Dissertations / Theses on the topic 'Nuclear disposal'
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1
Hoag, Christopher Ian. "Canister design for deep borehole disposal of nuclear waste." Thesis, (5 MB), 2006. http://handle.dtic.mil/100.2/ADA473223.
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Thesis (M.S. in Nuclear Science and Engineering)--Massachusetts Institute of Technology, 2006."May 2006." Description based on title screen as viewed on June 1, 2010. DTIC Descriptor(s): Boreholes, Radioactive Wastes, Disposal, Canisters, Thermal Properties, USSR, Diameters, Thickness, Stability, Permeability, Environments, Corrosion, Drilling, Flooding, Storage, Reactor Fuels, Nuclear Energy, Barriers, Emplacement, Internal, Fuels, Igneous Rock, Geothermy, Drills, Hazards, Performance (Engineering), Water, Theses, Granite, Steel, Containment (General). Includes bibliographical references (p. 122-125). Also available in print.
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Taiyabi, Asif A. "A multi-attribute analysis of nuclear waste disposal alternatives." Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-02022010-020127/.
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Hoag, Christopher Ian. "Canister design for deep borehole disposal of nuclear waste." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/41269.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, June 2006.Includes bibliographical references (p. 122-125).
The objective of this thesis was to design a canister for the disposal of spent nuclear fuel and other high-level waste in deep borehole repositories using currently available and proven oil, gas, and geothermal drilling technology. The canister is suitable for disposal of various waste forms, such as fuel assemblies and vitrified waste. The design addresses real and perceived hazards of transporting and placing high-level waste, in the form of spent reactor fuel, into a deep igneous rock environment with particular emphasis on thermal performance. The proposed boreholes are 3 to 5 km deep, in igneous rock such as granite. The rock must be in a geologically stable area from a volcanic and tectonic standpoint, and it should have low permeability, as shown in recent data taken from a Russian deep borehole. Although deep granite should remain dry, water in flooded boreholes is expected to be reducing, but potentially corrosive to steel. However, the granite and plug are the containment barrier, not the canister itself. The canisters use standard oil drilling casings. The inner diameter is 315.32mm in order to accommodate a PWR assembly with a width of 214mm. At five meters tall, each canister holds one PWR assembly. The canister thickness is 12.19mm, with an outer diameter of 339.7mm. A liner can extend to the bottom of the emplacement zone to aid in retrievability. The liner has an outer diameter of 406.4mm and a thickness of 9.52mm. The standard drill bit used with a liner of this size has an outer diameter of 444.5mm. Sample calculations were performed for a two kilometer deep emplacement zone in a four kilometer deep hole for the conservative case of PWR fuel having a burnup of 60,000 MWd/kg, cooled ten years before emplacement.
(cont.) Tensile and buckling stresses were calculated, and found to be tolerable for a high grade of steel used in the drilling industry. In the thermal analysis, a maximum borehole wall temperature of 2400C is computed from available correlations and used to calculate a maximum canister centerline temperature of 3370C, or 3190C if the hole floods with water. Borehole repository construction costs were calculated to be on the rate of 50 $/kg spent fuel, which is competitive with Yucca Mountain construction costs. Recommendations for future work on the very deep borehole concept are suggested in the areas of thermal analysis, plugging, corrosion of the steel canisters, site selection, and repository economics.
by Christopher Ian Hoag.
S.M.
4
Bonnett, Timothy Charles. "A systems view of the nuclear waste dilemma." Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-01202010-020205/.
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Kuo, Weng-Sheng. "Evaluation of deep drillholes for high level nuclear waste disposal." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/45197.
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Sizer, Calvin Gregory. "Minor actinide waste disposal in deep geological boreholes." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/41595.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2006.Includes bibliographical references (leaves 63-65).
The purpose of this investigation was to evaluate a waste canister design suitable for the disposal of vitrified minor actinide waste in deep geological boreholes using conventional oil/gas/geothermal drilling technology. The nature of minor actinide waste was considered, paying particular attention to nuclides whose decay energy and half lives were of relative significance to the minor actinide waste as a whole. Thermal Analysis was performed based on a reference borehole design, by Ian C. Hoag. The strategy of the thermal analysis is aimed at finding peak temperatures within the configuration, paying particular attention to the heat transfer under deep geological conditions in the air gap between the canister and the borehole. A first order economic analysis was made to compare the designed canister emplacement costs to that of intact spent fuel. The results of this analysis show that three minor actinide nuclides dominate heat generation after ten years cooling: Cm-244, Am-241, and Am-243 account for 97.5% of minor actinide decay heat. These three nuclides plus Np-237 account for 99% of the minor actinide mass. The thermal analysis was based on an irretrievable canister design, consisting of a 5 meter long synroc waste form, with minor actinides loaded to 1% wt, an outer radius of 15.8 cm and inner annular radius of 8.5 cm. Filling the annulus with a vitrified technetium and iodine waste form was found to be feasible using a multi-stage emplacement process. This process would only be required for three of the fifty boreholes because technetium and iodine have low heat generations after 10 years cooling. The suggested borehole waste form has a maximum centerline temperature of 349C. The costs of drilling boreholes to meet the demand of 100,000MT of PWR waste are estimated to be 3.5% of the current nuclear waste fund, or about $9.6/kg of original spent fuel.
by Calvin Gregory Sizer.
S.B.
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Gunderson, Katie Marie. "Radiation damage in phosphates and silicates for nuclear waste disposal." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608095.
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Pascual, Christopher C. "Evaporation measurements from simulated nuclear waste storage tanks." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/18208.
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Bates, Ethan Allen. "Optimization of deep boreholes for disposal of high-level nuclear waste." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97968.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 223-240).
This work advances the concept of deep borehole disposal (DBD), where spent nuclear fuel (SNF) is isolated at depths of several km in basement rock. Improvements to the engineered components of the DBD concept (e.g., plug, canister, and fill materials) are presented. Reference site parameters and models for radionuclide transport, dose, and cost are developed and coupled to optimize DBD design. A conservative and analytical representation of thermal expansion flow gives vertical velocities of fluids vs. time (and the results are compared against numerical models). When fluid breakthrough occurs rapidly, the chemical transport model is necessary to calculate radionuclide concentrations along the flow path to the surface. The model derived here incorporates conservative assumptions, including instantaneous dissolution of the SNF, high solubility, low sorption, no aquifer or isotopic dilution, and a host rock matrix that is saturated (at a steady state profile) for each radionuclide. For radionuclides that do not decay rapidly, sorb, or reach solubility limitations (e.g., 1-129), molecular diffusion in the host rock (transverse to the flow path) is the primary loss mechanism. The first design basis failure mode (DB 1) assumes the primary flow path is a 1.2 m diameter region with 100x higher permeability than the surrounding rock, while DB2 assumes a 0.1 mm diameter fracture. For the limiting design basis (DB 1), borehole repository design is constrained (via dose limits) by the areal loading of SNF (MTHM/km2 ), which increases linearly with disposal depth. In the final portion of the thesis, total costs (including drilling, site characterization, and emplacement) are minimized ($/kgHM) while borehole depth, disposal zone length, and borehole spacing are varied subject to the performance (maximum dose) constraint. Accounting for a large uncertainty in costs, the optimal design generally lies at the minimum specified disposal depth (assumed to be 1200 in), with disposal zone length of 800-1500 m and borehole spacing of 250-360 meters. Optimized costs range between $45 to $191/kgHM, largely depending on the assumed emplacement method and drilling cost. The best estimate (currently achievable), minimum cost is $134/kgHM, which corresponds to a disposal zone length of -900 meters and borehole spacing of 272 meters.
by Ethan Allen Bates.
