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In-place testing of multiple stage filter systems without disruption of plant operations in the Plutonium Facility at Los Alamos

Description: The Los Alamos National Laboratory Plutonium Facility has a number of multiple-stage air-cleaning systems. These systems operate on a continuous basis and economic considerations require that shutting down of the ventilation systems due to in-place testing be kept to a minimum. Earlier methods of testing multiple-stage filter systems required scheduled shut down of the filter system. Methods such as injecting the test aerosol between the stages have proven costly because of the need to install temporary injection ducts and completely close off the ventilation from the process area. Also, additional personnel were needed to install and move injection and bypass ducts from one system to another. After considering these costly methods, we improved our current methods of testing to prevent interrupting of plant operations. The modified procedure uses a laser particle size spectrometer that has the capability of counting single particles downstream of two filter stages where decontamination factors of the first stage and overall system effectiveness is established. This procedure is similar to that of Nuclear Standard NEF 3-4IT, In-Place Testing of HEPA filter systems by the Single-Particle, Particle-Size Spectrometer Method. Decontamination factors of 10/sup 9/ are measured downstream of two stages. Particle size analyses of the challenge and the aerosol penetrating the first and second stages have been established. A cost estimation comparing two test methods shows considerable savings in operational costs. 6 references, 9 figures, 1 table.
Date: January 1, 1984
Creator: Ortiz, J.P.
Partner: UNT Libraries Government Documents Department

Levelized Costs for Nuclear, Gas and Coal for Electricity, under the Mexican Scenario

Description: In the case of new nuclear power stations, it is necessary to pay special attention to the financial strategy that will be applied, time of construction, investment cost, and the discount and return rate. The levelized cost quantifies the unitary cost of the electricity (the kWh) generated during the lifetime of the nuclear power plant; and allows the immediate comparison with the cost of other alternative technologies. The present paper shows levelized cost for different nuclear technologies and it provides comparison among them as well as with gas and coal electricity plants. For the calculations we applied our own methodology to evaluate the levelized cost considering investment, fuel and operation and maintenance costs, making assumptions for the Mexican market, and taking into account the gas prices projections. The study also shows comparisons using different discount rates (5% and 10%), and some comparisons between our results and an OECD 1998 study. The results are i n good agreement and shows that nuclear option is cost competitive in Mexico on the basis of levelized costs.
Date: October 6, 2004
Creator: Palacios, J.C.; Alonso, G.; Ramirez, R.; Gomez, A.; Ortiz, J. & Longoria, L.C.
Partner: UNT Libraries Government Documents Department

Response of the Los Azufres Geothermal Field to Four Years of 25 MW Wellhead Generation

Description: Production and chemical data have been compiled and analyzed on a six-month averaged basis for the first four years of electric energy generation with five 5-MW wellhead generators at the Los Azufres geothermal field. The data were evaluated with respect to the extent of observable thermal drawdown of the reservoir from 25 MW of generation in relation to the estimated capacity of the field of several hundred megawatts of power. The analysis updates the previous one compiled after the first two years of continuous production, at which time the results indicated that differences in reservoir temperature estimated from geochemical thermometers and wellhead production data were not statistically significant based on the number of data and the standard deviations. Analysis of the data after four years of operation were made for the larger number of data and smaller standard deviations. The results review the adequacy of the sampling frequency and the reliability of the measurements from statistical t-Test of the means of the first and second two-year periods. 3 figs., 5 tabs., 20 refs.
Date: January 20, 1987
Creator: Kruger, P.; Ortiz, J.; Miranda, G. & Gallardo, M.
Partner: UNT Libraries Government Documents Department

Visible and Infrared Optical Design for the ITER Upper Ports

Description: This document contains the results of an optical design scoping study of visible-light and infrared optics for the ITER upper ports, performed by LLNL under contract for the US ITER Project Office. ITER is an international collaboration to build a large fusion energy tokamak with a goal of demonstrating net fusion power for pulses much longer than the energy confinement time. At the time of this report, six of the ITER upper ports are planned to each to contain a camera system for recording visible and infrared light, as well as other diagnostics. the performance specifications for the temporal and spatial resolution of this system are shown in the Section II, Functional Specifications. They acknowledge a debt to Y. Corre and co-authors of the CEA Cadarache report ''ITER wide-angle viewing and thermographic and visible system''. Several of the concepts used in this design are derived from that CEA report. The infrared spatial resolution for optics of this design is diffraction-limited by the size of the entrance aperture, at lower resolution than listed in the ITER diagnostic specifications. The size of the entrance aperture is a trade-off between spatial resolution, optics size in the port, and the location of relay optics. The signal-to-noise ratio allows operation at the specified time resolutions.
Date: March 1, 2007
Creator: Lasnier, C; Seppala, L; Morris, K; Groth, M; Fenstermacher, M; Allen, S et al.
Partner: UNT Libraries Government Documents Department

