Dissertations / Theses: 'Nuclear waste'

1

Hoffman, Edward Albert. "Neutron transmutation of nuclear waste." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16700.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Curtis, Deborah Claire. "Advancements in nuclear waste assay." Thesis, University of Birmingham, 2008. http://etheses.bham.ac.uk//id/eprint/153/.

Full text

Abstract:

The research described in this thesis is directed at advancing the state of the practice of the non-destructive gamma-ray assay of nuclear waste containers. A number of potentially accuracy-limiting issues were identified and addressed, resulting in new developments which were implemented on an instrument prior to entering it into service. A set of Pu reference sources used for experimental data have been studied to determine the internal composition (density and fill height) of the sources to assist with validation of a point kernel model. This model has been used to observe the behaviour of gamma-rays in lumps of fissile material from plutonium over the mass range 0.001g to 350g, for a number of densities corresponding to Pu, PuO$_2$ and PuF$_3$. Established lump corrections have been analysed and have been found to produce large over- and under-corrected results for the range of masses. Due to the inadequacies of current techniques, a new Pu self-absorption correction method has been developed using the data from numerical simulations, allowing nature to reveal the correlations rather than traditional approaches based upon approximate models. For a 25g 1cm-high Pu flat-plate of density 15g.cm$^{-3}$, the developed Pu correction produces a result of (24.9 ± 8.8)g compared to (19.5 ± 0.9)g for the Fleissner 2-line method, and (14.7 ± 0.4)g for the Infinite Energy Extrapolation method. The developed Pu correction method has been extended to the application of uranium lumps in waste matrices, provided the enrichment of the sample is known or may be determined via sophisticated isotopic analysis methods such as MGAU or FRAM. The U self-absorption correction method has been found to produce results within 30% of the true mass of the sample for the lumps studied. An analysis of ‘real drum’ effects has been performed, including the revisiting of the Total Measurement Uncertainty (incorporating the uncertainty components of the new Pu and U self-absorption corrections) and results from known sources placed in artificial inhomogeneous waste matrices assayed inside a Canberra Auto Q2 system.

APA, Harvard, Vancouver, ISO, and other styles

3

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

4

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

5

Short, Rick. "Incorporation of molybdenum in nuclear waste glasses." Thesis, University of Sheffield, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444469.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Pelendritis, Michalis. "Nuclear fuel waste extraction : third phase revisited." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/nuclear-fuel-waste-extraction-third-phase-revisited(55e7be69-dd39-49ec-97bc-fb7b7828c70e).html.

Full text

Abstract:

The problem of third phase formation plays a key role in the plutonium and uranium extraction process (PUREX). This process is responsible for the recycling of used nuclear fuel in order to save fuel usage and more importantly to reduce the amount of waste created (and afterwards disposed or stored) after the end of a nuclear fuel cycle. Understanding the role and behaviour of its components in the aqueous and organic phase, and more in depth on the process' extractant tributyl phosphate (TBP), will help give a better understanding of what causes the phase separation of the organic phase and the interactions occuring at that interface. The focus of this project is on the mean activity coefficients of aqueous uranyl nitrate (and other salts) under varying concentrations using the Statistical Associating Fluid Theory (SAFT). Also, apart from the thermodynamic aspect of the above, molecular dynamic simulations were performed on tributyl phosphate and its interactions with other third phase components to study the effects on the structure and behaviour of TBP. By studying TBP in dodecane mixtures it was found that TBP forms aggregates and filament structuring throughout the organic diluent at most TBP concentrations. Also nitric acid hinders this formation by contacting the polar group (P=O) of TBP via intermolecular forces; its action is physical (based on intermolecular interactions) as opposed to chemical. It is expected that this structuring of TBP in the organic phase has an important effect in the transport of metal nitrates from the aqueous to the organic phase in the PUREX process.

APA, Harvard, Vancouver, ISO, and other styles

7

Lee, S. (Sanyung). "Monumental Museum for Onkalo nuclear waste repository." Master's thesis, University of Oulu, 2018. http://jultika.oulu.fi/Record/nbnfioulu-201805312047.