Ph. D.
10
Shaikh, Samina. "Effective thermal conductivity measurements relevant to deep borehole nuclear waste disposal." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41301.
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Thesis (S.M. and S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007.Includes bibliographical references (leaves 106-107).
The objective of this work was to measure the effective thermal conductivity of a number of materials (particle beds, and fluids) proposed for use in and around canisters for disposal of high level nuclear waste in deep boreholes. This information is required to insure that waste temperatures will not exceed tolerable limits. Such experimental verification is essential because analytical models and empirical correlations can not accurately predict effective thermal conductivities for complex configurations of poorly characterized media, such as beds of irregular particles of mixed sizes. The experimental apparatus consisted of a 2.54 cm. diameter cylindrical heater (heated length = 0.5 m) , surrounded by a 5.0 cm inner diameter steel tube. Six pairs of thermocouples were located axially on the inside of the heater sheath, and in grooves on the air-fan-cooled outer tube. Test media were used to fill the annular gap, and the temperature drop across the gap measured at several power levels covering the range of heat fluxes expected on a waste canister soon after emplacement. Values of effective thermal conductivity were measured for air, water; particle beds of sand, SiC, graphite and aluminum; and an air gap subdivided by a thin metal sleeve insert. Results are compared to literature values and analytical models for conduction, convection and radiation. Agreement within a factor of 2 was common, and the results confirm the adequacy, and reduce the uncertainty of prior borehole system design calculations. All particle bed data fell between 0.3 and 0.5 W/moC, hence other attributes can determine usage.
by Samina Shaikh.
S.M.and S.B.
11
Dozier, Frances Elizabeth. "Feasibility of very deep borehole disposal of US nuclear defense wastes." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76944.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 171-176).
This thesis analyzes the feasibility of emplacing DOE-owned defense nuclear waste from weapons production into a permanent borehole repository drilled ~4 km into granite basement rock. Two canister options were analyzed throughout the thesis: the canister currently used by the DOE for vitrified defense waste and a reference canister with a smaller diameter. In a thermal analysis, the maximum temperatures attained by the rock surrounding the waste, waste form, canister, liner, and gaps during the post-emplacement period were calculated. From this data, simple analytic equations were formed that can be used to calculate the maximum temperature differences for both defense waste and spent fuel when one does not want to repeat the analysis. Canister corrosion and waste form dissolution analyses were performed using Pourbaix diagrams. Finally, the cost and time for drilling the borehole and emplacing the defense waste were calculated. The temperature change in the granite is 15.1°C for the reference canister and 45.7°C for the DOE Canister. The resulting maximum temperature at the bottom of the borehole is 135.1°C (reference canister) and 165.7°C (DOE canister) for the bounding defense waste. The centerline temperature for the borosilicate glass waste package is approximately 150°C for the reference canister and 207°C for the DOE canister. Because of the thermodynamic properties, overall corrosion resistance, and reasonable cost, pure copper was shown to be the best borehole outer canister material. High-chromium stainless steel could also be a good option for borehole canisters because it has been shown to be highly corrosion-resistant in environments similar to predicted borehole environments. Cesium ion was found to have the highest concentration in the borehole environment. However, the relatively low half life of the most abundant cesium isotope suggests that the cesium would decay before the canister is breached. For the reference canister, the drilling and emplacement costs are not expected to exceed $46/kg of vitrified waste and the total disposal cost was found to be $153/kg of vitrified waste. The total cost of disposal of defense waste in DOE containers is not expected to exceed $53/kg of vitrified waste. Based on these analyses, disposal of vitrified defense waste in deep boreholes is expected to be technically and economically feasible.
by Frances Elizabeth Dozier.
S.M.
12
Hoffman, Edward Albert. "Neutron transmutation of nuclear waste." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16700.
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Richter, Jennifer. "New Mexico's nuclear enchantment| Local politics, national imperatives, and radioactive waste disposal." Thesis, The University of New Mexico, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3601288.
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The use of nuclear technologies has left an indelible mark on American society. The environmental, political, economic, and social costs of creating, producing, and utilizing technologies such as nuclear weapons and nuclear energy have left a legacy of radioactive waste. To date, there is no comprehensive path for disposing of the different kinds of waste produced by the nuclear industry, including spent nuclear fuel that is now held on site at nuclear power plants. The question of how to deal with nuclear waste has plagued the nuclear industry, governmental agencies, and the concerned public for most of the nuclear era.
There is one permanent geologic repository in the U.S., called the Waste Isolation Pilot Plant (WIPP), located in the salt beds outside of Carlsbad, New Mexico. Presently, WIPP is only allowed to hold low-level transuranic waste produced by military installations during the Cold War. This project looks at the ways that federal attention has turned to this remote site in the Chihuahuan Desert as a potential solution for storing high-level nuclear waste as well. Using ethnographies, archival research, and the ideas expressed at numerous public meeting held in the region, this project shows how nuclear communities are framed in discourses surrounding nuclear waste through the concept of nuclearism, which posits that nuclear technologies are wholly beneficial to society. Specifically, this project examines how concepts involving the immutability of nature and science interact to form problematic assumptions regarding the behavior of the environment in relation to nuclear waste. Furthermore, conversations that focus solely on the production of "sound science" ignore the political and social consequences of creating and moving nuclear waste across the country, ensnaring more communities into the web of potential nuclear consequences. Nuclear issues also intersect different scales, troubling the idea of local consent, the idea of a homogenous public, and whether nuclear technologies can be tools of democracy. The events at the Fukushima nuclear power plant on March 11, 2011 underscored the delicate balance of technology and nature, and showed the inherent vulnerabilities of complex technological systems. By connecting the complex natures of the desert, salt, radiation, and time together with questions of political representation, this project looks at how the nuclear future is being shaped in the desert of New Mexico.
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Cabeche, Dion Tunick. "Water borne transport of high level nuclear waste in very deep borehole disposal of high level nuclear waste." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/76933.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 52).
The purpose of this report is to examine the feasibility of the very deep borehole experiment and to determine if it is a reasonable method of storing high level nuclear waste for an extended period of time. The objective of this thesis is to determine the escape mechanisms of radionuclides and to determine if naturally occurring salinity gradients could counteract this phenomenon. Because of the large dependence on the water density, the relationship between water density and the salinity was measured and agreed with the literature values with a less than 1% difference. The resultant relationship between the density and salinity is a linear relationship with the molality, and dependent upon the number of ions of the dissolved salt (e.g. CaCl₂ contains 3 and NaCl has 2). From the data, it was calculated that within a borehole with a host rock porosity of 10-⁵ Darcy, it would take approximately 10⁵ years for the radionuclides to escape. As the rock porosity decreases, the escape time scale increases, and the escape fraction decreases exponentially. Due to the conservative nature of the calculations, the actual escape timescale would be closer to 106 years and dominated by 1-129 in a reducing atmosphere. The expected borehole salinity values can offset the buoyancy effect due to a 50°C temperature increase.
by Dion Tunick Cabeche.
