Waste Disposition Research Articles

Environmental versus Conventional Planning for Machined Components

Environmentally conscious machining has become a topic of recent importance given issues in localized health hazard, resource utilization, waste disposition and energy efficiency. This paper presents an automatic process planning agent for CNC machining for minimal environmental impact along major categories. The process planner is designed to interact with a conventional generative planner (optimizing machining time and quality factors) as an advisory environmental “agent”. Remote feedback to the designer is provided through visual coding over the internet. Application of the agent to a complex machined component is presented.

1 Systems Engineering in the Development and Implementation of the Savannah River Site Transuranic Waste Disposition Program

The use of systems engineering facilitated the strategic planning and implementation of the Savannah River Site (SRS) transuranic waste disposal program. This application represented the first SRS use of systems engineering in the pre-program planning stages during the development of a comprehensive strategic plan for the disposal of transuranic waste at the Department of Energy Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. The use of systems engineering focused the efforts of the technical experts to devise a three initiative plan for the disposal of transuranic waste where previous efforts failed. Continued application of systems engineering facilitated the further development and implementation of the first initiative outlined in the strategic plan, i.e., set-up the program and process to begin to characterize and ship waste to the WIPP.This application of systems engineering to the transuranic waste program represented the first opportunity at the SRS for a comprehensive usage of systems engineering at all program levels. The application was initiated at the earliest possible point in the program development, i.e., strategic planning, and successively was used in detailed development and implementation of the program. Systems engineering successfully focused efforts to produce a comprehensive plan for the disposal of SRS transuranic wastemore » at the WIPP, and facilitated development of the SRS capability and infrastructure to characterize, certify, and ship waste.« less

Material-centric modeling of PWB fabrication: an economic and environmental comparison of conventional and photovia board fabrication processes

This paper presents an activity-based cost model for printed wiring board (PWB) fabrication in which the process steps are defined by material processing activities. The model is designed to be used during system planning and tradeoff analysis prior to physical design. In many activity-based manufacturing cost models, activities are based on equipment and facilities (equipment-centric). In the present model, the process steps are based on material processing activities (material-centric). Equipment-centric models are appropriate for integrated circuit (IC) manufacture where the processing cost is driven by facilities and equipment; however, in PWB manufacturing, where a significant portion of the cost is materials, it is more appropriate to focus the process modeling around material activities. The models presented in this paper compute the volume of materials used and wasted by the activities associated with the fabrication of PWBs, and in turn, use the computed volumes as inputs for predicting fabrication and waste disposition costs. Activities included in the model are open- and closed-loop plating, coating, etching, stripping, desmearing, plasma etching, lamination, drilling, filling, singulation, and scrapping. Additionally, waste disposition activities that operate on the waste inventory are supported. The models presented here have been integrated into a software tradeoff environment that concurrently performs cost and performance analysis for electronic systems. A tradeoff study is presented that compares the cost and waste associated with fabricating mechanically drilled and plated through-hole PWBs with conventional and alternative resists and two fully-additive photolithographic microvia PWB fabrication processes.

Las plantas de selección de basura de México, Distrito Federal : escenografía de la modernidad

La apertura en 1984 de una agencia del Departamento del Distrito Federal que concentraba las competencias relacionadas con la gestión de los residuos sólidos –la Dirección Generalde Servicios Urbanos–, constituyó un intento de modernización del sistema de tratamiento y disposición final en el Distrito Federal. Se cerraron todos los tiraderos a cielo abierto existentes, excepto el de Santa Catarina, y se construyeron tres plantas de selección y aprovechamiento de residuos sólidos. Se pretendía de esta forma controlar las graves consecuencias ambientales de aquellos sitios, así como mejorar las condiciones de vida de los miles de pepenadores que habitaban y trabajaban en los mismos, mediante su incorporación como mano de obra a las nuevas plantas. Además se construyó un relleno sanitario y se saneó el único tiradero que había sobrevivido a la ola de cierres.Después de grandes esfuerzos administrativos y, sobre todo, de una enorme inversión tecnológica y económica, la perseguida modernización ha quedado ahogada bajo la maraña de factores de tipo político y social que se desarrollaron en la etapa anterior de gestión de la basura en la ciudad (la que privilegiaba el modelo de los tiraderos a cielo abierto), imponiéndose los intereses de determinados actores a los intereses de tipo social que conlleva cualquier servicio supuestamente público.