Full text

Abstract:

Abstract. Contemporary civilization needs diverse resources to maintain its form, such as agriculture, knowledge, engineering, infrastructure, and energy, of course. In terms of the energy, the nuclear power is the thickest column to support our present civilization. However, sometimes the bigger advantage you get means the bigger responsibility you embrace. The powerful source of energy, nuclear power causes the crucial side effect behind which is tons of nuclear wastes, which is highly radioactive. Fortunately, many countries which own nuclear power plants are already working on this issue but still, most countries have no specific back-up plan how to deal with these critical but inevitable burdens. Finland is the fore-runner in this field and the Onkalo nuclear waste repository is one of a kind in this important subject. Still, the Onkalo is in the middle of research and engineering level right now, but it will be face the cultural and architectural questions for the Onkalo soon. As an echo of this subject the Onkalo will face, I propose the public facility to fulfill the additional needs and purposes of the Onkalo. OMM-Onkalo Monumental Museum which I am proposing will be the one of options for these demands. It can be a museum to memorize the place, the facility to maintain the place, the shelter to protect the place, and the hub to connect present to future.

APA, Harvard, Vancouver, ISO, and other styles

8

Künzel, Carsten. "Metakaolin based geopolymers to encapsulate nuclear waste." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/11172.

Full text

Abstract:

This thesis investigates the potential use of geopolymers to encapsulate intermediate level waste (ILW), particularly Magnox swarf contaminated with Al metal and Cs/Sr-loaded clinoptilolite. Both wastes have different interactions with the encapsulation matrix. For Magnox swarf waste containing trace Al metal, the pH of the encapsulating matrix is a key factor that controls corrosion and release of hydrogen. Cs and Sr can leach from contaminated clinoptilolite into the encapsulating geopolymer and therefore the chemical interactions of these ions with the matrix have been investigated. A fundamental understanding of the geopolymer system used for encapsulation was developed. This involved investigating the influence of different precursor on the mechanical properties. It was shown showed that metakaolin based geopolymers are unstable at room temperature when in contact with an atmosphere with a low relative humidity and excessive drying shrinkage occurs. This shrinkage can be reduced by adding inert fillers which have low impact on the mortar viscosity and mechanical strength. Magnox waste and Al-metal have been encapsulated in metakaolin based geopolymers and surface interactions studied using SEM-EDX and XRD. In addition the corrosion rates were determined. Magnox swarf does not react with the geopolymers matrix, while Al-metal rapidly corrodes. However, by using a metakaolin with a low molar Si:Al ratio and controlling the molar Al:Na ratio in geopolymers the corrosion can be significantly reduced and allows encapsulation of this difficult waste stream. Surface reactions of Cs/Sr-contaminated clinoptilolite and geopolymers were also studied. Simulated wastes containing Cs+ and Sr2+ salts were mixed with geopolymers and the influence of the cations on the geopolymer microstructure and leaching were investigated. Mixing Cs/Sr-contaminated clinoptilolite with activation solution causes surface dissolution of clinoptilolite with release of Cs and Sr ions into the matrix. Leaching of Cs contaminated geopolymers showed that Cs+ ions can be immobilised at concentrations up to 10 wt%. Sr2+ reacts with the activating solution and dissolved metakaolin and is build chemically into the structure. The research has resulted in a number of key conclusions related to the stability of metakaolin derived geopolymers and their interactions with the selected wastes.

APA, Harvard, Vancouver, ISO, and other styles

9

Paul, Neepa. "Characterisation of highly active nuclear waste simulants." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/8586/.

Full text

Abstract:

