), the laser (WBS 3), the experiment areas (WBS 4), the controls and data acquisition system (WBS 5), and the project integration (WBS 6). The experiment area has three target chambers and uses diagnostic hardware now in Janus. 12 …
Date: October 24, 1990
Creator: Hunt, J.; Boben, R.; Blocker, R.; Clark, J.; Henesian, M.; Victoria, J. et al.
Object Type: Report
System: The UNT Digital Library
Real-time multi-dimensional processing hardware designs research activities (open access)

Real-time multi-dimensional processing hardware designs research activities

In this final report, we summarize some of our results from September 1989 to October 1990. The design, construction, and testing of a four-processor prototype multi-processor (RTP) board using TI TMS320C25 DSP chips has been completed and is reported upon in our separately submitted Final Report on the RADON TRANSFORM COMPUTER'' Project.'' The design of our fully custom CMOS VLSI chip has been completed. The chip has been designed, the layout completed, and the chip is now going through its final pre-fabrication simulations. We are now finishing the extensive detailed final documentation of the R/Bchip. This extensive documentation will be provided to Steve Azevedo when we have submitted the chip for fabrication. The present status of the custom chip design activity is summarized in Section II. Evaluations of the hardware requirements for fast filtering of data for filtered backprojection (item 3) have been completed and are summarized in our separately submitted Final Report on the RADON TRANSFORM COMPUTER'' Project.'' We briefly summarize the new custom CMOS VLSI unified Radon transform/backprojection IC architecture, layout, and simulated performance.
Date: October 31, 1990
Creator: Current, W. (California Univ., Davis, CA (USA). Dept. of Electrical Engineering and Computer Science)
Object Type: Report
System: The UNT Digital Library
Development of high energy density fuels from mild gasification of coal (open access)

Development of high energy density fuels from mild gasification of coal

The overall objective of the program is the determination of the minimal processing requirements to produce High Energy Density Fuels (HEDF), meeting a minimal energy density of 130,000 Btu/gal (conventional jet fuels have energy densities in the vicinity of 115,000--120,000 Btu/gal) and having acceptable advanced fuel specifications in accordance with the three defined categories of HEDF. The program encompasses assessing current technology capability; selecting acceptable processing and refining schemes; and generating samples of advanced test fuels. A task breakdown structure was developed containing eight key tasks. This report summarizes the work that Amoco Oil Company (AOC), as key subcontractor, performed in the execution of Task 4, Proposed Upgrading Schemes for Advanced Fuel. The intent of the Task 4 study was to represent all the candidate processing options, that were either studied in the experimental efforts of Task 3 or were available from the prior art in the open literature, in a linear program (LP) model. The LP model would allow scaling of the bench-scale Task 3 results to commercial scale and would perform economic evaluations on any combination of the processes which might be used to make HEDF. Section 2.0 of this report summarizes the process and economic bases used. …
Date: October 1, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Edge fluctuations in the MST (Madison Symmetric Torus) reversed field pinch (open access)

Edge fluctuations in the MST (Madison Symmetric Torus) reversed field pinch

Edge magnetic and electrostatic fluctuations are measured in the Madison Symmetric Torus (MST) reversed field pinch. At low frequency (<25 kHz), the mode number spectra of magnetic fluctuations agree very well with theoretical prediction for nonlinearly saturated tearing fluctuations resonant in the core. At high frequency (50 kHz to 100 kHz) the magnetic spectra broaden and the modes become resonant in the reversal region. Nonlinear phenomena are under experimental investigation. The low frequency fluctuations phase-lock together to produce a rotating localized disturbance. Bi-spectral analysis in frequency also reveals nonlinear three-wave mode-coupling at low frequency. Electrostatic fluctuations are substantial and do not appear to obey a Boltzmann relation (i.e. e{tilde {phi}}/kT{sub e} > {tilde p}{sub e}/p{sub e} where {tilde {phi}} and {tilde p}{sub e} are the fluctuating potential and pressure, respectively). From measurements of the fluctuating density, temperature, and potential we infer that the electrostatic fluctuation induced transport of particles and energy can be substantial. 13 refs., 11 figs.
Date: October 1, 1990
Creator: Almagri, A.; Assadi, S.; Beckstead, J.; Chartas, G.; Crocker, N.; Den Hartog, D. et al.
Object Type: Article
System: The UNT Digital Library
Laboratory setup and results of experiments on two-dimensional multiphase flow in porous media (open access)