S.B.
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Anderson, Victoria Katherine 1980. "An evaluation of the feasibility of disposal of nuclear waste in very deep boreholes." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33638.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2004.Includes bibliographical references (leaves 117-119).
Deep boreholes, 3 to 5 km into igneous rock, such as granite, are evaluated for next- generation repository use in the disposal of spent nuclear fuel and other high level waste. The primary focus is on the stability and solubility of waste species, waste forms, and canister materials in saline, anoxic water, which is the most severe potential downhole environment given the sparse data available. Pourbaix (Eh-pH) diagrams and solubility products were calculated for 20 materials of interest. In general, extremely low dissolved concentrations were estimated. Copper was identified as the best canister material. Wall-to-far-field temperature increases were estimated to be about 20⁰ C for canisters containing two PWR assemblies, which is quite tolerable. Aspects requiring further work in the near term are detailed canister interior design to withstand crushing under a 1 km stack of same, and development of a borehole plug concept having a comparable or better impermeability and radionuclide holdup than the surrounding granite bedrock.
by Victoria Katherine Anderson.
S.M.
16
Park, Yongsoo S. M. Massachusetts Institute of Technology. "Improving heat transfer in spent nuclear fuel disposal packages using metallic void fillers." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107320.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 71-75).
Disposal packages containing high heat generating spent nuclear fuels (SNF) require improved heat transfer to keep the peak cladding temperature from going above the tolerance limit. Filling the accessible void spaces between the container and the SNF with a high heat conducting metal is a potential solution. In metal casting, it is well known that a gap forms at the metal-mold interface due to solidification shrinkage and it significantly reduces heat transfer during cooling. This negative heat transfer effect is persistent for a disposal package since the filler stays in the container after solidification. The key to close the gap is to promote metallic bonding by minimizing the oxidation of the container during the required preheating stage of the void filling process. However, direct contact between the container and the molten filler can lead to the growth of intermetallic phases, which can embrittle the container. The contribution of this work is twofold. First, through a down-scaled experiment, it was shown that coating a steel container with Zn and using Zn or Zn-4wt.%Al as a filler and unidirectionally cooling the melt from the bottom successfully suppressed the formation of the gap. Closing the gap increased the effective thermal conductivity of the package by a factor of roughly 6 under the employed experimental conditions. Second, tests showed that using near eutectic Zn-Al and executing the filling process at a temperature below the melting point of Zn suppressed the growth of any intermetallic phases. Specifically, this prevents the growth of Fe-Zn intermetallic phases due to the sufficiently high composition of Al, and it inhibits the dissolution and diffusion of Fe from the container by extending the presence of the ZnO diffusion barrier, which delays the growth of the Fe-Al intermetallic phases.
by Yongsoo Park.
S.M.
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Carver, S. J. "Application of geographic information systems to siting radioactive waste disposal facilities." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315467.
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Head, William Stephen. "Digital outcrop modelling and its application to deep geological disposal of nuclear waste." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/digital-outcrop-modelling-and-its-application-to-deep-geological-disposal-of-nuclear-waste(50ef93ea-b850-4c3b-a34a-ecf874beb26d).html.
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Disposal of the UK's legacy nuclear waste is the biggest challenge facing the industry at present. There is currently no long term storage facility in the UK and the inventory is continually growing. This project investigates the role that digital geoscientific data collection, analysis and modelling techniques play in the search for, and development of, a Geological Disposal Facility (GDF), critically analyses classical techniques and new, digital methodologies to assess what their impact would be on any site investigation. The Borrowdale Volcanic Group outcrop in Cumbria, NW England was chosen as it provides an analogue to a higher-strength crystalline basement setting for a GDF. Terrestrial lidar and photogrammetric surveys were conducted at four locations around the study area. These provided information on the fracture geostatistics which are the main fluid migration pathways in the subsurface in the BVG. The mechanics of deformation are identified by analysing the clustering of data points via digital stereonet analysis. The analysis shows the rocks sampled are highly fractured and their orientations and dips reflected the extensional tectonism experienced in the area. These are in the form of adjacent sets trending broadly NNE-SSW and NNW-SSE at very high angler dips (~70 degrees). A new workflow developed for this work demonstrates how a potential site's fracture statistics, and indeed the 3D geology, should be investigated as part of future GDF site investigations. Areas of complex geology such as the BVG present many difficulties in interpretation and analysis due to the poorly constrained polyphase nature of the deformation. These complexities make characterisation and modelling highly problematic, and as such, areas of simpler geology should be investigated first. Assessments which were based on early geological studies using traditional field data collection techniques underestimated the impact of heterogeneity on fluid flow migration modelling within the subsurface. This suggests that, should a GDF should be developed in such a geological setting, huge difficulties may be encountered. These will be associated with the development of performance assessments and safety cases which are typically based on geological models that should use such complex data. In addition to this, datasets collected using digital methods are a powerful visualisation tools for communication of complex geology, that can be utilised in stakeholder engagement activities that will form a key part of any GDF development process.
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Van, Wyck Peter C. "Signs of dangerdangerous signs : responding to nuclear threat." Thesis, McGill University, 1997. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35417.
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This doctoral thesis ("Signs of Danger/Dangerous Signs: Responding to Nuclear Threat") is a poststructural, interdisciplinary exploration of the social, political and cultural workings of nuclear threat. Drawing extensively on a nuclear waste burial initiative being undertaken by the United States Department of Energy, this work is a detailed critical analysis of the relationships between the threats posed by nuclear wastes, and the responses provoked in relation to such threats.Working through such theorists as Jacques Lacan and Slavoj Zˆizˆek (the second death, and le Reel), Francois Ewald (thresholds), Ulrich Beck (risk society), and Felix Guattari (ecology of the virtual), this work demonstrates the manner in which ecological threats, such as that posed by the nuclear, are (paradoxically) "creative" forces; that is, they have a propensity to cut through traditional social divisions (e.g., class, race), assembling news lines of affinity, and new constituencies of those at risk. Indeed, it seem that nuclear threat constitutes a novel form of threat. A form of threat that is irreducibly material, yet admits of no objective ground upon which decisions may be made. A form of threat that threatens the very biological foundations of life, yet whose ontology is to be determined through social and cultural responses.
The principle critical figure I use to analyse and illustrate the movement of threat is the vast monument/sign which is to be constructed above the Waste Isolation Pilot Plant (WIPP) in the desert near Carlsbad, New Mexico. If constructed, this monument will be one of the largest public works project in history. The purpose of this monument is to signify the danger which is to be buried below and thereby deter---for a legislated period of 10,000 years---inadvertent human intrusion into the site. Through analyses of the semiotic issues raised by the desert monument, the appropriation of the practice of burial and its relations to cultural conceptions of death, and the use of the desert as the mise-en-scene of waste, this dissertation shows how the larger context of waste burial demonstrates an extreme and unexamined field of cultural trauma and disavowal around issues of nuclear threat.
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Gibbs, Jonathan Sutton. "Feasibility of lateral emplacement in very deep borehole disposal of high level nuclear waste." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/10945/3685.