Nuclear power is a non-carbon emitting energy resource generating 18% of electricity to the UK. As with any type of industrial process the waste management strategy is an important step to define considering the environmental, economic and political factors. However, the nuclear industry faces ongoing challenges to underpin a well-defined waste treatment strategy due to the high heat load and the radioactive nature of the products produced. Reprocessing of spent nuclear fuel produces a highly active liquor (HAL) waste stream. HAL is currently stored in a number of highly active storage tanks (HASTs). Within the HASTs, solid materials are known to have precipitated from the HAL over time. Particle simulants provide a route for understanding the physical behaviour, it is the synthesis of the particle simulants and the characterisation of these solid-liquid systems that are the interest of this study. An understanding of the HAL waste properties is required for its safe transport, storage and eventual disposal of the HASTs are to be safely emptied and decommissioned. Collaboration with the National Nuclear Laboratory (NNL), at Sellafield UK, provided the opportunity to manufacture the HAL simulants, caesium phosphomolybdate (CPM) and zirconium molybdate (ZM), on larger scale. Manipulation of the aspect ratio of ZM particles is also investigated. The initial step of the synthesis produces spherical CPM which leads to the production of cubic ZM, the final step requires the addition of an organic additive, citric acid, where cuboidal zirconium citratomolybdate (ZMCA) is formed. Molecular modelling analysis revealed growth inhibition of the {2 0 0}, {-2 0 0}, {0 2 0} and {0 -2 0} faces, due to greater number of Zr sites for citratomolybdate complex affiliation. Distinct particle properties are established for CPM, ZM and ZMCA and compared to a common oxide particle material titanium dioxide (TiO2). The results of this study highlight the influence of key aspects of the HAL particulates, such as size and shape, on relevant solid-liquid properties such as sedimentation and rheology. The influence of bulk liquid properties such as electrolyte concentration and pH were also investigated. Sedimentation behaviour was characterised by fitting the experimental data to the Richardson-Zaki model, yielding a fitting parameter n (cognate to particle size and shape) and thus demonstrated a settling relationship with particle shape, sphere > cubic > cuboidal. The rheological behaviour explored was categorised into four groups: (i) flow behaviour data was fitted to a simplified Cross model yielding two parameters K (related to viscosity) and n (extent of shear-thinning); (ii) dependency of viscosity on particle volume fraction was characterised using the Krieger-Dougherty model yielding fitting parameter [µ] (particle’s contribution to suspension viscosity) and maximum packing fraction m, this demonstrated the relationship, cuboidal > sphere > cube; (iii) yield stress was characterised using an empirical model derived by Heymann et al (2002) yielding a fitting parameter σ^* (cognate to particle shape and size) and demonstrating a relationship, sphere > cuboidal > cubic; (iv) characterisation of compressive yield stress demonstrated the relationship, cuboidal > cubic > sphere. The results indicate various possible behaviours within the tanks which may impact the storage, remobilisation and pipeline transport of this class of nuclear waste. Ultimately, it is of importance to establish the effect of solid-liquid properties on the behaviour of HAL for current processing, post operational clean out (POCO) and life-time assessment.

APA, Harvard, Vancouver, ISO, and other styles

10

Miller, James. "Modelling melt viscosity for nuclear waste glass." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/9110/.

Full text

Abstract:

This work forms part of a Collaborative Awards in Science and Engineering industrial studentship (iCASE), jointly funded by the Engineering and Physical Sciences Research Council and the National Nuclear Laboratory. The aim is to develop improved models for calculating viscosities of vitreous nuclear waste melts, particularly with respect to the variation in temperature and composition. Both in vitro and in situ experimentation on nuclear material is complicated by radioactivity and its associated expenses, so computational modelling is the principal means we use to study these industrially important glasses. The problem is approached with both top-down and bottom-up methods. From a more fundamental perspective, beginning in Section 7 Molecular Dynamics techniques are used to simulate glass melts at atomic resolution. An audit of literature forcefields, using a systematic methodology for particulate systems generation, involved calculation of structural and diffusive properties to reveal the advantages and disadvantages of contemporary sodium-borosilicate models. After developing an improved glass model, from Section 11 different methods of viscosity computation were trialled to determine that most appropriate for the conditions of the nuclear glass melters. In Section 14 the Inoue2 SBN forcefield was combined with the Green-Kubo technique, using simulated runtimes more than double those of previous literature work. The analyses produced qualitative agreement in compositional and temperature trends, as well as order-of-magnitude quantitative agreement between experimental and computational viscosity results for ternary nuclear glass frits. Complimentary top-down approaches were also used, with rotary viscometry experimentation employed in Section 4 to gather temperature-composition-viscometry data for nuclear waste glasses. These data were used with different fitting algorithms in Section 15 to compare the efficacy of theoretical descriptions for glass viscosity, described in Section 3. A combination of fitting techniques assembles in Section 17 an interpolative second-order model for which the maximum discrepancy between prediction and experiment is 17% of the absolute viscosity.

APA, Harvard, Vancouver, ISO, and other styles

11

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/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Pascual, Christopher C. "Evaporation measurements from simulated nuclear waste storage tanks." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/18208.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Fan, Mei-Fang. "Nuclear waste management and environmental justice in Taiwan." Thesis, Lancaster University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429978.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Houston, Christine Margaret. "Laser ionisation studies : applications in nuclear waste monitoring." Thesis, University of Glasgow, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481125.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Las, Thamzil. "Use of natural zeolites for nuclear waste treatment." Thesis, University of Salford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327939.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Maher, John III (John Edward). "Permanence : aligning architecture, nuclear waste, and the Public." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87146.

