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In 1960, Hansen analyzed the problem of assembling fissionable material in the presence of a weak neutron source. Using point kinetics, he derived the weak source condition and analyzed the consequences of delayed initiation during ramp reactivity additions. Although not clearly stated in Hansen`s work, the neutron source strength that appears in the weak source condition actually corresponds to the equivalent, fundamental-mode source. In this work, they describe the concept of an equivalent, fundamental-mode source and they derive a deterministic expression for a factor, g*, that converts any arbitrary source distribution to an equivalent, fundamental-mode source. They also demonstrate a simplified method for calculating g* in subcritical systems. And finally, they present a new experimental method that can be employed to measure the equivalent, fundamental-mode source strength in a multiplying assembly. They demonstrate the method on the zero-power, XIX-1 assembly at the Fast Critical Assembly (FCA) Facility, Japan Atomic Energy Research Institute (JAERI).

{sup 13}C-carbon black substituted composite LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} cathodes were tested in model electrochemical cells to monitor qualitatively and quantitatively carbon additive(s) distribution changes within tested cells and establish possible links with other detrimental phenomena. Raman qualitative and semi-quantitative analysis of {sup 13}C in the cell components was carried out to trace the possible carbon rearrangement/movement in the cell. Small amounts of cathode carbon additives were found trapped in the separator, at the surface of Li-foil anode, in the electrolyte. The structure of the carried away carbon particles was highly amorphous unlike the original {sup 12}C graphite and {sup 13}C carbon black additives. The role of the carbon additive, the mechanism of carbon retreat in composite cathodes and its correlation with the increase of the cathode interfacial charge-transfer impedance, which accounts for the observed cell power and capacity loss is investigated and discussed.

Two scenarios were examined for small-scale electricity production from biomass using a gasifier/fuel cell system. In one case, a stand-alone BCL/FERC gasifier is used to produce synthesis gas that is reformed and distributed through a pipeline network to individual phosphoric acid fuel cells. In the second design, the gasifier is integrated with a molten carbonate fuel cell stack and a steam bottoming cycle. In both cases, the gasifiers are fed the same amount of material, with the integrated system producing 4 MW of electricity, and the stand-alone design generating 2 MW of electricity.

The Solar Energy Research Institute has conducted a limited sensitivity analysis on a System for Projecting the Utilization of Renewable Resources (SPURR). The study utilized the Domestic Policy Review scenario for SPURR agricultural and industrial process heat and utility market sectors. This sensitivity analysis determines whether variations in solar system capital cost, operation and maintenance cost, and fuel cost (biomass only) correlate with intuitive expectations. The results of this effort contribute to a much larger issue: validation of SPURR. Such a study has practical applications for engineering improvements in solar technologies and is useful as a planning tool in the R and D allocation process.

This report describes work under Phase II of a Photovoltaic Manufacturing Technology project to conduct laboratory problem definition with an emphasis on controlled aging studies to evaluate the influence of various compositional, processing, and operating parameters on ethylene vinyl acetate (EVA) discoloration. In support of future accelerated UV aging studies (AAS) of coupon-sized EVA laminates, an Atlas xenon arc Ci35A Weather-Ometer was procured, installed, and calibrated for temperature and irradiance. In preparing for the AAS studies, UV-visible spectroscopy measurements were performed on various types of low-iron glass, representive of materials used for module superstrates. It was discovered that the transmission spectra of some of the grades in the UV region from 250 to 400 nm was significantly different. Older grades of Solatex and solite, and StarPhire 'cut off' well below 290 nm, while newer grades of Solatex and Solite, and StarPhire and Airphire greatly reduce the UV transmittance between 280 and 330 nm. Controlled aging studies are presently underway at 0.55 W/m2, 340 nm, and 100 degrees C, and we expect comparative data on yellowing to be available soon.