INITIAL CHEMICAL AND RESERVOIR CONDITIONS AT LOS AZUFRES WELLHEAD POWER PLANT STARTUP

Description: One of the major concerns of electric utilities in installing geothermal power plants is not only the longevity of the steam supply, but also the potential for changes in thermodynamic properties of the resource that might reduce the conversion efficiency of the design plant equipment. Production was initiated at Los Azufres geothermal field with wellhead generators not only to obtain electric energy at a relatively early date, but also to acquire needed information about the resource so that plans for large central power plants could be finalized. Commercial electric energy production started at Los Azufres during the summer of 1982 with five 5-MWe wellhead turbine-generator units. The wells associated with these units had undergone extensive testing and have since been essentially in constant production. The Los Azufres geothermal reservoir is a complex structural and thermodynamic system, intersected by at least 4 major parallel faults and producing geothermal fluids from almost all water to all steam. The five wellhead generators are associated with wells of about 30%, 60%, and 100% steam fraction. A study to compile existing data on the chemical and reservoir conditions during the first two years of operation has been completed. Data have been compiled on mean values of wellhead and separator pressures, steam and liquid flowrates, steam fraction, enthalpy, and pertinent chemical components. The compilation serves both as a database of conditions during the start-up period and as an initial point to observe changes with continued and increased production. Current plans are to add additional wellhead generators in about two years followed by central power plants when the data have been sufficiently evaluated for optimum plant design. During the next two years, the data acquired at the five 5-MWe wellhead generator units can be compared to this database to observe any significant changes in reservoir behavior at ...
Date: January 22, 1985
Creator: Kruger, P.; Semprini, L.; Verma, S.; Barragan, R.; Molinar, R.; Aragon, A. et al.
Partner: UNT Libraries Government Documents Department

Chemical and Isotopic Evidence of Steam Upflow and Partial Condensation in Los Azufres Reservoir

Description: Data of chemical and isotopic composition of fluids from Los Azufres wells, collected over a two year period, provide evidence of a process of upward flow and partial condensation of steam in the reservoir, which explains part of the previously reported heterogeneity in isotopic composition of the liquid phase (Nieva et al, 1983). For the southern part of the field, a direct correlation is found between chloride and oxygen-18 concentrations, and an inverse correlation between these parameters and deuterium and carbon dioxide concentrations in the liquid phase of the reservoir. Chloride ion concentrations increase gradually from ca 660 ppm in the production zones of shallow wells to ca 1900 ppm in the case of deep wells. This observation agrees with predictions based on the well-known model for vapor dominated systems of White et al (1971). For the northern part of the field the same correlations are observed, except for the deuterium concentration which in this case correlates directly with oxygen-18. It is concluded that the same process of steam upflow occurs in the northern section but that some other process — perhaps a mixture with other hydrothermal fluid — is also occurring. 3 tabs., 16 refs., 8 figs.
Date: January 20, 1987
Creator: Nieva, D.; Verma, M.; Santoyo, E.; Barragan, R.M.; Portugal, E.; Ortiz, J. et al.
Partner: UNT Libraries Government Documents Department

A multiplexed reverse transcriptase PCR assay for identification of viral respiratory pathogens at point-of-care

Description: We have developed a nucleic acid-based assay that is rapid, sensitive, specific, and can be used for the simultaneous detection of 5 common human respiratory pathogens including influenza A, influenza B, parainfluenza type 1 and 3, respiratory syncytial virus, and adenovirus group B, C, and E. Typically, diagnosis on an un-extracted clinical sample can be provided in less than 3 hours, including sample collection, preparation, and processing, as well as data analysis. Such a multiplexed panel would enable rapid broad-spectrum pathogen testing on nasal swabs, and therefore allow implementation of infection control measures, and timely administration of antiviral therapies. This article presents a summary of the assay performance in terms of sensitivity and specificity. Limits of detection are provided for each targeted respiratory pathogen, and result comparisons are performed on clinical samples, our goal being to compare the sensitivity and specificity of the multiplexed assay to the combination of immunofluorescence and shell vial culture currently implemented at the UCDMC hospital. Overall, the use of the multiplexed RT-PCR assay reduced the rate of false negatives by 4% and reduced the rate of false positives by up to 10%. The assay correctly identified 99.3% of the clinical negatives, 97% of adenovirus, 95% of RSV, 92% of influenza B, and 77% of influenza A without any extraction performed on the clinical samples. The data also showed that extraction will be needed for parainfluenza virus, which was only identified correctly 24% of the time on un-extracted samples.
Date: April 11, 2007
Creator: Letant, S. E.; Ortiz, J. I.; Tammero, L.; Birch, J. M.; Derlet, R. W.; Cohen, S. et al.
Partner: UNT Libraries Government Documents Department