Full text

Abstract:

Thesis: M. Arch., Massachusetts Institute of Technology, Department of Architecture, 2014.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 137).
Permanence is intended as a provocation to question the current relationship of time and architecture. Architecture has always had a relationship with time, but historically this relationship has been troubled. In 2013 we as architects are currently operating under a false assumption that architecture should only be in a relationship with commodity. This is producing architecture with a very short shelf life, and the architecture is secondary to the commodity it houses. Contemporary architecture only lasts for thirty to one hundred and fifty years and is constrained by budget, the building industry and material warranties. Contemporary society is fast paced and rapidly changing. This rapid change has manifested itself in our architecture and our perception of scales of time. In the modern era, when something is considered permanent it only lasts roughly one hundred years. Our perception of time in the future and the past is small in the grand scheme of history. However, this has not always been the case. We have produced architecture that spanned millennia in the past and when we did we've produced great architecture. How is it that great architecture of the past was able to overcome budget, and dedicate itself to time? These great architectures all had great motivating factors that trumped budget, and were perceived as permanent. These motivating factors include; religion, body politic, or precious resources such as water. The societies that built the architecture though that their way of life, their government, etcetera, as permanent. This thesis states that it is possible to align architecture back with time when dedicated to a motivating factor without a limit of time. The thesis project aligns itself with nuclear waste. Nuclear energy will be necessary to serve the energy needs of a rapidly growing population, and as the technology becomes safer and more efficient it will be more prevalent in cities. The only problem with Nuclear energy is the waste. I'm proposing an architecture that aligns nuclear waste with the public through a public bath. Bathing is a tradition in most cultures that has lasted for thousands of years, and will continue in some way for thousands more. The time is 3013 and the site is an inundated Cambridge, Massachusetts. MIT has moved it's nuclear research facilities to an island just east of what was once Central Square, and the nuclear waste from the research is used to warm the waters of a public bath.
by John Maher.
M. Arch.

APA, Harvard, Vancouver, ISO, and other styles

17

Smith, Christopher David Ph D. Massachusetts Institute of Technology. "Enhancing trust in US nuclear waste management institutions." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118075.

Full text

Abstract:

Thesis: Ph. D. in Public Policy and Planning, Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 353-399).
The failure of US policymakers to develop a permanent geological disposal solution has led to the accumulation of spent nuclear fuel and high-level radioactive waste material at nuclear power plants and former weapons manufacturing facilities. This situation poses a growing long-term public safety hazard, and it hampers the possibility of a revival of commercial nuclear power generation for electricity decarbonization. Policymakers have struggled to resolve the nuclear waste management problem in the face of determined opposition from state governments and some host communities. At present we have a policy process stalemate. A key factor contributing to the stalemate has been a deficiency of public trust in nuclear waste management institutions. I argue that nuclear waste management institutions, such as the Department of Energy, have inspired distrust as a result of behavior that has undermined public perceptions of their trustworthiness, including their competence and fairness. In exploring parallel policy system cases involving high levels of complexity, uncertainty, and risk, I find that strong consent regimes produce three approaches to achieving public consent: coercion, cooperation, and concession. Policy systems with relatively weak consent regimes allow governance institutions to exercise greater autonomy but at risk of losing legitimacy. I argue that the cooperation approach is the best fit for pursuing public consent for high-level nuclear waste policies, and that institutional trust makes the cooperation approach more effective. I propose the adoption of a national "trust strategy" to enhance trust in nuclear waste management institutions by demonstrating and promoting institutional trustworthiness. Repairing damaged trust will be as important a strategic objective as building new levels of trust.
by Christopher David Smith.
Ph. D. in Public Policy and Planning

APA, Harvard, Vancouver, ISO, and other styles

18

Herrera, Martínez Adonai. "Transmutation of nuclear waste in accelerator-driven systems." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614706.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Coe, Gabriela R. "Economic evalutation of nuclear waste underground emplacement concepts." Master's thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-10242009-020147/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Park, Jin-Goo 1961. "Microwave induced plasma sintering of nuclear waste calcines." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276916.

Full text

Abstract:

The microwave induced plasma was used to sinter synthetic Idaho Chemical Processing Plant (ICPP) alumina and zirconia based high level nuclear waste calcines in a nitrogen atmosphere. The sintering behavior of these nuclear waste calcines was observed with identification of the phases formed. A sintered density of higher than 3.20 g/cm3 was obtained within 10 minutes of plasma sintering of pure calcines. The addition of frit in pure calcines to form glass-ceramics resulted in a decrease of density to less than 2.0 g/cm3. This was attributed to the reaction between frit and volatile substances in both zirconia based and alumina based calcines. The removal of volatile substances before sintering increased the sintered density of calcines. The lower sintered density was obtained for the more volatile samples. The phases formed in the plasma sintering of calcines were identified as a function of temperature and amount of frit.