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CIVINSThe U.S. Department of Energy recently filed a motion to withdraw the Nuclear Regulatory Commission license application for the High Level Waste Repository at Yucca Mountain in Nevada. As the U.S. has focused exclusively on geologic disposal in shallow mined repositories for the past two decades, an examination of disposal alternatives will be necessary should the Yucca Mountain Project be terminated. This provides an opportunity to study other promising waste disposal technologies. One such technology is the use of very deep boreholes in monolithic granite to permanently segregate high level wastes from the biosphere. While research in this field has focused on vertical emplacement techniques, horizontal emplacement offers the significant advantages of allowing increased emplacement lengths without crushing of the waste package and the use of a single vertical shaft for drilling multiple horizontal shafts. This project examines the application of currently deployed oil and natural gas directional drilling techniques to borehole design. A large trade-space of potential borehole configurations is evaluated and a final design selected using the "V-DeepBoRe" code, a Monte-Carlo simulation based cost model for borehole construction and waste package emplacement. Waste repackaging and reconstitution is evaluated to permit deployment of waste in borehole diameters too small for intact fuel assemblies. A 5 m x 195.26 mm (OD) cylindrical waste package is designed using P-110 drill string steel to meet strength and thermal loading requirements; fuel centerline temperatures are shown to not exceed 190°C by analytical and finite element methods. The total cost of a national borehole repository (including drilling, consolidating and encapsulating the fuel, emplacement, and closure) is shown to fall below $63/kgHM, well within the capacity of the DOE Commercial Spent Nuclear Fuel Waste Fund.
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Philp, J. C. "Corrosion of steel mediated by sulphate-reducing bacteria, with reference to nuclear waste disposal." Thesis, Edinburgh Napier University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377584.
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Of the multifarious economic activities of the sulphate-reducing bacteria, the best documented is that of steel corrosion. In the latter part of this century reports of SRB-induced corrosion have come from a variety of industries and much work has been done on practical as well as theoretical aspects of the problem. Despite this the corrosion mechanism has remained indeterminate. The bulk of the argument centres on the role of hydrogenase in the removal of hydrogen from cathodic sites on the steel surface, and whether this is important compared to cathodic depolarisation caused by biogenic ferrous sulphide. A relatively new industry where cognisably the SRB may manifest corrosion is the disposal of radioactive wastes, which concept entails the use of steel canisters. Many concepts for high-level waste disposal do envisage just this with burial in a mined repository, and backfilling with the clay mineral bentonite. For the UK concepts effort has been made to produce a safety assessment giving canister wall thicknesses to provide a steel canister of 500-1000 years integrity. The work effectuated for this thesis is of a dual nature. Firstly, consideration was given to the present theories of SRB-induced corrosion with experimentation aimed at deducing the most important mechanism(s) by a process of elimination. Secondly, and of equal emphasis, experiments were designed to examine what extra effect SRB may have on steel canister integrity under some conditions of high-level radioactive waste disposal, with a view to fitting any such extra effects into the safety analysis. SRB were found to be ubiquitous in proposed nuclear waste disposal sites examined for their presence. Laboratory corrosion studies using pure cultures of SRB (static and continuous culture) showed that corrosion of relevant mild carbon steel will be affected by levels of organic carbon, sulphate and phosphate which are unlikely to be present in significant quantities in a waste vault. Fe2+ availability was also shown to be a prerequisite to high corrosion rates. For high level radioactive waste the use of bentonite, a proposed backfilling material for waste canisters, containing SRB was shown to enhance corrosion of mild carbon steel. A model system to show this was set up using a bentonite clay/granitic groundwater mix in which SRB and steel coupons were present. Corrosion mechanisms which are likely to be involved include cathodic depolarisation and FeS production; it is not envisaged that the volatile phosphorus compound `identified' by Iverson as a corrosion product is involved. Genetic manipulation to produce hydrogenase-less mutants were unsuccessful during this study. It was aimed to produce such mutants to test the roles of the enzyme hydrogenase in rates of corrosion under repository conditions. Other factors (e.g. high pH) affecting the activity and effects of SRB on nuclear waste isolation materials were examined and are discussed for intermediate level radioactive waste disposal.
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Hietala, Marika. "Making distant futures : implementing geological disposal of nuclear waste in the UK and Finland." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/33976.
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This thesis explores the making of distant futures through two nuclear waste disposal projects. Geological disposal of nuclear waste (GD) has enjoyed a technopolitical consensus for decades as the best available method for the long-term management of hazardous radioactive material, yet, to date, no geological repository facilities exist anywhere in the world. These ‘disposal facilities’ are expected to seclude nuclear waste from the environment for up to one million years, raising challenges for technical knowledge production, policy implementation and public expectations. Examining the proposed implementation of GD in the UK and Finland, this thesis focuses on the ways in which the management of nuclear waste is crafted in the present day and projected on, million of years into the future, as necessitated by the waste half- lives and as demanded by regulatory practice. In exploring these two national contexts, the thesis traces how knowledge is made about distant futures that exist beyond contemporary knowledge making capacity. As a contribution to limited ethnographic discussion on nuclear waste matters, the making of distant nuclear futures is examined in spaces that have been overlooked in sociological literatures on GD e.g. materials science laboratories. The thesis draws from actor-network approaches, sociology of time and feminist STS literature to develop a ‘comparative-conversationalist’ framework. This approach enabled the comparison of wildly different cases by bringing them into conversation rather than direct comparison with each other. Based on participant-observations in two university research labs; interviews with civil servants, university researchers, technical consultants, regulators and industry representatives; and documentary analysis, I trace practices through which the future is made safe, and, nuclear wastes crafted as manageable. The thesis will demonstrate how future making around nuclear waste varies over time and space. I propose that, because of the very distant future that GD concerns, we should discuss the safety aspects of GD and the ability of disposal facilities to contain wastes as ‘real unrealised present possibilities’. Towards this, I develop the notion of contain-ability. Contain-ability directs attention towards the relational makings of safety in the present, and the uncertainty of containment in the very distant future. It underlines safety as an emergent feature rather than an inherent property of disposal concepts and facilities achieved by engineers. 3 Overall then, the thesis demonstrates that a distant nuclear future is a crafted through situated makings that depend on available sociotechnical conditions, including: geological environments; the scale and complexity of nuclear industries and waste inventories; available financial resources and cultural reserves; and imaginations of wastes, nuclear futures and pasts. The successes and failures of policies for the implementation of GD cannot be construed simply through public acceptance or opposition arguments and more attention needs to be directed to the contingencies of scientific knowledge production and future making.
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Stone, Michael. "An assessment of the modular high temperature gas-cooled reactor for actinide burning." Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/13369.
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BARBOZA, ALEX. "Gestao de rejeitos radioativos em servicos de medicina nuclear." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9377.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Min, Bryan B. "Selection of disposal method for nuclear spent fuel : a plan for the application of the systems engineering process /." Master's thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-02162010-020330/.
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Hetherington, Andrew. "Characterisation of reactor graphite to inform strategies for the disposal of reactor decommissioning waste." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4409/.