This document is the final report of work on a project concerned with the fragmentation of char particles during pulverized coal combustion that was conducted at the High Temperature Gasdynamics Laboratory at Stanford University, Stanford, California. The project is intended to satisfy, in part, PETC`s research efforts to understand the chemical and physical processes that govern coal combustion. The overall objectives of the project were: (1) to characterize the fragmentation events as a function of combustion environment, (2) to characterize fragmentation with respect to particle porosity and mineral loadings, (3) to assess overall mass loss rates with respect to particle fragmentation, and (4) to quantify the impact of fragmentation on unburned carbon in ash. The knowledge obtained during the course of this project can be used to predict accurately the overall mass loss rates of coals based on both the physical and chemical characteristics of their chars. The work provides a means of assessing reasons for unburned carbon in the ash of coal fired boilers and furnaces.

This report analyzes the local wind resource and evaluates the costs and benefits of supplementing the current diesel-powered energy system on San Nicolas Island, California (SNI), with wind turbines. In Section 2.0 the SNI site, naval operations, and current energy system are described, as are the data collection and analysis procedures. Section 3.0 summarizes the wind resource data and analyses that were presented in NREL/TP 442-20231. Sections 4.0 and 5.0 present the conceptual design and cost analysis of a hybrid wind and diesel energy system on SNI, with conclusions following in Section 6. Appendix A presents summary pages of the hybrid system spreadsheet model, and Appendix B contains input and output files for the HYBRID2 program.

This engineering and economic study is concerned with the question of using the natural heat of the earth, or geothermal energy, as an alternative to other energy sources such as oil and natural gas which are increasing in cost. This document represents a quarterly progress report on the effort directed to determine the availability of geothermal energy within the Fort Peck Indian Reservation, Montana (Figure 1), and the feasibility of beneficial use of this resource including engineering, economic and environmental considerations. The project is being carried out by the Tribal Research office, Assinboine and Sioux Tribes, Fort Peck Indian Reservation, Poplar, Montana under a contract to the United States Department of Energy. PRC TOUPS, the major subcontractor, is responsible for engineering and economic studies and the Council of Energy Resource Tribes (CERT) is providing support in the areas of environment and finance, the results of which will appear in the Final Report. The existence of potentially valuable geothermal resource within the Fort Peck Indian Reservation was first detected from an analysis of temperatures encountered in oil wells drilled in the area. This data, produced by the Montana Bureau of Mines and Geology, pointed to a possible moderate to high temperaturemore » source near the town of Poplar, Montana, which is the location of the Tribal Headquarters for the Fort Peck Reservation. During the first phase of this project, additional data was collected to better characterize the nature of this geothermal resource and to analyze means of gaining access to it. As a result of this investigation, it has been learned that not only is there a potential geothermal resource in the region but that the producing oil wells north of the town of Poplar bring to the surface nearly 20,000 barrels a day (589 gal/min) of geothermal fluid in a temperature range of 185-200 F. Following oil separation, these fluids are disposed of by pumping into a deep groundwater aquifer. While beneficial uses may be found for these geothermal fluids, even higher temperatures (in excess of 260 F) may be found directly beneath the town of Poplar and the new residential development which is being planned in the area. This project is primarily concerned with the use of geothermal energy for space heating and domestic hot water for the town of Poplar (Figure 2 and Photograph 1) and a new residential development of 250 homes which is planned for an area approximately 4 miles east of Poplar along U.S. Route 2 (Figure 2 and Photograph 2). A number of alternative engineering design approaches have been evaluated, and the cost of these systems has been compared to existing and expected heating costs.« less

This report describes the overall goal to engineer and develop flexible manufacturing methods and equipment to process Silicon-Film solar cells and modules. Three major thrusts of this three-year effort were to: develop a new larger-area (208 mm x 208 mm) Silicon-Film solar cell, the APx-8; construct and operate a new high-throughput wafer-making system; and develop a 15-MW single-thread manufacturing process. Specific technical accomplishments from this period are: Increase solar cell area by 80%, increase the generation capacity of a Silicon-Film wafer-making system by 350%, use a new in-line HF etch system in solar cell production, design and develop an in-line NaOH etch system, eliminate cassettes in solar cell processing, and design a new family of module products.