Characterization of Composite Ceramic High Level Waste Forms

ABSTRACTArgonne National Laboratory has developed a composite ceramic waste form for the disposition of high level radioactive waste produced during electrometallurgical conditioning of spent nuclear fuel. The electrorefiner LiCl/KCl eutectic salt, containing fission products and transuranics in the chloride form, is contacted with a zeolite material which removes the fission products from the salt. After salt contact, the zeolite is mixed with a glass binder. The zeolite/glass mixture is then hot isostatic pressed (HIPed) to produce the composite ceramic waste form. The ceramic waste form provides a durable medium that is well suited to incorporate fission products and transuranics in the chloride form. Presented are preliminary results of the process qualification and characterization studies, which include chemical and physical measurements and product durability testing, of the ceramic waste form.

Plutonium Solubility and Speciation to be Applied to the Separation of Hydrothermal Waste Treatment Effluent

ABSTRACTOne of the most complex problems concerning nuclear waste management and the restoration of plutonium production sites is the treatment and disposition of mixed and TRU wastes. Hydrothermal oxidation, which has been shown to be effective in oxidizing a wide variety of organic material to CO2, water, salts and other nonhazardous oxides, is a promising new technology for the treatment and volume reduction of actinide-containing waste. Information on the speciation and solubility of plutonium under process effluent conditions will facilitate the development of separation techniques for removing it from the treated solutions. Such a strongly oxidizing environment will generate plutonium(VT); and upon the destruction of organics, hydrothermal reactor solutions will contain carbonate. We are investigating the solubility and speciation of the plutonium(VI) carbonate system as a function of ionic strength (0.1 to 5.0 M). Formation constants for the tris- and biscarbonato complexes of plutonium(IV) were determined to be, log β130= 17.7 and log β120= 13.6, respectively, by spectrophotometry. These formation constants indicate that PuO2CO3(aq)is the plutonium (VI) carbonate solution species with the largest relevant stability range. We prepared and characterized the corresponding solid using XRD, EXAFS, and diffuse reflectance, and initiated solubility experiments in 0.1, 0.2, 0.5, 1,2, and 5 M NaCl at 22±1°C under 100% CO2. Data collected thus far yield the solubility products, log Kspmol2/kg2= -12.9 (0.1 m NaCl), -12.4 (0.2 m NaCl), -12.5 (0.5 m NaCl), -12.3 (1 m NaCl), -12.2 (2 m NaCl), -12.3 (5 m NaCl).

Rapid Monitoring of Soil, Water, and Air Dusts by Direct Large-Area Alpha Spectrometry

During retrieval and disposition of wastes containing transuranium elements, continuous monitoring of the air, water, and soil for alpha emitters was required to ensure that safety limits were not exceeded and that the waste itself was not disturbed unknowingly. Direct measurements by alpha spectrometry were particularly promising because of their potential speed, sensitivity, and their ability to identify transuranium radionuclides under field conditions. Soil samples or settled dusts were finely ground, suspended in 80% ethanol, sprayed onto circular stainless steel pans, and dried on a hotplate. Water samples were mounted directly by spraying. Air dusts were collected with a high-volume air sampler on 20- by 25-cm membrane filters. The samples were then analyzed directly in a large pressurized gridded ionization chamber without further sample preparation. The lower limits of detection for 10-min counting times were 1.5 Bq g-1 (40 pCi g-1) for 100-mg soil samples, and 4 x 10(-2) Bq m-3 (10(-12) microCi mL-1) for a 10-min air sample taken at 0.4 m3 min-1 (14 cubic feet per minute) and counted without waiting for decay of radon progeny.

Separation of Strontium-90 from Hanford High-Level Radioactive Waste

Abstract Current guidelines for disposing of high-level radioactive wastes stored in underground tanks at the U.S. Department of Energy's Hanford Site call for vitrifying high-level waste (HLW) in borosilicate glass and burying the glass canisters in a deep geologic repository. Disposition of the low-level waste (LLW) is yet to be determined, but it will likely be immobilized in a glass matrix and disposed of on site. To lower the radiological risk associated with the LLW form, methods are being developed to separate 90Sr from the bulk waste material so this isotope can be routed to the HLW stream. A solvent extraction method is being investigated to separate 90Sr from acid-dissolved Hanford tank wastes. Results of experiments with actual tank waste indicate that this method can be used to achieve separation of 90Sr from the bulk waste components. Greater than 99% of the 90Sr was removed from an acidic dissolved sludge solution by extraction with di-t-butylcyclohexano-18-crown-6 in 1-octanol (the SREX pro...