Laboratory setup and results of experiments on two-dimensional multiphase flow in porous media

In the event of an accidental release into earth's subsurface of an immiscible organic liquid, such as a petroleum hydrocarbon or chlorinated organic solvent, the spatial and temporal distribution of the organic liquid is of great interest when considering efforts to prevent groundwater contamination or restore contaminated groundwater. An accurate prediction of immiscible organic liquid migration requires the incorporation of relevant physical principles in models of multiphase flow in porous media; these physical principles must be determined from physical experiments. This report presents a series of such experiments performed during the 1970s at the Swiss Federal Institute of Technology (ETH) in Zurich, Switzerland. The experiments were designed to study the transient, two-dimensional displacement of three immiscible fluids in a porous medium. This experimental study appears to be the most detailed published to date. The data obtained from these experiments are suitable for the validation and test calibration of multiphase flow codes. 73 refs., 140 figs.
Date: October 1, 1990
Creator: McBride, J.F. (ed.) (Pacific Northwest Lab., Richland, WA (USA)); Graham, D.N. (ed.) & Schiegg, H.O. (SIMULTEC Ltd., Meilen/Zurich (Switzerland))
Object Type: Report
System: The UNT Digital Library
Graded Al sub x Ga sub 1-x as photoconductive devices for high efficiency picosecond optoelectronic switching (open access)

Graded Al sub x Ga sub 1-x as photoconductive devices for high efficiency picosecond optoelectronic switching

Picosecond photoconductivity has been achieved for a variety of semiconductor materials by techniques which have now become almost standard. Enhanced scattering by the excessive amount of deep level defects which provide for picosecond recombination lifetimes significantly reduce the mobility, degrading the responsivity of the photoconductor. This paper will present a concept where improved responsivity is achievable by utilizing a graded bandgap Al{sub x}Ga{sub 1-x}As active detecting layer grown on a high defect density GaAs layer by molecular beam epitaxy (MBE). 7 refs., 6 figs.
Date: October 1, 1990
Creator: Morse, J.D.; Mariella, R.P. (Lawrence Livermore National Lab., CA (USA)) & Dutton, R.W. (Stanford Univ., CA (USA). Center for Integrated Systems)
Object Type: Article
System: The UNT Digital Library
A guide to using material model No. 11 in NIKE2D: An internal variable, viscoplasticity model (open access)

A guide to using material model No. 11 in NIKE2D: An internal variable, viscoplasticity model

The need to accurately model the superplastic forming process which is highly rate and temperature dependent motivated the evaluation of Bammann's internal variable, viscoplasticity material model. The model is based upon the concepts of unified creep plasticity, but employs a yield surface for efficient implementation into large-scale numerical computer codes. It has proven elsewhere to be quite successful in describing large strain, thermal-mechanical behavior of crystalline materials. Features of the model enable it to simulate the apparent strain-rate behavior exhibited by many metals above one half the melt temperature. It is the efficient incorporation of features that make the model attractive for use in finite element modeling of metal deformation processes. Although this model was implemented into the Lawrence Livermore National Laboratory's NIKE2D finite element program in 1986, there have been no known reports of successful use by NIKE2D users. The purpose of this report is to provide the user the proper format to input model parameters, a procedure for determining appropriate values for material constants from experimental data, and supplemental information on the model relevant to the implementation in the NIKE2D finite element program. Detailed accounts of the theoretical aspects of the model can be found in the cited …
Date: October 30, 1990
Creator: Flower, E. C. & Nikkel, D. J. Jr.
Object Type: Report
System: The UNT Digital Library
The determination of the Fe sup 2+ /Fe sup 3+ ratio in simulated nuclear waste glass by ion chromatography (open access)