APA, Harvard, Vancouver, ISO, and other styles

21

Johnson, Michael Charles. "Gas retention and release from nuclear legacy waste." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/20268/.

Full text

Abstract:

Many consolidated sediments experience in situ gas generation from methanogenesis, corrosion or radiolysis reactions, while the strength of the sediment matrix can immobilise bubbles for long periods. Particular research interest is motivated by the need to mitigate against periodic acute release of flammable hydrogen from nuclear legacy waste sludge at Sellafield, UK and Hanford, USA to ensure safe decommissioning of ageing facilities. Gas retention within nuclear legacy waste silos is mimicked at laboratory scale by decomposing hydrogen peroxide within Mg(OH)_2 sediments, using clinical x-ray computed tomography to capture the bubbles' size, shape and mobility. Tomography revealed that modest yield stresses of 7Pa were sufficient for sediments to inhibit buoyant migration of relatively large 6-9 mm diameter bubbles during 8 h of imaging, causing the bed to swell to significant voidages in the order of 30 %. Sediments up to 800Pa yield stress exhibited sufficient gas holdup to reduce the bulk sediment density to below that of an aqueous supernatant, raising the potential for acute gas release through Rayleigh-Taylor instabilities. In the absence of buoyant migration or deep drainage channels, chronic gas release from low-intermediate strength (7-1112Pa) sediments appears to be governed by diffusion along extensive networks of partially coalesced submillimetre microvoids, observed here for the first time. Lattice Boltzmann and Monte Carlo simulations reveal these networks to be highly gas-pervious, with permeabilities in the 10.1-151.6 × 10^−12 m^2 range and effective hydrogen diffusivities of 3.7-12.5 × 10^−5 m^2 s^−1. Bubbles within kiloPascal strength sediments were observed to grow by the induction of high aspect ratio lateral fractures, promoting low-tortuosity pathways for efficient gas migration and reduced holdup. Conversely, a 30Pa sediment with an additional coarse (100−800 μm) particle fraction and constricted pore throats supported large 1-8 mm bubbles of high sphericity, forming short range ganglia of < 42 bubbles which spanned < 25mm in range, thereby truncating the avenues for chronic hydrogen release.

APA, Harvard, Vancouver, ISO, and other styles

22

Mauer, Andrew N. "A superconducting fusion transmutation of waste reactor." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15970.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Ji, Yaqi Verfasser], Dirk [Akademischer Betreuer] [Bosbach, and Georg [Akademischer Betreuer] Roth. "Atomistic modeling of nuclear waste materials : cases of ceramic waste forms and nuclear graphite / Yaqi Ji ; Dirk Adolf Bosbach, Georg Roth." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069511/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Ji, Yaqi [Verfasser], Dirk [Akademischer Betreuer] Bosbach, and Georg [Akademischer Betreuer] Roth. "Atomistic modeling of nuclear waste materials : cases of ceramic waste forms and nuclear graphite / Yaqi Ji ; Dirk Adolf Bosbach, Georg Roth." Aachen : Universitätsbibliothek der RWTH Aachen, 2018. http://d-nb.info/1186069511/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

FERREIRA, RAFAEL V. de P. "Biodegradacao de rejeitos radioativos liquidos organicos provenientes do processamento do combustivel nuclear." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11740.

Full text

Abstract:

Made available in DSpace on 2014-10-09T12:55:17Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:06:02Z (GMT). No. of bitstreams: 0
Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

APA, Harvard, Vancouver, ISO, and other styles

26

Curtis, John Huntley. "Economic considerations for Hanford tank waste disposition." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37762.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Hoag, Christopher Ian. "Canister design for deep borehole disposal of nuclear waste." Thesis, (5 MB), 2006. http://handle.dtic.mil/100.2/ADA473223.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

28

Källgren, Therese. "Friction stir welding of copper canisters for nuclear waste." Licentiate thesis, KTH, Materials Science and Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-318.

Full text

Abstract:

The Swedish model for final disposal of nuclear fuel waste is based on copper canisters as a corrosion barrier with an inner pressure holding insert of cast iron. One of the methods to seal the copper canister is to use the Friction Stir Welding (FSW), a method invented by The Welding Institute (TWI).