Lateral width of shower image in the auger fluorescence detector

Description: The impact of the lateral distribution of light in extensive air showers on the detection and reconstruction of shower profiles is investigated for the Auger fluorescence telescopes. Based on three-dimensional simulations, the capability of the Auger telescopes to measure the lateral distribution of light is evaluated. The ability to infer the actual lateral distribution is confirmed by the comparison of detailed simulations with real data. The contribution of pixels located far from the axis of the shower image is calculated and the accepted signal is rescaled in order to reconstruct a correct shower profile. The analysis presented here shows that: (a) the Auger telescopes are able to observe the lateral distribution of showers and (b) the energy corrections to account for the signal in outlying pixels can exceed 10%, depending on shower geometry.
Date: September 1, 2005
Creator: Barbosa, H.; de Souza, V.; Dobrigkeit, C.; Engel, R.; Gora, D.; Heck, D. et al.
Partner: UNT Libraries Government Documents Department

Sperm Whale Seismic Study in the Gulf of Mexico. Summary Report: 2002-2004

Description: Report on the effect of human-generated sounds from offshore drilling on Sperm Whale in order to mitigate the negative impact of anthropogenic sound on whale behavior, navigation, and ability to communicate and locate effectively.
Date: June 2006
Creator: Jochens, A.; Biggs, D.; Engelhaupt, D.; Gordon, J.; Jaquet, N.; Johnson, M. et al.
Partner: UNT Libraries Government Documents Department

Permeability enhancement due to cold water injection: A Case Study at the Los Azufres Geothermal Field, Mexico

Description: Pressure transient buildup and falloff data from 3 wells at the Los Azufres geothermal field have been evaluated to determine the extent to which cold water infection increases the permeability of the near-bore reservoir formation. Simultaneous analysis of the buildup and falloff data provides estimates of the permeability-thickness of the reservoir, the skin factor of the well, and the degree of permeability enhancement in the region behind the thermal front. Estimates of permeability enhancement range from a factor of 4 to 9, for a temperature change of about 150{degree}C. The permeability enhancement is attributed to thermally induced contraction and stress-cracking of the formation. 9 refs., 18 figs.
Date: April 1, 1989
Creator: Benson, S.M.; Daggett, J.; Ortiz, J.; Iglesias, E. (Lawrence Berkeley Lab., CA (USA); Comision Federal de Electricidad, Morelia (Mexico) & Instituto de Investigaciones Electricas, Cuernavaca (Mexico))
Partner: UNT Libraries Government Documents Department

A Multiplexed Diagnostic Platform for Point-of-Care Pathogen Detection

Description: We developed an automated point-of-care diagnostic instrument that is capable of analyzing nasal swab samples for the presence of respiratory diseases. This robust instrument, called FluIDx, performs autonomous multiplexed RT-PCR reactions that are analyzed by microsphere xMAP technology. We evaluated the performance of FluIDx, in comparison rapid tests specific for influenza and respiratory syncytial virus, in a clinical study performed at the UC Davis Medical Center. The clinical study included samples positive for RSV (n = 71), influenza A (n = 16), influenza B (n = 4), adenovirus (n = 5), parainfluenza virus (n = 2), and 44 negative samples, according to a composite reference method. FluIDx and the rapid tests detected 85.9% and 62.0% of the RSV positive samples, respectively. Similar sensitivities were recorded for the influenza B samples; whereas the influenza A samples were poorly detected, likely due to the utilization of an influenza A signature that did not accurately match currently circulating influenza A strains. Data for all pathogens were compiled and indicate that FluIDx is more sensitive than the rapid tests, detecting 74.2% (95% C.I. of 64.7-81.9%) of the positive samples in comparison to 53.6% (95% C.I. of 43.7-63.2%) for the rapid tests. The higher sensitivity of FluIDx was partially offset by a lower specificity, 77.3% versus 100.0%. Overall, these data suggest automated flow-through PCR-based instruments that perform multiplexed assays can successfully screen clinical samples for infectious diseases.
Date: February 4, 2008
Creator: Regan, J F; Letant, S E; Adams, K L; Mahnke, R C; Nguyen, N T; Dzenitis, J M et al.
Partner: UNT Libraries Government Documents Department