The determination of the Fe sup 2+ /Fe sup 3+ ratio in simulated nuclear waste glass by ion chromatography

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass in the Defense Waste Processing Facility (DWPF). In this facility, control of the oxidation/reduction (redox) equilibrium in the glass melter is critical for processing of the nuclear waste. Therefore, the development of a rapid and reliable analytical method for the determination of the redox equilibrium is of considerable interest. Redox has been determined by measuring the ratio of ferrous to ferric ions in the glass melt. Two analytical techniques for glass redox measurement have been investigated for the DWPF: Mossbauer Spectroscopy which may be subject to interferences from the radiation in actual waste, and a rapid and simple chemical dissolution/spectrophotometric technique. Comparisons of these techniques have been made at several laboratories including Clemson University. In the study attached, the determination of the redox ratio by Ion Chromatography (IC) was investigated as a potential new technology. Clemson University performed IC analyses on the same glasses as previously examined by wet chemical and Mossbauer techniques. Results from all three techniques were highly correlated and IC was reported to be a promising new technology for redox measurement. 19 refs., 19 figs., 5 tabs.
Date: October 1, 1990
Creator: Jantzen, Carol M.
Object Type: Report
System: The UNT Digital Library
Monolithic JFET preamplifier for ionization chamber calorimeter (open access)

Monolithic JFET preamplifier for ionization chamber calorimeter

A monolithic charge sensitive preamplifier using exclusively n-channel diffused JFETs has been designed and is now being fabricated by INTERFET Corp. by means of a dielectrically isolated process which allows preserving as much as possible the technology upon which discrete JFETs are based. A first prototype built by means of junction isolated process has been delivered. The characteristics of monolithically integrated JFETs compare favorably with discrete devices. First results of tests of a preamplifier which uses these devices are reported. 4 refs.
Date: October 1, 1990
Creator: Radeka, V.; Rescia, S. (Brookhaven National Lab., Upton, NY (United States)); Manfredi, P.F. & Speziali, V. (Pavia Univ. (Italy). Dipt. di Elettronica)
Object Type: Article
System: The UNT Digital Library
Shapes and textures for rendering coral (open access)

Shapes and textures for rendering coral

A growth algorithm has been developed to build coral shapes out of a tree of spheres. A volume density defined by the spheres is contoured to give a soft object.'' The resulting contour surfaces are rendered by ray tracing, using a generalized volume texture to produce shading and bump mapped'' normal perturbations. 16 refs., 8 figs.
Date: October 18, 1990
Creator: Max, N.L. (Lawrence Livermore National Lab., CA (USA)) & Wyvill, G. (Otago Univ., Dunedin (New Zealand))
Object Type: Article
System: The UNT Digital Library
Accelerator magnet designs using superconducting magnetic shields (open access)

Accelerator magnet designs using superconducting magnetic shields

Superconducting dipoles and quadrupoles for existing accelerators have a coil surrounded by an iron shield. The shield limits the fringe field of the magnet while having minimal effect on the field shape and providing a small enhancement of the field strength. Shields using superconducting materials can be thinner and lighter and will not experience the potential of a large de-centering force. Boundary conditions for these materials, material properties, mechanical force considerations, cryostat considerations and some possible geometrical configurations for superconducting shields will be described. 7 refs., 3 figs., 3 tabs.
Date: October 1, 1990
Creator: Brown, B.C.
Object Type: Article
System: The UNT Digital Library
Ecological Research Division Theoretical Ecology Program. [Contains abstracts] (open access)

Ecological Research Division Theoretical Ecology Program. [Contains abstracts]

This report presents the goals of the Theoretical Ecology Program and abstracts of research in progress. Abstracts cover both theoretical research that began as part of the terrestrial ecology core program and new projects funded by the theoretical program begun in 1988. Projects have been clustered into four major categories: Ecosystem dynamics; landscape/scaling dynamics; population dynamics; and experiment/sample design.
Date: October 1, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Electrochemical processing of nitrate waste solutions (open access)