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Graphite has been used extensively in UK reactors since the 1950s. The UK nuclear decommissioning programme will result in some 90,000 tonnes of waste graphite being removed from Magnox, AGR, research reactors and plutonium production reactors. It is necessary to understand the radiological characteristics of reactor graphite as a prerequisite for decisions about its interim management as well as final disposition. There is in particular a need to improve confidence in the disposal inventory of the long-lived radionuclides carbon-14 and chlorine-36. Models have been developed to predict the distribution of principal radionuclides for Chapelcross reactor 1 and Wylfa reactor 1, and the calculated inventory compared with published experimental measurements on active samples. The models show good agreement with experimental values for carbon-14 and cobalt-60. However, for the highly mobile and volatile radionuclides chlorine-36 and tritium agreement is poor. The models provide a crude upper limit on the inventory, but certain radionuclides may be released during irradiation. For Wylfa it is predicted that all graphite waste arisings will be ILW. For Chapelcross of the order of 16% of the graphite core may be classified as LLW after the C&M period, but levels of carbon-14 rule out disposal to the LLWR facility.
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English, Myles. "Coupled process modelling with applications to radionuclide storage and disposal." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/9950.
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Radioactive waste repositories, designed in accordance with the current UK concept, would be required to provide containment for thousands of years beneath hundreds of metres of rock. The physical processes, both geological and other processes, that might lead to migration of radionuclides are slow in comparison to human timescales — it is impractical to make an experiment of the whole system and so these systems are typically investigated through the use of numerical models. Predictive models are based on combinations of: assumptions, mathematical formulations and parameter values derived from experimental observations. The Ventilation Experiment in the Opalinus Clay at Mont Terri, Switzerland, was designed to involve geological and other physical processes that would be active during the excavation and construction phases of a repository, and with consequences for the repository performance during the operational phase. The experiment consisted of a 10m long tunnel of 1:3m diameter through which air of known relative humidity was circulated in order to force drying and re-saturation through the tunnel wall. Two such cycles over four years have been observed via installed instrumentation. Several numerical models have been constructed of the ventilation experiment by different international teams under the decovalex project using different approaches for cross-validation. Through participation in this project, a 1D model using Richards’ Equation was developed that effectively reproduces the hydrodynamic, mechanical and conservative mass transport results. During the course of developing that model, many other domains, meshes, formulations and software versions were investigated. Now that the field scale Ventilation Experiment can be reproduced with numerical models, the findings (assumptions, formulations, parameter values, computational methods and software) would be transferable to other argillaceous formations to enable predictive modelling of similar scenarios and contribute to the safe disposal of nuclear waste and other problems involving similar geological processes. Work of this type fills the gap between laboratory scale experiments and regional scale modelling of geological systems. The gap is especially wide for low-permeability formations because the size and time-scale limitations effect the ability to make direct observations and measurements. Two particular problems were also addressed in this work: that of the use relative permeability functions and also the computational treatment of the physical interface between the tunnel domain and the rock domain. A sensitive component in many models of unsaturated flow through porous media and covering a wide variety of applications, including reservoir engineering, is the representation of permeability at an unsaturated point (kx) as a scaling of the saturated permeability (ksat) by introducing some function of the pressure head, or saturation as the relative permeability (krel) in the relation kx = ksatkrel. The choice of the particular function and its parameter values adds little to our understanding of the physical parameters. A solution is proposed to the second problem, of how to computationally represent, implement and manage the interface between two physical (i.e. spatial) domains. The scheme maps every part of the boundary of one domain onto the corresponding part of the boundary of the other domain, storing the state variables in shared memory and converting between physical components.
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Macgregor, Timothy Scott. "Nuclear power source and nuclear waste disposal activities of states beyond national territorial limits : a spatial perspective of obligations in public international law /." Genève : Institut universitaire de hautes études internationales, 1989. http://catalogue.bnf.fr/ark:/12148/cb351069961.
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Shooshpasha, Issa. "Performance of clay based buffer material developed for use in a nuclear fuel waste disposal vault." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=26016.
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This study is designed to evaluate water diffusion parameters of clay based buffer material (mixture of clay and sand) used in nuclear fuel waste disposal vault for the following three cases: (a) No volume change in the soil fabric with no air loss. (b) No volume change in the soil fabric with air loss. (c) A complete change in the soil fabric with air loss.One dimensional diffusion type unsaturated flow equation was solved by finite difference method. Powell's optimization technique was used to minimize the material parameters in the proposed diffusion function. The adopted technique makes the use of both theory and experimental data. In this concern several tests have been performed for the three aforementioned conditions to measure the volumetric water content and the soil water potential distributions as a function of time and space.
The calculated diffusion parameters were used to predict the volumetric water content and the soil water potential as a function of space and time for longer period of time.
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Saurí, Suárez Héctor [Verfasser], and R. [Akademischer Betreuer] Stieglitz. "Individual dosimetry in disposal facilities for high-level nuclear waste / Héctor Saurí Suárez ; Betreuer: R. Stieglitz." Karlsruhe : KIT-Bibliothek, 2018. http://d-nb.info/1162540648/34.
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Stitt, Camilla Amy de-Maid. "In-situ and time resolved observation of uranium corrosion applied to nuclear waste storage and disposal." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685545.
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The presence of uranium in grouted Magnox intermediate level waste (ILW) containers is a concern for the nuclear waste industry. Recent inspection of 16 randomly selected ILW containers revealed bulging around the circumference of 3 containers, the cause of which is currently unknown. The bulges are suspected to be related to the intermittent existence of large uranium masses, the corrosion of which produces products almost twice the volume of uranium metal. Formation of hydrogen and uranium hydride through the oxidation of uranium and Magnox with water is of particular concern owing to their pyrophoric nature on exposure to oxidising conditions should the container fail. The understanding of uranium corrosion mechanisms and rates in ILW containment is therefore vital in assessing the risk posed by the bulging waste containers during container storage, transportation and disposal. The following study aimed to contribute to this understanding by performing experiments that transition from laboratory based investigations to conditions more relevant to real ILW scenarios.
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Williams, J. R. (James Robert) 1960. "THE SEALING PERFORMANCE OF BENTONITE/CRUSHED ROCK BOREHOLE PLUGS (NUCLEAR, BASALT, WASTE, REPOSITORY)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/275560.
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Lindenlauf, Astrid. "Waste management in ancient Greece from the Homeric to the Classical period : concepts and practices of waste, dirt, recycling and disposal." Thesis, University College London (University of London), 2000. http://discovery.ucl.ac.uk/1317693/.
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This doctoral thesis has two purposes. First, it develops a universally applicable model for the analysis of waste disposal and recycling practices. This model synthesises Schiffer's behavioural analysis of the formation processes of the archaeological record with the history, sociology and anthropology of conceptualisations of dirt. Second, it shows how this model may be applied to ancient Greece. In the tradition of material culture studies, it aims to challenge the entrenched oppositions between archaeology, philology, history and sociology, and to interpret archaeological, epigraphic and literary sources within an integrated theoretical-methodological framework. The model is used to explore various aspects of ancient Greek waste management. It analyses the interdependence of ancient Greek waste management practices with changing concepts of dirt, pollution and cleanliness in the context of the development of the Greek polis. It also examines the universal analytical categories of waste disposal and recycling practices within diverse social and historical situations and settings with a view to analysing the cultural categories of these practices. Practices of disposal and recycling of solid and liquid waste are analysed in various contexts, including sanctuaries, settlements, agorai, and cemeteries, with respect to depositional processes, diversion rate and range of recycling practices. Materials studied include organic waste, potsherds, ostraka, building material, slaughter and consumption waste, funerary implements, votive offerings, architectural features and water. These examples allow the analysis - within the limits of a study using data in an exemplificatory rather than a statistically valid way - of the influence of the concepts of the sacred and the profane on the treatment of waste in ancient Greece and the degrees to which economic, political, social or symbolic aspects of recycling practices were stressed in different contexts.