Comparative analysis of environmental impact of fast reactor fuel cycles

There is an increasing interest in the development of processes for separation of minor actinides from the fission products and their elimination through transmutation. Fast reactor systems have certain advantages over thermal reactors in achieving this and the overall success is influenced by the choice of the fuel cycle. A comparative analysis of the different options is attempted in this paper taking into account long term waste management, extraction of maximum fuel value and intercompatibility among the different fuel cycles. It is considered more appropriate that, from the long term environmental point of view, the choice of the fuel, core design and fuel cycle technology is based on considerations of ultimate disposition of radioactive wastes. The integrated metal fuel cycle employing the pyroprocess flow sheet and the associated waste processing schemes emerges as a more attractive option in this context.

Conceptual design study of accelerator-based transmutation system with liquid tru-alloy target and molten-salt blanket

Conceptual design study of accelerator-based transmutation system with liquid TRU-alloy target and molten-salt blanket was performed at the Japan Atomic Energy Research Institute within the framework of the OMEGA program. This system was designed to transmute transuranium (TRU) and long lived fission products from ten or more 1000-MWe class LWRs to reduce the long-term risks from disposition of the high-level radioactive waste into a deep geological formation. System concept of the system were described here and result of neutronics calculation for liquid TRU-alloy target/molten-salt blanket system was presented.

Microbial Approaches to Characterization of Composting Processes

▪ Passage in 1979 of the Resource Conservation and Recovery Act (RCRA) and the Clean Water Act by Congress resulted in a mandate to control and regulate the use of solid wastes on the land (Federal Register, 1979). The more recent landfill crisis followed by the ocean dumping ban and tightening of air emission standards has significantly influenced solid waste practice in the direction of biodegradation via composting.A rapid increase in composting technologies concomitant with increased environmental concern regarding the fate of bacteria, particularly pathogens, means that new opportunities and dangers exist with regard to microbial disposition of solid waste. The impact of new compost technologies on microorganism selection is not known and uncertainty exists as to survival mechanisms of potential pathogens initially present in waste. New microbial methodologies are needed to characterize bacteria involved in composting, and to determine the influence of compost technology on bacterial species selection, especially pathogens.

A review of solidification/stabilization interferences

Decisions on the appropriate disposition of wastes containing both organic and inorganic compounds rely on first determining whether any waste constituents compromise the strength or stability of the waste form or are highly leachable. Often the means exist to overcome interferences and decrease the leachability of the waste constituents. This paper reviews the literature on interferences between hazardous wastes and cement and the fundamental chemical mechanisms by which the inhibition of cement set takes place. From this fundamental information, it is possible to reach some conclusions about the potential effects of most waste constituents even in the absence of particular studies on specific compounds. Organic and inorganic wastes and low-level radioactive wastes are considered.

Landscape and road network transformation in the Community of Madrid between 1972 and 1982

The increasingly intense influence of man on the environment offers numerous examples of regressive actions: ploughing, public works, disposition of wastes etc.. which, due to their frequency and territorial dimensions, alter landscapes and cause many important impacts. These actions arise from different policies which require general transformation of the environment in order to reach their objectives. In this context, the present article explains the methodology followed and the results obtained in a research whose principal purpose was to relate the transformation which the landscape of the Madrid Community underwent in the period between 1972- I982 with the road network evolution and the changes in accessibility to different points of the territory registered during this period. These changes happened as a direct consequence of the transport policy developed in the decade.

廃食油の処理と再利用に関する調査研究(第2報) : 廃食油石けん作りの教材化について

廃食油の処理と再利用に関する調査研究(第2報) : 廃食油石けん作りの教材化について

Mass Burning of MSW With Energy Recovery

There are four or five options for the final disposition of municipal waste, each with its own drawbacks and limitations. One system has been proven by 25 yrs or more of successful operation in Europe and some record of success in the U.S. This is mass burning of unsorted waste in a refractory or water wall furnace with a heat recovery boiler. Heat recovery is a misnomer as actually these systems should be referred to as municipal waste fired boilers or mass burning systems. Municipical waste-mass burning systems are appropriate for waste quantity from about 200 tons/day to about 3,000 and is a logical alternative to landfilling as the final disposition of municipal solid waste. Mass burning has the advantages of 90% volume reduction to a completely odorless inert product, potential for recovery of valuable heat energy and existing technology to remove dust and pollutants from the flue gas to meet the most severe environmental requirements.