Electrochemical processing of nitrate waste solutions

Nitrate and nitrite have been almost completely removed from the synthetic effluent steam with good efficiency by affecting a separation across a pair of ion exchange membranes. In addition to recovering acid and base in this process, the volume of the remaining effluent is reduced considerably by transport of water across the membrane. One of the problems that remains with this process, however, is the stability of the membranes and particularly the stability of the anion exchange membrane. This membrane is exposed to both nitric acid and strongly alkaline solutions in the cell and to date long term stability has been a problem with the membranes tested. It is recommended that further work should evaluate other newly available membranes as well as study the effects of radiation on the performance of the membranes. The direct reduction of nitrate and nitrite has been studied at several different electrode materials and it has been demonstrated that cathode material has a large effect on both the efficiency and the gas product distribution. Highest current efficiencies for the reduction process are seen at those electrode materials that are known to show high hydrogen overpotentials. Flow cell studies have demonstrated that temperature and current density …
Date: October 12, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Novel metal ion surface modification technique (open access)

Novel metal ion surface modification technique

We describe a method for applying metal ions to the near-surface region of solid materials. The added species can be energetically implanted below the surface or built up as a surface film with an atomically mixed interface with the substrate; the metal ion species can be the same as the substrate species or different from it, and more than one kind of metal species can be applied, either simultaneously or sequentially. Surface structures can be fabricated, including coatings and thin films of single metals, tailored alloys, or metallic multilayers, and they can be implanted or added onto the surface and ion beam mixed. We report two simple demonstrations of the method: implantation of yttrium into a silicon substrate at a mean energy of 70 keV and a dose of 1 {times} 10{sup 16} atoms/cm{sup 2}, and the formation of a titanium-yttrium multilayer structure with ion beam mixing to the substrate. 17 refs., 3 figs.
Date: October 1, 1990
Creator: Brown, I.G.; Godechot, X. & Yu, K.M.
Object Type: Report
System: The UNT Digital Library
Experimental studies of elementary particle interactions at high energies (open access)

Experimental studies of elementary particle interactions at high energies

This report reviews research program at cern; research program at fermilab; and proposals for experiments and detector systems at the SSC.
Date: October 9, 1990
Creator: Deleuse, B.W.
Object Type: Report
System: The UNT Digital Library
Liquid Phase Methanol Laporte Process Development Unit: Modification, Operation, and Support Studies (open access)

Liquid Phase Methanol Laporte Process Development Unit: Modification, Operation, and Support Studies

The objectives of this program are to implement and test the process improvements identified through the engineering studies of the current program to demonstrate the capability of long-term catalyst activity maintenance, and to perform process and design engineering work that can be applied to a scaled-up Liquid Phase Methanol (LPMEOH) facility. An optional series of PDU runs is offered to extend the testing of the process improvements. A parallel research program will be performed to enhance the LPMEOH technical data base to improve the likelihood of commercialization of the LPMEOH process. Activities this quarter include: Flow sheet development for La Porte PDU modifications continues. A preliminary P ID review was completed and flow sheet modifications were identified and are being incorporated. A preliminary hazards review was completed on 22 May. Some minor flow sheet modifications resulted and a number of action items were identified. The most significant action item is to develop a materials reactivity and compatibility grid for the different alcohols, ethers, and esters which will be produced at the PDU. Heat and material balances were completed for the maximum production case of the mixed DME/MEOH synthesis campaign. An improved rate expression was developed. 1 fig.
Date: October 23, 1990
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Combustion front propagation in underground coal gasification (open access)