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Hoffman, Edward A. "Low activation tokamak reactors." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/16679.
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Holmén, Johan G. "On the flow of groundwater in closed tunnels generic hydrogeological modelling of nuclear waste repository, SFL 3-5 /." [Uppsala] : Uppsala University, 1997. http://books.google.com/books?id=b_VRAAAAMAAJ.
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Van, Duyn Lee B. "Evaluation of the Mechanical Behavior of a Metal-Matrix Dispersion Fuel for Plutonium Burning." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5303.
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Recent nuclear proliferation concerns and disarmament agreements have encouraged the U.S. to decrease the excess amount of weapons-grade and reactor-grade plutonium. Continued use of nuclear power without a permanent solution for waste disposition has also led to the need for a reliable method by which the waste products, specifically plutonium, can be utilized or destroyed. One possible solution to plutonium destruction is achieved by manufacturing it into small microspheres and embedding it within an inert metal matrix, then placing it inside a conventional nuclear reactor. This process would burn some of the plutonium while producing electricity. PuO2Zr dispersion fuel has been proposed for such a purpose. Prior to its use, however, this non-fertile metal matrix dispersion fuel must be shown to be mechanically stable in the reactor environment.
The internal mechanical interactions of dispersion fuel were modeled using finite element analysis. The results were used to assess the stability of PuO2Zr dispersion fuel inside a reactor. Several parameters, including fuel particle size, volumetric loading, temperature, and burnup, were varied to determine the maximum amount of plutonium that can be burned while maintaining fuel integrity. Earlier experiments using UO2 stainless steel dispersion fuels were used to validate the model and establish a failure criterion. The validated model was then used to determine the parameter space over which PuO2Zr dispersion fuel can be successfully used. These results show that PuO2Zr dispersion fuel is robust and may offer a reliable method for plutonium disposal in current reactors.
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Foster, Jack Warren. "Development and implementation of a response-function concept for spent nuclear fuel cask analysis." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/17275.
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Hinchliff, John. "Diffusion and advection of radionuclides through a cementitious backfill with potential to be used in the deep disposal of nuclear waste." Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/17184.
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This work focuses on diffusion and advection through cementitious media, the work arises from two research contracts undertaken at Loughborough University: Experiments to Demonstrate Chemical Containment funded by UK NDA and the SKIN project, funded by the European Atomic Energy Community's Seventh Framework Programme. Diffusion will be one of the most significant mechanisms controlling any radionuclide migration from a nuclear waste, deep geological disposal facility. Advection may also occur, particularly as the immediate post closure groundwater rebound and equilibration proceeds but is expected to be limited by effective siting and management during the operational phase of the facility. In this work advection is investigated at laboratory scale as a possible shorter timescale technique for providing insight into the much slower process of diffusion. Radial techniques for diffusion and advection have been developed and the developmental process is presented in some detail. Both techniques use a cylindrical sample geometry that allows the radionuclide of interest to be introduced into a core drilled through the centre of the test material. For diffusion the core is sealed and submerged in a container of receiving solution which is sampled and analysed as the radionuclide diffuses into it. For advection, a cell has been designed that allows inflow via the central core to pass through the sample in a radial manner and be collected as it exits from the outer surface. The radionuclide of interest can be injected directly into the central core without significant disturbance to the advective flow. Minor improvements continue to be made but both techniques have provided good quality, reproducible results. The majority of the work is concentrated on a potential cemetitious backfill known as NRVB (Nirex Reference Vault Backfill) this is a high porosity, high calcium carbonate content cementitious material. The radioisotopes used in this work are 3H (in tritiated water), 137Cs, 125I, 90Sr, 45Ca, 63Ni, 152Eu, 241Am along with U and Th salts. In addition the effect of cellulose degradation products (CDP) on radioisotope mobility was investigated by manufacturing solutions where paper tissues were degraded in water, at 80°C, in the absence of air and at high pH due to the presence of the components of NRVB. All diffusion experiments were carried out under a nitrogen atmosphere. All advection experiments were undertaken using an eluent reservoir pressurised with nitrogen where the system remained closed up to the point of final sample collection. Results for tritiated water and the monovalent ions of Cs and I were produced on a timescale of weeks to months for both diffusion and advection. The divalent ions of Sr, Ca and Ni produced results on a timescale of months to years. Variations of the experiments were undertaken using the CDP solutions. The effects of CDP were much more apparent at radiotracer concentration than the much higher radiotracer with non-active carrier, concentration. In the presence of CDP Cs, I and Ni were found to migrate more quickly; Sr and Ca were found to migrate more slowly. Additional Sr experiments were undertaken at elevated ionic strength to evaluate the effect of the higher dissolved solids content of the CDP solutions. Some of the results for HTO, Cs, I and Sr have been modelled using a simple numerical representation of the system in GoldSim to estimate effective diffusivity and partition coefficient. The diffusion model successfully produced outputs that were comparable to literature values. The advection model is not yet producing good matches with the observed data but it continues to be developed and more processes will be added as new results become available. Autoradiography has been used to visualise the radionuclide migration and several images are reproduced that show the fate of the radiotracers retained on the NRVB at the end of the experiments. As the experimental programme progressed it was clear that results could not be produced in a suitable timescale for Eu, Am U and Th. These experiments have been retained and will be monitored every six months until either diffusion is detected or the volume of receiving liquid is inadequate to ensure the NRVB is saturated.
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Black, Greg. "Irradiated graphite waste : analysis and modelling of radionuclide production with a view to long term disposal." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/irradiated-graphite-waste-analysis-and-modelling-of-radionuclide-production-with-a-view-to-long-term-disposal(9993a76a-15c6-4cbe-a4a3-4c0bc88c3134).html.
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The University of Manchester Greg BlackThesis submitted for the degree of Doctor of EngineeringIrradiated Graphite Waste: Analysis and Modelling of Radionuclide Production with a View to Long Term Disposal23rd June 2014The UK has predominantly used graphite moderator reactor designs in both its research and civil nuclear programmes. This material will become activated during operation and, once all reactors are shutdown, will represent a waste legacy of 96,000 tonnes [1]. The safe and effective management of this material will require a full understanding of the final radiological inventory. The activity is known to arise from impurities present in the graphite at start of life as well as from contamination products transported from other components in the reactor circuit. The process is further complicated by radiolytic oxidation which leads to considerable weightloss of the graphite components. A comprehensive modelling methodology has been developed and validated to estimate the activity of the principle radionuclides of concern, 3H, 14C, 36Cl and 60Co. This methodology involves the simulation of neutron flux using the reactor physics code WIMS, and radiation transport code MCBEND. Activation calculations have been performed using the neutron activation software FISPACT. The final methodology developed allows full consideration of all processes which may contribute to the final radiological inventory of the material. The final activity and production pathway of each radionuclide has been researched in depth, as well as operational parameters such as the effect of changes in flux, fuel burnup, graphite weightloss and irradiation time. Methods to experimentally determine the activity, and distribution of key radionuclides within irradiated graphite samples have been developed in this research using a combination of both gamma spectroscopy and autoradiography. This work has been externally validated and provides confidence in the accuracy of the final modelling predictions. This work has been undertaken as part of the EU FP7 EURATOM Project: CARBOWASTE, and was funded by the Office for Nuclear Regulation.