Disposition of wastes including volatile radioactive compounds

Disposition of wastes including volatile radioactive compounds

Disposition of radioactive organic liquid waste by incineration--pretreatment for incineration by demulsification

Disposition of radioactive organic liquid waste by incineration--pretreatment for incineration by demulsification

Chemical wastes: An approach to estimate public health impacts

The disposition of chemical wastes has created a multitude of present problems from past practices. The evaluation of potential health effects from chemical waste sites on neighboring residents is a complex effort that involves a number of technical areas. A scheme is presented for guidance to make a preliminary assessment which emphasizes early estimation of exposure. Levels of response are defined based on magnitude of exposure.

Interaction Between High Levels of Applied Heavy Metals and Indigenous Soil Manganese

AbstractThe importance of indigenous soil Mn level on plant Mn uptake from metal salt or sewage sludge amended soils was investigated. Twelve soil materials, six surface and six subsurface, were amended with either varying rates of a composite of Cd, Cu, Ni, and Zn sulfate salts, equivalent to the total of these metals present in a digested sewage sludge (Washington, D.C.) at rates of 0–896 dry metric tons/ha or with the sludge itself, at 224 dry metric tons/ha. Corn (Zea mays L.) was grown in the greenhouse for 30 days, 1 year after amendment application. Two pH levels of about 5.5 and 6.5 were maintained during the experiment on the metal salt amended soil materials.Plant tissue Mn levels increased with the application of Cd, Cu, Ni, and Zn (in combination) as metal salts or as sewage sludge over the range of soil materials used. The amount of increase with a given increase in applied metals was greater for the unlimed than for the limed metal salt treatments. Elevated tissue Mn concentrations were positively and significantly correlated with the indigenous levels of soil Mn. A tissue Mn level of over 3,000 µg/g was observed with unlimed metal salts equivalent to 896 dry metric tons/ha of sludge with Manor Ap horizon soil material. Studies by others suggest that elevation of tissue Mn levels may be related to replacement of Mn from Mn “oxides” by the applied heavy metals.The interaction between applied heavy metals and indigenous soil Mn may affect guidelines for disposition of metal‐bearing wastes on soils. Soils regarded as acceptable for waste disposition, but which have high native Mn levels, may produce higher plant tissue Mn levels than similar soils with lower native Mn.

Management of radioactive wastes

There are several areas of current concern either bordering on or regarding radioacitve waste management in the nuclear fuel eycle. These areas have local, regional and global aspects and require either immediate attention or preparation for future implications. Those areas requiring immediate attention are better management and control over mill tailings, a shortage of irradiated fuel storage space, and decommissioning criteria. Fuel storage should be recognized as a viable alternative to reprocessing for at least the next decade and suitable storage space incorporated in nuclear reactor facilities. Regulatory bodies should establish decommissioning criteria which then should be taken into account during the planning and design of a nuclear facility. Areas indicating future implications are removal and confinement of gaseous radionuclides, particularly tritium and krypton-85. There is now also some concern regarding carbon-14 which should be investigated. Resolving the high-level and alpha-bearing waste disposal question seems to be one of the most serious problems and highest priority objectives facing the nuclear industry today. Use of suitable geologic formations appears to be the only technology which will be available for the next several decades. The alternative is surface storage in engineered facilities which does not finally answer the question. Consequently, demonstrating the disposition of high-level and alpha-bearing wastes in suitable geologic formations should proceed without delay. International co-operation in the establishment and use of regional centres rather than having a proliferation of local facilities for fuel reprocessing should facilitate significantly the management of the resulting radioactive wastes. It also would reduce the hazards associated with having a large number of sources for radioactive releases. Nuclear power programmes can come closer to maturity through international co-operation in resolving the waste disposal question and minimizing the number of facilities involved in fuel reprocessing and radioactive waste management.