Combustion front propagation in underground coal gasification

Reverse Combustion (RC) enhances coal seam permeability prior to Underground Coal Gasification. Understanding RC is necessary to improve its reliability and economics. A curved RC front propagation model is developed, then solved by high activation energy asymptotics. It explicitly incorporates extinction (stoichiometric and thermal) and tangential heat transport (THT) (convection and conduction). THT arises from variation in combustion front temperature caused by tangential variation in the oxidant gas flux to the channel surface. Front temperature depends only weakly on THT; front velocity is strongly affected, with heat loss slowing propagation. The front propagation speed displays a maximum with respect to gas flux. Combustion promoters speed front propagation; inhibitors slow front propagation. The propagation model is incorporated into 2-D simulations of RC channel evolution utilizing the boundary element method with cubic hermetian elements to solve the flow from gas injection wells through the coal to the convoluted, temporally evolving, channel surface, and through the channel to a gas production well. RC channel propagation is studied using 17 cm diameter subbituminous horizontally drilled coal cores. Sixteen experiments at pressures between 2000 and 3600 kPa, injected gas oxygen contents between 21% and 75%, and flows between 1 and 4 standard liters per minute …
Date: October 1990
Creator: Dobbs, Richard L., II & Krantz, William B.
Object Type: Report
System: The UNT Digital Library
Use of DWPF redox measurement technique on glasses from West Valley Nuclear Fuel Services Demonstration Project (open access)

Use of DWPF redox measurement technique on glasses from West Valley Nuclear Fuel Services Demonstration Project

Liquid high-level nuclear waste will be immobilized at the Savannah River Site (SRS) by vitrification in borosilicate glass in the Defense Waste Processing Facility (DWPF). A similar vitrification facility exists at the West Valley Nuclear Fuel Services. In both of these facilities, control of the oxidation/reduction (redox) equilibrium in the glass melter is critical for processing of the nuclear waste. Redox can be determined by measuring the ratio of ferrous to ferric ions in the glass melt. A colorimetric procedure has been developed for the DWPF which has been shown to give rapid and reliable analytical results. This colorimetric technique has been shown to measure the Fe{sup 2+} component of glasses more accurately than other existing redox measurement methods. The DWPF redox technique was applied to a series of six glasses taken from the West Valley melter during a transient melter excursion. This excursion caused the glasses to become progressively more reducing with time. Application of the DWPF redox technique to these glasses correctly indicated the redox trends with a higher precision and with more accuracy than the West Valley wet chemical method and/or Alfred University's Mossbauer method. 1 fig., 18 refs.
Date: October 1, 1990
Creator: Jantzen, Carol M.
Object Type: Report
System: The UNT Digital Library
MCNP S(. alpha. beta. ) detector scheme (open access)

MCNP S(. alpha. beta. ) detector scheme

An approximate method to allow S({alpha},{Beta}) thermal collision contributions to point detectors and DXTRAN by Prael has been implemented in MCNP4. The method is described and test results are presented, including some results that indicate inadequacies in the NJOY processing of the nuclear data. 9 refs., 53 figs., 6 tabs.
Date: October 1, 1990
Creator: Hendricks, J.S. & Prael, R.E.
Object Type: Report
System: The UNT Digital Library
Radio frequency and microwave plasma for optical thin film deposition (open access)

Radio frequency and microwave plasma for optical thin film deposition

For the next generation of fusion lasers reflecting mirrors with laser damage thresholds of at least 40 J/cm{sup 2} for 10 ns laser pulses at 1.064 {mu}m are needed. Up to now, no deposition technique has been developed to produce such mirrors. Best R D-values realized today are around 30 J/cm{sup 2} for e-beam evaporated mirrors. R D on conventional e-beam coating processes over the last 10 years has come up with marginal improvements in laser damage thresholds only. However, new technologies, like PICVD developed for the fabrication of ultra-low loss fiber preforms, seem to offer the potential to solve this problem. It is well known that fused silica produced by CVD processes can have laser damage thresholds as high as 80 J/cm{sup 2}. However, the thickness of a single deposited film is in the {mu}m-range for most of the CVD processes used for preform manufacturing; since interference optics need films in the{lambda}/4n range the use of preform-fabrication processes for the purpose of interference mirror fabrication is limited to a few plasma based CVD technologies, namely PCVD. Especially PICVD is a very powerful technology to fabricate thin film multilayers for interference mirrors, because this technique is able to produce films …
Date: October 18, 1990
Creator: Otto, J.; Paquet, V.; Kersten, R.T.; Etzkorn, J.W. (Schott Glaswerke, Mainz (Germany, F.R.)); Brusasco, R.M.; Britten, J. et al.
Object Type: Article
System: The UNT Digital Library
Study of multiparticle jet production using calorimeters, high energy channeling, and other high energy physics research (open access)