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Barr, Logan. "Radiation resistance of novel polymeric encapsulants." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/radiation-resistance-of-novel-polymeric-encapsulants(4a16b78f-f810-407d-815f-db63027aa014).html.
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The generation of nuclear energy leads to the generation of contaminated, radioactive wastes. The current strategy in the UK is to dispose of high and intermediate level wastes to a geological disposal facility with no possibility for retrieval. The waste is contained in an encapsulation matrix, which is usually cement, however cement is unsuitable for certain waste types, for which epoxy resins have been proposed as an alternative. The radiation resistance of two candidate epoxy/amine resin formulations under repository conditions were tested with regards to the degradation of the backbone structure and the release of potential organic ligands from the polymer. The difference in the polymers was the choice of amine curing agent. Analysis of the polymer by infra-red spectroscopy and nuclear magnetic resonance spectroscopy revealed that the carbon nitrogen bonds are the most susceptible to radiation damage, regardless of the atmospheric and aqueous environment. The presence of an aqueous phase greatly reduces the availability of oxygen and reduces the rate of degradation when irradiated under an atmosphere of air. The properties of the aqueous phase has little effect on the degradation of the polymer. Thermal analysis revealed that the effects of the environment are limited to a thin surface layer of the polymer. Leachate analysis revealed that both organic and nitrogen containing compounds are leached from the polymer when irradiated in pure water. Under repository conditions however very little carbon and nitrogen is observed, suggesting that the calcium hydroxide present in repositories is capable of removing the leached species from solution. The generation of nitrate ions from air radiolysis over water is suppressed in the presence of the polymers, suggesting that nitrate is removed from solution by leached species or reaction with the polymer.
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Van, Gerven Jesse. "Inconsiderate consideration claims making and the high-level nuclear waste repository at Yucca Mountain, Nevada /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5014.
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Thesis (M.A.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on January 11, 2008) Includes bibliographical references.
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Montsho, Obakeng Johannes. "Real options valuation for South African nuclear waste management using a fuzzy mathematical approach." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1003051.
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The feasibility of capital projects in an uncertain world can be determined in several ways. One of these methods is real options valuation which arose from financial option valuation theory. On the other hand fuzzy set theory was developed as a mathematical framework to capture uncertainty in project management. The valuation of real options using fuzzy numbers represents an important refinement to determining capital projects' feasibility using the real options approach. The aim of this study is to determine whether the deferral of the decommissioning time (by a decade) of an electricity-generating nuclear plant in South Africa increases decommissioning costs. Using the fuzzy binomial approach, decommissioning costs increase when decommissioning is postponed by a decade whereas use of the fuzzy Black-Scholes approach yields the opposite result. A python code was developed to assist in the computation of fuzzy binomial trees required in our study and the results of the program are incorporated in this thesis.KMBT_363
Adobe Acrobat 9.54 Paper Capture Plug-in
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Kazi-tani, Zakaria, and Alvarez André Ramirez. "Optimizing the Nuclear Waste Fund's Profit." Thesis, Stockholms universitet, Företagsekonomiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-163865.
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The Nuclear Waste Fund constitutes a financial system that finances future costs of the management of spent nuclear fuel as well as decommissioning of nuclear power plants. The fund invests its capital under strict rules which are stipulated in the investment policy established by the board. The policy stipulates that the fund can only invest according to certain allocation limits, and restricts it to invest solely in nominal and inflation-linked bonds issued by the Swedish state as well as treasury securities. A norm portfolio is built to compare the performance of the NWF’s investments. On average, the NWF has outperformed the norm portfolio on recent years, but it may not always have been optimal. Recent studies suggest that allocation limits should be revised over time as the return and risk parameters may change over time. This study focused on simulating three different portfolios where the allocation limits and investment options were extended to see if these extensions would outperform the norm portfolio while maintaining a set risk limit. Portfolio A consisted of OMRX REAL and OMRX TBOND indexes, Portfolio B consisted of OMRX REAL, OMRX TBOND and S&P Sweden 1+ Year Investment Grade Corporate Bond Indexes, and Portfolio C consisted of OMXR REAL, OMRX TBOND and OMXSPI indexes. The return of each portfolio for different weight distributions of the assets were simulated in MATLAB, and polynomial regression models were built in order to optimize the return as a function of the assets’ weights using a Lagrange Multiplier approach for each portfolio. The results depicted that the maximal returns of Portfolios A, B and C were 4.00%, 4.13% and 7.93% respectively, outperforming the norm portfolio’s average return of 3.69% over the time period 2009-2016.
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Tourchi, Saeed. "THM analysis of argillaceous rocks with application to nuclear waste underground storage." Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/670899.
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Argillaceous rocks (Stiff sedimentary clays) provide the geological background to many civil engineering projects. In recent years, interest in these types of material has increased, because they are being considered as potential host geological media for underground repositories of high-level radioactive waste (HLW). The possible use of these types of clay as geological hosts for radioactive waste has prompted the construction of several underground laboratories. Among the very different topics addressed in the Underground Research Laboratories (URLs), the thermo-hydro-mechanical (THM) behaviour of the host rock is the one that most concerns the present research. In situ observations have revealed a considerable number of coupled THM processes in the operation of an HLW repository.