This work has been focused on characterisation of the FSW joints, and modelling of the process, both analytically and numerically. The first simulations were based on Rosenthal’s analytical medium plate model. The model is simple to use, but has limitations. Finite element models were developed, initially with a two-dimensional geometry. Due to the requirements of describing both the heat flow and the tool movement, three-dimensional models were developed. These models take into account heat transfer, material flow, and continuum mechanics. The geometries of the models are based on the simulation experiments carried out at TWI and at Swedish Nuclear Fuel Waste and Management Co (SKB). Temperature distribution, material flow and their effects on the thermal expansion were predicted for a full-scale canister and lid. The steady state solutions have been compared with temperature measurements, showing good agreement.

Microstructure and hardness profiles have been investigated by optical microscope, Scanning Electron Microscope (SEM), Electron Back Scatter Diffraction (EBSD) and Rockwell hardness measurements. EBSD visualisation has been used to determine the grain size distribution and the appearance of twins and misorientation within grains. The orientation maps show a fine uniform equiaxed grain structure. The root of the weld exhibits the smallest grains and many annealing twins. This may be due to deformation after recrystallisation. The appearance of the nugget and the grain size depends on the position of the weld. A large difference can be seen both in hardness and grain size between the start of the weld and when the steady state is reached.

APA, Harvard, Vancouver, ISO, and other styles

29

Cline, Donna MacGrath. "Chemical and evaporative behaviors of synthetic liquid nuclear waste." FIU Digital Commons, 1991. http://digitalcommons.fiu.edu/etd/2390.

Full text

Abstract:

In the 1960's the Department of Energy at Oak Ridge National Laboratory designed eight 50,000 gallon storage tanks for the liquid nuclear waste. Each tank was designed with its own ventilation system to purge radiolytic hydrogen and oxygen from the tank. This design induced water removal and necessitated the additional requirement of entraining radioactivity from the exiting system by the use of demisters and HEPA filters. Up until the 1980's this was a sufficient method, via the hydrofracture process, of disposing the liquid nuclear waste. However since then, this method has been terminated and the tanks are nearing capacity. In the transfer of the liquid waste to the holding tanks, large amounts of water are used to prevent line clogging and solid build up in the pipes. Utilizing the existing system, this thesis proposes the idea of sparging air into the liquid waste and increasing the tank temperature in order to eliminate excess water. Parameters such as increasing the sparging air temperature, and dehumidifying and eliminating carbon dioxide from the sparging air, are investigated theoretically and experimentally in small scale experiments. In addition, the effects of vapor pressure lowering and its simultaneous effect on the evaporation rate are investigated through the activity coefficient of sodium nitrate, the major component of the liquid waste. Precipitate blockage formations in the sparging tube have also been addressed.

APA, Harvard, Vancouver, ISO, and other styles

30

Källgren, Therese. "Friction stir welding of copper canisters for nuclear waste /." Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-318.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

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/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Aggarwal, S. "Studies on simulated nuclear waste of mixed solvent type." Thesis, University of Salford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255339.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Al-Hindi, Al-Attar Lina. "Nuclear waste treatment using novel inorganic ion exchange materials." Thesis, University of Salford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272932.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Savva, Savvaki N. "New materials for strontium removal from nuclear waste streams." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6690/.

Full text

Abstract:

The primary aim of this project is to investigate potential new materials for application in ion exchange processes to remove $^9$$^0$Sr from nuclear waste streams. This work can be broadly split in to two sections, work on attempts to synthesise new materials and work to investigate ion exchange properties of two recently prepared materials AV-7, a synthetic analogue of tin-kostylvite and AV-3, a synthetic analogue of petarasite. Synthesis on new materials was focused on metal silicate materials, in particular titanium, zirconium and tin silicates containing exchangeable group I and II cations. These synthesis attempts initially were focus on targeted mineral phases such as noonkanbahite, BaKNaTi$_2$(Si$_4$O$_1$$_2$)O$_2$, followed by a series of brief surveys examining the effects of various changes to precursor gels such as concentration of bases such as NaOH, metal to silicon ratios and the presence of mineralizing agents such as sodium fluoride. The synthesis of two synthetic mineral phases potentially interesting for ion exchange is also reported here, titanite and fresnoite. Ion exchange studies focused mainly on AV-7 and AV-3 but also included well known ion exchange materials for comparison such as clinoptilolite and Nb-doped crystalline silicotitanate and brief investigations in to the ion exchange of fresnoite and titanite. Ion exchange was followed using X-Ray fluorescence, ion chromatography and radioactive $^8$$^5$Sr exchanges measured using scintillation counters.