Study of multiparticle jet production using calorimeters, high energy channeling, and other high energy physics research

During this period, work was started on the construction of the backward gamma chambers to be used in experiment E683 at Fermilab. Work also is proceeding on various auxiliary experiments that can be performed with the experimental set-up. Work on the SSC accelerator and experiments began in 1984 with the participation of the principal investigator in the Snomass summer studies and continues with the funding of the accelerator and the location of its site in Texas. We are working with the large EMPACT/TEXAS collaboration on a large detector that the group has proposed. As well, the principal investigator is working on smaller experiments that can be executed at the SSC with less resources. Also, we are working on detector development and radiation tolerance of detectors such as scintillating fibers and data acquisition electronics. Experiments continue at Lehigh on growing whiskers'' in wire chambers. These whiskers affect the performance of wire chambers by providing corona discharge points within the chambers. We are able to study the growth of the whiskers in the laboratory and measure the whisker composition using Auger and ESCA spectroscopy and the scanning electron microscope. We are further developing results that were obtained earlier from various Monte-Carlo programs, …
Date: October 1, 1990
Creator: Kanofsky, A. S.
Object Type: Report
System: The UNT Digital Library
Savannah River Reactor Operation: Indices of risk for emergency planning (open access)

Savannah River Reactor Operation: Indices of risk for emergency planning

Periodically it is necessary to re-examine the implications of new source terms for neighboring offsite populations as Probabilistic Risk Assessment (PRA) and Severe Accident studies mature, and lead to a better understanding of the progression of hypothetical core melt accidents in the Savannah River Site (SRS) reactors. In this application multiple-system failure, low-frequency events, and consequently higher radiological source terms than from normal operation or design basis accidents (DBAs) are considered. Measures of consequence such as constant dose vs distance, boundary doses, and health effects to close-in populations are usually examined in this context. A set of source terms developed for the Safety Information Document (SID) for support of the Reactor Operation Environmental Impact Statement (EIS) forms the basis for the revised risk evaluation discussed herein. The intent of this review is not to completely substantiate the sufficiency of the current Emergency Planning Zone (EPZ). However, the two principal measures (200-rem red-bone marrow dose vs distance and 300-rem thyroid dose vs distance) for setting an EPZ are considered. Additional dose-at-distance calculations and consideration of DBA doses would be needed to complete a re-evaluation of the current EPZ. These subject areas are not addressed in the current document. Also, this report …
Date: October 1, 1990
Creator: O'Kula, K.R. & East, J.M.
Object Type: Report
System: The UNT Digital Library
West Valley low-level radioactive waste site revisited: Microbiological analysis of leachates (open access)

West Valley low-level radioactive waste site revisited: Microbiological analysis of leachates

The abundance and types of microorganisms in leachate samples from the West Valley low-level radioactive waste disposal site were enumerated. This study was undertaken in support of the study conducted by Ecology and Environment, Inc., to assess the extent of radioactive gas emissions from the site. Total aerobic and anaerobic bacteria were enumerated as colony forming units (CFU) by dilution agar plate technique, and denitrifiers, sulfate-reducers and methanogens by the most probable number technique (MPN). Of the three trenches 3, 9, and 11 sampled, trench 11 contained the most number of organisms in the leachate. Concentrations of carbon-14 and tritium were highest in trench 11 leachate. Populations of aerobes and anaerobes in trench 9 leachate were one order of magnitude less than in trench 11 leachate while the methanogens were three orders of magnitude greater than in trench 11 leachate. The methane content from trench 9 was high due to the presence of a large number of methanogens; the gas in this trench also contained the most radioactivity. Trench 3 leachate contained the least number of microorganisms. Comparison of microbial populations in leachates sampled from trenches 3 and 9 during October 1978 and 1989 showed differences in the total number …
Date: October 1, 1990
Creator: Gillow, J. B. & Francis, A. J.
Object Type: Report
System: The UNT Digital Library