In this context, the main objective of the present study is to describes the performance, observations and interpretation of the full-scale in situ heating test conducted on Callovo-Oxfordian (COx) claystone in the Meuse / Haute-Marne URL simulating a heat-emitting, high-level radioactive waste disposal concept. The test is fully instrumented, and attention is focused on the near-field region's the THM behaviour consisting of the sleeve surrounding the heater and the host rock. The interpretation of the test is assisted by the performance of a coupled numerical analysis based on a coupled formulation incorporating the relevant THM phenomena. The calculations have used a reference isothermal constitutive model especially developed for this type of material. The reference model later has been extended to non-isothermal condition by incorporating thermal dependency of strength parameters and stiffness. The thermomechanical model has been successfully used in the simulation of triaxial tests on COx claystone. The numerical analysis performed has proved able to represent the progress of the experiment very satisfactorily. The performance and analysis of the in-situ test has significantly enhanced the understanding of a complex THM problem and have proved the capability of the numerical formulation and non-isothermal constitutive model to provide adequate predictive capacity.Las rocas argiláceas (arcillas sedimentarias rígidas) proporcionan el trasfondo geológico de muchos proyectos de ingeniería civil. En los últimos años, ha aumentado el interés por este tipo de materiales, porque están siendo considerados como posibles medios geológicos hospedadores de depósitos subterráneos de desechos radiactivos de alta actividad (HLW). El posible uso de este tipo de arcilla como hospedante geológico de residuos radiactivos ha impulsado la construcción de varios laboratorios subterráneos. Entre los muy diferentes temas que se abordan en los Laboratorios de Investigación Subterránea (URL), el comportamiento termo-hidromecánico (THM) de la roca huésped es el que más preocupa a la presente investigación. Las observaciones in situ han revelado un número considerable de procesos THM acoplados en el funcionamiento de un depósito de HLW. En este contexto, el objetivo principal del presente estudio es describir el rendimiento, las observaciones y la interpretación de la prueba de calentamiento in situ a gran escala realizada en piedra arcillosa Callovo-Oxfordian (COx) en la URL de Mosa / Haute-Marne simulando un calor- concepto de eliminación de desechos radiactivos de alto nivel emisor. La prueba está totalmente instrumentada y la atención se centra en el comportamiento del THM de la región de campo cercano que consiste en la manga que rodea el calentador y la roca anfitriona. La interpretación de la prueba es asistida por la realización de un análisis numérico acoplado basado en una formulación acoplada que incorpora los fenómenos de THM relevantes. Los cálculos han utilizado un modelo constitutivo isotérmico de referencia especialmente desarrollado para este tipo de material. Posteriormente, el modelo de referencia se ha ampliado a condiciones no isotérmicas incorporando la dependencia térmica de los parámetros de resistencia y rigidez. El modelo termomecánico se ha utilizado con éxito en la simulación de ensayos triaxiales en arcillas COx. El análisis numérico realizado ha demostrado ser capaz de representar de forma muy satisfactoria el avance del experimento. El rendimiento y el análisis de la prueba in situ ha mejorado significativamente la comprensión de un problema THM complejo y ha demostrado la capacidad de la
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Brown, Ashley Richards. "The impact of ionizing radiation on microbial cells pertinent to the storage, disposal and remediation of radioactive waste." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/the-impact-of-ionizing-radiation-on-microbial-cells-pertinent-to-the-storage-disposal-and-remediation-of-radioactive-waste(1935e25b-3bcd-48b8-b2b9-50c33518eb3f).html.
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Microorganisms control many processes pertinent to the stability of radwaste inventories in nuclear storage and disposal facilities. Furthermore, numerous subsurface bacteria, such as Shewanella spp. have the ability to couple the oxidation of organic matter to the reduction of a range of metals, anions and radionuclides, thus providing the potential for the use of such versatile species in the bioremediation of radionuclide contaminated land. However, the organisms promoting these processes will likely be subject to significant radiation doses. Hence, the impact of acute doses of ionizing radiation on the physiological status of a key Fe(III)-reducing organism, Shewanella oneidensis, was assessed. FT-IR spectroscopy and MALDI-TOF-MS suggested that the metabolic response to radiation is underpinned by alterations to proteins and lipids. Multivariate statistical analysis indicated that the phenotypic response was somewhat predictable although dependent upon radiation dose and stage of recovery. In addition to the cellular environment, the impact of radiation on the extracellular environment was also assessed. Gamma radiation activated ferrihydrite and the usually recalcitrant hematite for reduction by S. oneidensis. TEM, SAED and Mössbauer spectroscopy revealed that this was a result of radiation induced changes to crystallinity. Despite these observations, environments exposed to radiation fluxes will be much more complex, with a range of electron acceptors, electron donors and a diverse microbial community. In addition, environmental dose rates will be much lower than those used in previous experiments. Sediment microcosms irradiated over a two month period at chronic dose rates exhibited enhanced Fe(III)-reduction despite receiving potentially lethal doses. The microbial ecology was probed throughout irradiations using pyrosequencing to reveal significant shifts in the microbial communities, dependent on dose and availability of organic electron donors. The radiation tolerance of an algal contaminant of a spent nuclear fuel pond was also assessed. FT-IR spectroscopy revealed a resistant phenotype of Haematococcus pluvialis, whose metabolism may be protected by the radiation induced production of an astaxanthin carotenoid. The experiments of this thesis provide evidence for a range of impacts of ionizing radiation on microorganisms, including the potential for radiation to provide the basis for novel ecosystems. These results have important implications to the long-term storage of nuclear waste and the geomicrobiology of nuclear environments.
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Wiles, Anne (Anne Marit) Carleton University Dissertation Geography. "Environmental assessment and the concept for the disposal of high-level nuclear waste; technology, the environment and the political contestation of culture." Ottawa, 1994.
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Sumner, Tyler Scott. "A safety and dynamics analysis of the subcritical advanced burner reactor: SABR." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24636.
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Bower, William. "Radiation damage in silicate mineral systems and the characterisation of a spent nuclear fuel pond wall." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/radiation-damage-in-silicate-mineral-systems-and-the-characterisation-of-a-spent-nuclear-fuel-pond-wall(f352d038-d016-49f4-8202-744098e36ec6).html.
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The safety case for a proposed geological disposal facility (GDF) for radioactive wastes relies upon a series of engineered and natural barrier systems to limit the migration of harmful radionuclides into the geosphere over geological timescales. Natural minerals, dominantly phyllosilicates, are expected to be the most reactive components of both the host rock and the clay-based backfill surrounding the highly radioactive waste canisters for as long as 100,000 years. Upon eventual canister degradation, alpha-emitting radionuclides will leach into the backfill material (and eventually beyond) and the constituent mineral systems will accumulate radiation damage upon radionuclide uptake and/or surface precipitation. The following study is an assessment of the structural and chemical effects caused by alpha-particle bombardment of silicate minerals, as proxies for the radiation stability of natural materials present in the near and far field of a GDF.Microscopy and spectroscopy studies from naturally occurring radiation damage accumulated in silicates over geological timescales (forming distinct 'radiohaloes') have shown that both alpha-particle and alpha-recoil bombardment results in altered unit cell dimensions caused by the accumulation of point (Frenkel) defects. In the example of highly damaged biotite, structural breakdown through the reorientation of discrete lattice crystallites was observed; the variability of the interlayer spacing within these regions reveal the potential for damaged mica to adopt the structure of phyllosilicate breakdown products over geological time. Controlled alpha-particle irradiation using the Dalton Cumbrian Facility's 5 MV tandem pelletron ion accelerator, combined with microfocus spectroscopy analysis has revealed the mechanisms of high fluence alpha-radiation damage across 2:1 phyllosilicate minerals (biotite and chlorite); reducing the layered structures into a series of loosely connected domains of alternating lattice expansion and collapse. Radiation induced Fe redox changes have been revealed, with Fe reduction apparent at relatively low alpha-particle doses, giving way to Fe oxidation at high doses. A 'redox gradient', based on alpha-particle energy deposition through a silicate structure has therefore been proposed. In addition, the increase in 'edge' sites generated by structural deformation has been shown to be favourable for the adsorption of the Se(IV) oxyanion to the mica surface. Comprising a body of additional work, a core sample has been extracted from a spent nuclear fuel pond wall at the decommissioned Hunterston A nuclear power station and the radioactive contamination on the painted core surface has been analysed by microfocus spectroscopy. The contaminant radiostrontium has been shown to be associated with the Ti rich pigment in the surface paint, resulting in a 'patchy' accumulation of radioactivity at the core surface. In addition, inert Cs reactivity experiments using the underlying concrete have shown that Cs is preferentially uptaken by phyllosilicates within the altered mafic clasts used in the concrete aggregate.
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Takeuchi, Hisae. "Leadership Roles in Energy and Environmental Projects." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263751.
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REGO, MARIA E. de M. "Gestão dos rejeitos radioativos gerados na produção de 99Mo por fissão nuclear." reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10584.
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