APA, Harvard, Vancouver, ISO, and other styles

35

Wolford, Andrew Joseph. "Uncertainty-optimized predictive testing for a nuclear waste container." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/14950.

Full text

Abstract:

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1987.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 209-217.
by Andrew Joseph Wolford.
Sc.D.

APA, Harvard, Vancouver, ISO, and other styles

36

Simonson, Scott A. "Modeling of radiation effects on nuclear waste package materials." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/36921.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Ghosh, Suchandra Tina 1973. "Risk-informing decisions about high-level nuclear waste repositories." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/33643.

Full text

Abstract:

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2004.
Includes bibliographical references (p. 129-137).
Performance assessments (PAs) are important sources of information for societal decisions in high-level radioactive waste (HLW) management, particularly in evaluating safety cases for proposed HLW repository development. Assessing risk from geologic repositories for HLW poses a significant challenge due to the uncertainties in modeling complex systems of such large temporal and spatial scales. Because of the extensive uncertainties, a typical safety case for a proposed HLW repository is comprised of PA results coupled with various defense-in-depth elements, such as the multi-barrier requirement for repository design, and insights from supplementary analyses. This thesis proposes an additional supplementary analysis, the Strategic Partitioning of Assumption Ranges and Consequences (SPARC), that could be used: (1) in a safety case to help build confidence in a repository system, (2) to provide risk information for decisions on how to allocate resources for future research, and (3) to provide risk information for stakeholder deliberation.
(cont.) The SPARC method extracts risk information from existing PAs and supporting databases by uncovering what sets of model parameter values taken together could result in a substantially-increased-dose (SID) from the repository, and displays the results in SPARC trees. The SPARC method is applied to the proposed Yucca Mountain HLW repository (YMR), as a demonstrative example. The YMR is a particularly interesting example since there have been many public disagreements about it from the inception of the project. This thesis demonstrates how risk information could be extracted from existing PAs for the YMR, with particular attention to addressing the concerns raised by stakeholders. Preliminary application of the SPARC method to the YMR shows that it yields interesting insights into 'savior' attributes of the repository, i.e., those parameter assumption ranges that, if true, are projected to prevent SIDs to different dose receptors (at 10-km or 20-km from the repository, for different future time periods) with very high probability. The thesis also explores how the SPARC method could contribute to other confidence-building exercises, such as assessing repository barrier capability and prioritizing future research efforts.
by Suchandra Tina Ghosh.
Ph.D.

APA, Harvard, Vancouver, ISO, and other styles

38

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.

Full text

Abstract:

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.

APA, Harvard, Vancouver, ISO, and other styles

39

French, Matthew William. "Hydrothermal synthesis and characterisation of nuclear waste storage materials." Thesis, Keele University, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.699682.

Full text

Abstract:

The production of nuclear waste is undoubtedly a major downside to nuclear energy. In the UK, much of our intermediate and high level waste is currently stored in temporary facilities with the aim of burying it in deep underground facilities by 2040. In order to achieve this, the radionuclides require immobilising to prevent them from leaching into the environment. This can be achieved by incorporating the radionuclides into minerals, ceramics or glasses before encapsulation in disposal containers. In order for a material to be successful in this role it must be chemically durable, thermally stable and radiation resistant. The current plan for the disposal of high level waste is to combine it with molten borosilicate glass before encapsulation in stainless steel containers (vitrification). This is a far from perfect solution however as, amongst other faults, these glasses have been found to undergo amorphisation of the newly-formed crystalline phase which over time can lead to microcracking and swelling; thus reducing the integrity of the wasteform. This study is therefore focused on ceramic wasteforms as an alternative to vitrification, specifically the orthosilicate, ASi04, and pyrochlore, A2B207, structure types. This research will describe how low temperature hydrothermal synthesis (at temperatures of just 150-240 QC) offers significantly greater control over the product structure and morphology than traditional solid state methods. The wasteform materials produced were also found to exhibit outstanding thcll11al stability and excellent chemical durability.

APA, Harvard, Vancouver, ISO, and other styles

40

Gilbert, Martin John. "Aspects of waste materials management in the nuclear industry." Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414789.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Smith, David Nigel. "Interfacial deposits formed during nuclear fuel reprocessing." Thesis, University of Bradford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308803.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

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.

Full text

Abstract:

Made available in DSpace on 2014-10-09T12:26:21Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:09:59Z (GMT). No. of bitstreams: 0
Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

APA, Harvard, Vancouver, ISO, and other styles

43

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.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Murphy, Brenda Lee. "Canadian nuclear fuel waste, current contexts and future management prospects." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ61982.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Westlen, Daniel. "Transmutation of nuclear waste in gas-cooled sub-critical reactors /." Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-578.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Dahlfors, Marcus. "Studies of Accelerator-Driven Systems for Transmutation of Nuclear Waste." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Universitetsbiblioteket [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6341.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Rushton, M. J. D. "Simulations of glass and ceramic systems for nuclear waste applications." Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/11894.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Rose, Peter Bramwell. "The crystallisation and aqueous durability of borosilicate nuclear waste glasses." Thesis, University of Sheffield, 2008. http://etheses.whiterose.ac.uk/3654/.

Full text

Abstract:

Two simulated (non-radioactive) borosilicate high-level waste (HLW) glasses were supplied by Nexia Solutions; Blend glass and Oxide glass. This work is primarily concerned with identifying the crystal phases present in both as-cast and heat treated (simulating the retarded cooling experienced by 'real ' (radioactive) borosilicate HLW glasses after pouring) samples of these two glasses; as well as determining the aqueous durability of these samples. An as-cast Oxide glass sample contained a 'yellow phase' inclusion which was also investigated. Combined direct current plasma atomic emission spectroscopy (DCP-AES) and X-ray fluorescence spectroscopy (XRF) determined the chemical composition of both glasses. Differential thermal analysis (DTA) identified their glass transition temperatures, whilst Archimedes' principle yielded their densities. X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) identified crystal phases and, in the case of microscopy, determined microstructural homogeneity. As-cast Blend glass samples were compositionally homogeneous and contained RU02 crystals. Heat treated Blend glass samples contained Cel- (x+y)ZrxGdy0 2- (y/2), (Sr,Nd,La) molybdate and lanthanide (Nd,Gd,La,Ce) silicate crystals. As-cast Oxide glass samples were either compositionally homogeneous (Type I microstructure) or compositionally inhomogeneous (Type II microstructure). RU02, metallic Pd-Te and (Cr,Fe,Ni)304 crystals were observed in both Type I and Type II microstructures, with Na3Li(Mo04)2 . 6H20 crystals occasionally detected. Zrl- (x+y)CexGdy0 2- (y/2) and lanthanide (Nd,Gd,La,Ce) silicate crystals were only detected in Type II microstructures. Heat treated Oxide glass samples displayed either: extensive crystallisation and matrix cracking (Type A microstructure) or 'banded' crystallisation (Type B microstructure), depending on their parent (as-cast) microstructure (Type I or Type II respectively). (Na,Sr,Nd,La)Mo04, Cel- (x+y)ZrxGdy0 2- (y!2) and aNi-rich crystal phase were detected in both Type A and Type B microstructures. a-cristobalite crystals were found exclusively in Type A microstructures, whilst lanthanide (Nd,Gd,La,Ce) silicate and zektzerite crystals were only detected in Type B microstructures. A modified product consistency test (modified PCT-B) determined the aqueous durability of as-cast and heat treated samples of both glasses. Heat treatment of Blend glass improved its aqueous durability marginally. Heat treatment of Oxide glass decreased its aqueous durability significantly (as-cast and heat treated Oxide glass samples had Type I and Type A microstructures respectively). Combined DCP-AES and XRF revealed the chemical composition of the 'yellow phase' inclusion, showing it to be enriched in Mo, Cs, Na, Li, Cr, Ba, Sr and Te compared to Oxide glass. XRD identified the 'yellow phase' inclusion as crystalline, containing CsLiMo04, Na3Li(Mo04)2 . 6H20, (Na,Sr,Nd)Mo04 and BalxSrxMo04 (where 0

APA, Harvard, Vancouver, ISO, and other styles

49

Stupay, Robert Irving. "The necessity for permanence : making a nuclear waste storage facility." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/70196.

Full text

Abstract:

Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 1991.
Includes bibliographical references (leaves 74-75).
The United States Department of Energy is proposing to build a nuclear waste storage facility in southern Nevada. This facility will be designed to last 10,000 years. It must prevent the waste from contaminating the environment by either natural causes or by human intervention. This thesis investigates techniques of preventing curious or oblivious people from breaking into this highly toxic repository. It is a situation where the form must communicate meaning over many millennia in the absence of a cultural context.
Robert Irving Stupay.
M.Arch.

APA, Harvard, Vancouver, ISO, and other styles

50

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.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Nuclear waste'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles